IceCube Current News

The 2021 Bruno Rossi Prize was awarded to Francis Halzen and the IceCube Collaboration “for the discovery of a high-energy neutrino flux of astrophysical origin.”

The South Pole has its traditions for ringing in the new year, which includes a ceremony at the geographic pole to set a new pole marker into place.

The “Race Around the World” is a fun run around the South Pole that crosses through all the world’s time zones.

The holiday season is often a busy time of year for many people, and things are no different at the South Pole.

Download the 2021 IceCube Calendar! Featuring a dozen stunning photos taken by our "winterovers," this calendar will teach you something new about the IceCube Neutrino Observatory and the South Pole every month.

It was a fairly busy week at the Pole. IceCube’s new winterovers made their first IceTop snow measurements, an outdoor task that requires daylight to perform.

The sun provided all sorts of photo opportunities at the Pole last week. Here we see IceCube winterover Josh framed nicely in front of a sun halo with faint sun dogs.

Since 2016, the IceCube Collaboration has used a fast-response analysis pipeline to perform follow-up neutrino searches on interesting detections in other messengers that might have neutrino counterparts. As of July 2020, the pipeline led to 58 analyses, none of which found significant neutrino signals but enabled researchers to constrain neutrino emission from some potential sources. The collaboration described their results in a paper recently submitted to The Astrophysical Journal.

More planes (and more fresh faces) arrived at the Pole last week. With five planes total during the week, most of the winter crew has departed.

The IceCube Collaboration searches for neutrino sources using a variety of analysis methods. In a paper submitted yesterday to The Astrophysical Journal, the collaboration describes a time-dependent all-sky scan using five years of IceCube data as well as a specific analysis of blazar 3C 279. The analyses did not reveal any new neutrino point sources.

The first Basler plane arrived at the South Pole last week, bringing a few newcomers and carrying away some outgoing winterovers.

Last week it warmed up a bit at the Pole, rising from about -45 ºF (-43 ºC) to about -15 ºF (-26 ºC) over the course of the week. Much more summerlike.

Every year, the IceCube Collaboration sends two winterovers to the South Pole for at least 12 months. Their special duty is to keep the IceCube detector running smoothly. This year, we are delighted to have one new winterover, Josh Veitch-Michaelis, and welcome back a veteran winterover, Martin Wolf.

Last week, IceCube’s current winterovers, John and Yuya, officially completed a full year at the South Pole, and they’re still going. Their new replacements have not yet arrived, but they are on their way.

In a paper submitted recently to JCAP, the IceCube Collaboration describes a search for sub-TeV neutrino emission from astrophysical “transient” sources. This is the first transient result from IceCube to use all neutrino flavors in the 1-100 GeV energy region. In the absence of any observed sources in three years of archival IceCube data, the researchers established new limits on the volumetric rate of transients.

It’s a harsh environment at the South Pole. And on windy days, you can really feel it—even in the photos. The flags at the ceremonial South Pole really take a beating.

The number of neutrinos that IceCube detects is dependent on many factors, including the “neutrino cross section”: how likely it is for neutrinos to interact with nuclei in the ice. In a paper submitted today to Physical Review D, the IceCube Collaboration reports a new cross section measurement obtained by using 7.5 years of IceCube data. This is the first such measurement to incorporate all three neutrino flavors.

The Wisconsin IceCube Particle Astrophysics Center (WIPAC), headquarters for the IceCube Neutrino Observatory, is sponsoring its first display for the 32nd annual Holiday Fantasy in Lights event in Madison, WI! The inaugural display depicts a neutrino event in IceCube as well as the iconic IceCube Laboratory.

The scene outside the South Pole station—now that there’s sunlight to see by—is rather changed from how the winterovers remember it last summer. There’s quite a build-up of drifted snow around the tower end of the station.

Like the vast majority of conferences and meetings this year, ScienceWriters 2020 went virtual in response to the coronavirus pandemic. And instead of field trips typically organized by the host institution of the conference, organizers called on attendees to create a virtual, Zoom-able experience about the science happening in their part of the world. It was the perfect opportunity to showcase IceCube.

Sunbathing at the South Pole? Well, why not! The sun is out and there’s a nice smooth snowbank for reclining on.

The IceCube Lab has accumulated quite a bit of snow over the winter. And that snow, there and elsewhere, must be cleared away before planes bringing fresh crew arrive—plenty to do.

Now that the sun is up 24/7 at the South Pole, it’s hard for the winterovers to even imagine the auroras they were enjoying in the dark sky just a month or so ago. Everything is now visible.

IceCubeAR, aka IceBear, is a new augmented reality (AR) app that allows anyone in the world can see what’s happening under the South Pole ice in the IceCube Neutrino Observatory—using their smartphone!

The sun is up but still low on the horizon, casting long shadows, as seen here peeking through the exhaust plumes from the power plant.

As the long winter comes to an end with the sunrise at the South Pole, the winterovers embark on spring cleaning around the station.

Today marked the end of the 2020 Fall IceCube Collaboration Meeting, the second collaboration meeting held virtually due to the pandemic. Despite its drawbacks, the virtual meeting format has proven beneficial in some respects. This collaboration meeting had 312 registrants, possibly the most of any IceCube Collaboration meeting ever.

Last week was somewhat busy for the IceCube detector. Otherwise, the sun continues its slow rise, leaving things outside appearing blue and frosty.

What did we just say about the dawn sky at the South Pole? That it can present quite a colorful display, as evidenced by this week’s outdoor photos.

While a blue sky may seem boring to some, especially after the many displays of auroras throughout the winter, the long twilight actually provides plenty of dawn colors to enjoy while outdoors.

You never know which aurora images from the Pole will be the last of the season. But if it’s this week’s images, then this year’s aurora season is clearly going out with a bang.

In a paper submitted today to The Astrophysical Journal, the AMON team, together with the IceCube and HAWC collaborations, present the analysis approach that they developed and reveal the first results from their analysis, as applied to three years of archival data from 2015 to 2018. During those three years, they identified two coincident events that met their criteria for distribution as a public alert, but there were no particularly important astronomical sources seen near either position.

Look who’s at the South Pole. Okay, we can’t see their faces in this image, but we trust that those are IceCube’s winterovers.

In a white paper recently submitted to the Journal of Physics G, the international IceCube-Gen2 Collaboration outlines the need for and design of a next-generation extension of IceCube. By adding new optical and radio instruments to the existing detector, IceCube-Gen2 will increase the annual rate of cosmic neutrino observations by an order of magnitude, and its sensitivity to point sources will increase to five times that of IceCube.

The sky was the center of attention at the Pole last week—and for a number of reasons. Sure, there were auroras, stunning as always. But there was also a moon bright enough to be confused with a sunset.

Last week was the first time this year that temperatures dipped to -100 °F, what one winterover deemed “properly cold.” The moon was out, though, so they didn’t let the extreme cold stop them from enjoying the clear skies for outdoor photography.

Since their arrival at the South Pole last November, John and Yuya have reached hundreds of people around the world through virtual talks and presentations.

Another quiet week at the Pole. But there is a bit more “camera” commotion now as the darkest part of the (long) polar night is coming to an end.

It was a quiet week at the Pole. And just as well…some folks appreciated some time to recover from the Polympics. But the sky was not quiet.

Last week, 52 high school students in Minnesota finished a two-week course taught by IceCube-trained educators. The class was organized by Upward Bound, a federally funded program that provides precollege opportunities for high school students from low-income families whose parents didn’t attend college.

Here we see IceCube winterover John removing the cover from the IceAct field telescope, while the sky is still grabbing its deserved attention.

While we have seen neutrinos and electromagnetic radiation with a common origin, researchers have yet to detect neutrinos and gravitational waves coming from the same place. So the IceCube Collaboration recently performed an analysis to look for neutrino emission that correlates with gravitational waves detected by the LIGO and Virgo Collaborations during their first two observing runs, O1 and O2. Their results are described in a paper published today in The Astrophysical Journal Letters. No coincidence was found, but the researchers are already at work on further analyses.

Word-of-the-day: yukimarimo. New for some, while others may already be familiar with this uncommon word, which refers to tiny, lightweight snowball-tumbleweeds of the Antarctic.

It was a green sky last week as the biggest aurora storm of the season swept over the South Pole. No long camera exposure needed for this fantastic aurora scene.

The IceCube Collaboration recently performed an analysis to try to expand our understanding of the solar magnetic field by studying the time-dependent cosmic-ray Sun shadow. They also wanted to explore how the cosmic-ray Sun shadow changes at different energy regimes. The results, recently submitted to Physical Review D, show that more solar activity leads to a weaker Sun shadow. There were also indications that, in times of high solar activity, the shadow becomes stronger at higher energies—a hint at Sun-shadow energy dependence that will be explored more in future studies.

The IceCube Collaboration has a robust cohort presenting at the 29th biennial Neutrino conference, the world’s biggest conference in neutrino physics. Three IceCube collaborators will give plenary talks, and there are 30 virtual posters by collaborators.

Everything that has a beginning and an end has a middle, too—and that goes for winter. Last week at the South Pole they celebrated midwinter, the marking of the winter solstice.

In two new papers, the IceCube Collaboration updates their eV-scale sterile neutrino search using an eight-year dataset and improved event selection. The analysis found no evidence of sterile neutrinos at this energy scale and was consistent with the no-sterile-neutrino hypothesis.

They got some great outdoor photos last week under bright moonlight—no headlamps needed to walk around outside.

IceCube has found a way to detect cosmic rays of lower energies previously unreachable by IceTop. In a paper submitted to Physical Review D, “Cosmic Ray Spectrum from 250 TeV to 10 PeV using IceTop,” the IceCube Collaboration explains how they implemented a new two-station trigger as well as the machine-learning method developed to analyze these events

Submitted ideas for the next pole marker are on display. The winterovers will vote on their favorite design for the 2021 marker.

The leadership of the IceCube Neutrino Observatory stands in unity with the members of the global community striving to overcome hundreds of years of systemic racism.

OK, so the weather’s cold (June average of -64° F), but there was lots of “cool” stuff at the Pole last week for IceCube’s winterovers.

It’s cold at the South Pole, no matter how you slice and dice it. And as winter settles in, temperatures go even lower.

Last week was a relatively quiet week at the Pole. Well, quiet as far as the IceCube detector was concerned, but there were a variety of things going on as usual.

The recent photos from the Pole reflect a peacefulness outside, with the impending darkness of winter still held off by a bright moon.

The skies are getting darker as the period of twilight comes to an end. As dark as it is, IceCube’s winterovers find it surprising how colorful the sky can become.

Now that they’re here (they = auroras), we’ll likely see a lot of them. Which is a good thing—no one ever seems to tire of seeing auroras.

Due to the COVID-19 pandemic, the IceCube Collaboration is holding its annual spring collaboration meeting virtually. Sessions began this past week and will continue through May 15.

There’s a first time for everything, including seeing an aurora waft across the winter sky at the South Pole. And that first came up last week for IceCube’s winterovers John and Yuya.

Although there is still a bit of light from the sun far below the horizon, the skies are dark, and the brightest object in the sky last week was the moon.

Want to explore and learn more about IceCube from the comfort of your own home? Check out the following resources and activities for you to engage in without leaving the house.

Still light outside after the sun has set? Well, it does take a while for the sunlight to completely diminish—the entire process takes weeks, going through several stages of twilight.

Now that the sun has set, indoor leisure activities have taken hold. It turns out the station gym is just big enough for last week’s new sport, wiffle ball.

In a paper recently submitted to The Astrophysical Journal, the IceCube Collaboration outlines an analysis that searched for neutrino emission from 35 pulsar wind nebulae in 9.5 years of IceCube data. They did not find any significant correlation, so the researchers set upper limits on total neutrino emission from these objects.

Our number one priority has always been the health and safety of the people that make up IceCube. We are following the precautions outlined by our local, state, and national authorities. The IceCube Neutrino Observatory at the South Pole is fully operational.

It finally happened—the lowering sun disappeared below the horizon at the South Pole, leaving everything in dusk.

Tap into your creativity and try your hand at one of our IceCube-themed coloring sheets. Perfect for calming your mind or unleashing your artistic side.

So, is it a watercolor or a photograph? Well, it is a photograph, but the hazy bands of color in the sky make it definitely reminiscent of a watercolor.

Dark matter is one of the biggest mysteries in science today, and neutrinos might be able to help. IceCube and ANTARES Collaborations recently probed a known dark matter hotspot—the center of the Milky Way—by combining data from their respective neutrino telescopes. They did not find any unusual excesses of neutrinos, but they put stronger constraints on the dark matter annihilation cross section averaged over the dark matter velocity. The results of the analysis are outlined in a paper submitted recently to Physical Review D.

With temperatures around –50 °C (–58 °F) and winds at 15 knots (over 17 mph), there’s no getting around the frosty face look when you’re out walking around at the South Pole.

This summer season, IceCube sent more than 30 people from 12 institutions to the Pole to work on a variety of tasks to maintain and upgrade the observatory. Despite a number of delays, the IceCube team got a lot done in a short amount of time.

After the South Pole station closes for the winter, the remaining winter crew has a few short weeks to take care of any outdoor business before the sun sets and leaves them in darkness for months.

A few aircraft stopped at the South Pole last week for refueling. The plane here is a Basler BT-67, flying for the Australian Antarctic Program.

So that’s it—the station has officially closed, leaving 42 individuals at the Pole to take care of business during the winter months.

Fast radio bursts (FRBs) are some of the most enigmatic phenomena in the universe. These millisecond-long pulses of radio waves most likely originate outside of our galaxy, but we don’t know much more than that. The IceCube Collaboration recently looked for neutrino events that coincided with 28 nonrepeating FRBs and one repeating FRB. Searching for neutrinos emitted from the same part of the sky as FRBs could provide clues to help test models that suggest particle acceleration near the FRB source. Results from this search are outlined in a paper published today in The Astrophysical Journal.

Since the sun will soon be gone for quite a long stretch, you might as well try to get as much of it while you can. Last week, IceCube winterover Yuya did just that with his camera, capturing a nice time-lapse of the sun around midnight that made a little “smile” in the sky.

The last of IceCube’s summer crew have departed from the South Pole, leaving IceCube winterovers John and Yuya on their own. They are well trained and ready for their adventure.

Katherine Rawlins, a University of Alaska Anchorage physics professor and IceCube collaborator, is spending her sabbatical year flying around the continental United States in her own Cessna 172 airplane. It turns out that IceCube played a role in helping Rawlins achieve her dream of flight.

In a paper recently submitted to Physical Review Letters, the IceCube Collaboration presents new results of an analysis to determine and characterize, with unprecedented precision and across the entire sky, the combined flux of astrophysical electron and tau neutrinos.

For South Pole experiments like the IceCube Neutrino Observatory, all instruments—whether in the ice or on the surface—must undergo feasibility studies to make sure they can operate in the harsh Antarctic conditions. Optical instruments, especially, are subject to icing and snow accumulation. Recently, the IceCube Collaboration proved the successful operation of a new instrument, an imaging air-Cherenkov telescope, at the Pole. They outline the details of the study in a paper published today in the Journal of Instrumentation.

Researchers in the IceCube Collaboration are always looking for ways to improve the understanding of the PMTs so they can get the highest-quality data from the DOMs. Most recently, they implemented a new method for more accurately characterizing individual PMT charge distributions, which was shown to improve PMT calibration and simulation. The method is described in a technical report submitted today to the Journal of Instrumentation.

Last week the IceCube team completed their planned upgrades for the radio and scintillator arrays. Here we see an antenna that got deployed on the ice.

Although summer is coming to an end, it’s not over yet. Planes are still flying to and from the Pole—here we see two twin otters in the air.

Our winterovers for the 2018-2019 season, Kathrin Mallot and Benjamin Eberhardt, returned from Antarctica last November. Now that they’ve had a couple of months to relax and readjust to life “up north,” we asked them to reflect upon their recent experience at the South Pole. Read our Q&A to find out what they missed the most, what they learned while they were there, and other things they shared about their adventure.

Ah, penguins! Who doesn’t love them? Both of IceCube’s winterovers got to view and photograph penguins recently, but not at the South Pole—no animals can survive the extreme cold temperatures of the Pole.

Life at the South Pole is full of traditions. And as one year ends and another begins, anticipation always mounts for a special tradition: the unveiling of the new South Pole marker.

The IceCube Collaboration recently performed the first-ever experimental search for solar atmospheric neutrinos. Such a detection would have important implications for understanding solar magnetic fields and how cosmic rays propagate in the inner solar system, and it could even provide additional background to solar dark matter searches. But after investigating seven years of IceCube data, IceCube researchers did not detect any solar atmospheric neutrinos and so set an upper limit on the flux. Their results are outlined in a paper that was recently submitted to the Journal of Cosmology and Astroparticle Physics.

The IceCube Collaboration recently conducted a combined IceCube-ANTARES search for neutrino point-like and extended sources in the southern sky. They didn’t find any significant evidence for cosmic neutrino sources, but the analysis shows the strong potential for combining data sets from both experiments. Their results were submitted to The Astrophysical Journal.

The last full week of 2019 was a busy one at the South Pole. Yes, there were the holiday festivities (and a group photo!), but plenty of work was going on as well.

IceCube isn’t the only neutrino experiment in Antarctica. There is also the ANITA (the ANtarctic Impulsive Transient Antenna) experiment, which flies a balloon over the continent and points radio antennae toward the ground in search of extremely high-energy neutrinos.

The IceCube Collaboration recently followed up on events detected by ANITA and presented their results in a paper submitted today to The Astrophysical Journal. The collaboration found that these neutrinos could not have come from an intense point source. Other explanations for the anomalous signals—possibly involving exotic physics—need to be considered.

It’s always a white Christmas at the South Pole. It was also summer solstice at the Pole, and the winterovers got outdoors for some nice shots of the station.

Why are the winterovers playing chess out on the ice? The answer might just be a question itself—why not? Yes, it’s cold outside...but you just can’t let the weather get in your way.

’Tis the season for snowflakes—made of ice or paper! Try one (or more) of our festive, IceCube-themed snowflake templates to decorate your space. Choose from a DOM, the IceCube Lab, penguins Rosie and Gibbs, or even our PI, Professor Francis Halzen.

Last week, long-awaited cargo arrived, and just as exciting, the South Pole traverse also showed up. The traverse travels overland to bring fuel to the Pole that would otherwise need to be flown in.

IceCube was running smoothly last week. But it hasn’t been such smooth sailing this year for cargo arrivals (delays). On the plus side, a supply of IceCube beanie hats arrived!

IceCube has not yet found neutrino sources within our galaxy, but there may be sources that are not too much farther out. To test this possibility, the IceCube Collaboration recently performed an analysis scouring the local universe for potential neutrino sources. They conducted two different searches that looked for correlations between neutrino emission and dense regions in a catalog of galaxies called the 2MASS Redshift Survey (2MRS). While they did not find significant sources, they were able to put constraints on neutrino emission from nearby galaxies, which they present in a paper recently submitted to the Journal of Cosmology and Astroparticle Physics.

