Scientists from the Telescope Array Collaboration announced in their study published in the journal Science detection of ultra high-energy cosmic rays (shortly UHECR), which shows an energy level of approx 244 exa-electronvolts, i.e. roughly 40 joules. This measurement, made by the Surface Detector Array in Utah, represents one of the highest energy levels ever observed for cosmic rays. To give you an idea, this measured energy is approximately, according to the scientists a million times higher than the most powerful human-made particle accelerators can produce.
The Telescope Array project is a joint effort of universities and institutions from the United States, Japan, Korea, Russia, and Belgium, and its goal is to identify precisely this extremely powerful cosmic ray. It must be said that the planet Earth is continuously bombarded by cosmic radiation. This radiation comes from both local sources and distant extragalactic regions.
The Telescope Array in Utah detects extremely rare high-energy cosmic rays using a network of 507 detection stations spread over an area of 700 square kilometers. These stations capture secondary particles that are created when cosmic rays hit the atmosphere and create extensive air sprays (EAS). The system includes plastic scintillators that light up when charged particles pass through them, and fluorescence detectors to measure EAS energy. Data from the stations, analyzed using GPS and simulations, help determine the energy, mass and direction of arrival of cosmic rays.
The detected cosmic radiation UHECR is but extremely rare and it is assumed that it comes from the most energetic processes in the universe, such as black holes and gamma-ray bursts. It is therefore a major astronomical event.
Source of this extragalactic cosmic ray, detected on May 27, 2021, remains a mystery, because the direction it came from does not match any known astronomical object. The arrival path of the cosmic ray, which is close to the disk of the Milky Way, suggests that there were probably only small variations in the magnetic fields as it passed, meaning that the cosmic ray probably traveled almost directly from where it originated.
However, the direction of its source does not correlate with any known galaxy or astronomical object that is usually associated with the UHECR. Instead, it seems that it comes from an empty region in the universe with very few galaxies, of which very few have been described, none of which scientists believe are capable of producing such strong cosmic rays, meaning they could come from an as-yet-undiscovered astronomical object near the edge of our galaxy. Alternatively, this anomaly could reveal gaps in our current understanding of physics.