All articles tagged with #cosmic rays
Earth's magnetic field has weakened by 9% over the last two centuries, potentially signaling an upcoming pole reversal. While this does not cause current global warming, a reversal could increase atmospheric ionization from cosmic rays by 13% at sea level, potentially influencing cloud formation and future climate patterns.
Astronomers have identified the first confirmed microblazar in the Milky Way, a stellar-mass black hole system named IRAS 18293-0941. Located 12,000 light-years away, this system features a black hole feeding on a companion star and launching jets at 75% the speed of light. One jet points directly at Earth, while the other impacts a molecular cloud, potentially accelerating particles to ultra-high energies. This discovery validates a 30-year-old theoretical prediction and offers a nearby laboratory for studying cosmic ray origins.
Astronomers have identified IRAS 18293-0941 as the first confirmed microblazar in the Milky Way, a stellar-mass black hole system emitting jets at near-light speed. Located 12,000 light-years away, the system consists of a black hole roughly 10 times the mass of the Sun orbiting a companion star every 11 days. The discovery, published in Astronomy & Astrophysics, resolves a 30-year search for a galactic analog to distant blazars. The system’s jets, one pointing directly at Earth and the other impacting a dense gas cloud, may explain the origin of ultra-high-energy cosmic rays, acting as a natural particle accelerator 100 times more powerful than the Large Hadron Collider.
A sprawling grid of 1,660 orange water tanks spread over 3,000 square kilometers in Mendoza, Argentina, collects Cherenkov light from cascades produced by ultra-high-energy cosmic rays to infer their energy and direction—an experiment designed to wait decades for a rare event, underscoring how nature’s accelerators outpace human technology and the value of patient, long-term science.
Physicists at CERN used the Large Hadron Collider to collide oxygen nuclei with protons, recreating the birth of cosmic ray air showers in the lab. Analyzing the resulting particle sprays with the ATLAS detector, they achieved tenfold-precision measurements that challenge existing models and help determine the hydrogen versus heavier-element makeup of cosmic rays, shedding light on their origins; results are published in Physical Review Letters.
Earth is constantly bathed in cosmic particles. About 100 trillion neutrinos pass through each of us every second, mostly from the Sun, and nearly all go through without interacting. Cosmic-ray showers also create muons—tens to hundreds pass through a person each second (roughly one or two through a hand). Neutrino interactions are extremely rare; detectors like the IceCube Neutrino Observatory infer their numbers from tiny Cherenkov flashes. Cosmic radiation adds about 0.4 millisieverts per year to our exposure, within a natural ~2.4 mSv/year background. In short, we’re continuously bathed in invisible particles, but they pose negligible health risk and connect us to the cosmos.
A jellyfish-shaped shadow spotted in a 2023 Curiosity NavCam image is not a real Martian organism but a cosmic-ray artifact hitting the camera sensor; such glitches are common on Mars due to its thin atmosphere and lack of a global magnetic field, and are typically seen in a single frame or a few frames, not on the surface. NASA/JPL notes that without detailed imaging analysis, the anomaly is best explained as a camera artifact rather than evidence of life.
NASA's Curiosity captured a jellyfish-like dark mark in a 2023 NavCam image, but scientists say it's almost certainly a cosmic-ray artifact hitting the camera sensor rather than a Martian jellyfish; Mars's thin atmosphere and lack of a global magnetic field let cosmic rays strike detectors, and Curiosity routinely takes multiple frames to distinguish real features from glitches.
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.