Since it’s summer at the Pole, more people are arriving than leaving. However, last week two people departed who had been at the Pole for an extended time—yes, we’re talking about Benjamin Eberhardt and Kathrin Mallot, IceCube’s winterovers for the past year, shown here among the red parkas walking toward the plane above.

A plane landing in daylight means summer season and new arrivals at the South Pole. So far things have started off busy for IceCube’s new winterovers.

IceCube’s South Pole crew will have another pair of helping hands (and flippers) this summer season: Jocelyn Argueta will be at the Pole from November 30 to December 27 as our 2019 PolarTREC educator. (As for the flippers…keep reading to find out.)

Jocelyn is a bilingual scientist-performer with Phantom Projects Theatre Group in La Mirada, California. She has a Bachelor’s degree in biochemistry and molecular biology from the University of California, Irvine, and has her own show based around her character, Jargie the Science Girl!

The IceCube Neutrino Observatory recently took center stage at Supercomputing 2019—the largest high-performance computing conference in the world—when NVIDIA CEO, Jensen Huang, gave a keynote address. In it, Huang highlighted science projects using NVIDIA hardware and forthcoming products that focus on scientific innovation. One of these projects involved IceCube.

Two fresh faces have arrived at the Pole—IceCube’s next winterovers, John Hardin and Yuya Makino, ready for service. Here is the plane that brought them, a low-flying Basler.

Neutrino mass ordering is one of the foremost problems in neutrino physics today. But two new neutrino oscillation experiments are on the horizon—the IceCube Upgrade and JUNO. So the IceCube Collaboration and the JUNO Collaboration studied the combined performance of their respective experiments, which employ very distinct and complementary routes in order to resolve the neutrino mass ordering. In a paper submitted recently to Physical Review D, they show that a combined analysis could eliminate the wrong mass ordering in as few as three years from the start of data taking.

American photographer Shaun O’Boyle is about to embark on his third Antarctic expedition. His unique trips are possible through the National Science Foundation’s Antarctic Artists and Writers (AAW) Program, which has sent him to McMurdo Station, Palmer Station, and now the South Pole. On this trip, O'Boyle plans on photographing IceCube's scientific instruments.

Cascade events are more difficult to reconstruct than tracks, which are usually used in searches for astrophysical neutrino sources, but cascades have their own advantages, including providing a better measurement of neutrino energy. In a paper published in The Astrophysical Journal, the IceCube Collaboration outlined recent results from a source search that used seven years of data from cascade events. While they did not find any statistically significant sources of neutrino emissions, this work is an improvement on the previous source search with cascades.

Things "warmed" up a bit at the Pole last week. And there were sun dogs back in the skies and some interesting snow formations on the ground.

On November 7, 2019, the Nishina Memorial Foundation announced that Prof. Shigeru Yoshida and Prof. Aya Ishihara were selected as the recipients of the 2019 Nishina Memorial Prize, the oldest and most prestigious physics award in Japan. Yoshida and Ishihara lead the IceCube group at Chiba University.

From November 2019 to November 2020, IceCube’s winterovers will be Yuya Makino and John Hardin. Here are some quick facts about the newest members of our South Pole squad.

One of the first flights of the season is shown in this monochromatic image that rather dramatically portrays the desolate landscape of the Pole.

What's missing from your Halloween celebration? Some IceCube-themed pumpkins, probably. Never fear! We are providing you with a variety of stencils to use in your Halloween decor.

Well, there it is, the first plane to arrive at the South Pole for the season—a Basler. It only stopped long enough to refuel, but that was plenty of time to unload its precious cargo of fresh fruit.

In a paper recently published in Physical Review D, the IceCube Collaboration reports on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using three years of data from the IceCube Neutrino Observatory.

Dark matter is one of the biggest mysteries in modern astronomy and physics. In a paper recently submitted to the European Physical Journal C, scientists from IceCube and PICO determined new constraints on particle physics properties of dark matter. Though these are less stringent than previous constraints, they take into consideration the latest research on the distribution of dark matter in our galaxy.

After 10 years of searching for origins of astrophysical neutrinos, a new all-sky search provides the most sensitive probe of time-integrated neutrino emission of point-like sources. The IceCube Collaboration presents the results of this scan in a paper submitted today to Physical Review Letters.

The sun is well above the horizon, so there’s plenty of light for outdoor photography. And IceCube’s winterovers got right out there to take some splashy photos—that actually involved a splash of sorts, by throwing water out into an arc overhead that quickly turned into a spray of ice crystals.

The sunrise is over now at the South Pole, with the sun fully risen. But if you position yourself just so, near a large snowdrift, it can almost appear as though the sun is rising right there.

It’s time for sunglasses now at the South Pole—the sun has definitely made its presence clear. And it’s here to stay, or rather for a good long while anyway.

Some weeks at the Pole are quiet, and some—like last week—are busy. The IceCube detector had a number of hiccups that required the winterovers’ attention. On top of taking care of IceCube, there were plenty of other things to attend to as far as getting the station ready for the summer crews.

The fall IceCube Collaboration meeting wrapped up last Friday in Chiba, Japan. About two thirds of the collaboration, representing 38 institutions in 11 countries, assembled at Chiba University, the home institution of the International Center for Hadron Astrophysics (ICEHAP) group, from September 16–20.

The sky just gets brighter and brighter along the horizon. And although auroras are exciting, the dawn sky with its changing colors holds its own special appeal.

The IceCube Collaboration performed a search for point-source populations using a technique called the non-Poissonian template fit (NPTF) and published their findings in a paper submitted to The Astrophysical Journal. This was the first time the NPTF was used on IceCube neutrino data, and while they did not find any neutrino point-source populations, they proved the technique’s viability.

The sky is beginning to take on different colors at the Pole, depending on which direction you’re looking. There’s a hazy band of orange along the horizon, but facing away toward the station the sky appears blue.

It was a quiet week at the Pole. And with some bad weather, it was a good time to roam around and take some indoor photos.

The IceCube Neutrino Observatory is an array of over 5,000 optical sensors embedded in a cubic kilometer of ice at the South Pole. Optical impurities in the ice affect how light travels through the IceCube detector and thus how the neutrino interactions appear. In a technical paper submitted to the Journal of Cosmology and Astroparticle Physics, the IceCube Collaboration presents a new method to understand the optical properties of the ice, called the SnowStorm method.

While the IceCube Neutrino Observatory is mostly known for detecting neutrinos, it is also the experiment most sensitive to PeV-scale gamma rays in the Southern Hemisphere. In a recent paper by the IceCube Collaboration submitted to The Astrophysical Journal, they discuss the results of a recent search for PeV gamma rays. No evidence of PeV gamma rays were found, but they established the most stringent constraints on PeV gamma-ray emission to date.

It’s a slow sunrise at the South Pole, with light creeping up from the horizon little by little each day. But even as the twilight approaches and the sky brightens, it’s still dark enough to discern some auroras here and there.

Sometimes the moon is so bright at the Pole that it lights up the dark winter skies. The moon was setting last week, and as it left there was a slow transition to the first visible signs of sunlight along the horizon.

The auroras were still out in full force last week, as if lingering in their farewell before twilight steps up.

That’s a lot of green!—it looks like a backdrop fit for Wicked. But views like this, of strong auroras over the IceCube Lab (ICL), will soon be gone, so the winterovers are capturing the night sky while they still can.

The 36th International Cosmic Ray Conference took place last week at the University of Wisconsin–Madison. There were 82 IceCube contributions at this year’s meeting: two highlight talks, 36 parallel talks, and 43 posters.

From July 22-24, the Multimessenger Diversity Network (MDN) met at the Wisconsin IceCube Particle Astrophysics Center, located at the University of Wisconsin–Madison, the lead institution of the IceCube Neutrino Observatory.

The Commission on Astroparticle Physics (C4) of the International Union of Pure and Applied Physics (IUPAP) has awarded the 2019 Yodh Prize to Francis Halzen, PI of the IceCube Neutrino Observatory.

Last week was a mostly quiet one at the South Pole station. With winds blowing up to 40 knots for the early part of the week, people were trying to stay indoors.

Dr. Jaya Yodh shared memories about her dad, Dr. Gaurang Yodh, a prominent physicist, professor, and cosmic ray researcher who was part of the early efforts of the IceCube Collaboration and whose brilliant career spanned over five decades. Dr. Gaurang Yodh passed away in early June at age 90 in his home in Irvine, California.

It was a busy week all around at the Pole. The IceCube detector itself had a few issues for the winterovers to attend to, while the final week of the Polympics kept them busy as well.

The second annual Polympics (Pole Olympics) began last week at the Pole. This event is a modern competition that includes not only sports but also e-sports and other contests, like sled pulling.

Last week, IceCube's winterovers spent time outdoors taking advantage of the photogenic night skies.

The National Science Foundation (NSF) has approved full funding to upgrade the IceCube detector, extending its scientific capabilities to lower energies and thus enabling IceCube to reach neutrino energies that overlap with the energy ranges of smaller existing neutrino detectors worldwide.

The IceCube Upgrade project is an international collaboration made possible not only by support from the National Science Foundation but also thanks to significant contributions from partner institutions in the U.S. and around the world.

As a thank you for the fine midwinter dinner put together by the galley crew, the scientists at the Pole took their turn at meal preparation. First up was pizza night, with lots of different toppings, including a duck-honey-hoisin pizza that garnered some praise.

Winter is aurora season, which means that green tends to dominate the color scheme of images from the South Pole. But this week, the green is from vegetation—indoors. Check out these cucumbers.

A quiet week at the Pole—but that doesn’t mean that nothing happened. First of all, look at that sky! Lots of stars and swirling auroras, but also a bright rising moon make for a very picturesque setting.

Since the moon was down last week, many winterovers—including IceCube’s—were outside braving the (extreme) cold, looking to catch some good shots of the Milky Way or the aurora australis, also known as the southern lights.

A bright swath of auroras extending low across the sky with a clear view of the Milky Way above—what more could one want (except perhaps to see it in person)? Well, those who winterover at the South Pole station count themselves among the lucky ones.

How does slow equal fast? Well, apparently for fire rescue teams, slow mean smooth, and smooth means fast. Last week, the teams competed for time in donning their gear and saving colleagues from across the gym.

Look what showed up in the dish pits lately. Hmmm. At least this shark infestation poses no real danger.

IceCube’s winterovers just sat down to take in the view after finishing up some outdoor IceAct snow accumulation measurements. It was a view worth sitting down for. But for a relatively quiet week at the Pole, they still found themselves with plenty to do.

It’s still not completely dark, but we know that eventually, and soon enough, the darkness will come to envelope everything.

The third edition of the IceCube Impact Awards was celebrated during the banquet dinner of the spring collaboration meeting last week in Madison. The awardees for this meeting are Joshua Wood of the University of Wisconsin–Madison, Tessa Carver of the University of Geneva, and Michael Larson of the University of Copenhagen, and the legacy award goes to Chris Weaver for his long-term contributions as a PhD candidate at UW–Madison and later as a postdoc at the University of Alberta.

The extreme environment of the South Pole poses numerous challenges for those who work there, especially during the winter. One difficulty is simply dealing with things that break. You can’t just order a replacement online.

It’s not the first aurora of the season, but it is the first one to be captured on camera by IceCube winterover Kathrin—a pretty, swirling aurora along the horizon, with a bright moon illuminating the icy surface from above.

The Wisconsin IceCube Particle Astrophysics Center (WIPAC) is pleased to host the IceCube Collaboration 2019 spring meeting. The meeting begins today, April 30, and runs through May 4.

The sky was still bright enough last week to take a photo of an ozone balloon launch, the first one to send up a special plastic balloon in the hopes of a better survival as it ascends in the cold atmosphere.

The sixth edition of the IceCube Masterclass hosted over 150 students at 13 institutions in Belgium, Germany, Switzerland, and the United States. The masterclasses were held on January 30, March 20, April 4 and April 11.

There’s still just a bit of sunlight lingering, as seen in the image—what’s not so easily discernible in the image are the stars, but the winterovers report having seen them for the first time in months.

Although the sun has set and winter has begun, it takes a while before it actually gets dark at the South Pole. Twilight is a prolonged process there, lasting weeks. Here there’s still plenty of daylight to see the station as it starts to look nice and frosty without direct sunlight.

IceCube's winterovers had the good luck to enjoy clear weather last week. They were able to capture some dramatic photos of the sunset.

As the sun sinks low behind the IceCube Lab, the building’s shadow grows long—it’s almost reaching the South Pole Telescope, as shown here.

The sun is getting lower and lower, and the folks at the South Pole station continue to get everything ready for winter. The winds were strong last week, on some days making it hard to distinguish ground from sky.

This past weekend, the first members of the new Multimessenger Diversity Network (MDN) met at the University of Wisconsin–Madison, hosted by the Wisconsin IceCube Particle Astrophysics Center. The MDN foundational members are LIGO, VERITAS, and LSST observatories together with IceCube.

The sun is still out at the South Pole, but it’s getting low in the sky (they have one loooong sunset down there). And it’s cold as usual—a quick run around the block leaves one looking a little frosty.

Last week, with the IceCube detector behaving well, winterovers Benjamin and Kathrin had a bit more time for extracurriculars. They enjoyed a live webcast with a classroom in Italy and tried their hand at mastering the unicycle.

Tradition is strong at the South Pole, and last week was validation of that. After the final plane departed with the remaining summer personnel, the winterovering station crew all gathered in the gym for the traditional screening of all three versions of “The Thing.” They engage in this marathon viewing each year.

In a new paper by the IceCube Collaboration, physicists use the inner and denser DeepCore detector within IceCube to try to answer this question. A weak preference is shown for NO, a result that is complementary to and in agreement with results from other experiments. This paper has been submitted to the European Physical Journal.

In a recent paper by the IceCube Collaboration, two new techniques have improved searches at energies from 100 TeV down to 100 GeV. When tested with a few years of IceCube data, these new selections improve the sensitivity and discovery potential, for the first time allowing the search for galactic point-like sources using track events created by muon neutrinos, which in many cases are indistinguishable from atmospheric muon tracks. These results have just been submitted to the journal Astroparticle Physics .

Time flies, even at the South Pole.  The winterover staff are getting ready for the pending station close—here IceCube winterover Kathrin is parking one of the last Hercs to have landed for awhile.

IceCube winterovers Benjamin and Kathrin are showing off a thermometer reading from last week, when temperatures in Madison, WI, and many other midwestern areas were colder than at the Pole.

In a recent publication submitted to Astronomy and Astrophysics, the IceCube Collaboration and Pan-STARRS1 scientists have searched for counterpart transient optical emission associated with IceCube high-energy neutrino alerts. When following five alerts sent during 2016-17, researchers found one supernova worth studying, SN PS16cgx. However, a more detailed analysis showed that it is most likely a Type Ia supernova, i.e., the result of a white dwarf explosion, which is not expected to produce neutrinos.

Flight delays are not uncommon at the South Pole, which can be frustrating. But sometimes there’s an upside, as there was for a recent cohort of IceCube personnel waiting to leave the Pole. They were rewarded for their delay with a flight out on a Basler aircraft (much smaller than the Herc they were waiting on), which gave them fantastic views on the way to McMurdo Station.

In a new paper by the IceCube Collaboration in partnership with scientists from the Fermi-LAT collaboration and the ASAS-SN telescopes, researchers went back to eight years of archived IceCube.

The results of this long-term search of high-energy neutrino emission from blazars confirm that this type of active galaxy cannot account for the majority of the diffuse neutrino flux seen by IceCube and that the source of most of the high-energy neutrinos is still unknown. These results have recently been submitted to Astronomy and Astrophysics.

Even though the end of the summer season feels like it’s fast approaching, things have still been busy at the South Pole. Work got underway for both the new surface radio antennas and the new IceAct telescopes.

There were different groups of South Pole visitors last week—some human, and some not. The nonhuman visitor came from Japan—IceCube-san, seen here on the snow outside the IceCube Lab. The other visitors were adventure travelers, who were based at a campsite not far from the station.

The IceCube Collaboration has just performed its first measurement of tau neutrino appearance in oscillations of atmospheric muon neutrinos, which excluded the absence of tau neutrino oscillations at a significance of 3.2σ, confirming previous observations by OPERA and Super-Kamiokande. These results have just been submitted to the journal Physical Review D.

Last week at the Pole started in 2018 but ended in 2019. What better way to launch into the new year than by unveiling something shiny and bright? That’s the tradition at the South Pole, with a special ceremony held each January 1 to reset the marker at the geographic South Pole.

There are so many different ways to celebrate the holidays around the world, but there’s only one special event that actually takes you around the world. It’s the occasion of the annual “Race Around the World” at the South Pole—a fun run that circles around the South Pole, traversing all of the world’s time zones.

The second South Pole Overland Traverse (SPOT) arrived and toured the IceCube Lab last week. Defueling the SPOT bladders can be a rough job, especially if the weather’s bad.

Another action-packed week at the Pole. IceCube was relatively quiet, but some amazing sun dogs garnered folks’ attention. The station celebrated the 107th anniversary of Roald Amundsen’s arrival at the South Pole, with the station manager dressed up as Amundsen for a photo shoot at the geographic South Pole.

An action-packed week with summer activities in full swing. There was lots of work in the field—digging, measuring, installing equipment.

In an attempt to better understand the anisotropy, the IceCube Neutrino Observatory and the HAWC gamma-ray observatory have united their efforts to study cosmic-ray arrival directions in both hemispheres at the same primary energy. The goal of this combined observation was to get a nearly full-sky coverage to study the propagation of cosmic rays with median energy of 10 TeV through our local interstellar medium as well as the interactions between interstellar and heliospheric magnetic fields. Results have just been accepted for publication in The Astrophysical Journal and include measurements on how the anisotropy modulations are distributed over different angular scales.

What better way to spend a nice sunny day than lying on a blanket enjoying an ice cream cone. That’s what IceCube’s winterovers thought. No matter that the nice day is at the South Pole, sunny maybe but definitely not warm.

Last week, two of three large cargo crates holding new servers and other equipment were delivered to the IceCube Lab, or ICL. Extra hands helped with opening and unloading of all the temperature-sensitive equipment.

IceCube’s new winterovers, Benjamin and Kathrin, are now fending for themselves as they said goodbye last week to Johannes and Raffaela, who finally left the Pole after some delays. (Thanks, guys!)

Neutrinos allow us to test our models at higher energies than do gamma rays. In a first-time effort to combine IceCube and ANTARES data to constrain galactic cosmic-ray models, scientists from both collaborations have set new limits on some of these models as well as a new limit for the galactic contribution to the IceCube neutrino flux. These results have been published this week in the journal Astrophysical Journal Letters.

