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.

Science 5 January 2001:
Vol. 291. no. 5501, pp. 73 - 79
DOI: 10.1126/science.291.5501.73
Prev | Table of Contents | Next

Review

Ultrahigh-Energy Cosmic Rays: Physics and Astrophysics at Extreme Energies

Günter Sigl

The origin of cosmic rays is one of the major unresolved questions in astrophysics. In particular, the highest energy cosmic rays observed have macroscopic energies up to several 1020 electron volts and thus provide a probe of physics and astrophysics at energies unattained in laboratory experiments. Theoretical explanations range from astrophysical acceleration of charged particles, to particle physics beyond the established standard model, and processes taking place at the earliest moments of our universe. Distinguishing between these scenarios requires detectors with effective areas in the 1000-square-kilometer range, which are now under construction or in the planning stage. Close connections with gamma -ray and neutrino astrophysics add to the interdisciplinary character of this field.

Institut d'Astrophysique de Paris, CNRS, 98bis Boulevard Arago, 75014 Paris, France. E-mail: sigl{at}iap.fr

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)