Topic: Space

A team of scientists has found that some high-energy cosmic rays may be atomic nuclei heavier than iron. This discovery could help us understand where these powerful particles come from.

The origin of the most energetic particles ever detected is a long-standing mystery in modern astrophysics. One example is the 'Amaterasu particle', which was detected by the Telescope Array in Utah in 2021 and named for the sun goddess in Japanese mythology. Its reported energy ranks it among the most powerful cosmic-ray events ever observed, placing it in the same rare category as the 'Oh-My-God particle' recorded in 1991.

Scientists at Penn State have been working to solve this mystery. They used computer simulations to investigate what kinds of particles could still reach Earth at such extraordinary energies. Their research suggests that some of the highest-energy cosmic rays may be atomic nuclei heavier than iron.

These ultraheavy nuclei lose energy more slowly than protons or lighter nuclei while crossing intergalactic space, which means they could survive the journey to Earth while still carrying extreme amounts of energy. This discovery could help scientists identify the types of cosmic objects powerful enough to launch such particles.

The Amaterasu particle has been especially difficult to explain because its estimated arrival direction traces back to a cosmic void, a region of space with no clear source capable of producing ultrahigh-energy cosmic rays. The origins and acceleration mechanisms of ultrahigh-energy cosmic rays have been among the biggest mysteries in the field for more than 60 years.

The researchers ran detailed computer simulations to investigate what kinds of particles could still reach Earth at such extraordinary energies. They modeled how particles of different sizes would gain or lose energy while traveling through intergalactic space. Their research showed that ultraheavy nuclei lose energy more slowly than protons or intermediate-mass nuclei, making them better able to survive cosmic distances and reach Earth.

This discovery could help scientists identify the types of cosmic objects powerful enough to launch such particles. It may also help us understand where these high-energy particles come from and how they are accelerated.

Why It Matters

Understanding the origin of high-energy cosmic rays can help us better comprehend the universe and its mysteries. This knowledge can also inspire new technologies and innovations, benefiting society as a whole.

Key Facts

• Scientists have found that some high-energy cosmic rays may be atomic nuclei heavier than iron.
• These ultraheavy nuclei lose energy more slowly than protons or lighter nuclei while crossing intergalactic space.
• The Amaterasu particle has been especially difficult to explain because its estimated arrival direction traces back to a cosmic void.
• The origins and acceleration mechanisms of ultrahigh-energy cosmic rays have been among the biggest mysteries in the field for more than 60 years.
• The researchers used computer simulations to investigate what kinds of particles could still reach Earth at such extraordinary energies.

Key Terms

Cosmic Rays

High-energy particles from space that slam into Earth

Implications

Understanding the origin of high-energy cosmic rays can help us better comprehend the universe and its mysteries. This knowledge can also inspire new technologies and innovations, benefiting society as a whole.