In a new attempt to lay siege to the steady sources of neutrinos, the IceCube Collaboration has improved the search for sources in the Northern Hemisphere using muon neutrino data. The new search with eight years of IceCube data and an upgraded event selection and reconstruction resulted in enhanced sensitivity and the most stringent limits yet on emission from steady sources. These results have just been submitted to the journal European Physical Journal C .

Last week began with cold, beautiful weather. The sun was out when all four winterovers set off in a pisten bully to visit all the IceTop stations. These trips are part of the regular task of measuring snow accumulation at the stations. Looks like they were having a good time.

The IceCube, LIGO, Virgo, and ANTARES collaborations have used data from the first observing period of Advanced LIGO and from the two neutrino detectors to search for coincident neutrino and gravitational wave emission from transient sources. Scientists did not find any significant coincidence. The results, recently submitted to The Astrophysical Journal, set a constraint on the density of these sources.

And then there were four. Last week saw the arrival of IceCube’s two new winterovers, Kathrin and Benjamin, joining departing winterovers Raffaela and Johannes before they leave the Pole. On their first visit to the ICL, they set up a camera timer to capture a group photo. But the timer was a bit fast for getting back into their planned arrangement atop a giant snowdrift—so, antics ensued.

The IceCube Collaboration has measured the Sun’s cosmic-ray shadow for the first time, from data covering a period of five years. The results, submitted today to The Astrophysical Journal, show a clear but different shadow pattern every year. When looking at the yearly variation, scientists have found that the shadow pattern follows changes in the solar activity, which we know are correlated with the strength of the Sun’s magnetic field. Thus, this study opens a new line of research for the Antarctic neutrino observatory: the study of the Sun’s magnetic field using IceCube cosmic-ray data.

IceCube was quiet and well behaved last week, but the week was full of all sorts of other activity now that the summer season is officially underway. Here we see IceCube winterover Raffaela getting ready to help park the first passenger aircraft of the season.

Ok, so you’ve completed that giant 18,000-piece jigsaw puzzle, now what? Well, you might not want to take it apart again, at least not for a while. The folks at the South Pole decided to give theirs a place of honor on the wall in the B2 science lab.

Ignacio Taboada, Associate Professor in the Department of Physics at Georgia Tech and a longtime IceCuber, is one of the 2018 Fellows announced by the American Physical Society (APS) a few days ago. This award acknowledges his contributions to the study of transient sources of very high energy gamma rays and neutrinos with the HAWC and IceCube observatories.

Bad weather at the Pole last week kept the first flights from arriving, but it also meant lots of snow shoveling and fuel line testing to continue their readiness for incoming flights once conditions do improve.

While they wait at the Pole for the first arriving flights of the season, there are still chores to do, like snow removal. The snowcat in this image is poised for action.

The main entrance to the South Pole station is known as Destination Alpha—this image shows a view out onto the frosty tundra from there at early sunrise.

The launch of the so-called IceCube Upgrade—which will deploy seven new strings at the bottom of the detector array—sets a milestone in what IceCubers have designed as an incremental extension of the Antarctic detector.

The equinox occurred last week, and the sun has finally risen above the horizon. The sky in turn is showing off an array of beautiful colors, providing a nice backdrop for outdoor photos.

Just because the sun’s coming up, doesn’t mean it’s getting warmer yet. In fact, they’ve had some tremendously cold days at the Pole, with the thermometer hitting –100 F last week.

The Astroparticle Immersive Synthesizer is not only a huge piece of art, but also a sound laboratory and an experiment in psychoacoustics.

The IceCube Collaboration has, once more, looked for extremely high-energy neutrinos. And now, after analyzing nine years of IceCube data, scientists set the most stringent limits on the existence of cosmogenic neutrinos to date. As a result, the idea that ultra-high-energy cosmic rays are mostly protons is vanishing. These results were published in the journal Physical Review D last week.

As the sun rises and brightens the sky, thoughts turn to the arrival of summer visitors. Still a ways off, but there is plenty of station prep and cleaning to be done in the meantime. Outside, the IceCube Lab and some other structures are now becoming visible again in daylight.

The satellite dome sits frosted over as it waits for the sunrise—here it’s shown backlit by a full moon. It’s a peaceful scene, which is also how IceCube’s winterovers generally described last week at the Pole.

The IceCube Collaboration has recently presented its first measurements of the neutrino inelasticity, which are also the first-ever at very high energies—from 1 TeV up to nearly 800 TeV. The inelasticity distribution was found to be in good agreement with Standard Model prediction and was later used to perform other measurements, such as charm production in neutrino interactions or flavor composition of astrophysical neutrinos.

IceCube winterover Johannes’s camera withstood a time-lapse session outdoors last week—a little frosty looking afterward but still able to crank out some fine-looking photos.

False alarm from week 32—aurora viewing remained in full force last week at the Pole. In fact, the skies were graced with some purple auroras, pretty rare in general, even at the bottom of the world.

Who knows, but it could be that this fantastic shot is the last we’ll see of the auroras from the Pole for a while. So, why not go out with a bang—big, bright, and set against a starry Milky Way backdrop.

It was a pretty busy time last week at the Pole. IceCube’s winterovers had some unrelated hardware incidents that required troubleshooting and fixing, and a trip out to the IceCube Lab. And look what a great photo winterover Raffaela captured on that trip, with the ICL backlit by a full moon.

Stefan Westerhoff, a professor in the physics department at the University of Wisconsin–Madison, passed away on Sunday, August 5, 2018, after a long illness. He was 50.

Last week the weather was a bit mixed, and the winterovers had their lunar eclipse viewing marred by blowing snow. Regardless, they still got together outdoors for a group photo.

In a new search for neutrino sources, the IceCube Collaboration and other collaborators have looked for short-lived transient sources, including gamma-ray bursts, core-collapse supernovae, or neutron star mergers. The search, which looked for two or more neutrinos detected within 100 seconds from the same location, included transients that might not emit gamma rays and might be pointing to uncharted objects in the universe. The results submitted this week to Physical Review Letters did not identify any individual source but did show that the number of bright short-lived transient neutrino sources must be small or they must be fairly faint.

So much ice, yet it’s no mean feat to keep a stable water supply for the folks at the South Pole. Housed in the shack shown in this image is a rodwell, which is how they get their water. Hot water is sent down a hole to a cavity deep in the ice, and a continuous flow of water is maintained to prevent the rodwell from freezing.

There were two bingos last week at the Pole: (1) the game, where some improvising was required for the tiles, and (2) the exclamation, which was well warranted for IceCube’s recent multimessenger results.

A new measurement of the IceCube Collaboration has put Lorentz symmetry to the test and found—yet again—that neutrinos behave as expected. The results, published in Nature Physics, are the most stringent limits to date in the neutrino sector on the existence of a Lorentz violating field.

Last week at the Pole, the weather was perfect for starting out the second half of winter—cold but calm conditions, with some of the prettiest auroras.

Observations made by the IceCube Neutrino Observatory at the Amundsen–Scott South Pole Station and confirmed by telescopes around the globe and in Earth’s orbit have for the first time provided evidence for a known blazar as a source of high-energy neutrinos. These results are presented in two papers published this week in the journal Science.

The 4th of July is now behind us, but this view of the South Pole station continues with the red, white, and blue theme, while the other side of the station just shows the blue sky and the white snow. These image were only possible due to a bright moon, bright enough to illuminate the tracks in the snow surface.

The recent stretch of bad weather finally broke, showing off some nice auroras. Here, you can make out a bright spot in the sky, which is Mars, soon to reach its closest approach to Earth in many years.

Midwinter is approaching, so the winterovers got together for a group photo that they’ll use to send out traditional greetings to other stations. Looks like a bunch of happy campers.

Nice snow drift! Or sastruga, as one might say at the Pole. This enormous snow structure appeared inside the logistics arch, which is a large unheated storage facility, pushed through to the inside through closed doors. That is one strong wind (or one leaky door).

Since it’s nighttime all the time during winter at the South Pole, it can be pretty dark outside, depending on the weather. But with clear conditions, you can get a wondrous night sky. Here we have the IceCube Lab under quite the starry sky, with the Milky Way in clear view and an Iridium flare making a noticeable mark.

The 2018 IceCube delegation at the Neutrino conference includes 22 researchers presenting 20 posters and two plenary talks.

Last time it was frosted glasses, now it’s a frosty staircase. Blowing snow during the recent storms has left its mark on the staircase and platforms of the IceCube Lab (ICL). At some point, that snow will need to be removed—but that’s for another day.

The winds kept at it last week. The blowing snow not only obstructs the view when trying to take photos, but it makes it tricky to see the flags that mark your way in this dangerously cold landscape. The weather did clear at one point, though, long enough to capture some amazing shots of the Milky Way.

A quiet week at the Pole for the detector, but he photos were just striking! Here we have a nice shot of the ceremonial pole marker, with a bright moon situated just behind the sphere and flags flapping in the wind.

Even in winter, you can get an impressive halo—here it’s the moon. Halos are caused by light interacting with ice crystals suspended in the atmosphere, and these circular halos, which can form around the sun or the moon, are called 22-degree halos. They’re fairly common, seen more frequently than rainbows.

Hosted by Georgia Tech, the spring IceCube Collaboration meeting starts today in Atlanta. Two hundred IceCube collaborators from 49 institutions will meet to discuss about a variety of topics, including the future expansion of IceCube.

Last week was fairly relaxed at the Pole. Some testing and troubleshooting with the detector, but all went rather smoothly. As for the skies? They were glowing. And swirling, and shimmering. The auroras sometimes swirl into shapes suggesting all kinds of things.

Although the sky is not yet dark, auroras appeared for the first time this austral winter. It was a good thing the detector ran well this week, because the winterovers were excited to experiment photographing the colorful night sky.

Each winter, once it gets dark enough, the station covers up all of its windows to prevent light from interfering with light-sensitive projects at the South Pole. This year they decided to have a contest for the window cover art entries.

Didn’t we say the sun had set already? We did. But that doesn’t mean the sky goes absolutely dark right away. It’s a slow sunset, with light lingering even after the sun has dipped below the horizon. This image shows a great twilight shot of a clear sky with some color along the horizon and the IceCube Lab in the distance.

The IceCube Collaboration has tested a few models of heavy dark matter and found no evidence that the high-energy neutrinos can be attributed to the decay of dark matter particles. This nondetection resulted in a new lower limit for the lifetime of dark matter particles with a mass of 10 TeV or above. The paper summarizing these results has just been submitted to the European Physical Journal C.

Who needs the sun when you have a moon like this! This image shows the moon hanging low above the Dark Sector, home to the South Pole Telescope, shown here, in addition to the IceCube Lab, BICEP, and MAPO.

At the South Pole, you never know whether the skies will be clear enough to capture a nice image of that last flicker before the sun goes below the horizon. Last week a big storm rolled in that threatened things, but it cleared in time for the winterovers to capture some great photos and bid the sun adieu for a while.

Last week was stormy at the Pole, according to IceCube’s winterovers. Guess that’s where these icy blotches stuck to the window came from. The detector was relatively quiet, but there was plenty of other activity to keep the winterovers busy.

The fifth edition of the IceCube Masterclass hosted over 300 students at 17 institutions in Belgium, Denmark, Germany, Switzerland, and the United States.

It takes a long time for the sun to set at the South Pole. Maybe just as well for last week. It allowed IceCube’s winterovers to continue taking outdoor photographs of the landscape, and it gave them some light to see what they were doing while out in the field, driving around and measuring the snow height at all the IceTop stations.

With better and larger neutrino telescopes on the horizon, researchers are now designing more efficient analysis techniques that will boost our understanding of neutrinos and advance searches for new physics, including additional neutrino flavors or new interactions. These techniques not only provide more accurate and robust results but also reduce expenses and time in computation that could limit improvements in the design of new detectors or the discovery potential of existing facilities. Details of these new techniques are given in a paper by the IceCube-Gen2 Collaboration submitted this week to Computer Physics Communications.

The fuel arch under the station is one of the coldest—and creepiest—places at the Pole, accessed from a network of underground ice tunnels. The tunnels maintain an even temperature of around -50 °C at all times.

A quiet week at the Pole. And when the quiet stems from a well-behaved detector, there’s nothing to complain about. IceCube winter Johannes and others took advantage of the remaining daylight to get in some Frisbee while they still can.

That’s it—the South Pole station is officially closed for the season. The few remaining summer people have departed on the last plane out, which brought to the Pole a nice supply of “freshies,” as they like to refer to their perishable produce.

It was a busy week at the Pole. There are always lots of preparations to be made before hunkering down for the many months of isolation and darkness. With the busy airfield, IceCube winterover Raffaela was out helping park a Herc.

The summer season is nearing its end. So IceCube’s winterovers were busy helping summer crew wrap up their tasks. That included some cleaning and recabling in the ICL.

IceCube winterover Raffaela got to see some amazing wildlife on her break, but check out what Johannes spotted on his R&R trip to McMurdo. That’s an icebreaker, which is needed to cut channels through the thick sea ice to allow fuel and cargo vessels to reach McMurdo Station.

When you see mountains and wildlife, you know we’re not at the South Pole anymore. But we are still in Antarctica, and these first few images are from IceCube winterover Raffaela’s R&R trip to McMurdo.

Since the winterovers spend a full year at the Pole, they get to fit in some R&R at McMurdo Station on the coast before the long stretch of winter isolation sets in. IceCube winterover Raffaela was off last week, after a two-day flight delay, leaving Johannes to hold down the fort on his own.

The IceCube detector started out the year with no major issues. Yay! But there was plenty of excitement in other arenas. Everyone gathered at the geographic South Pole for the unveiling of the new pole marker.

Last week was the third annual “Bermingman,” where folks go out into the berms to dig for buried treasure. Things are buried because of accumulated snow, not from actual snowfall but from storms and winds that blow in and deposit snow. In fact, just after the Bermingman, a huge wall of snow appeared on the horizon

If you didn’t have snow over your holidays, you can enjoy it vicariously through these South Pole pictures. They had all kinds of fun in the snow—sledding and tubing, snowmobiling, and running! The sledding worked up their appetite for celebrations.

Last week was a busy one at the Pole. A lot of holiday preparations and some visitors on station, including folks from Arctic Trucks, getting a station tour and giving tours of their vehicles.

Although fast radio bursts’ (FRBs) progenitors are supposed to be compact and perhaps catastrophic cosmic events that may also produce neutrinos, IceCube has not detected any such neutrinos that could be associated with a known FRB in six years of data. These results are far from precluding the eventual detection of neutrinos from FRBs in the future, but they have set the best limits yet on how many are emitted. The results have been submitted today to ''The Astrophysical Journal''.

There’s always something going on at the Pole, and last week was no different. On the fun side, the winterovers got in some outdoor photography—well, technically indoors for this shot of the icy stairwell down in the fuel arches

The many flight delays this season affected the arrival of not only personnel but cargo, too. It eventually showed up though, and last week IceCube’s winterovers were busy managing it all at the IceCube Lab. It was a lot of carrying and exhausting, but they were still smiling after it was all said and done

It was a busy week for IceCube’s newest winterovers. A plane arrived after a long hiatus, bringing some new folks to the station and taking away last year’s winterovers, finally. But much of the excitement came from alarms going off—the ones for fire were false alarms thankfully. But it gave the new winterovers a chance to apply their training to emergency response operations.

Last week kept IceCube’s newest winterovers busy, but not too busy, with a number of activities. Johannes was on call, and got his first page to deal with a detector issue, but not too big of a problem. Both winterovers were trained on the PistenBully, or snowcat, and then drove around to the IceTop stations to take snow height measurements.

Neutrinos are abundant subatomic particles that are famous for passing through anything and everything, only very rarely interacting with matter. Now, scientists have demonstrated that the Earth stops very energetic neutrinos—they do not go through everything. The study is published online today by the journal Nature.

Flight canceled? Well, that happens. But, canceled … again? Welcome to plane travel at the Pole. The changeable weather patterns in the harsh climate of Antarctica make flights in and out susceptible to delays. It’s part and parcel of the whole experience.

Lots of firsts as a new summer season begins at the South Pole. Last week saw the first LC-30 to arrive, seen here as it’s being marshaled in and later after landing and releasing a group of red parkas onto the ice, the first group of many to come. The changing-of-the-guard period at the Pole has begun.

Shoveling snow might not be that much fun, but at least at the South Pole, afterward you can walk away with a pretty “epic” beard, as the winterovers recently put it. Well, if you have a beard to begin with, that is.

After a long, cold winter at the South Pole, it might be hard to decide which is more exciting: the first plane of the season or its contents. Apparently, people get pretty excited at the sight of a bowl of tangerines after going without any fresh fruit for eight or nine months.

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Now that you can see what you’re doing outside, it’s time for outdoor activities. Unfortunately, it’s still cold (very cold), and there’s no guarantee that the sun will be out. In fact, here’s IceCube winterover James braving what appears to be rather poor conditions to take some height measurements for calibrating a new IceTop sensor.

In a joint effort by the ANTARES, IceCube, Pierre Auger, LIGO, and Virgo collaborations, scientists have searched for neutrino emission from this merger. The search looked for neutrinos in the GeV to EeV energy range and did not find any neutrino in directional coincidence with the host galaxy. The nondetection agrees well with our expectation from short GRB models of observations at a large off-axis angle, which is most likely the case for the GRB detected in conjunction with GW170817. These results have just been submitted to The Astrophysical Journal.

The sun sure does make things shiny. The face of the station appears dark and flat, but the “beer can,” the large cylindrical tower on the end that connects the aboveground station to belowground corridors, is glowing in the face of the newly risen sun. So is that interesting snowdrift in the foreground.

Just because the sun is now up, doesn’t mean you can see everything clearly. Check out the poor visibility in this image of a flag line just outside the station, disappearing into whiteness. The 40-knot storm made outdoor work impossible and therefore restricted.

Last week we saw that someone had pulled up a chair to watch the sunrise, this week there are two. And these two people are actually watching the sun—it has been climbing higher and higher all week and is now officially up.

The fall IceCube Collaboration meeting begins today in Berlin (Germany) hosted by the Humboldt University and DESY. More than 225 IceCube collaborators from around the globe will meet in person.

In a new search for nonstandard neutrino interactions, the IceCube Collaboration has tested theories that introduce heavy bosons, such as some Grand Unified Theories. The study resulted in new constraints on these models, which are among the world’s best limits for nonstandard interactions in the muon-tau neutrino sector. These results have just been submitted to Physical Review D.

Their time at the Pole may be coming to an end, but apparently their beards are not! IceCube winterovers Martin and James are sporting some fine beards while they happily tackle their work in the dish pit.

The new South Pole Experiment Contest run by the IceCube Collaboration is a contest developed for middle school students from around the world.

