Cosmic rays are high-energy particles that travel through space and occasionally reach Earth. They mostly come from outside our solar system, often originating from supernovae or other energetic events in the universe. When these particles collide with atoms in the Earth's atmosphere, they create a shower of secondary particles, which can be detected by special instruments. These rays are important for scientists because they help us understand the universe's origins and the processes happening in distant galaxies. Additionally, studying cosmic rays can provide insights into particle physics and even the effects of radiation on human health during space travel.