Cosmic rays are high-energy particles traveling near light speed. Some may originate from supernovae seeded by early Big Bang conditions. Their energy and composition provide clues about the universe’s infancy. Studying them helps understand particle acceleration and cosmology. Cosmic rays can penetrate Earth’s atmosphere, producing showers detectable by ground-based instruments. They are natural experiments in extreme physics.
It matters because cosmic rays trace energetic processes linked to the early universe.
It also informs particle physics and astrophysics on Earth.
Cosmic rays may carry fingerprints of the early universe’s explosions.
National Aeronautics and Space Administration [nasa.gov]