Just because it’s light enough to take pictures outdoors, doesn’t mean the sun is up. Not yet—or not officially—anyway. The one and only sunrise each year at the South Pole is a slow process.

Now you see him, now you don’t! Winterover Martin had some fun taking photos at the ceremonial pole last week. Although it was still quite cold outside, the light was sufficient for a much faster a selfie.

With a near perfect uptime and very few detector issues, winterovers enjoyed a quiet week.

Winterovers have been waiting for the sun for many months and the growing anticipation was heightened this week when the temperature reached a frigid -104◦F.

It was a relatively quiet week at the Pole, with most of the action outside. IceCube winterover Martin captured a nice shot of the moon, with halo and moon dogs, over the Dark Sector. You can discern a faint glow along the horizon of an impending sunrise.

No, not yet—that’s the moon, not the sun. But so bright, one would be forgiven for mistaking it for the sun. Not only is this full moon bright, but it’s sporting a nice clear halo, too, providing an excellent backdrop for a shot of the IceCube Lab.

A fairly laid back week, all things considered. The moon was rising, and IceCube winterover Martin focused his camera outside on some snowed-in heavy machinery. Looks like quite a covering for a place that hardly sees any snowfall.

Last week at the Pole, life for the IceCube winterovers was bookended by a very busy beginning and a fun and lighthearted ending. For the first few days, they had to contend with some detector issues arising from run transitions and test runs performed, but all went well. By the end of the week, they were celebrating Christmas in July.

This week, the IceCube Collaboration presents a new measurement of the oscillation parameters that for the first time is competitive with the best measurements to date. These results have just been submitted to Physical Review Letters.

The sun will rise again … at some point. But in the meanwhile, it’s still winter and the skies remain dark. A bright moon had been lighting things up lately, but last week it was gone, leaving it up to the auroras to provide the overhead entertainment.

The International Cosmic Ray Conference, ICRC, closed yesterday in Busan, Korea, after almost ten days of exciting science on astroparticle physics topics, including several highlighted talks and updates from IceCube and even a few awards to IceCube collaborators.

Although the poker tournament continues, last week’s focus was all about the Games—the South Pole Winter Games, where they had actual medals, a closing ceremony, and even an Olympic flame.

The IceCube Collaboration presents a new search for neutrino emission associated with the galactic plane with seven years of IceCube data. The results, submitted to The Astrophysical Journal, are not conclusive but set new constraints on the possible galactic contribution.

Let the games begin! The South Pole Winter Games, that is. They feature an eclectic line-up of events, including vertical tower sprint and photography. IceCube winterovers James and Martin signed up for some individual trials but also formed a team to compete in volleyball.

Last week the IceCube detector had almost perfect uptime. There was also a continuing poker tournament, a birthday celebration, and auroras that appear to be getting into the 4th of July spirit.

What a busy week at the Pole. It was Midwinter there, marking the halfway point of the long, dark winter. They held their traditional viewing of “The Shining” and celebratory dinner, including salads, menus, and fancy décor. Also last week was the culmination of a station-wide facial hair contest.

The moon was up last week, making it quite bright outside—it almost looks like sunshine. But it’s winter at the Pole, and IceCube’s winterovers have been busy. They had to trek out to the ICL for one thing or another, and they also performed some regular maintenance procedures on DOMs, both in the ice and in IceTop

Another busy week for IceCube’s winterovers—they were paged several times to deal with crashes and other irregularities. Despite the activity, the detector was quite stable with minimal down time. The station had a special Memorial Day lunch last week, complete with hamburgers and hotdogs. And auroras!

Last week, IceCube’s winterovers were quite busy. There were a few battery and other power supply failures to troubleshoot and reckon with, and a couple of other minor detector issues—all resolved smoothly though. In station life, they celebrated The Big Lebowski Night and international Towel Day.

The astrophysical neutrino flux observed by IceCube has been the focus of many studies, by both the IceCube Collaboration and other scientists around the world. The collaboration announces today a new study that finds an excess of muon neutrinos at energies above 126 TeV, which is compatible with recent measurements of the astrophysical neutrino flux and constitutes the first model-independent measurement of this flux. These results have been submitted recently to the European Physical Journal C.

Last week at the Pole saw the start of a new physics run and some other detector maintenance tasks. Meanwhile, the bright moon had set, allowing auroras to take over the skies once again. And take over they did.

It’s that time of the year. Down at the South Pole, our team is in the darkness of the austral winter, enjoying beautiful auroras while monitoring IceCube data taking. Up north, the team has completed all updates and checks to the new data systems running live in the IceCube Lab (ICL), sitting on top of the IceCube detector on Antarctica’s surface.

IceCube has proven to be a champion detector for indirect searches of dark matter using neutrinos. In the most recent study, the collaboration sets the best limits on a neutrino signal from dark matter particles with masses between 10 and 100 GeV. These results have recently been submitted to the European Physical Journal C.

There are privileges that come with winterovering at the South Pole. Being able to step outside and gaze up at spectacular aurora displays is one of them. Working in the dish pit? Well, maybe that’s on the other side of that coin.

IceCube is still a young experiment, and it feels like there is always something new going on. But, a spokesperson transition brings us the perfect moment to talk about accomplishments and future plans.

If you find yourself at the South Pole, and the sky above you is sparkling with stars and shimmering with auroras, you might just want to lie down and stare straight up for best effect. That’s what winterover Martin did recently, seen here in front of the flags at the ceremonial South Pole.

The IceCube Collaboration presents the first search for neutrino sources using cascade events with an energy above 1 TeV. Although no significant clustering was observed, this method provides an independent technique to search for astrophysical neutrino sources. These results have just been submitted to The Astrophysical Journal.

It surely is a staircase to the stars. That’s the ICL’s staircase, set against a backdrop of bright auroras low in the sky with a wide swath of the Milky Way above. Last week at the Pole was very much like the previous one—a well-behaved, quiet detector and an active night sky.

Arms up—let’s hear it for auroras! With an extremely stable IceCube detector that needed little attention last week, IceCube winterover Martin was able to train his focus on the glorious skies.

Last week’s photos from the Pole were full of blue and green. The first visible auroras were out, and they appeared as bright green swaths and swirls against a blue sky. A bright full moon and a tiny speck of Jupiter also made appearances.

The Commission on Astroparticle Physics of the International Union of Pure and Applied Physics (IUPAP) has awarded the 2017 O’Ceallaigh Medal to Christian Spiering, an IceCube collaborator and a researcher at DESY-Zeuthen, for his “outstanding contributions to cosmic ray physics and to the newly emerging field of neutrino astronomy in particular.” Spiering will receive the award during the International Cosmic Ray Conference (ICRC), in July 2017, in Busan, South Korea.

Aya Ishihara, an IceCube collaborator and an associate professor of physics at Chiba University in Japan, has been awarded the 37th annual Saruhashi Prize, given each year to a female researcher in the natural sciences. This award recognizes women scientists under 50 for exceptional research accomplishments and for mentoring of other women scientists.

Another amazing week at the Pole—not only was the detector performing well but the twilight photographs continued to be stunning. IceCube winterover Martin captured another great time-lapse shot of a NOAA weather balloon launch along with some striking images of the station and the IceCube Lab.

In honor of Len Shulman, 1950-2017

The International Union of Pure and Applied Physics (IUPAP) and the Tata Institute of Fundamental Research (TIFR) in Mumbai, India have given the 2017 Homi Bhabha Award to Subir Sarkar, an IceCube collaborator and a professor of physics at both the universities of Oxford and Copenhagen, for his “distinguished contributions in the field of high energy cosmic ray physics and astro-particle physics over an extended academic career.” Prof. Sarkar will receive the award certificate and medal during the inauguration session of the International Cosmic Ray Conference, on July 20, 2017, in Busan, South Korea.

The sun has set, they’ve held their traditional sunset dinner, and yet … it’s still light outside. Well, that’s twilight. Even after the sun falls below the horizon, the scattering of light in the upper atmosphere illuminates the lower atmosphere and the Earth’s surface.

The IceCube, ANTARES, Virgo and LIGO collaborations have joined efforts to look for neutrino emission from the second gravitational wave (GW) event as well as from a previous GW candidate. IceCube and ANTARES searched for neutrinos in temporal coincidence and from the directional constraints provided by LIGO. Within 500 seconds around the two GW signals, no neutrino events were found that come within from the signal region in either detector. These results have recently been submitted to Physical Review D.

The American Physical Society has awarded Benjamin Jones, an IceCube collaborator and an assistant professor of physics at the University of Texas at Arlington, the Mitsuyoshi Tanaka Dissertation Award in Experimental Particle Physics, which is widely considered the most prestigious dissertation award in the field.

This photo at sunset is a picture that paints a thousand words, reminding us that the South Pole is technically a desert. The windswept snow forms into sastrugi, or sharp, irregular grooves and ridges on the hard snow surface. They can create interesting shapes and take on strange appearances, sometimes looking a bit like waves crashing to shore.

Pull up a chair—sunset at the South Pole takes weeks, not hours. And why is that? Because the Earth’s rotational axis is tilted, the poles gradually proceed from full exposure to full shadow (and back again) as the Earth travels around the sun.

The fourth edition of the IceCube Masterclass hosted over 200 students at 14 institutions in Belgium, Denmark, Germany, and the US. Stony Brook University, which joined the masterclass program for the first time, had a full program for women. The positive interaction with scientists is again one of the things that students value most from this program. The masterclasses were held on March 8, 11 and 22.

A tree grows at the South Pole. Well, not really. It’s not an actual tree (rather, a sculpture made of copper), and it’s definitely not growing. But it looks like a tree—great photo!

Up until almost the last minute, the summer activities at the Pole kept the IceCube crew busy. This summer, a dozen IceCube researchers and staff, from eight institutions and six countries, spent some time at the Admundsen-Scott South Pole Station to perform maintenance and operations for IceCube and help prepare for a future deployment of the Askaryan Radio Array (ARA) detector. A PolarTREC teacher, Kate Miller, also traveled to the Pole to join the team, contributing to an extensive educational and outreach program that is still in progress.

It was rather overcast last week. In fact, in this photo of the IceCube Lab (ICL), it’s almost hard to tell where the snowy landscape ends and the cloudy sky begins. This view of the ICL is from the vantage point of the geographic South Pole.

Another week, another sun dog. This nice photo taken of sun dogs at the Pole also shows off a blue sky, some low-lying clouds, and the South Pole Telescope far off to the left.

A clear sky last week showed off some faint sun dogs around a bright sun. Clear skies also made for fine flying conditions—the last flights to leave the Pole took off last week. The station is officially closed for the season.

The IceCube Collaboration presents an update to previous GRB searches and broadens the search to the Southern Hemisphere using data through May 2015. The inspection of the southern sky increases the sensitivity to the highest-energy neutrinos, which are largely absorbed before reaching IceCube after sailing through the Earth. Researchers looked for neutrino emission in conjunction with prompt gamma-ray emission from 1172 GRBs and did not find any significant correlation with neutrinos detected in IceCube. These results set the strongest constraints yet on GRBs as primary sources of UHECRs. This study has just been submitted to The Astrophysical Journal.

On February 17, 2016, IceCube detected the most significant multiplet since the start of the optical follow-up program: three neutrinos appearing within 100 seconds and consistent with a point source origin. This rare neutrino coincidence has allowed further testing of the capabilities of the IceCube follow-up program, which is able to trigger observations in near real time to search for transient sources. These results have been submitted today to the journal Astronomy & Astrophysics.

The IceCube Collaboration has continued the hunt for sterile neutrinos with a search using lower energy atmospheric neutrinos. This new search looked into three years of IceCube data and again has not found any hint of a light sterile neutrino. These results have been submitted today to Physical Review D.

Shadows are getting longer as the first large group of summer workers heads out from the Pole. Soon enough the flights will end, leaving the winter crew alone for the dark months to come.

Winter is just around the corner, but the South Pole greenhouse doesn’t know about it. Fresh vegetables are growing in there. IceCube winterover Martin had some greenhouse training last week, and harvested a striking (but not very ripe looking) tomato.

Darren Grant, who leads the IceCube team at the University of Alberta, has been awarded the E.W.R. Steacie Memorial Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Doesn’t it sometimes seem that folks at the South Pole are always smiling? Well, for many, getting to spend time at the Pole—extremely cold temperatures notwithstanding—is the dream of a lifetime. Still, this group shot shows summer crew about to leave for warmer climes. Maybe that’s why they’re smiling.

The IceCube Collaboration has recently presented an update to the search for dark matter annihilation in the sun using the first three years of data with the completed detector. The search, which again did not find evidence of neutrinos originating from dark matter annihilations, has now improved these limits by a factor of 2 to 4. These are again the most stringent limits on the spin-dependent dark-matter–proton scattering for WIMP masses above 50 GeV. This study was submitted to the European Physical Journal C.

New measurements of neutrino oscillations, observed at the IceCube Neutrino Observatory at the South Pole, have shed light on outstanding questions regarding fundamental properties of neutrinos. These new measurements of neutrinos as they change from one type to another while they travel were presented at the American Physical Society Meeting in Washington.

Last week’s photos sum up the main activities for IceCube folks currently at the South Pole—snowmobiling, shoveling, and sunbathing.

Wait a minute—seals? penguins? at the South Pole? Well, you’re right to wonder, because the climate at the South Pole, in central Antarctica, is too harsh for survival even for animals adapted to lower temperatures. But winterovers deserve a break from Pole life when possible, and IceCube winterover Martin made it to McMurdo station last week for a few days of R&R, where he was able to capture penguins, seals, and a skua—all in the same shot.

A relatively quiet week at the Pole … but sunny! IceCube winterover Martin captured a bright, radiating sun as it appeared to rest on the roof of the IceCube Lab (ICL). Sunny or not, no flights made it in or out last week, postponing Martin’s week of R&R that had been scheduled.

The year’s end doesn’t mean an end to the work going on at the Pole. Last week, continued detector upgrades and some inventory tasks were on the work roster. There was also considerable progress made on a new IceTop snow-depth sensor project, documented in this image.

Last week, Christmas was celebrated in many parts of the world, and that includes the South Pole. They had a makeshift “cargo” tree, presents for the winterovers, a fancy dinner—complete with a printed menu and assorted European desserts, and a party in the gym.

It might be cold, but it’s summer at the South Pole, and the sun was out in full force, captured in this image of the IceCube Lab (ICL) with a striking mass of clouds cutting a swath through the sky.

The IceCube team in Brussels has been getting ready for a special deployment to the South Pole. On December 11, Gwen de Wasseige, a graduate student at the Interuniversity Institute for High Energy Physics (IIHE), left Belgium for Antarctica, to take part in the austral summer maintenance and operations activities at the IceCube Neutrino Observatory. However, she was not flying on her own but in the company of one of the most famous Belgians of all time, Tintin.

For the first time, the IceCube Collaboration is making public every detail of the only cubic-kilometer neutrino detector to date, from a flasher board in the digital optical modules—aka DOMs—to the calibration processes that allow researchers to measure the properties of neutrinos, or to the IceCube Live website that IceCubers use to monitor what is going on in the detector. The publication, over 70 pages long, has just been submitted to the Journal of Instrumentation.

A busy week at the South Pole, but not too busy for fun and games. Last week they held a foosball tournament at the geographic pole. In fact, it apparently was the first international southernmost foosball tournament, period. And IceCube winterover Martin was one of the winners. Yay, team!

Not many people have the opportunity to go to the South Pole. It’s remoteness and extreme climate make traveling there complicated, and access to the South Pole station and other research facilities at the Pole is restricted or limited at best.

Have we mentioned all the cables? Well, there are a lot of cables in the IceCube Lab, and sometimes they’re a bit in the way, as they appear to be in this image of winterover Martin trying to get at something in the computer rack that needs attention.

Ok, they’re gone, but you can see them one last time in this photo taken mere moments before they left. Who? IceCube’s outgoing winterovers, whose departures from the Pole had suffered some delays. The group photo includes IceCuber Ralf Auer, just arrived on the plane that was soon to take Christian and Mack away, along with current winterovers James and Martin.

A new study from the IceCube Collaboration searched in three years of IceCube data for directional clustering of neutrinos around gamma-ray sources associated with blazars from the second Fermi-LAT AGN catalog. Although some enhancements in the observed neutrino rate from these blazars were found in the 3–30 TeV region, all of them are compatible with fluctuations of the atmospheric neutrino background. These results, recently submitted to The Astrophysical Journal, open several new analyses exploring blazars as very high energy neutrino sources.

Last week at the Pole was a week of no airplanes. Not only did that postpone the departure of current IceCube winterovers Mack and Christian (who was captured in this image expressing his feelings about the delay), but it prevented US Secretary of State John Kerry from making a scheduled visit to the South Pole.

Last week brought two new IceCube winterovers (James Casey and Martin Wolf) to the South Pole, fresh and ready for action. Outgoing winterovers (Christian Krueger and Mack van Rossem) were still at the Pole, available to provide some welcome training before they leave the ice (which can feel as though it may never happen, with only 3 of 12 planned flights making it last week due to one issue or another—such is life at the South Pole).

Come summer, station personnel eagerly await the first provisions of “freshies,” as they’re called at the Pole. Despite continuing delays last week, a couple more planes have come and gone, leaving a few new faces along with the fresh fruit and bringing the station population to over 50.

This nice sun halo (properly called a 22º halo) that appeared directly above the IceCube Lab meant that there were ice crystals in the atmosphere, one of the reasons that the skiway wasn’t seeing enough action last week. Some folks were all packed up and ready to leave, but no plane was there to take them away as the flight schedule kept being pushed back due to weather. Such is life at the South Pole.

Last week at the Pole, the first two planes of the season arrived (and then departed again—both had short stays). They were small planes, but still, any plane landing at the Pole these days is an exciting event after the long, dark, quiet winter.

Although the South Pole is essentially a desert, a hefty accumulation of snow occurs on and around the buildings there each winter. How is that? Well, it’s the wind. Antarctica is a windy place—even with so little precipitation, it features some extraordinary blizzards thanks to strong winds.

IceCube’s collaborative efforts with gamma-ray, X-ray, and optical telescopes started long ago. Now, the IceCube, MAGIC and VERITAS collaborations present updates to their follow-up programs that will allow the gamma-ray community to collect data from specific sources during periods when IceCube detects a higher number of neutrinos. Details of the very high energy gamma-ray follow-up program have been submitted to the Journal of Instrumentation.

With the sun out, you can see again—and here we see all the flags surrounding the marker at the ceremonial pole. They didn’t just appear out of the darkness, though. They were recently replaced for the summer season after being taken down for the winter.

Flags serve an important purpose at the Pole, marking out routes between places for when visibility is poor. Here you can see the IceCube Lab (ICL) in focus behind a flag line in the foreground.

