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Earth as seen by CGRO
Credit: NASA/CGRO/EGRET/Dirk Petry


Bathed in Gamma Rays

Most high energy observatories take pains to avoid looking at the earth. Gamma-ray observatories, however, have such wide fields of view that the earth is bound to fall into the observing window at least part of the time. What does the earth look like in gamma rays? The false-color images above show the answer to this question. These images, compiled from years of data from the Compton Gamma-Ray Observatory, show the earth as a rather bright gamma-ray source, up to very high gamma-ray energies. The gamma-ray emission is due to the interaction of the earth's atmosphere with cosmic rays. The edges of the earth are brighter than the center because the production of gamma rays is not isotropic but mostly beamed in a narrow cone around the cosmic ray arrival direction.


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Each week the HEASARC brings you new, exciting and beautiful images from X-ray and Gamma ray astronomy. Check back each week and be sure to check out the HEAPOW archive!


Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:26:05 EDT