What are cosmic rays? How do they affect earth?
Cosmic rays are high energy atomic nuclei.
They mainly consist of protons and nuclei of lighter elements. They have high energy and most likely originate from supernova explosions.
They have little effect on Earth as the atmosphere blocks almost all of them. Some of the more energetic particles do reach the surface of the Earth.
There are surface based cosmic ray detectors which are typically fields of interconnected sensing devices.