The IceCube Collaboration fall 2016 meeting ends today at Johannes Gutenberg Universität Mainz in Germany. Professors Sebastian Böser and Lutz Köpke hosted the weeklong meeting.

"It’s been a total thrill to see how fast we as a collaboration are moving forward on so many fronts in parallel," says Sebastian Böser. "I hope everyone has enjoyed the meeting in Mainz as much as we've enjoyed hosting the collaboration."

Up, up, and away. That’s a NOAA balloon launch shown in a time-lapse photo—pretty nice! Last week at the Pole was all about the camera.

A new temperature record for 2016 was set at the Pole last week—a low of –107.9 °F. The extremely cold temperatures didn’t stop one station inhabitant from climbing the outdoor staircase is short sleeves.

The IceCube Collaboration has just announced the results of a search for point-like sources using track-like neutrino candidates detected by IceCube over seven years, from 2008 to 2015. No source has been identified, but the sensitivity keeps improving at a fast pace and will allow IceCube to test accurate models that suggest that sources could soon be observed. These results have just been submitted to The Astrophysical Journal.

One unique aspect of living at the Pole for a year is experiencing only one sunset, at the equinox in March, and only one sunrise, which occurs in September, while you’re there. Since the sun rises just once during the whole year, it’s kind of a big deal. It’s also a slow process, with daylight increasing little by little as the sun’s arrival nears.

Despite the encroaching twilight, this photo of a Scott tent near the South Pole marker also captured some faint auroras. Auroras have been caught in many shapes and forms, conjuring up cinnamon rolls and question marks, but in this case, it’s a grumpy face. At least, once it has been suggested, it’s difficult not to see it.

The IceCube Collaboration has expanded dark matter studies with a search for annihilations in the center of the Earth. Researchers have used one year of data—May 2011 to May 2012—and have not found an excess of neutrinos above the expected background. The results have set new limits on the annihilation rate of WIMPs in the Earth that are an order of magnitude stronger than previous results by AMANDA and that also improve the IceCube spin-independent cross section limits for a WIMP mass of 50 GeV. This study has just been submitted to The European Physical Journal C.

A full moon is doing just as good a job as the sun in lighting up the sky. Here the moon, surrounded by a clear halo, is shown hiding behind one of the frosty towers of the ICL. A large snow drift looms in the foreground.

Growing up on a small, secluded hobby farm in southwestern Wisconsin, the night sky played a major role in my upbringing. Since there is almost no light pollution, the night sky was always bright and clear. In the summer months, my bedtime was determined by the time a specific satellite went over the house. Every year, my family would gather up all the blankets in the house and lay outside to watch meteor showers for hours. From a young age, I loved the idea of learning more about the stars and planets, and as I got into high school, I fell in love with physics. My original plan was to become a high school physics teacher, and I found the University of Wisconsin–River Falls (UWRF) not only has a fantastic physics program but is also involved with IceCube. I had heard about IceCube in 2013, when it won Physics World’s Breakthrough of the Year, and working for IceCube became my new goal and dream.

The igloo—the prime attraction at the South Pole for the last few weeks—is no more. But before “disappearing,” its existence was memorialized in some final photos. Here you can see it with the names of its builders carved into the side, and it appears to almost glow from the soft white light from within.

During my summer abroad, I worked with Dr. Jon Dumm, who is searching for an excess of neutrino events originating in the plane of the Milky Way. Dr. Dumm’s analysis is designed to look for a diffuse neutrino flux from the galactic plane in agreement with a map of where pion decay is expected to occur. However, this analysis is sensitive to a neutrino flux from point sources that are not necessarily distributed as the pion decay map predicts. We simulated four possible models of cosmic-ray source density in the galaxy as proxies for possible distributions of unresolved neutrino point sources. In doing so, we established limits on the total flux from various numbers of sources to which the primary pion-decay-based analysis is sensitive.

At the start of the summer, UW-River Falls student Nick Jensen and I set out to create a 1:1000 scale model of the IceCube detector using LEDs to represent DOMs. To do this, we needed a wide assortment of parts to construct the model from the ground up. We spent the first half of the summer trying to gather all the parts needed for building.

The igloo from last week is finally finished. What began as an afternoon project ended up taking an entire week (well, high winds were partly to blame). In the image, you can see the igloo lit from within, and perhaps even discern that there are only few blocks missing to complete the ceiling.

That’s not the IceCube Lab all frosted up in this photo but the ARO (Atmospheric Research Observatory) building, with its LIDAR beams shown shooting straight up into the sky.

In an effort to fill in the blanks of the Standard Model of particle physics, science has been conducting a diligent search for a hypothesized particle known as the “sterile neutrino.” Now, with the latest results from an icy particle detector at the South Pole, scientists are almost certain that there is no such particle.

Station life was quiet at the South Pole last week, but not too quiet. They celebrated Christmas in July with a special dinner. Popular in many parts of the world, for various reasons, Christmas in July is only one of numerous celebrations held throughout the year at the Pole.

In summer at the South Pole, the traditional place for photo ops is the ceremonial Pole, where a mirrored sphere is mounted on a post and surrounded by a semicircular lineup of flags. But in the dark of winter, any place is as good as another as long as you have a nice aurora as backdrop

The IceCube Collaboration is now accumulating more statistics in the search for the sources of very high energy neutrinos, but also to learn more about their nature. In a new study, submitted this week to the Astrophysical Journal, the collaboration reports a substantially improved observation of the diffuse muon neutrino flux in the Northern Hemisphere using six years of IceCube data with about a tenfold increase in statistics. Once more, a clear astrophysical contribution has been found, which at the highest energies excludes a purely atmospheric origin at the 5.6 sigma level. Also, the accuracy of the measurement of the spectral properties has been improved.

The sky was not disappointing anyone last week at the Pole; it had it all—stars, Milky Way, and auroras. Work-wise it was rather quiet for IceCube’s winterovers. But they had other activities going on, including emergency response training and showcasing their LEGO creations in a blog post for LEGO fans.

The IceCube Collaboration has made public today that a new search for cosmogenic neutrinos resulted in two very high energy neutrinos. These neutrinos, which are found to be of astrophysical origin with a 92.3% probability, include the highest energy neutrino detected to date. While of astrophysical origin, the energy of these neutrinos does not match the expectation for a cosmogenic neutrino flux. The lack of evidence for such events in a search of seven years of IceCube data places very strong constraints on the sources of UHECR. Proton-dominated sources are greatly disfavored, and testing mixed and heavy nuclei cosmic-ray sources will require much bigger instruments, such as an extension of IceCube or radio Askaryan neutrino detectors. These results have been submitted yesterday to Physical Review Letters.

The IceCube Collaboration presents results from a search for sources of high-energy neutrons using four years of data from IceTop, the surface detector array. Researchers have not found any evidence for astrophysical neutrons, but the results have allowed the collaboration to set new limits that constrain the possible galactic neutron sources. These results have just been submitted to the Astrophysical Journal.

The Precision IceCube Next Generation Upgrade (PINGU) is the proposed infill extension in a region at the center of the IceCube Neutrino Observatory that will lower the energy threshold to a few GeV, dramatically increasing both the number of GeV-scale neutrinos detected by IceCube and, more importantly, the precision with which they are measured.

South Pole, dead of winter, no sun for months. So, that rules out a rainbow in the above image. Instead it’s an aurora, but it was doing its best, with its graceful arch, to imitate a rainbow.

IceCube researchers are once more joining the longstanding biennial Neutrino conference. The 27th International Conference on Neutrino Physics and Astrophysics, Neutrino 2016, started on Monday in London, England, and runs through Saturday, July 9.

It’s the middle of winter at the South Pole, and not only is it dark outside, but there are restrictions in place to keep it as dark as possible (exterior lights limited to a red spectrum, to reduce interference) for the benefit of research projects that rely on the dark night sky.

Last week, they were observing midwinter at the South Pole station, which traditionally includes a fancy dinner and a viewing of "The Shining."

A completed jigsaw puzzle serves as a base for holding a sizeable LEGO creation. This model looks to be of London’s Tower Bridge, but perhaps someone should talk to the LEGO folks about designing one for the ICL (the IceCube Lab). Wouldn’t that be fun?

Last week at the Pole the entire winterover crew got together to take a group photo. They normally do this each year, but not always with such spectacular results. This year they chose an outdoor venue with an aurora backdrop.

Station life was quiet last week. Outside, the auroras kept themselves a bit quiet, too. Instead, folks were treated to a nice moon halo on display.

On Sunday, June 5, IceCube will be part of the “take over” of Washington Square Park for Street Science, a free World Science Festival event. Dozens of research groups are offering hands-on activities, demonstrations, and exhibits to engage curious visitors of all ages.

The IceCube Collaboration presents a new search for dark matter annihilation from the galactic center and halo using cascade events, i.e., particle showers created by the interaction of electron and tau neutrinos and Z-boson mediated muon neutrinos. Scientists searched for interactions starting in the DeepCore subarray between May 2011 and May 2012 and found no neutrino excess with respect to the background-only hypothesis, which allowed them to derive upper limits on dark matter candidates with masses between 30 GeV and 10 TeV. These results have been submitted today to the European Physical Journal C.

Space: the final frontier. These are the images of IceCube winterover Mack van Rossem. Well, he’s not in space, and he may not exactly be “boldly going where no man has gone before,” but he is spending a year in one of the most remote locations on Earth—the South Pole.

“On behalf of the operations group, I’m happy to report that as of run 127950 on 2016-05-20, 20:38:47 UTC, we have started the IC86-2016 physics run.” With these words, every IceCuber learned that we were entering a new year of data for IceCube.

Not a particularly busy or hectic week at the Pole—quiet punctuated by work, or work punctuated by quiet, depending on how you look at things. Now, depending on where, not how, you’re looking, you get to see where the action is this time of year at the South Pole.

Under a sky lit by auroras, you can see the path through the Dark Sector, bright enough to make out the flag line for quite a ways into the distance. It’s a different story when there are no auroras or bright moon to illuminate things.

It’s aurora season at the South Pole. Two lone figures—both of IceCube’s winterovers—were out on the ice capturing images of the night sky. Although it’s a night sky, that tells us nothing about what time of day it is since it’s winter there and the sun remains down for about six months at a stretch.

The IceCube Collaboration has performed two independent searches for light sterile neutrinos, both with one year of data, searching for sterile neutrinos in the energy range between approximately 320 GeV and 20 TeV. IceCube has not found any anomalous disappearance of muon neutrinos and has placed new exclusion limits on the parameter space of the 3+1 model, a scenario with only one sterile neutrino. These results have been submitted today to Physical Review Letters.

IceCube winterover Mack’s Ecuadorian devil’s mask looks extra devilish under the red lights as he stands for a photo in his cold weather gear after coming in from outside.

Today, the IceCube Collaboration presents a new technique to lower the energy threshold for neutrino detection while keeping a pointing resolution to within less than a degree. IceCube researchers have used this technique in a joint search with data from a previous analysis using throughgoing muon neutrinos. No point source has been found, but sensitivity for searches below 100 TeV has been improved by a factor of ten.

IceCube winterover Mack van Rossem stands, with a full moon and the IceCube Lab (ICL) in the background, all geared up and ready to tackle IceTop measurements. Nice mask!

With the darkness of winter settling in, it’s time to cover the windows. It’s also time for winterizing outdoor equipment and vehicles. Although a large fleet of vehicles is needed for summer activity, most of them are left idle for the winter.

The IceCube spring 2016 meeting begins today at Stony Brook University. Assistant Professor Joanna Kiryluk is hosting the weeklong meeting at the Charles B. Wang Center. Pre-meetings were held at Columbia University in New York on April 16-18.

It was a relatively tranquil week at the Pole, but not without its interruptions—April Fool's Day pranks among them. The waning light in the sky is beginning to lend a little eeriness to photos.

A mushroom cloud … at the South Pole? What’s going on down there? What’s going on is actually a rising full moon getting distorted by the atmosphere. Pretty cool image.

With so little time left above the horizon, the sun is making a nice spectacle of itself at the South Pole. Here we see it bright and orange and surrounded by a clear halo as it hovers above the satellite stations.

The National Science Foundation today, March 30, 2016, announced that it has renewed a cooperative agreement with the University of Wisconsin–Madison to operate IceCube. The five-year, $35 million award entails the continued operation and management of the observatory located at NSF’s Amundsen-Scott South Pole Station. In 2013, the IceCube Collaboration reported the first detection of high-energy cosmic neutrinos, opening a new astronomical vista on the universe and on some of its most violent phenomena.

Last week there were a few alarm calls in the cryo building. The first one interrupted an outreach webcast, and then there was another one later the same day. The photo shows the emergency response team on their return from one of those calls. You can see that the sun is still out, just a few degrees above the horizon.

On a clear sunny day, it’s easy to make out the buildings at the end of the road to the Dark Sector, but the flag line is set up for the winter months, when darkness and extreme temperatures reign and you really can’t afford to get lost out there.

The third edition of the IceCube Masterclass hosted over 200 students at 10 institutions in Belgium, Germany, and the US. Madison (WI) hosted the first edition in Spanish, attended by 28 Hispanic high school students. Masterclasses were held on March 2 and March 9.

There’s a beautiful half moon in this image, can you spot it? Well, it is a little small in the photo—but sometimes we don’t notice the moon out during the day because we’re not expecting it. However, we shouldn’t be surprised see it then, since it’s often visible.

The IceCube Collaboration is updating the cosmic ray anisotropy maps using 318 billion cosmic-ray-induced muon events detected in IceCube between May 2009 and May 2015. The larger data sample allowed discerning new regions in the anisotropy maps, which shed some light on the physical processes that stir up the variations in the arrival direction of cosmic rays. These results have been recently submitted to The Astrophysical Journal.

Chairs and sofas (and mattresses!) have been set up in the gym, all for the sake of movie-watching comfort. It’s unclear how they vied for best seats. But some padding or support is imperative when you’re going to hunker down for three movies in a row—or rather, three versions of the same movie. Yes, we’re talking about The Thing, the traditional entertainment springboard to ring in the beginning of the winter season at the South Pole.

A cloud of snow dust appears in the wake of the last flight out of the South Pole for the season. Well…almost. It was supposed to be the last flight, but unforeseen circumstances (they do crop up every so often) caused a few summer personnel to delay their departure a few more days. Delays can be a nuisance, but so close to the end of the summer season, they’re even more likely to produce anxiety since in winter there’s no leaving the Pole once the last flight has gone.

Maybe we should all do this with our packages from now on. Mail and cargo arrived last week, and someone set out the contents of one of the boxes quite decoratively for the photo. To efficiently unload the goods when they arrived, they formed an assembly line going up the stairs to the station.

The detection of the first gravitational wave (GW) event by LIGO represents one of the greatest scientific breakthroughs of recent years. After receiving the gravitational wave alert in September 2015 from the Advanced LIGO detector, the IceCube and ANTARES neutrino telescopes analyzed the data they had recorded at the same time in order to search for neutrinos that might have been emitted from the same event. Neither search identified any neutrinos that could be associated with the burst. These results set the first limits on neutrino emission from a GW transient event.

Last week, the South Pole traverse finished unloading the supply of fuel it had brought, transferring it all to the tanks on station. They should be all set for winter, which is long at the South Pole and is fast approaching.

When traveling to the South Pole, you have to be prepared for delays. But last week it was the station, not the travelers, that was not quite prepared—with a summer population close to its limits, it had to creatively house dozens of passengers left behind from departing planes that boomeranged.

Four new arrivals reported to the South Pole ready for duty after experiencing considerable travel delays. They donned their white lab coats and got to work, performing test runs and installing cabling (looks like fun!)—and they even fit in some time to join a scheduled outreach webcast to talk about their work and travels.

Today, the IceCube Collaboration announces a new search for neutrino emission from GRBs with a first-ever search that covers all flavors and the full sky. Five events were found to have a low-significance correlation with five GRBs. Consequently, the analysis places tight constraints on current models of neutrino and ultra-high-energy cosmic ray (UHECR) production in GRBs. These results have just been submitted to The Astrophysical Journal.

Now you see it, now you don’t. These images show the spot of the geographical South Pole, just before and after the old marker was removed. At the beginning of each year, a new marker is situated at the current location, which shifts constantly due to the movement of the ice sheet.

Every New Year’s Day, they have a celebration at the Pole in which they plant a newly designed marker for the location of the ever-shifting geographic pole. The spot is repositioned annually due to movement of the polar ice sheet at about 10 meters per year.

Last week saw the arrival of IceCube’s second winterover, Mack van Rossem, finally (an unusual glitch this year left IceCube with only one winterover until now). Mack got to jump right in, driving the scout for the regular December snow survey. He also arrived in time for traditional holiday events and festivities.

In 2013, the IceCube Collaboration published the world’s best limits on the spin-dependent cross section for weakly interacting dark matter particles. They were derived from the non-observation of annihilation into neutrinos of dark matter gravitationally trapped by the Sun.

Now, the collaboration presents a new likelihood formalism that allows easy integration of any neutrino telescope data into analyses of dark matter theories.

It was a rather busy week at the Pole. Besides people coming and going, there was the first IceCube webcast of the season, with a school from Wisconsin and two schools from Greece joining the event. An unexpected fire drill was also held last week. It turned out to be a timely drill, since the next day a genuine fire alarm sounded, triggered by a faulty oxygen sensor, not by an actual fire.

Decades ago, the aspiration to build a kilometer-scale neutrino detector at the South Pole seemed farfetched; today, we celebrate the 5-year anniversary of this incredible achievement. Shortly after 6 pm New Zealand time on December 18, 2010, the final sensor was lowered into the ice. This completed the decade-long construction effort that started with the design and fabrication of detector systems and concluded with the installation of the final string of sensors.

We’ve discussed sastrugi before, but this one deserves special attention for its shape. It sure does look like a frozen finger, doesn’t it? And it’s pointing the way to IceCube.

The number of IceCube personnel at the South Pole station during the past few summers is nothing like it used to be. Back in the days of detector construction, the number of staff on the ice would be in the double digits at this point. Instead, this week’s current count is six, including the recent arrival seen in the photo.

We weren’t kidding that there are a lot of training sessions for activities at the Pole. Last week saw some more training—fire fighters in search and rescue missions. Afterward, they all lined up for a group photo on the stairs outside the ICL.

In a new study by the IceCube, Pierre Auger, and Telescope Array Collaborations, scientists have looked for correlations between the highest energy neutrino candidates in IceCube and the highest energy cosmic rays in these two cosmic-ray observatories. The results, submitted today to the Journal of Cosmology and Astroparticle Physics, have not found any correlation at discovery level. However, potentially interesting results have been found and will continue to be studied in future joint analyses.

