The Amaterasu particle is what scientists at the Telescope Array experiment are calling an ultra-high-energy cosmic ray particle that flew to Earth in May 2021. In terms of energy, it is second only to the legendary Oh My God particle, discovered more than 30 years ago. The origin of the new phenomenon is unclear; There is apparently nothing in the part of the sky it came from.

The Telescope Array project is a giant cosmic ray detector located in the American state of Utah. It consists of 507 stations spread over a network of approximately 700 square kilometers. With its help, scientists have already “caught” more than 30 cosmic rays with the highest energies.

In 2021, during another routine check of the detector, astronomer Toshihiro Fuji from Osaka City University (Japan) noticed unusual signals. 23 detectors in the Northwest Telescope Array responded to the cosmic ray. According to the astronomer, at first he thought he was observing a software error.

Analysis of the data confirmed that it was a cosmic ray, some of which reached an energy of 240 exaelectron volts (2.4×10).²⁰ electron volt). In the entire history of observation, the energy was higher only in the Oh My God particle discovered in 1991 – 320 exaelectron volts. At the time, scientists had no idea what could create such particles.

Today, astrophysicists assume that such energetic particles are born from relativistic jets of black holes, gamma-ray bursts of active galactic nuclei and other most energetic cosmic events.

The location of the assumed source of the new particle turned out to be quite desolate, consisting of a small number of galaxies. The authors of the study also checked objects and galaxies near this area, but there were no suitable candidates. A portion of the cosmic ray was named Amaterasu in honor of the Japanese Sun goddess. The results of the study were published in the journal Science.

Cosmic rays are considered high energy when their energy exceeds 5×10.¹⁹ electron volt They consist of protons (89%), helium nuclei (10%) and heavier nuclei.

According to theoretical calculations, if the proton cannot fly freely in space, it has limited energy. Because it will begin to interact with residual radiation and “lose” energy. This value is called the Greisen-Zatsepin-Kuzmin boundary. If the observed particles did not “dissipate” their energy, they did not form that far away. According to scientists, approximately 50-100 megaparsecs.

“Magnetic fields in the galaxy and in intergalactic space shouldn’t affect particles that have that high of energy. So you have to be able to pinpoint the location of its source in the sky. But my God, you trace the particle and this new particle back to the source, and there’s nothing there that could create a particle with that energy,” he said. explained University of Utah professor John Matthews and a representative Telescope Array.

It is possible that magnetic fields are strong enough to deflect the flight of the cosmic ray, but this conflicts with other observations. Scientists do not forget that the problem may be in the standard model of physics. An improved theory may be needed to explain the phenomenon of these particles. While scientists are busy improving detectors Telescope Array. After the upgrade, the device will become four times more sensitive, allowing for more accurate monitoring of particle sources.