Cosmic Rays Interacting with the Atmosphere (image) Technical University of Denmark Share Print E-Mail Caption Cosmic rays interacting with the Earth's atmosphere producing ions that helps turn small aerosols into cloud condensation nuclei -- seeds on which liquid water droplets form to make clouds. A proton with energy of 100 GeV interact at the top of the atmosphere and produces a cascade of secondary particles who ionize molecules when traveling through the air. One 100 GeV proton hits every m2 at the top of the atmosphere every second. Credit Illustration: H. Svensmark/DTU Usage Restrictions Please credit Illustration: H. Svensmark/DTU Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.