There are training sessions for just about everything that goes on at the South Pole. Dropping cargo from an airplane is no exception. Last week, a C-17 performed the annual air drop training, shown here against a spectacular blue-sky backdrop just after releasing its cargo, which can be seen as a tiny speck off to the left, slowly parachuting to the ground

A steady wind shows the flags at the ceremonial South Pole aligning themselves quite neatly. Flying conditions were good for most of the week, with several incoming flights bringing more summer visitors to the Pole, including the first IceCube team members to join the winterovers this season.

Clear weather allowed most of the scheduled flights to make it to the Pole last week, with a stream of new arrivals from each plane. Inside the galley, the new summer crowd and the few remaining winterover staff do a good job of filling up the space.

New results submitted today to the Astrophysical Journal are the outcome of a combined search for neutrino point sources performed by the ANTARES and IceCube collaborations. No source has been identified, but the combined search improves the sensitivity to point sources by up to a factor of two, which delivers more stringent upper limits on the flux for the candidate sources considered in this analysis.

It’s that time of year for the “changing of the guard”—for IceCube’s winterovers, that is. Last week, Christian Krueger, one of IceCube’s 2015-16 winterovers, arrived alone and can be seen walking back from the plane alongside Stephan Richter, current winterover, who was on hand to greet him.

The IceCube Collaboration today presents a search for relativistic and mildly relativistic monopoles using two years of data. No monopole candidate was observed, but IceCube data allowed setting very stringent limits for the range of velocities studied. These results have been submitted today to European Physical Journal C.

IceCube winterover Stephan Richter took this wide angle shot of the South Pole station's galley---in a completely empty state, not likely to found this way much longer since summer personnel will be arriving soon. The galley will be a bit busier with the expanded station population.

Neutrino physicists spend a lot of time in the dark. As a figurative statement this reflects how difficult neutrinos are to understand, but it also reveals the literal sense that we work with experiments that do not see a lot of sun—and it’s not just the South Pole, it’s also in mines, tunnels, and deep underwater in seas and lakes. But just like a rare neutrino interaction, every so often a brief flash of light offers some new truth about the nature of our universe.

The first planes of the season have arrived at the South Pole. Two planes landed last week, first a Basler (bearing gifts) and later a Twin Otter, shown in this image.

The winterover crew gathered at the geographic South Pole for their annual group shot.

It was a relatively quiet week for the IceCube detector, but busy in general for the station. It’s that time of year, post sunrise, when preparations for summer arrivals are in full swing.

The IceCube Collaboration’s fall 2015 meeting begins today at the Niels Bohr Institute in Copenhagen, Denmark. Assistant Professor Jason Koskinen and Niels Bohr Professor Subir Sarkar of the University of Copenhagen host the weeklong meeting.

The last thing you want to forget to pack when you’re off to the South Pole for a year is … your lederhosen. Afterall, Oktoberfest is among the many things that winterovering folks celebrate at the station.

With the sun now up, outdoor preparations for summer activity at the South Pole station will move into higher gear. Calm weather last week provided an opportunity to groom the skiway, shown in this image, where the Earth’s shadow is still visible in the sky as a blue band just above the horizon.

The National Research Foundation of Korea has awarded Seongjin In, a graduate student at Sungkyunkwan University (SKKU) and known as Jin within the IceCube community, with a 2015 Global PhD Fellowship (GPF).

Sunrise is slowly coming along at the South Pole, with some refracted light showing over the horizon on clear days. The impending orange glow appears to be approaching the ICL in this image.

The Physics Department of UW–River Falls hosts summer internships for young college students that allow them to engage in IceCube and other polar science projects. Over the 10-week internship, they become a member of the team, where they learn to program and to tackle challenging scientific questions. And, as you will read here, they also get a chance to share their experience.

Today the IceCube Collaboration has presented a search for tau neutrinos at energies above 214 TeV that, although it did not find any events, allowed setting upper limits on the astrophysical tau neutrino flux. This search sets limits on tau neutrinos at energies three orders of magnitude lower than the energies reached by previous dedicated tau neutrino searches. And more importantly, the results now submitted to Physical Review D also prove that tau neutrino searches in IceCube are reaching the sensitivity for a potential discovery.

The landscape at the South Pole continues to brighten, making it perhaps harder to ignore the extent of snow accumulation at the IceCube Lab. But snow removal wasn’t on the table last week, which was a quiet one all around for the IceCube winterovers.

In a paper submitted today to the Astrophysical Journal, the IceCube Collaboration presents results of a search for astrophysical sources of transient neutrino emission using a sample of low-energy—30 to 300 GeV—muon neutrino events from DeepCore. Although no source is singled out, the study sets limits on soft-spectra models, such as energetic or nearby choked GRBs.

Although the sunrise is still not officially here, the South Pole is enjoying a period of twilight. The horizon is clearly visible in the direction of the sun and is showing some characteristic orange color. The photo shows this nicely, with the added effect that reflection in the station windows gives the appearance of a clear view through the windows of the continuous horizon.

The “IRES: U.S.-European International Research Experience-Particle Astrophysics for Undergraduates” program, funded by NSF and led by the University of Wisconsin–River Falls, brought us to Johannes Gutenburg University in Mainz, Germany, this summer to work with Professor Lutz Köpke and Professor Sebastian Böser.

Francis Halzen, IceCube principal investigator and Hilldale and Gregory Breit Distinguished Professor at the University of Wisconsin–Madison, was announced yesterday as one of the prestigious international 2015 Balzan prizewinners.

The South Pole station’s windows were exposed last week, after being covered up (decoratively, we might add) for over four months now. Outside, it still looks more like night than day, but things will gradually brighten up, and then the windows might need to be covered for a different reason—to promote a better sleeping environment.

International Research Experiences for Students (IRES) is a program funded by the National Science Foundation to support active participation of US undergraduates in international research projects. Laura Lusardi from New Richmond, WI, and Kelsey Kolell from Fond du Lac, WI, participated in the IRES program through UW–River Falls to work on IceCube research for the summer.

We are both third-year undergraduate students, studying physics at the University of Wisconsin–River Falls. This summer, we had the wonderful opportunity to travel to Germany through IRES to work with IceCube researchers. Even though we both ended up attending the same university, we took wildly different paths to get here.

The sun is not yet up, but the sky is definitely brightening in its direction. The image below, however, shows that it’s still early twilight and generally quite dark at the Pole. This photo was taken at the same location and time as the one above, just in the opposite direction—quite the contrast.

When I came to Yale three years ago, I did not expect to major in physics. Yet, after taking my first class in the subject, it was not long before its fundamental nature and incredible universality had reeled me in for good. Since then, I have sought out opportunities to explore the field and learn what it really means to be a physicist. I joined Assistant Professor Reina Maruyama’s lab this past January and a few months later found myself working on DM-Ice and IceCube. Now, as I gear up for my final year of college, I am spending my summer on campus, conducting research on coincident muon events between the enormous IceCube (1 cubic km) and comparatively miniature (2,309 cubic cm) DM-Ice17 detectors.

The previous week’s feature image showed the South Pole Telescope with the moon setting behind it. Here we see it again, but set against an aurora backdrop while its dish is scanning the sky for CMB (cosmic microwave background) mapping.

Today, the IceCube Collaboration announces a new observation of high-energy neutrinos that originated beyond our solar system. This study, which looked for neutrinos coming from the Northern Hemisphere, confirms their cosmic origin as well as the presence of extragalactic neutrinos and the intensity of the neutrino rate. The first evidence for astrophysical neutrinos was announced by the collaboration in November 2013. The results published now in ''Physical Review Letters'' are the first independent confirmation of this discovery.

It’s still dark at the South Pole, with sunrise not for a while yet. So don’t be confused—that was the moon, not the sun, setting behind the South Pole Telescope. Once it had set, some bright and lively green auroras took over the sky.

Last week at the Pole they had Christmas in July. Since the seasons in the Southern Hemisphere are the reverse of the Northern Hemisphere, many southern locales celebrate in July or August so that they can have a wintry feel to their festivities. The South Pole station had a tree, presents, and plenty of sweets on hand for theirs.

The IceCube Collaboration has a strong presence at the 34th International Cosmic Ray Conference (ICRC 2015) with over 50 presentations and posters. ICRC started on July 30 and runs through August 6 in The Hague, Netherlands.

The Astrophysical Multimessenger Observatory Network (AMON) will link existing and future high-energy astrophysical observatories into a single virtual system, enabling near real-time coincidence searches for multimessenger astrophysical transients and their electromagnetic counterparts and providing alerts to follow-up observatories.

You might not know you’re at the South Pole from the photo of this watermelon. But there it is, growing in the greenhouse at the station, only a little bigger than a tennis ball at the moment. With it’s supportive, handmade hammock, hopefully it will reach a nice size and ripeness for the crew to enjoy.

It’s dark at the Pole, and even a headlamp’s light only goes so far. Paths to outlying buildings are lined with flags before winter arrives, when there’s still sufficient light for the installation. On a moonless winter night, though, there’s no question that the flag line has a value much greater than the sum of its parts. It’s a real lifesaver.

They’re watching something—but what? This is the communications (or “Comms”) office at the South Pole station. Not normally the site for recreational activities, but last week it played host to participants in an international darts tournament among the Antarctic stations.

The IceCube Collaboration is now revisiting these results in a combined analysis accepted for publication in The Astrophysical Journal. The analysis is based on the results of six individual studies and uses up to three observables—energy, zenith angle and event topology—to derive improved constraints on the energy spectrum and the composition of neutrino flavors of the astrophysical neutrino flux.

Jakob van Santen, a former graduate student working on IceCube at the Wisconsin IceCube Particle Astrophysics Center (WIPAC) and currently a postdoc at DESY (Deutsches Elektronen-Synchrotron) in Zeuthen, and Juan Pablo Yáñez, also working on IceCube at DESY in Zeuthen, were recently awarded a Dissertation Prize from the Global Neutrino Network. This is the first year that the GNN Dissertation Prize has been awarded. It recognizes young postdoctoral candidates who have written an outstanding thesis and contributed significantly to their projects.

Ah, the 4th of July—barbecues everywhere, even at the South Pole. But, not only is it winter there now, with snow and ice, it’s been extremely cold lately, with long stretches of low temperatures, down to below –100 °F.

IceCube winterover Erik Beiser was captured in the above image silhouetted by the rising moon while out taking aurora photos himself.

In a new study presented a few days ago, the IceCube Collaboration reports the potential of atmospheric muons detected in IceCube to help our understanding of important properties of cosmic rays in a wide range of energies. These muons are also shown to be useful for investigating systematic uncertainties in neutrino studies in IceCube. Measurements of the composition of primary cosmic rays, the high-energy spectrum of muons, and the prompt flux are three of the highlights of this paper, which was submitted last Friday to Astroparticle Physics.

If you blur your vision slightly, the green tablecloth might be mistaken as grass and the entire scene as one of a summertime outdoor picnic. But it’s still winter at the South Pole—midwinter to be precise, one of several milestones they traditionally celebrate with a special dinner.

South Pole … greenhouse? That’s right. One of the coldest places on the planet hosts a very nice, warm greenhouse, replete with tomatoes and leafy greens. It’s a jungle in there.

They’re getting fancy at the Pole—wide angles showing off curves and long exposures leaving star trails in the night sky. With its long stretch of darkness broken only by spells of auroras or the rising of a sunlike moon, winter makes the South Pole a captivating place.

On March 30, 2012, IceCube detected two high-energy neutrino events. IceCube immediately sent an alert to several optical and X-ray telescopes—the Robotic Optical Transient Search Experiment (ROTSE), the Palomar Transient Factory (PTF) and the Swift satellite—and a core-collapse supernova was discovered in the PTF images. However, physicists have shown that this was a coincidental discovery and that this supernova is not likely to be the source of the neutrinos in IceCube. These results have been submitted today to the Astrophysical Journal and are the outcome of a joint study between the IceCube Collaboration and members of the PTF Collaboration, the Swift Collaboration and the Pan-STARRS1 Science Consortium.

In a new analysis of the IceCube Collaboration, a search for dark matter annihilation at the Galactic Center is presented using data from May 2010 to May 2011. The highest density of dark matter in the Milky Way is anticipated to concentrate in its center. Dark-matter self-annihilation should then produce a flux of muon neutrinos and other particles that peaks in the direction of this region, which is seen in the Southern Hemisphere by IceCube. The search did not find a neutrino excess, and the researchers have set new limits on the dark-matter self-annihilation cross section. These results have been submitted today to European Physical Journal C.

Is that the sun or the moon? That’s the moon alright—since it’s still winter at the South Pole, we know the sun has set and won’t show itself again for awhile. But with such a bright moon, you can see for quite some distance.

The auroras have been been bright and lively lately. And even though this one curves downward, it does not bring a frown to mind. In fact, in the the full-sky panorama view it converts to a smile.

Prof. Botner is now starting her second term as the spokesperson for IceCube. Her colleagues have again chosen her to lead the collaboration, and she is ready to continue what is a highly demanding but also rewarding task.

Last week was fairly quiet as far as the IceCube detector went—no major happenings there. But the sky, on the other hand, what a scene! The auroras (australis, that is) were particularly brilliant and striking.

Not everyone begins a new year on January 1, right? That includes IceCubers, who decided a while ago that mid May would be a good time to start a new year of data for the South Pole neutrino observatory.

The IC86-2014 physics run ended on May 18, 2015, wrapping up another successful year for the IceCube detector.

With the sun gone, they can cover up their windows all they want to prevent indoor light from getting outdoors, but they can’t stop the moon from shining. And last week, the moon was out full force, illuminating some interesting structures in the landscape.

Winterovers at the South Pole keep their emergency response skills fresh by holding regular drills. Last week was the missing person drill. And even though they are in the Dark Sector, where outdoor lighting is generally eliminated in winter, they had to turn flood lights on the outside of the station to be able to safely guide the drill team back.

IceCube’s winterovers spend about thirteen months at the South Pole, trained for and ready to tackle a variety of situations needing their attention. Some weeks are very busy, and some weeks less so, but there is always something going on.

The Wisconsin IceCube Particle Astrophysics Center (WIPAC) is pleased to host the IceCube Spring Collaboration Meeting, from April 27th to May 2nd, as well as the 2015 IceCube Particle Astrophysics Symposium: Cosmic Neutrinos, What Next? (IPA 2015), from May 4th to 6th. Both conferences will be held at Union South on the University of Wisconsin–Madison campus.

Although there is still a little bit of twilight left in the direction of the sun, the auroras have made their appearance at the South Pole. And the winterover team was treated to several good displays this week.

In a new analysis by the IceCube Collaboration, the atmospheric electron neutrino spectrum is measured at energies between 0.1 TeV and 100 TeV, extending previous measurements to higher energies and yielding improved precision. The results, which have been submitted to Physical Review D, find good agreement with models of the conventional electron neutrino flux.

Have we mentioned that the ICL (IceCube Lab) is a rather photogenic building? I think we have, recently—and although the sun has now officially set, there was still enough residual light last week to get a nice shot of the ICL—in shadow with a clear, colorful sky behind it.

Very little snow actually falls at the South Pole. Antarctica as a whole is the driest continent on Earth, and the South Pole, with its high altitude and distance from the coasts, receives the least precipitation. Yet, there is snow everywhere, blown in from elsewhere, and drifts can quickly become unwieldy if not dealt with.

The sun takes its time setting at the South Pole. And even after it has officially set, there remains an afterglow in the sky. This lingering light and some low horizontal clouds produced a beautiful orange backdrop last week to some of the dark sector buildings.

With the equinox last week, the annual sunset dinner was held at the South Pole station. It’s a celebration for a unique sunset that most of us don’t get to experience—where the sun sets slowly over time and, once set, does not reappear for another six months.

The South Pole observatory IceCube has recorded evidence that elusive elementary particles called neutrinos changing their identity as they travel through the Earth and its atmosphere. The observation of these neutrino oscillations, first announced in 1998 by the Super Kamiokande experiment in Japan, opens up new possibilities for particle physics with the Antarctic telescope that was originally designed to detect neutrinos from faraway sources in the cosmos.

The second edition of the IceCube Masterclass took place on Wednesday, March 18, at nine institutions in the US and Europe, and on Saturday, March 14, at the University of Ghent. All in all, 175 high school students analyzed IceCube data in the search for astrophysical neutrinos and cosmic rays.

Close up, with the sun behind it, or from a distance, with the sun shining upon its face, the ICL, or IceCube Lab, is a rather photogenic building, with its blue, elevated structure and shiny, symmetrical towers. A low, bright sun makes its towers gleam, and the shadows that it casts stretch on and on.

The temperatures have been dropping, into the –50s °C, while the sun continues to get lower in the sky. These overcast photos give a sense of the impending darkness.

It was a week of acronyms and snow surveys. Each year at the Pole, before the darkness of winter sets in, IceCube winterovers take advantage of the still available daylight to complete tasks that can’t be managed well in the dark. This week, one of those chores was surveying snow depths from accumulations around the IceTop stations. They got going after they drove an LMC out of the VMF.

Searches with IceCube have so far persistently shown us that more data is needed to reveal the first cosmic ray source. But IceCube researchers are convinced that success also requires a resolute determination to exploit IceCube data in every possible manner. In a new study submitted today to the Astrophysical Journal, the collaboration presents a search for time-dependent astrophysical neutrino sources that did not find any evidence for their existence. The study did however make it possible to set upper limits on the neutrino flux from several source candidates and has proven IceCube’s capabilities for long-term monitoring of sources triggered by multiwavelength information from several experiments.

AMANDA collaborator, first IceCube spokesperson, initiated DeepCore, esteemed colleague and beloved friend.

What’s the easiest way to get a nicely centered picture of an approaching airplane on the ice at the South Pole? Have it taxi straight toward you. Here's the last Herc of the season to arrive at the Pole, just as it came to a stop.

The week began with some extra-nice halos and ended with an exodus of most of the summer people at the Pole. In between, there was typical detector maintenance as well as continued snow management around the IceCube Lab.

Giant spools sure do serve as a great photo prop. Now empty, these spools had a previous life, brought to the Pole full of cable and ready for action, for use on IceCube and other nearby experiments. But then what to do with them?

In a new measurement of the flavor ratio of astrophysical neutrinos, submitted today to Physical Review Letters, the IceCube Collaboration has found good agreement with the standard source model. The collaboration also sets limits on nonstandard flavor compositions, which could be a signature for new physics in the neutrino sector, such as neutrino decay or sterile neutrinos.

Last week we saw a sun halo, and a few weeks back we saw the newly inaugurated South Pole marker. Lo and behold, they have come together. Great shot!

Dawn Williams, Associate Professor in the Department of Physics and Astronomy at the University of Alabama in Tuscaloosa, has been named the February Woman Physicist of the Month by APS’s Committee on the Status of Women in Physics.

This “ring around the sun” is a halo, an optical phenomenon that occurs from light interacting with ice crystals in the atmosphere. It’s not an uncommon phenomenon, but for those who have never seen one, it’s quite something to behold. Halos can appear around the moon as well as the sun.

