Scientists are currently grappling with a cosmic conundrum that stretches the very fabric of our understanding of the universe. Recently, a particle known as the “Amaterasu” has been detected, which boasts an almost incomprehensible level of energy. This discovery has left experts scratching their heads, as the origins of such a particle remain elusive.
On May 27, 2021, the Telescope Array project in Utah’s West Desert first detected the Amaterasu particle, a cosmic ray with energy measured at approximately 244 exa-electron volts. For context, that’s roughly equivalent to the energy imparted by a brick falling on a toe from waist height — except concentrated in a subatomic particle. This is not the first time such an energetic cosmic visitor has been observed; in 1991, the “Oh-My-God” particle, which had even more energy than Amaterasu, was detected.
A rare, extremely energetic cosmic ray has mysterious origins – Science News Magazine https://t.co/7u1zI9z46A
— Astronomy Share (@AstronomyShare) November 23, 2023
Cosmic rays are charged particles cascading into Earth’s atmosphere from outer space. The sources of low-energy cosmic rays are relatively well-understood — they generally originate from the sun. However, ultra-high-energy cosmic rays such as the Amaterasu particle are believed to come from beyond our galaxy, possibly from distant extragalactic events.
The incredible rarity of these high-energy particles adds to the challenge of understanding them. John Matthews, a research professor at the University of Utah and study co-author, likens their frequency to about one per square kilometer per century.
The Telescope Array, consisting of 507 surface detectors spread over 270 square miles, is designed to capture these rare events. When cosmic rays collide with the nuclei of atoms in Earth’s atmosphere, they trigger a shower of other detectable particles. By analyzing the timing and distribution of these secondary particles, scientists can backtrack to determine the cosmic ray’s original path.
The advanced detection capability has led to a paradoxical finding. The supposed source of the Amaterasu particle is the Local Void, a vast empty space near the Milky Way, devoid of the violent celestial events typically associated with such high-energy phenomena.
This finding raises more questions than answers. If these ultra-high-energy cosmic rays do not stem from observable violent events, where do they originate? Some scientists suggest that we need to enhance our understanding of the magnetic fields in our galaxy, as these can significantly alter the paths of cosmic rays, thus obscuring their true origins. The fact that this recent discovery points to “the middle of nowhere” indicates there might be critical gaps in our current knowledge of cosmic phenomena.
Currently, the Telescope Array is undergoing an expansion that will add 500 new detectors, covering an area of roughly 1,120 square miles. This enhancement aims to increase the chances of capturing more such cosmic ray events, potentially offering clues that could unravel this astronomical mystery.
The discovery of the Amaterasu particle has presented a cosmic puzzle that challenges current astrophysical theories. While the phenomenon is rare and poses minimal threat to human life due to Earth’s protective atmosphere, its study is crucial for expanding our understanding of the universe. As science continues to peel back the layers of this mystery, it is clear that each finding is a significant piece of the larger puzzle that is our cosmos.