A Giant Gamma-Ray Bubble is a Source of Extreme Cosmic Rays

An artist's depiction of a gamma-ray burst's relativistic jet full of very-high-energy photons breaking out of a collapsing star. Credit: DESY, Science Communication Lab

Gamma-ray bursts (GRBs) are one of the most powerful phenomena in the Universe and something that astronomers have been studying furiously to learn more about their origins. In recent years, astronomers have set new records for the most powerful GRB ever observed – this includes GRB 190114C, observed by the Hubble Space Telescope in 2019, and GRB 221009A, detected by the Gemini South telescope in 2022. The same is true for high-energy cosmic rays that originate from within the Milky Way, whose origins are still not fully understood.

In a recent study, members of China’s Large High Altitude Air Shower Observatory (LHAASO) Collaboration discovered a massive gamma-ray burst (designated GRB 221009A) in the Cygnus star-forming region that was more powerful than 10 peta-electronvolts (PeV, 1PeV=1015eV), over ten times the average. In addition to being the brightest GRB studied to date, the team was able to precisely measure the energy spectrum of the burst, making this the first time astronomers have traced cosmic rays with this energy level back to their source.

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The Second Most Energetic Cosmic Ray Ever Found

An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. Credit: NAOJ/Hyper Suprime-Cam (HSC) Collaboration

“Oh My God,” someone must have said in 1991 when researchers detected the most energetic cosmic ray ever to strike Earth. Those three words were adopted as the name for the phenomenon: the Oh-My-God particle. Where did it come from?

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Air Showers Ruin Astrophotos, but They Could be a New Method for Studying the Universe

An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. Credit: NAOJ/Hyper Suprime-Cam (HSC) Collaboration

Cosmic rays are a fascinating and potentially hazardous phenomenon. These high-energy particles typically consist of protons that have been stripped of their electrons and accelerated to nearly the speed of light. When these rays collide with Earth’s atmosphere, an enormous amount of secondary particles known as an “air shower” results. Ordinarily, these showers are a source of frustration for astronomers since they leave “tracks” on telescope images that obscure the celestial objects (asteroids, stars, galaxies, exoplanets, etc.) being observed.

However, a research team from the National Astronomical Observatory of Japan (NAOJ) and Osaka Metropolitan University has found a new application for these energetic particles. Using a novel method, they could observe these extensive cosmic-ray air showers with unprecedented precision. The key to their method is the Subaru Prime Focus Camera (Suprime-Cam) mounted on the Subaru Telescope atop the Mauna Kea volcano in Hawaii. This method and the team’s findings could provide a new method for studying the Universe’s most energetic particles.

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China Chooses the Site for their TRIDENT Neutrino Detector

Chinese researchers are working on a new neutrino observatory called TRIDENT. They built an underwater simulator to develop their plan. Image Credit: TRIDENT

China is building a new neutrino detector named TRIDENT, the Tropical Deep-sea Neutrino Telescope. They’re building it in the South China Sea, near the equator. This next-generation neutrino telescope will feature improved sensitivity and should help clear up the mystery around cosmic rays and their origins.

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Anti-Helium Generated in the Large Hadron Collider can Help in the Search for Dark Matter

The ALICE detector on CERN's Large Hadron Collider. Credit: A Saba/CERN

For decades, astrophysicists have theorized that the majority of matter in our Universe is made up of a mysterious invisible mass known as “Dark Matter” (DM). While scientists have not yet found any direct evidence of this invisible mass or confirmed what it looks like, there are several possible ways we could search for it soon. One theory is that Dark Matter particles could collide and annihilate each other to produce cosmic rays that proliferate throughout our galaxy – similar to how cosmic ray collisions with the interstellar medium (ISM) do.

This theory could be tested soon, thanks to research conducted using the A Large Ion Collider Experiment (ALICE), one of several detector experiments at CERN’s Large Hadron Collider (LHC). ALICE is optimized to study the results from collisions between nuclei that travel very close to the speed of light (ultra-relativistic velocities). According to new research by the ALICE Collaboration, dedicated instruments could detect anti-helium-3 nuclei (the anti-matter counterpart to He3) as they reach Earth’s atmosphere, thus providing evidence for DM.

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The Most Devastating Solar Storms in History are Scoured Into Tree Rings

Scientists study tree rings because they retain a record of climatic events and changes. They also record the Sun's activity. Image Credit: Rbreidbrown/Wikimedia Commons, CC BY-SA

Trees are like sentinels that preserve a record of shifting climates. Their growth rings hold that history and dendrochronology studies those rings. Scientists can determine the exact ages of trees and correlate their growth with climatic and environmental changes.

But they also record the effects of more distant changes, including the Sun’s activity.

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Cosmic Rays can Help Keep the World's Clocks in Sync

The world has a robust, accurate timekeeping system that regulates our clocks. Humanity uses it for everything we do, from our financial systems to satellite navigation, computer and phone networks, and GPS. But the current system is not perfect, and has vulnerabilities to cyber-attack and disruption. Given the importance of accurate timekeeping to our society (as a fundamental underpinning of life in the 21st century), experts are always looking for ways to improve the system and add redundancy. Researchers at the University of Tokyo have taken a big step in this direction, developing a new method of time synchronization that takes advantage of cosmic rays to calibrate the world’s clocks.

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Finally an Answer to why Gamma Rays are Coming From Seemingly Empty Space

The cosmic glow of the gamma ray background. Credit: NASA/DOE/Fermi LAT Collaboration

Gamma rays strike Earth from all directions of the sky. Our planet is bathed in a diffuse glow of high-energy photons. It doesn’t affect us much, and we don’t really notice it, because our atmosphere is very good at absorbing gamma rays. It’s so good that we didn’t notice cosmic gamma rays until the 1960s when gamma-ray detectors were launched into space to look for signs of atomic weapons tests. Even then, what we noticed were intense flashes of gamma rays known as gamma ray bursts.

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Cosmic Rays Erode Away All But the Largest Interstellar Objects

Artist’s impression of the first interstellar asteroid/comet, "Oumuamua". This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

So far we know of only two interstellar objects (ISO) to visit our Solar System. They are ‘Oumuamua and 2I/Borisov. There’s a third possible ISO named CNEOS 2014-01-08, and research suggests there should be many more.

But a new research letter shows that cosmic ray erosion limits the lifespan of icy ISOs, and though there may be many more of them, they simply don’t last as long as thought. If it’s true, then ‘Oumuamua was probably substantially larger when it started its journey, wherever that was.

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