At first glance it looks like IceCube winterover Stephan has sprouted some new teeth at the Pole. But they’re just ice clumps, not to worry. Stephan got them while he was participating in a half marathon—and out in the extreme cold, with temperatures around -30 °C, this is not an event for the faint of heart.

Tagged any good muons lately? Maybe you just aren’t using the right equipment. Last week at the South Pole, IceCube folks set up equipment for some muon tagger runs—special calibration tests of the IceTop stations. You can see the various components that they set up, with the IceCube Laboratory (ICL) some distance off in the background.

Yet another year has come to an end for IceCube with plenty of new science results, an always growing international collaboration, and plans for an update to the IceCube Neutrino Observatory. In the meantime, the detector’s performance has broken still another record, and many outreach activities, including the recently launched IceCube Masterclass, accompanied this hectic scientific activity.

The IceCube Neutrino Observatory team is anxiously awaiting the arrival of Armando Caussade at the South Pole. Caussade’s long journey from Puerto Rico to the frozen, windy desert that he will call home for a couple of weeks started on January 2, 2015. Although he arrived as scheduled at McMurdo Station on the coast of Antarctica on January 5, 2015, the last leg of his journey to the South Pole has been delayed two days so far due to poor weather.

Although you might expect that it would remain fixed, the marker at the geographic South Pole is moved on a regular basis. Since the polar ice sheet is constantly shifting, at about 10 meters per year, the marker at the South Pole must be relocated to maintain its position. A new marker is crafted each year and inaugurated in a special ceremony on January 1st.

The year wrapped up nicely at the South Pole, with the traditional holiday dinner and the Race Around the World on Christmas morning. Both of IceCube’s winterovers participated in the run. Other winterovers were busy constructing a handsome gingerbread house for seasonal charm.

Gamma-ray bursts (GRBs) were once the most promising candidate source of ultra-high-energy cosmic rays (UHECRs). They release extremely large amounts of energy in short periods of time, so if they could accelerate protons as they do electrons, then GRBs could account for most of the observed UHECRs.

Summer upgrades to the SPS (South Pole System), part of IceCube’s computing infrastructure, were completed this week, and two IceCubers who had been working at the Pole, Ralf and James, left for warmer climes.

Prof. Olga Botner, IceCube spokesperson and a physics professor at the University of Uppsala, and Prof. Francis Halzen, IceCube principal investigator and a professor at the University of Wisconsin–Madison, tell us about the plans for an upgrade to the IceCube Neutrino Observatory. As an extension of the current detector, it can be built in a few years and within an affordable budget, thanks to expertise acquired with IceCube.

Building a cubic-kilometer telescope at the South Pole seemed a chimera even for some of those involved in the project. The goal was simple in words but seemingly impossible in practice: 86 boreholes, each 60 cm in diameter and 2,500 m deep, had to be drilled and instrumented in seven austral summer seasons. Safety was a must, fuel needed to be used cautiously and the South Pole environment was just unavoidable.

Indoor tasks can be done just about any time, but for outdoor activities you need some cooperation from the weather. A bright sunny day makes things better still. Even with a few bouts of bad weather that caused postponements, there was plenty of outdoor work accomplished this week.

Registration for the 2015 IceCube Masterclass, to take place on March 18th at ten IceCube hosting institutions, is open to high school students in their last two years before college.

Just in time for Thanksgiving dinner, the South Pole traverse arrived, bringing fuel that would otherwise have had to come by plane. IceCube winterover Stefan skied out to check it out

It’s a bird, it’s a plane, it’s … no, wait, it’s just a plane. Actually, it’s a particular plane—a C-17, a large military transport aircraft—training for air drops over the South Pole station.

The IceCube Collaboration is saddened to hear of the loss of Thomas Lawrence Atkins, a contract worker at NSF's Amundsen-Scott South Pole Station. We greatly appreciate the sacrifice that contractors make to support science teams like ours at the South Pole. We extend our heartfelt condolences to Atkins’ family and friends at this difficult time.

Last week, winterovers Erik and Stephan arrived, and this week Dag and Ian are leaving. Here they are, all four together out on the ice for the last time.

Another summer season at the South Pole station means another changing of the guard for IceCube’s winterovers. This year’s Erik Beiser and Stephan Richter have arrived, two fresh faces ready to embark on their yearlong adventure, while Dag Larsen and Ian Rees, last year’s winterovers, made their final preparations for leaving the ice.

After a long winter, South Pole inhabitants are getting used to the sunlight again. Up north, a bunch of IceCubers are getting ready for their Antarctic adventure. For some of them, it’s all about the excitement of a first trip to Antarctica. For some others, it’s an almost annual appointment that makes their job a special one.

There’s a bit of prep work involved in getting the station ready for its summer opening. IceCube winterovers Ian and Dag used this time to perform an IceTop snow survey and to finish up snow removal around the ICL.

For a place that receives so little precipitation, there’s an awful lot of snow around. So much snow that bulldozers are sometimes enlisted to move it out of the way, as shown here in front of this parked Basler aircraft. Planes can get stuck at the South Pole for days on end due to bad weather. And if high winds are part of that bad weather, then snow accumulation can be a problem.

Last year, an initial measurement of the neutrino oscillation parameters was a hint that IceCube could become an important detector for studying neutrino oscillations. Today, the IceCube Collaboration has submitted new results to Physical Review Letters that present an improved measurement of the oscillation parameters, via atmospheric muon neutrino disappearance, which is compatible and comparable in precision to those of dedicated oscillation experiments such as MINOS, T2K or Super-Kamiokande.

After the sun’s arrival come the planes. The first of the season to reach the South Pole were a pair of Twin Otters, one of which appears parked in the accompanying image. Behind it is a Basler plane—a somewhat larger ski aircraft—shown just as it was landing, a few days later.

Water restrictions prompt innovation. When already limited showers get rationed even further, as they have been recently at the South Pole station, you start thinking of ways to work around the problem.

Francis Halzen, the University of Wisconsin-Madison physicist who was the driving force behind the giant neutrino telescope known as IceCube at the South Pole, has been named a winner of the 2014 American Ingenuity Award.

Ah, the things we take for granted. Sunshine might be one of them. Running water might be another. At the Pole, sometimes you have to do without.

The IceCube Collaboration has expanded the search for neutrino interactions in IceCube, lowering the range of deposited energy down to 1 TeV. The goal was a better understanding of the different contributions to the neutrino flux in IceCube and hopefully to measure the charmed-meson component for the first time. The results of this study have been submitted today to Physical Review D.

Now that the sun is back at the South Pole, there’s nowhere to hide. You can walk outside and see everything—everything that was there in the darkness all winter long, like buildings and fixed structures, as well as other things that weren’t there but have recently reappeared, like the flags at the ceremonial pole.

After months and months of darkness, it’s no wonder that the sun’s return to the South Pole is anxiously awaited. Finally, thanks to sufficient ambient light levels, the current winterovers can get a nice group photo outside.

As dawn approaches, the sky is cast in a glow that reflects off the sides of the South Pole station. Inside the station, they’ve begun to remove the window covers that remain in place all winter, there to minimize light pollution for sensitive experiments at the Pole.

The IceCube Collaboration has submitted a paper today to the European Physical Journal C describing a new analysis scheme for the measurement of the atmospheric neutrino spectrum with the IceCube detector.

There’s the moon, but where’s the sun? It’s coming, it’s coming. At the South Pole, the sun rises only once a year (and it sets only once a year, too).

The IceCube Collaboration’s fall 2014 meeting begins today at CERN in Geneva, Switzerland. The weeklong meeting is hosted by professor Teresa Montaruli of the University of Geneva.

As with any week at the Pole, activities involved a mix of work and play, from maintenance on a large Cat loader to announcement of results from the Winter Antarctic Film Festival.

If you’ve seen one, you’ve seen them all. Not so for auroras. These spellbinding light shows come in various patterns, shapes, and colors. They might appear as bright, strong bands of color, stretching across the full sky. Or as wispy, cloud-like streaks, confined to a single quadrant.

Kids, don’t try this at home. At least not without proper equipment. Here some winterovers are learning to use what they call the “confidence chair,” a specialized piece of equipment for evacuating injured people from multilevel buildings.

Sun or moon? From the photo it’s hard to tell. It sure looks like a bright sunny day, but this is the South Pole, where it’s still winter and the sun has not yet returned. That’s the moon lighting up the sky—amazing how bright it can seem.

It’s the photographer’s trifecta for wintering at the South Pole—a shot of the sky with a star-studded background, a nice aurora effect, and the Milky Way visible. You can’t beat that.

In a new analysis by the IceCube Collaboration, a search for faint point sources, by looking for small-scale anisotropies in the diffuse neutrino flux, was found to be consistent with the background expectation. These results have just been submitted to Astroparticle Physics.

The auroras tell you it’s winter at the South Pole—you can’t see auroras there during the summer because the sun is out the whole time. But in winter, the folks who station at the South Pole get to witness these auroras in all their glory.

It looks as if the smoke stacks are releasing a plume of green smoke along with their stream of exhaust, but it’s just an artifact of the camera angle. The green splash across the sky reminds us that it’s still aurora season at the South Pole.

Winter is long at the South Pole, at least when measured by the last plane out and the first plane back in. That’s roughly eight to nine months with no one (and no things) coming or going, quite a long period of isolation for the 40 or so winterovers at the station. You need a large store of provisions to cover the crew’s needs during that time.

How to make any 4th of July celebration special? Start with a dish decorated in red, white and blue.

Since bundling up to go outdoors is a bit of an ordeal, you don’t want to have to make unnecessary trips out to the ICL if you can avoid it. But there were a few of those unavoidable trips for the IceCube winterovers this past week. One was to replace a modem because of problems with an Iridium link.

In a joint analysis by the IceCube, LIGO and Virgo collaborations to be submitted to the journal Physical Review D, researchers aimed to identify GW events and high-energy neutrinos that could originate from the same astrophysical source and to determine their joint significance. No significant coincident events were found, but the search allowed researchers to derive upper limits on the rate of joint sources for a range of source emission parameters.

Last week we mentioned that they were celebrating midwinter at the South Pole, but we didn’t really cover all the festivities. First, there was the traditional viewing of “The Shining,” Stanley Kubrick’s classic horror movie about an off-season caretaker in an isolated (also cold and white) location.

The quest for galactic halo dark matter includes high-energy neutrino searches that might be produced by the self-annihilation of dark matter particles in our galaxy. If this is the case, IceCube should observe a characteristic anisotropy in the neutrino flux due to the additional dark-matter induced neutrinos. So far, the IceCube Collaboration has not found any significant deviation from the background expectation, following new results that have been submitted today to The European Physical Journal C.

The IceCube Collaboration presents several searches for extended and point-like astrophysical neutrino sources using four years of data. No evidence of neutrino emission has been found yet, but a few models have been ruled out. This research has been submitted today to The Astrophysical Journal.

Life at the Pole may be different than life elsewhere, but some things are the same just about everywhere. One of those things is celebrating holidays. Who knows? Maybe holidays are even more important when you live in small, isolated communities. Last week, at the South Pole and all over Antarctica, they were celebrating midwinter, a cultural event held in many places around the world in recognition of the winter solstice, an astronomical occurrence.

This photograph of the ICL (IceCube Lab) almost looks as if it’s set against an artificial backdrop, but it is just the eerie effect of the sky lit by a rising moon.

Dag Larsen and Ian Rees arrived at the South Pole in November 2013. The brand-new winterovers had already been working for IceCube for a few weeks in Madison, learning all the ins and outs of their new job. Now they were ready to take over for Blaise Kuo Tiong and Felipe Pedreros, who had been at the Pole maintaining the detector for the previous 12 months.

Some very bright auroras have been unfolding in the sky above the South Pole lately. But that doesn’t mean the only way to see an aurora is by looking upward. Here’s an aurora reflected in the metallic sphere atop the marker at the ceremonial South Pole.

It looks like IceCube winterover Ian Rees is back to taking photographs. A good thing, too, or we wouldn’t have gotten this image of a nice aurora filling up the sky over the ICL.

The 26th International Conference on Neutrino Physics and Astrophysics, Neutrino 2014, starts today and includes presentations from several IceCube researchers. The conference runs through June 7 in Boston, Massachusetts.

A bright moon hovers above a row of summer camp buildings at the South Pole. It’s not summer there now, of course, but with such a brightly lit sky, the winterovers may be having flashbacks to a time not so long ago when the sun shone down on this camp. They still have a way to go before the sun rises here again, with lots of photos to take in the meantime.

What better time and place for an outdoor astronomy class than midwinter at the South Pole? Clear skies present a group of expectant gazers with a multitude of stars for their viewing pleasure.

Strong evidence for a very high energy neutrino flux of extraterrestrial origin was found in November 2013, and new data from IceCube now confirms the discovery. Once more, the Antarctic detector brings us still the highest energy neutrino ever observed.

The IceCube collaboration is launching a new activity for high school students, the IceCube Masterclass. Students will learn about neutrinos and what they tell us about the universe while also learning about a unique experiment: IceCube, a cubic-kilometer neutrino detector buried in Antarctica’s ice

It helps for IceCube winterovers to be handy and versatile. With no incoming supplies during the winter months, they have to make do with what they have on hand—if they need a new tool, they craft it, or if something breaks (or rips), they fix it.

Around mid-May each year, new detector configurations are applied to IceCube to keep up its performance and to improve scientific results. Last week, on May 6, the IC86-2014 physics run was launched.

Now there’s a flashy aurora! You know (and it’s not hard to imagine), they say a photo really can’t do justice to these aurora australis—to how impressive they really are when viewed in person.

This is what the ICL porch looks like as it gets darker outside, bathed in red light (just two short weeks ago things looked a bit different). For the benefit of research projects that monitor the sky during winter darkness, outdoor lighting at the South Pole is minimized and kept to a red spectrum, which reduces interference.

See anything? Well, there is something there, in this season's first photo of an aurora from the IceCube winterovers. Many more aurora shots to come, guaranteed.

The one-day workshop "Neutrinos Beyond IceCube" is being held today in Arlington, Virginia. The workshop brings in experts to review and discuss potential enhancements to the IceCube Neutrino Observatory.

The IceCube Laboratory (ICL) is home to a computer complex that collects and processes data from the experiment’s optical sensors buried in the ice.

The darkness of night tells us that we’re in the Earth’s shadow. But who thinks about the Earth’s shadow during the day? Actually, it’s often visible but we fail to recognize it.

Through a partnership with PolarTREC, Armando Caussade, a STEM educator from Puerto Rico, will travel to the South Pole during the 2014–2015 polar season to support maintenance work on the IceCube Neutrino Observatory.

So many images from last week … where to begin? The IceCube winterovers captured quite a few shots of the sun as it continued to set. Looks like they also built an igloo.

Surprise, surprise—a little creature snuck in to the South Pole station, presumably in the last fresh food shipment. “Dustin” the moth was found fluttering around the lab.

It’s a small community wintering over at the South Pole—they help each other out. When not immediately involved in their detector duties, IceCube’s winterovers might be found volunteering their assistance with other scientific projects.

Former IceCube PhD student Anne Schukraft is being honored today by the German Physical Society, or Deutsche Physikalische Gesellschaft (DPG), for her contribution to the measurement of the neutrino energy spectrum.

What is this? And where would you find it at the South Pole station? It might remind UW–Madison folks of the “What are you looking at?” feature in Inside UW–Madison, a weekly newsletter that periodically spotlights a cropped photo for which readers can guess the campus location.

At the South Pole, apparently there’s “cold” and then there’s “really cold.” IceCube winterover Dag’s frosted visage tells you he’s in cold country, but his open coat perhaps gives away that it’s not yet “really cold.”

Expectations were high for this past season. The largest upgrade to IceCube’s hardware and software was completed on schedule. The new servers and readout computer upgrades brought new equipment to the Pole but also new opportunities for the scientists of the IceCube Collaboration, spread in a dozen or so countries around the world.

The IceCube Collaboration spring 2014 meeting begins today in Banff, Canada. The meeting is hosted by IceCube collaborator and University of Alberta Physics Professor Darren Grant.

In a paper recently published in Science Express, cosmic ray data from IceCube was used alongside observations from NASA’s Interstellar Boundary Explorer, or IBEX, in a study of the magnetic fields that surround our solar system.

It’s not dark yet, but the temperatures have been dropping. They’re back to being lower than they are in the Midwest, as it should be, unlike last month where some record low temperatures created days where the South Pole was a relatively warm place.

Nathan Whitehorn, a postdoctoral researcher on the IceCube project at the University of Wisconsin-Madison, has been named a “Young Star” by the Division of Astrophysics of the American Physical Society (APS).

The South Pole station is gearing up for its seasonal closing. There are still flights coming and going—the plane above is shown offloading fuel supplies—but they will eventually end as the season closes and weather becomes inhospitable to aircraft.

In a new paper submitted to The European Physical Journal C, the IceCube Collaboration presents a search for non-relativistic (slow) magnetic monopoles that, despite being fruitless, has set the best experimental limits for a wide range of assumed speeds and catalysis cross sections.

IceCube winterover Ian Rees was invited to fly around in a Twin Otter and photograph South Pole buildings from above. Here’s a nice aerial shot that he took of the ICL (IceCube Lab). You can clearly see the shadow of the aircraft as they passed by.

Signs are everywhere. When you’re lost or unsure about which way to go, a sign with an arrow can be very helpful.

A weird-looking contraption hanging from a frame, three kneeling people huddled on the ground, a tank-treaded vehicle in the distance, and snow as far as the eye can see. What’s going on here?

2013 was, no doubt, a great year for IceCube. Scientific results reached a crescendo with a beautiful IceCube neutrino event gracing the cover of Science magazine on November 21. It was also the year that Prof. Olga Botner, of Uppsala University, was elected IceCube spokesperson, following Prof. Greg Sullivan from the University of Maryland. Also, four new institutions joined the IceCube Collaboration. And, last but not least, the NSF review committee resoundingly approved the collaboration´s efforts.

What’s new at the Pole? Well, some new people are there—it’s still summer, so groups of people are still coming and going.

Out with the old, in with the new. This might pertain to many things as one year changes to the next, but at the South Pole it also applies to the South Pole marker, which indicates the spot of the geographic South Pole.

The Race Around the World, an approximately two-mile course at the South Pole, is one that some folks take seriously, with planning and preparations aimed at bringing them across the finish line first. After all, the prize, an extralong shower, is something anyone living at the South Pole station would covet, as shower time is rationed there.

PINGU, the Precision IceCube Next Generation Upgrade, proposes a extension inside the current IceCube array designed to measure the mass of the three known neutrino types.

The summer season isn’t long at the South Pole, from about late October through early February. Folks typically arrive in shifts, spending a few weeks, give or take, working at the Pole. But delays are common, whether coming or going—and when they happen around the holidays it can be all the more frustrating.

