Four years ago, the IceCube Neutrino Observatory announced evidence for high-energy neutrinos emanating from NGC 1068, an active galactic nucleus (AGN) with a central, supermassive black hole that actively gobbles up surrounding matter. In AGNs like NGC 1068, X-rays can escape the dense environment around the supermassive black hole and provide information about its properties. […]
Ever since high-energy astrophysical neutrinos were first observed in 2013, the IceCube Neutrino Observatory at the South Pole has continued searching for their elusive sources. Thus far, IceCube has identified two galaxies as neutrino sources and observed neutrinos from our own Milky Way galaxy. Astrophysical phenomena that are transient—occurring temporarily—in a timescale of weeks to […]
The so-called “hierarchy problem” remains one of the biggest unresolved questions in modern physics. It asks why the weak force, which governs transformations between different types of quarks, is trillions upon trillions of times stronger than gravity. This discrepancy causes major holes in our theoretical understanding of particle physics. For example, without an explanation for […]
Since high-energy astrophysical neutrinos were first observed by the IceCube Neutrino Observatory in 2013, the IceCube Collaboration has continued hunting for their elusive sources. Thus far, IceCube has found compelling evidence that active galaxies are among the sources of high-energy neutrinos and likely sites of hadronic particle acceleration. While these sources were detected at high […]
The properties of the interior of the Earth remain one of science’s greatest unsolved mysteries. Despite information from indirect methods, such as seismic and gravitational measurements, used to investigate the Earth’s internal structure, many questions remain unanswered. Atmospheric neutrinos, which are produced in cosmic-ray-induced air showers in the Earth’s atmosphere, are detected by the IceCube […]
The IceCube Neutrino Observatory at the South Pole searches for weakly interacting particles called neutrinos that are able to travel undisturbed through the cosmos. When a neutrino interacts with a molecule of ice, it produces secondary particles that emit blue light, which is then detected by IceCube. From the shape of that light pattern, the […]
Gravitational waves (GWs) are produced by some of the most violent and energetic astrophysical phenomena, such as black holes and neutron star mergers. They have long been suspected of being astrophysical sources of neutrinos, ghostlike cosmic messengers hurtling through space unimpeded. Thus far, common astrophysical sources of neutrinos and photons have been identified, as have […]
Gravitational waves (GWs) are produced by some of the most violent and energetic astrophysical phenomena, such as black hole and neutron star mergers. During the merger of two black holes or neutron stars, particle acceleration is expected to occur. This can produce a short gamma-ray burst as well as neutrinos, cosmic messengers hurtling through space […]
The nature of dark matter (DM) remains one of the greatest unsolved mysteries in modern physics. Although it is thought to make up 85% of all matter in the universe, scientists have yet to determine what it is made of. A possible candidate for DM is theoretical particles called weakly interacting massive particles. When these […]
The IceCube Neutrino Observatory, embedded in a cubic kilometer of Antarctic ice, searches for weakly interacting particles called neutrinos that are able to travel undisturbed through the cosmos. Of interest are high-energy astrophysical neutrinos that can arise from cosmic-ray interactions with matter or photons in astrophysical sources. In the emerging field of multimessenger astronomy, measurements […]