Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
HIGH-ENERGY ASTROPHYSICS: Hot on the Trail of Cosmic Rays
Daniel Clery
CAMBRIDGE, U.K.--Researchers are closing in on finding the source of galactic cosmic rays, charged particles that whiz around the galaxy in huge numbers and constantly bombard Earth's upper atmosphere.