Mysterious and rare high-energy particle detected falling to Earth

ASTRONOMERS have detected a rare and extremely high-energy particle falling to Earth from space.

Named Amaterasu, after the sun goddess in Japanese mythology, it is one of the highest-energy cosmic rays ever detected, according to the scientists. Its origins remain unknown but experts believe only the most powerful of celestial events – much bigger than a star explosion – can produce them.

John Matthews, a research professor at University of Utah’s department of physics and astronomy in the US, said: “Things that people think of as energetic, like supernova, are nowhere near energetic enough for this.

“You need huge amounts of energy, really high magnetic fields to confine the particle while it gets accelerated.”

The Amaterasu particle has an energy exceeding 240 exa-electron volts (EeV), which is millions of times more than what particles achieve at the Large Hadron Collider, the most powerful accelerator ever built. It comes only second to the Oh-My-God particle, another ultra-high-energy cosmic ray which was detected in 1991, possessing 320 EeV of energy. Toshihiro Fujii, an associate professor at Osaka Metropolitan University in Japan, said: “When I first discovered this ultra-high-energy cosmic ray, I thought there must have been a mistake, as it showed an energy level unprecedented in the last three decades.”

When ultra-high-energy cosmic rays hit Earth’s atmosphere, they initiate a cascade of secondary particles and electromagnetic radiation in what is known as an extensive air shower. Charged particles in the air shower produce a type of electromagnetic radiation that can be detected by specialised instruments. One such instrument is the Telescope Array observatory in Utah, US, which found the Amaterasu particle.

This mysterious event appeared to emerge from the Local Void, an empty area of space bordering the Milky Way galaxy. The experts suggest this could indicate a much larger magnetic deflection than predicted, an unidentified source in the Local Void, or an incomplete understanding of high-energy particle physics.