It was a week filled with movement outdoors. First up, snow needed to be moved. A survey was done of snow depths over the IceTop stations, and excess snow was removed. You can see the IceCube crew in the snowcat, or “pisten bully,” (above) while out on their rounds.

It looks like IceCube winterover Ian Rees is practicing a good luge position, but he’s just taking advantage of his perch to capture photos. He’s lying atop some boxes bearing new equipment as part of an extensive server upgrade. This photo gives the sense of peace and quiet, but they’re moving and the flags are up, so with a little effort you might imagine there to be some wind noise.

The IceCube project has been awarded the 2013 Breakthrough of the Year by the British magazine Physics World. The Antarctic observatory has been selected for making the first observation of cosmic neutrinos, but also for overcoming the many challenges of creating and operating a colossal detector deep under the ice at the South Pole.

In a paper recently published in the Journal of Glaciology, the IceCube Collaboration presents a study of South Pole climate over the past 100,000 years, using high-resolution 3D laser images of the ice sheet.

That’s IceCube winterover Ian Rees (facing) near the drill while it’s being prepared to access a rod well, which is a deep cavity used to melt ice for drinking water. Rod wells are named after Paul Rodriguez, an Army engineer who developed them while at Camp Century in Greenland in the early 1960s.

This austral summer, on November 4, Ian Rees was the first IceCuber to reach the Amundsen-Scott station, after a long trip from Boulder, Colorado. From now until the end of the IceCube polar season, 20 people will fly to the Pole from Madison, Maryland and Delaware in the US, but also from Canada, Germany, Sweden, and Belgium.

In a new study, the IceCube Collaboration searches for neutrino-induced particle showers in one year of data taken during the construction phase of IceCube, when about half the detector was operational. Above 100 TeV, a 2.7σ excess of events was found, which is consistent with results published by the IceCube Collaboration in Science. The current paper has been submitted to the journal Physical Review D.

Open coat? No hat? It must be summer at the South Pole. Well, although it’s sunny outside it would probably be a stretch to call it warm, for those of us not used to it anyway. Dag Larsen, one of IceCube’s two winterovers for this season, has finally arrived (above), and he may or may not be used to the cold, but one thing is sure—he has plenty of time to get used to it.

In an analysis published today, the IceCube Collaboration reports on a search for a diffuse astrophysical neutrino signal, looking at high-energy upward-going muon tracks, with data taken between May 2009 and May 2010, when the detector was running in its 59-string configuration. The search found a high-energy neutrino excess of 1.8σ compared to the background scenario of a pure conventional atmospheric model, a measurement consistent with the astrophysical neutrino flux described in Science. The results of this research have been submitted to Physical Review D.

The IceCube Neutrino Observatory is a demonstration of the power of the human passion for discovery, where scientific ingenuity meets technological innovation. Today, nearly 25 years after the pioneering idea of detecting neutrinos in ice, the IceCube Collaboration announces the observation of 28 very high-energy particle events that constitute the first solid evidence for astrophysical neutrinos from cosmic accelerators. Details of the research appear in an article published tomorrow, November 22, in Science.

Outgoing winterovers Felipe Pedreros (left) and Blaise Kuo Tiong (right) greet newcomer Ian Rees (center) on his arrival. Thanks to Felipe and Blaise for a great year of photos and reports, and welcome to Ian and Dag (Larsen, still to come), fresh and ready to capture the year’s adventure ahead.

It always seems as if they have just about everything at the South Pole, but apparently they didn’t have a unicycle. Until recently. Winter is officially over, and new arrivals to the station have come bearing goodies of all sorts, from “freshies” to toys—like this unicycle, which IceCube winterover Blaise is testing out in good form.

Life’s a tradeoff. At the South Pole, when winter comes to a close, you trade cold, dark, isolated for (still) cold, but bright, and less isolated. With the sun out, you also get sundogs—scientific name, parhelion. The tradeoff there? No more auroras for a while.

A few short weeks ago this scene would have looked quite different. But now the sun is out, full force, and the snow is bright white. The camera was apparently caught in a stare down with a Basler ski-plane that was stranded for a few days at the Pole due to bad weather.

The IceCube collaboration presents new results that rule out the possibility—at a confidence level greater than 90%—that the two PeV events detected in IceCube are cosmogenic neutrinos. However, the long exposure of the analyzed data, from May 2010 to May 2012, and the lack of detected events with higher energies, have allowed a new probe into the cosmogenic neutrino flux, which has been used to set the most stringent limit for the energy range from 1 PeV to 10 EeV. This analysis has just been submitted to the journal Physical Review D.

Greenery, and flowers, … this doesn’t look like much like the South Pole. But this photo was taken at an important place in the South Pole station—the greenhouse. If it weren’t for the greenhouse, they wouldn’t have any fresh vegetables during the long winter.

What do a rock, an egg, and a kiwi all have in common? They can all be found at the South Pole. Maybe not readily or easily, but they were all found at the South Pole recently. This rock was discovered outside on a snowdrift, a finding that spurred some scientific tests to examine the nature of the rock.

Now that looks like the sun—finally! It’s rising up over the flags at the ceremonial South Pole.

The sun is rising at the Pole, but this once-a-year occurrence is a much more gradual happening than the once-a-day occurrence most of us experience (or don’t, if we sleep through it, as the case may be). Here, increasing sunlight lets you clearly see the flag path leading to the Dark Sector.

There is little to no snowfall at the South Pole—it’s basically a desert. But there is a lot of snow on the ground. High winds carry the snow that does come down all over the place, leaving drifts that can bury equipment or even buildings.

Sky-watchers around the world were anticipating this close encounter of celestial objects last week. It was the conjunction of the moon and Venus, and the South Pole was a great place to capture a shot. Check out some other photos from the week—the conjunction, snow drifts, and glowing horizon. Nice scenery, whether you’re just watching the sky or launching balloons.

All appears to be tranquil, but there was more commotion than usual last week. A power outage occurred at the Pole that affected all the facilities at the station, including the IceCube Lab, or ICL (shown above).

In May 2013, the IceCube Collaboration elected Professor Olga Botner of Uppsala University, Sweden, as its new spokesperson, following a two-year service by Professor Greg Sullivan from the University of Maryland.

The sun has not officially risen at the Pole yet, but things do keep getting brighter. Outside that is. Inside? Well, maybe thoughts of the sun’s arrival led to thoughts of summer foods.

A new study by the IceCube Collaboration shows that the muon track reconstruction performed in the early stages of the analysis can be significantly improved by using robust statistical methods to estimate particle trajectories through the detector. The new algorithm results in a 13% gain in the angular resolution of the muon track and a 98% accuracy rate in determining the number of muons in coincident events. The paper has just been submitted to Nuclear Instruments and Methods in Physics Research Section A.

The yellow light cast on the ground makes the scene look almost like a sandy beach, with a shorefront edging into dark waters. But it’s just an illusion, we’re still at the Pole. That’s SPTR-2, one of the South Pole satellite domes.

Before there was IceCube, there was AMANDA, and before there was AMANDA, there were a couple people testing the idea for an in-ice neutrino detector in Greenland.

It’s still dark at the Pole these days, but knowing that the sunrise is not that far off, station staff are taking every opportunity to capture some great night photos.

A failed Acopian power supply is on the table for investigation. The IceCube winterovers have a broad range of job duties, but of course maintaining (and fixing if necessary) all of the computer hardware involved in collecting data from the detector is a high priority task.

Since December is a summer month in the Southern Hemisphere, many countries like Australia and New Zealand hold Christmas in July events in order to have a Christmas with a wintry feel. They were celebrating Christmas in July at the Pole last week, but of course their climate is always wintry so maybe it was just an excuse to bake some sweet treats.

The South Pole has been described as an otherworldly place. So it’s befitting for those working there to take a moment once in a while to just sit and contemplate their surroundings. Especially when there’s some natural light to see by—the moon can really light the place up.

A search for neutrino point sources using throughgoing muons in IceCube has not found any excess of neutrinos above the atmospheric background in any given direction in the sky. Neither did dedicated searches of a priori selected objects. However, IceCube data provide insights into the nature of cosmic ray sources even from non-discovery results. These results have been submitted today to The Astrophysical Journal.

Don’t let these bright lights in the South Pole station gym (nice facilities, huh?) confuse you—it’s dark down there. Winter at the Pole means six months with no sunlight at all.

Which to marvel at more—the dark, star-studded sky or the fantastic aurora shimmering up from all along the horizon? Being able to step outside and regularly witness these amazing light shows is definitely one of the perks of winterovering at the South Pole station.

The IceCube Collaboration publishes today a new measurement of the all-particle cosmic ray energy spectrum in the energy range from 1.6 PeV to 1.3 EeV using data from IceTop, the surface component of the IceCube Neutrino Observatory. The measured spectrum exhibits clear deviations from power law behavior. These resultshave just been submitted to Physical Review D.

They work hard, and they play hard. This week, play involved some billiards—the annual tournament is on. IceCube winterover Felipe is concentrating on his next move.

The IceCube Collaboration presents the results of a first search for self-annihilating dark matter in nearby galaxies and galaxy clusters. This analysis has been submitted today to Physical Review D.

Aya Ishihara recognized at ICRC 2013 by the International Union of Pure and Applied Physics for her discovery of two extremely high-energy neutrinos.

They’re halfway there! It’s midwinter at the South Pole, and they’re celebrating.

With nearly fifty presentations and posters, the IceCube Collaboration will contribute heavily to the International Cosmic Ray Conference (ICRC), which begins today in Rio de Janerio, Brazil.

It was the first winter open mic session and IceCube winterover Felipe was behind his drums and cymbals. They really do have everything down there, don't they?

Could they ever tire of viewing auroras at the Pole? Hmm, not sure. But regardless, they do have other things to do besides stare up at the sky. First, there’s work. Then, there are extracurricular activities. ...

A green sky flecked with swirling patterns of white lines. That’s what you get from sixty 30-second exposures taken through a ceiling dome at the South Pole station and made into a composite image. The IceCube winterovers have been capturing some amazing photos at the South Pole.

Antarctica is often described as the coldest, driest, and windiest place on earth. Cold and dry might be hard to discern from photos, but windy? These flags give it away—here, they’re taking a real beating. The group photo below (also with flags flapping away) was orchestrated to commemorate the invention of the Ethernet 40 years ago (they’re posing with a long Ethernet cable held between themselves). The photo garnered a response from the inventor himself, Bob Metcalfe, then at Xerox PARC.

A recent measurement of the Moon shadow in TeV cosmic rays with the IceCube telescope sets an upper limit on the detector’s absolute pointing accuracy to 0.2 degrees. The IceCube Collaboration presents these results in a paper submitted today to Physical Review D.

There was plenty of action this week at the Pole, indoors and out. Inside there was crocheting and a 5K race. Outside the auroras continued, bigger and brighter than ever.

The IceCube Neutrino Observatory, which comprises the IceCube and DeepCore detectors, has been designed to contribute heavily to our understanding of neutrino physics. In a paper submitted today to Physical Review Letters, the IceCube Collaboration has announced the first statistically significant detection of neutrino oscillations in the high-energy region (20–100 GeV).

The aurora season is in full swing at the South Pole, as exemplified by this photo taken of the ARO (Atmospheric Research Observatory) building, bathed in a green glow. ARO is an NSF facility that supports long-term climate research programs. The building is located about 500 m from the main station and, like other outlying buildings, has no running water or sewage system. Hmm, guess you’re not making ice cream out there. But, back at the station, it looks like the IceCube winterovers’ foray into ice cream making continues—flavor of the week: Aurora Green Tea with Fresh Lavender.

The Wisconsin IceCube Particle Astrophysics Center (WIPAC) is pleased to host the international IceCube Collaboration for the annual spring meeting May 07-11, 2013.

What’s this? Almost looks like a sample from the sushi plate (yep, we’ve already confirmed they eat well at the Pole) fell off outside and rolled around in the snow. But no, it’s yukimarimo. You heard right—a real word for a real thing—tiny, lightweight tumbleweeds of the Antarctic.

The auroras were busy this week, curling themselves up to look like cinnamon rolls. The IceCube winterovers were busy as well with several videoconferences, some with schools in the US and one with The Mind Museum in Manila. The photo below shows Blaise and Felipe (left to right) posing recently at the geographic South Pole (no, the pole marker is not bent, it’s just a wide-angle shot). There’s also a great shot of some sastrugi (we’ve learned about them before) pointing their way to the moon. Finally, check out this short time lapse video of an aurora unfolding above the moon—next best thing to being there.

Here they come. The auroras, that is. Although the sky is still allowing the sun’s presence to be somewhat felt from just below the horizon, it is also giving the winterovers their first glimpses of these special treats—from faint, wisping hints to full-on sprays of color.

This week had all the usual stuff—you know, calibrations, detector statistics, data handling, that kind of stuff. But it also had … Yuri’s Night. This is a global celebration held each April 12th to commemorate Yuri Gagarin, first man in space and an inspiration to many of the adventurous sort. The whole station observed the occasion with music and costumes.

In a paper submitted to Physical Review Letters, the IceCube Collaboration confirms highest energy neutrinos ever observed.

It’s cold and icy outside at the Pole, but not inside—although the blue tint of this image peeking in through an outside window of the ICL (IceCube Lab) might give the impression otherwise. The ICL is home to a serious cluster of computers, for the South Pole or anywhere. Below is a less formidable sort of computer also at the Pole, but just decorating someone’s desk. It’s a cardboard replica of the 1960s educational toy Digi-Comp I, a fully functional mechanical computer. Nice, just not up to snuff for IceCube’s needs. The kitchen seems to be a happening place lately. This week yielded authentic Chilean empanadas.

With the sun just below the horizon and a full moon in the sky, this landscape could be confused for a daytime shot. It was a quiet week for the detector but there was plenty going on to keep folks busy at the station:

-- a night off for galley staff brought other “chefs” to the kitchen for pizza making,

-- Easter egg decorating meant a hunt for “neutrinos,” and

-- World Table Top Game Day spawned a round of Carcassonne, a medieval-themed board game.

You may know that the University of Wisconsin–Whitewater is home to an observatory, giving people a look at the visual Universe. Many people don’t know, though, that Wisconsin played a major role in the construction and management of one of the world’s largest and most interesting telescopes, the IceCube Neutrino Observatory, located at the South Pole in Antarctica.

You’d think it was science and adventure that lured these winterovers to the Pole, but it looks like it might be the food. Those are some nice looking plates. Each year the station holds a special celebratory dinner—the sunset dinner—the last one before the sun leaves them for a good long while. That’s something worth celebrating.

Someone is up high, quite high in fact. That’s the ARO (Atmospheric Research Observatory) tower, a good spot for surveying the landscape. ARO is a National Science Foundation facility used in support of scientific research related to atmospheric phenomena. Its long-term research program measures trends of important trace gases and aerosols and investigates the influence of these gases and aerosols on the Earth's climate. They aren’t measuring gases inside the South Pole station’s greenhouse, but look what’s going on in there—lots of growth. What a difference two weeks make.

The lowering sun is providing for some great photos, like these long shadows in front of and behind the IceCube Lab (ICL). The winterovers spent some time doing various things out in the cold this week. They raised their country flags—Chile, the US, and the Philippines—on the roof of the ICL. They also helped out their neighbors in the SPUD experiment, moving a 300-lb mirror off the detector array.

What’s green and frilly and grows at the South Pole? Outside, nothing, but inside, we’re talking lettuce. Leafy greens, cucumbers, tomatoes…even cantaloupe—a variety of produce is grown in the South Pole greenhouse. These are the only fresh vegetables available from about mid-February to mid-October for the teams wintering over at the station. The sun has been getting lower, and they will soon be entrenched in their six months of darkness. Some fresh vegetables will at least brighten up their plates.

There’s work and then there’s play. And sometimes play can take a lot of work. Like building an igloo at the South Pole, for example—check it out. You can see it in progress during construction, above, and the view from inside, looking through the “sun roof,” after completion, below. The IceCube winterovers had cold temperatures and wind chills (below -60 °C) for their work, too, which was also outdoors this week. They performed a snow survey, in which they had to measure the height of all the posts located over the IceTop tanks (IceTop is the surface component of the IceCube detector).

A great shot of the last LC-130 leaving the station. It marks the beginning of the winter season, in which the Pole’s population remains steady, this year at 44 people. No one will be coming or going for a while, not until flights begin to arrive again October. About half of the winterovers are shown outside on the ice, below. And as tradition dictates, they ring in the beginning of winter with a showing of all three versions of the classic Antarctic horror film “The Thing.”

Everything coming to or leaving the Pole goes through McMurdo Station on the coast. And it’s a busy place—a complex logistics facility that includes a harbor, three airfields, and a heliport. Winterover Felipe Pedreros recently traveled through McMurdo and captured this shot of the Nathaniel B. Palmer, an icebreaker designed and built specifically for use by the U.S. Antarctic Program. Below is an aerial view captured on the flight to McMurdo.

For some, ice cream is a summertime treat. For others, it’s good just about anytime. Looks like the folks at the Pole fall into the “others” camp. They have ice cream on their menu daily, and this batch, made with liquid nitrogen, appears to be particularly rich and creamy. But there are healthier foods to be had as well. With a little help from the greenhouse, which is just getting started with some of their seedlings, they might be eating kale chips (or debuting some kale ice cream?) before too long.

It takes a lot people power to run the IceCube Neutrino Observatory. An international collaboration that includes hundreds of physicists, engineers, computer scientists, and administrators works year-round to run the detector, analyze data, and develop new projects.

A solemn ceremony was held at the South Pole to commemorate the crew of the Twin Otter, a plane that went down on its way from the Pole to Terra Nova Bay. Members of the ARFF (Aircraft Rescue Fire Fighting) team stood at attention for the changing of the flags. Below is a photo of the remaining summer crew at the South Pole station, a healthy number that will shortly dwindle down to about 50 or so for the long, isolating winter season.

From its vantage point at the geographic South Pole in Antarctica, the IceCube Neutrino Observatory is uniquely positioned to see neutrinos—mysterious, nearly massless, difficult-to-detect particles that are plentiful but little understood.

They are set up well at the South Pole station, with comfortable (enough) living quarters, tasty meals, and engaging activities. Included in the many happenings are interesting science talks and lectures. This week they had a few—two talks from a former astronaut/current medical director and a talk on cosmology from a collaborator of the SPUD telescope.

The Wisconsin IceCube Particle Astrophysics Center (WIPAC) is announcing a high school internship program for students in the Madison, Wisconsin area.

The IceCube winterovers have plenty of darkness to look forward to in the coming months, but in the meantime they’ve been outside in the sunlight doing all sorts of things. Filming a plane taking off, shoveling snow, and taking IceTop measurements. And with the sun out, they sometimes capture a photo of a sun halo, in this case (below) a double halo.