pääsmete

Pääsmete, also known as primary or primary cosmic rays, are high-energy particles that originate from outside the Earth's atmosphere. They are primarily composed of protons and atomic nuclei, with a smaller fraction consisting of electrons and positrons. These particles are accelerated to relativistic speeds by various astrophysical processes, such as supernova explosions and active galactic nuclei.

Upon entering the Earth's atmosphere, pääsmete interact with atmospheric particles, initiating a cascade of secondary particles known as extensive air showers. These showers consist of a complex mix of particles, including muons, electrons, photons, and neutrons, which can reach the Earth's surface and even penetrate underground.

The study of pääsmete is crucial for understanding the high-energy processes in the universe and for developing technologies to detect and measure these particles. Ground-based and space-based detectors are used to observe pääsmete and their interactions, providing valuable insights into the fundamental properties of matter and the nature of cosmic rays.

Pääsmete also play a significant role in atmospheric science, as they contribute to the ionization of the atmosphere and influence weather patterns. Additionally, the secondary particles produced by pääsmete can pose a radiation hazard to astronauts and aircraft crews, making the study of pääsmete important for space exploration and aviation safety.