Scientists have recently made an intriguing discovery by detecting the second-most powerful cosmic ray originating from beyond our galaxy. This "ultra-high-energy" particle, named the 'Amaterasu' particle after the sun goddess in Japanese mythology, has left researchers astounded by its sheer power.
Cosmic rays are charged particles, like protons or electrons, that travel through space at nearly the speed of light. These cosmic rays may be remnants of celestial events that have disintegrated matter into its subatomic components. Due to their charged nature, cosmic rays follow a zigzagging flight path as they navigate through electromagnetic fields in the cosmic microwave background.
The research was conducted at the Telescope Array located at the University of Utah, the same facility where the highest-energy cosmic ray ever recorded, known as the 'Oh-My-God' particle, was discovered in 1991. This particle was a source of great perplexity for physicists as it was believed that nothing within our galaxy could generate such high-energy cosmic rays. Moreover, it was previously thought to be impossible for cosmic rays to reach Earth from other galaxies.
Published in the journal Science, the study describes how the international team of physicists measured the particle's energy at a remarkable 2.4 x 10^20 electron Volts (eV).
The discovery of the 'Amaterasu' particle has provided scientists with more questions than answers.
Scientists are still searching for a conventional explanation for these phenomena and speculate that they may involve particle physics yet to be discovered. The trajectory of the 'Amaterasu' particle, cannot be traced back to any known high-energy source, adding to the mystery surrounding these cosmic rays.
The composition of the 'Amaterasu' particle suggests it is likely a proton, as its relatively straight trajectory indicates a lighter particle. Heavier particles, such as iron nuclei, would experience more bending due to magnetic fields. Physicists also argue that cosmic rays with energy exceeding the Greisen-Zatsepin-Kuzmin (GZK) cutoff, like the 'Amaterasu' particle, should not be significantly affected by the microwave background radiation. The GZK cutoff represents the maximum energy a proton can retain before its interactions with microwave background radiation deplete its energy.
However, the trajectory of the 'Amaterasu' particle leads researchers to empty space, deepening the mystery. The presence of stronger magnetic fields than previously thought could explain this, but it contradicts other observations that indicate these magnetic fields are not powerful enough to cause significant curvature at such high energies.