Scientists Detect Powerful Cosmic Ray, Origin Remains a Mystery

Scientists Detect Powerful Cosmic Ray, Origin Remains a Mystery

The recent detection of an incredibly powerful cosmic ray has left scientists puzzled, as its origin challenges current understanding of physics.

Scientists have recently made an extraordinary discovery in the realm of cosmic rays, detecting the most powerful cosmic ray in over three decades. This enigmatic particle, with an estimated energy of 240 exa-electronvolts (EeV), has left researchers perplexed about its origin and has sparked speculation about the need for new physics to explain its existence. The findings, published in Science, have opened up a new realm of possibilities for understanding the mysteries of the universe.

The Nature of Cosmic Rays:

Cosmic rays, despite their name, are not rays but rather high-energy subatomic particles, often protons, that travel through space at nearly the speed of light. Ultrahigh-energy cosmic rays, like the one recently detected, possess energy levels exceeding one EeV, which is a million times greater than what can be achieved by human-made particle accelerators. These cosmic rays are a rarity, with fewer than one of these particles reaching each square kilometer of Earth’s surface per century.

The Discovery of Amaterasu:

Toshihiro Fujii, an astronomer at Osaka Metropolitan University, stumbled upon an unusual signal on May 27, 2021, while conducting routine data analysis at the Telescope Array in Utah. The signal indicated that the detectors had been struck by an incredibly energetic particle. Initially skeptical, Fujii and his team soon realized that they had indeed detected an ultrahigh-energy cosmic ray. They affectionately named the particle ‘Amaterasu,’ after the Japanese Sun goddess.

The Mystery Deepens:

While the detection of Amaterasu was a significant achievement, the challenge lies in determining its origin. Typically, ultrahigh-energy cosmic rays travel smoothly through space, as they are less affected by magnetic fields compared to lower-energy cosmic rays. This makes it easier to trace their source, such as a stellar explosion or a black hole. However, Fujii and his team were unable to pinpoint the origin of Amaterasu. Calculations led them to a region with few galaxies, and attempts to match the cosmic ray with possible source galaxies yielded no results.

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Exploring New Physics:

The inability to identify the source of Amaterasu raises intriguing possibilities. One explanation could be that current models underestimating the influence of magnetic fields on cosmic rays require adjustment. This would imply that Amaterasu may have originated from a slightly different direction than initially calculated. Clancy James, an astronomer at Curtin University, suggests that the estimates may be flawed, emphasizing the need for further investigation.

Alternatively, the existence of ultrahigh-energy cosmic rays could imply the presence of unknown physical processes that allow them to travel vast distances. Jose Bellido Caceres, an astroparticle physicist at the University of Adelaide, suggests that this could point to new physics waiting to be discovered. Cosmic rays offer a unique opportunity to study particle interactions at extreme energies that cannot be replicated by Earth-based accelerators.

The Path Forward:

Fujii and his team are currently upgrading the Telescope Array to enhance its sensitivity fourfold. This upgrade will enable researchers to capture more ultrahigh-energy cosmic rays and provide a more precise understanding of their origins. By delving deeper into the mysteries of these powerful particles, scientists hope to shed light on the fundamental workings of the universe and potentially uncover new physics.


The recent detection of the most powerful cosmic ray in decades has left scientists both excited and perplexed. The enigmatic particle, named Amaterasu, challenges current understanding of cosmic rays and their origins. The inability to trace its source has led to speculation about the need for new physics or adjustments to existing models. As researchers continue to explore the mysteries of ultrahigh-energy cosmic rays, the upgraded Telescope Array holds the promise of unraveling the secrets of these powerful particles and providing insights into the fundamental nature of the universe.

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