💥 What is the origin of the Amaterasu particle, which violently struck Earth?

In 2021, a particle from space struck Earth with colossal energy. Where could such power come from, especially since its initial direction pointed towards a region of space that appeared empty?

These streams of charged particles traveling through the Universe at prodigious speeds are called cosmic rays. Among them, the one now named Amaterasu stands out for its energy level, far surpassing what our terrestrial accelerators can produce. Its detection immediately captured the attention of the astrophysics community, which seeks to understand its origin.


Amaterasu, named in homage to a Japanese sun goddess, carries energy equivalent to millions of times that generated by the Large Hadron Collider. This characteristic makes it the second most powerful cosmic ray ever observed, just behind the 'Oh-My-God' particle spotted in the 1990s.

The plot thickened when its trajectory appeared to come from the Local Void, a vast cosmic expanse devoid of galaxies and notable celestial objects. Yet, such particles are usually associated with cataclysmic events like stellar explosions or supermassive black holes.

To clarify this situation, Francesca Capel and Nadine Bourriche, from the Max Planck Institute for Physics, developed an innovative data-based approach. Their method uses realistic simulations coupled with advanced statistical techniques to trace the particle's probable journey through space.

The results of their work, published in The Astrophysical Journal, indicate that the origin of Amaterasu could lie in nearby galaxies, such as M82, rather than in the Local Void.

This advance helps to better target the cosmic environments where these extreme accelerations occur.

Interstellar magnetic fields

In space, magnetic fields play an essential role in deflecting the trajectory of charged particles like cosmic rays. These fields, often generated by the motions of gas and stars, create an invisible network that influences particle travel over vast distances.

When a high-energy cosmic ray passes through these magnetic regions, its direction can be significantly altered. This makes it difficult to pinpoint its original source precisely, as the particle does not follow a straight line from its starting point.

Scientists use models to simulate these interactions, taking into account the strength and orientation of magnetic fields. These simulations help reconstruct possible paths and identify the cosmic environments where particles are accelerated.