'Extremely powerful' cosmic ray hurtling towards Earth leaves scientists baffled
Scientists are on the hunt for the source of an "extremely" powerful cosmic ray which is on its way to Earth more than two years after it was first detected.
This particle from outer space had energy levels a whopping 244million times higher than the most powerful accelerators ever made by humans. The mystery particle has been named Amaterasu, after the sun goddess in Japanese mythology.
However, more than two years since it hit earth, its origin and exact nature remain unclear. This might sound like something from a sci-fi movie, but Amaterasu is actually the focus of major research led by Japanese academic Professor Toshihiro Fujii.
He explained that cosmic rays are energetic charged particles that come from galactic and extragalactic sources. However, cosmic rays with this much energy are exceptionally rare.
They can reach greater than 10 to the power of 18 electron volts or one exa-electron volt (EeV), which is roughly a million times higher than achieved by the most powerful accelerators ever made by humans. In pursuit of these space rays, Professor Fujii and an international team of scientists have been conducting the Telescope Array experiment since 2008.
'Weird' comet heading towards the sun could be from another solar systemThis specialised cosmic ray detector consists of 507 scintillator surface stations, covering a detection area of 700 square kilometres (270 sq miles) in Utah in the United States. On May 27, 2021, the research team detected a particle with a "whopping" energy level of 244 EeV.
John Matthews, a research professor at the University of Utah’s Department of Physics and Astronomy in the US, described the mystery.
He said: “The particles are so high energy, they shouldn’t be affected by galactic and extra-galactic magnetic fields. You should be able to point to where they come from in the sky. But in the case of the Oh-My-God particle and this new particle, you trace its trajectory to its source and there’s nothing high energy enough to have produced it. That’s the mystery of this – what the heck is going on?”
Professor Fujii also expressed his surprise: "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." He compared its energy level to the most energetic cosmic ray ever observed - the "Oh-My-God" particle - detected in 1991 with an estimated energy of 320 EeV.
The team named the particle "Amaterasu", after the sun goddess who, in Shinto beliefs, played a key role in creating Japan. Prof Fujii believes that the Amaterasu particle could help us understand the origins of cosmic rays, he wrote in Science journal.
He said: "No promising astronomical object matching the direction from which the cosmic ray arrived has been identified, suggesting possibilities of unknown astronomical phenomena and novel physical origins beyond the Standard Model." Looking ahead, Prof Fujii added: "In the future, we commit to continue operating the Telescope Array experiment, as we embark, through our ongoing upgraded experiment with fourfold sensitivities, dubbed TAx4, and next-generation observatories, on a more detailed investigation into the source of this extremely energetic particle."
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