Credit: University of Maryland Cosmic Ray Physics Laboratory
CREAM over Ice
Cosmic rays are atomic nuclei which are accelerated to high energies by enormously powerful processes in space. Since their discovery by in 1912 by Victor Hess, the origins of cosmic rays have been a mystery. We know today that some of these particles are produced by the sun, others produced by supernova explosions. Most cosmic rays are hydrogen nuclei, almost all the rest helium nuclei, with a smattering of nuclei of heavier elements. Low energy cosmic rays are now relatively well understood, but some extremely high-energy cosmic rays seem too energetic even for supernovae. Astronomers go to the ends of the earth (literally) to understand these mysterious high-energy cosmic rays. Pictured above is the Cosmic Ray Energetics and Mass (CREAM) experiment, an instrument designed to study very high energy cosmic rays and to determine their composition. CREAM is carried aloft on an enormous Ultra-Long Duration Balloon (almost as large as one and one half football fields) flown at the edge of space over the ice of the South Pole. CREAM has now flown four times, in 2004, 2005, 2007 and most recently in December, 2008. These flights have provided more than 100 days of observations (including a record-setting flight of 42 days), and have provided key measurements of the energy spectrum of important elements like carbon and oxygen.
Published: January 26, 2009
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:27:51 EDT