On Earth, we have the Large Hadron Collider, which can smash atoms and speed particles close to light speed. In space, however, cosmic rays pack an even bigger punch. Some of these high-energy rays are millions of times more powerful than anything we can recreate on Earth. A recent study highlights a cosmic ray called the Amaterasu particle, which crashed into Earth in 2021. It was 40 million times more energetic than anything produced by the Large Hadron Collider, making it one of the strongest cosmic rays ever detected.
But where do these particles come from? The origins of cosmic rays have baffled scientists for over 60 years. Researchers now suspect that these ultra-high-energy rays might be atomic nuclei of elements heavier than iron. This could explain how they gain such intense energy.
Kohta Murase, a researcher from Penn State University, emphasizes, “These cosmic rays are accelerated by some of the most powerful sources in the universe.” He and his team believe that extreme astrophysical events, like two neutron stars colliding or a massive star collapsing, could be responsible. For context, neutron stars are incredibly dense. A teaspoon of neutron star material would weigh roughly 10 million tons—about the same as 85,000 blue whales!
The Amaterasu particle seems to have come from a seemingly empty region of space, raising more questions about its origins. There’s a possibility that some of these cosmic rays come from massive cosmic explosions. Murase’s simulations suggest that heavier cosmic nuclei lose energy more slowly, allowing them to travel greater distances without diminishing in intensity.
Recent studies have indicated that around 90% of cosmic rays detected are protons. However, if heavier nuclei contribute significantly to high-energy cosmic rays, it could change our understanding of the universe’s most violent events.
Merging two neutron stars creates extreme conditions, and researchers believe this might be a primary source of the harshest cosmic rays. They not only contribute to cosmic rays but also cause gamma-ray bursts, which are among the universe’s most explosive phenomena.
Interestingly, scientists have noticed differences in cosmic rays coming from the northern and southern hemispheres. If heavier nuclei are indeed more common at these higher energy levels, future data may reveal a composition that’s heavier than iron.
The latest findings, published in the journal Physical Review Letters, provide a fresh perspective on an age-old mystery. Understanding the origins of these powerful cosmic rays could reshape our grasp of the universe and its most energetic events—the kinds that make folks on Earth look up and wonder.
