- A highly energetic atomic nucleus or other particle travelling through space at a speed approaching that of light.More example sentences
- This radioactive isotope is created when energetic particles in cosmic rays enter the Earth's atmosphere and split atomic nuclei of nitrogen and oxygen.
- Other sources that contribute to the near-Earth space environment include galactic cosmic ray particles, which originate from outside of the solar system.
- The Moon's regolith was created by the ceaseless bombardment of micrometeorites, cosmic rays and particles of solar wind breaking down rocks for billions of years.
More definitions of cosmic rayDefinition of cosmic ray in:
- The US English dictionary