All articles tagged with #cosmic rays
IceCube mapped the Milky Way with high-energy neutrinos over a decade, using deep learning to extract a faint galactic signal concentrated along the plane and toward the Galactic Center; the findings strongly indicate the Milky Way itself emits high-energy neutrinos, though no individual sources were pinpointed, and they pave the way for future IceCube upgrades and multimessenger studies.
Astronomers have identified LHAASO J1912+1014u as a proton PeVatron in the Milky Way, accelerating protons to PeV energies—well beyond the Large Hadron Collider—based on multiwavelength data from Fermi-LAT, FUGIN, and Chandra that rule out electrons as the gamma-ray source; the exact engine remains unknown, but such galactic PeVatrons may be common and help explain the origin of the most energetic cosmic rays.
The Oh-My-God particle, a subatomic nucleus detected in 1991 with energy around 3.2×10^20 eV, remains one of the most extreme cosmic rays ever observed. Since then, at least a dozen–plus similar events have been recorded, confirming ultra-high-energy cosmic rays are real but exceedingly rare: detectors like the Pierre Auger Observatory see roughly one such event per square kilometer per century, while the sources remain unknown. The leading possibilities are extragalactic, with candidates including magnetars and the supermassive black holes at centers of active galaxies, but no definitive origin has been identified.
Astronaut Don Pettit described seeing “luminous dancing fairies” in the ISS, a retinal flash caused by galactic cosmic rays that pierce the craft and the eye. Apollo crews reported similar flashes, and the ALTEA detectors on the ISS linked heavy-ion particles to these events, explained by direct ionization or Cherenkov radiation. Although brief and seemingly harmless, these particles pose long-term brain and eye health risks for deep-space missions, influencing radiation-mitigation strategies for Artemis and future journeys to the Moon and Mars.
Astronauts aboard the International Space Station report seeing flashes of light with eyes closed caused by high-energy cosmic rays passing through their bodies, either directly ionizing the retina or via Cherenkov radiation. Historical experiments (SilEye/ALTEA) linked particle tracks to the flashes, confirming the phenomenon and highlighting space radiation as a detectable, personal readout of exposure and a major shielding challenge for long-duration missions.
Apollo astronauts trying to sleep en route to the Moon saw brief, colorless flashes linked to cosmic rays passing through the eye; Apollo 16/17 detectors tied particle tracks to the reports, supporting retinal ionization and related mechanisms, though the exact biophysics remains debated. The finding highlights that deep-space radiation can be perceptible and poses a concern for long-duration missions beyond Earth.
The DAMPE space telescope has directly detected a universal spectral softening at about 15 teravolts across five cosmic-ray species, confirming a rigidity-dependent acceleration framework (the Peters cycle) and ruling out mass-dependent models with over 99.999% confidence, suggesting a nearby Galactic source as the accelerator.
New analysis of DAMPE data finds a universal spectral softening around 15 TeV across multiple high-energy cosmic-ray nuclei, suggesting rigidity—not energy per nucleon—shapes cosmic-ray behavior and tightening constraints on acceleration models; the result, published in Nature, was aided by AI-based event reconstruction and DAMPE’s Silicon-Tungsten Tracker.
New simulations suggest ultrahigh-energy cosmic rays hitting Earth could be atomic nuclei heavier than iron, which lose energy more slowly over cosmic distances; events like neutron-star mergers or massive star collapses into black holes may accelerate these ultraheavy nuclei, reshaping how scientists search for their sources and understand cosmic-ray acceleration.
A DAMPE study finds a consistent spectral softening in primary cosmic ray nuclei—from protons to iron—occurring around a rigidity of ~15 TV, implying that acceleration and propagation depend on rigidity rather than energy per nucleon; the result, published in Nature, challenges alternative models with 99.999% confidence and narrows the questions about where cosmic rays originate, aided by UNIGE researchers’ AI-based event reconstruction and the DAMPE Silicon-Tungsten Tracker for precise measurements.
Researchers buried antennas in Antarctic ice and identified 13 radio pulses from cosmic-ray cascades. New simulations applied to the 2019 data show the signals match the predicted Askaryan radiation in arrival direction, frequency, waveform and polarization at 5.1 sigma, confirming the model and distinguishing them from neutrinos. A full multi-year data release from all five ARA stations is expected soon, with up to seven candidate neutrino events.
A study using data from China’s Chang’e-4 lander identifies a region of reduced galactic cosmic-ray radiation in Earth–Moon space—a cavity that appears during the Moon’s local morning. The lower-energy protons drop by about 20% in this window, likely caused by Earth’s magnetosphere extending farther than previously thought. If confirmed, this timing could help plan safer lunar surface operations for upcoming missions (including Artemis II) by reducing astronauts’ radiation exposure. The findings are published in Science Advances (2026).
A Science Advances study using Chang’e-4 data and NASA’s LRO observations finds that Earth’s magnetosphere forms an extended “cavity” that provides extra shielding for the Moon, reducing lunar surface radiation by about 20% during certain orbital phases—specifically in a pre-noon geometry—even when the Moon is outside the magnetosphere. The effect, mainly affecting low-energy ions that contribute to skin dose, was observed across 31 lunar cycles and could inform radiation protection for future missions, such as Artemis.
JWST spectroscopic data of the ultraluminous infrared galaxy IRAS 07251-0248 reveal a rich mix of small organic molecules (benzene, methane, acetylene, diacetylene, triacetylene) and solid carbon-rich grains in its buried nucleus, along with the first outside-the Milky Way detection of the methyl radical CH3. The chemistry appears driven by cosmic rays fragmenting carbonaceous materials and PAHs, producing a diverse organic inventory far exceeding models’ predictions. This implies deeply obscured galactic nuclei can act as factories of organic molecules, with potential implications for prebiotic chemistry and galactic chemical evolution. Findings published in Nature Astronomy showcase JWST’s power to probe extreme, dust-shrouded environments.
The James Webb Space Telescope unveils a surprisingly rich set of organic molecules in IRAS 07251–0248, an ultra-luminous infrared galaxy about 10+ billion light-years away. Detected molecules include methane, acetylene, benzene, and the methyl radical, indicating a complex chemical network far exceeding current models and potentially driven by cosmic rays that fragment larger carbon-rich grains into smaller organics. This suggests distant galactic nuclei can be ongoing sources of carbon for prebiotic chemistry, offering new insights into the origins of life and showcasing JWST’s power to study chemical evolution in the early universe.