Introduction

In a significant scientific breakthrough, Japanese scientists discovered an ultra-high-energy cosmic ray in May 2021, which he named ‘Amaterasu’ after the Japanese sun goddess.

Discovery of Amaterasu

Event Identification: Dr. Toshihiro Fujii, an astronomer at Osaka Metropolitan University, discovered the cosmic ray named Amaterasu.
Measurement: Amaterasu had an energy of 240 exa-electron-volt (EeV), an extremely high level.
Comparison with Man-Made Accelerators: This energy is about 40 million times higher than that of protons accelerated by the Large Hadron Collider (LHC).

Unusual Origin: Amaterasu appears to have originated from an empty part of the universe.
Dr. Fujii’s Theories: Possible explanations include an unidentified source, interaction with a strong magnetic field, or the need for new physics models.
Previous Records: The “Oh My God” particle, detected in 1991 with an energy of 320 EeV, remains the most energetic cosmic ray recorded.

Composition: Cosmic rays are streams of energetic particles, including protons and alpha particles, originating from outer space and the sun.
Interaction with Earth: Most cosmic rays lose their energy in Earth’s atmosphere, preventing harmful high-intensity rays from reaching the surface.
Historical Significance: Studies of cosmic rays since the 1930s have led to the discovery of many subatomic particles, although their sources and high energy remain a mystery.

Galactic Cosmic Rays (GCR): Originating from beyond our solar system, possibly from supernovae.
Solar Cosmic Rays: Emitted by the sun, primarily in solar flares, consisting mainly of protons.
Composition Analysis: Studies show a helium-to-hydrogen nuclei mass ratio in cosmic rays similar to the early universe’s composition.

Ultra-high-energy cosmic Rays (UHECRs): These are extragalactic particles with energies exceeding 1 EeV.
Limitations in Space Travel: UHECRs with more than 60 EeV energy face suppression due to interaction with cosmic microwave background (CMB) radiation, limiting their travel distance to 50-100 megaparsecs.