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Science 22 December 1995:
Vol. 270. no. 5244, p. 1899
DOI:

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This Week in Science

The origin of cosmic rays, which consist of energetic atomic nuclei from outer space, remains a puzzle. Sigl et al. (p. 1977) report an analysis of recent experimental data for ultra high energy cosmic rays (above 1018 eV) that indicates unusual structure in the energy spectrum. There appears to be a dip in the spectrum around 1020 eV, and cosmic rays above this energy may not result from acceleration mechanisms, but rather from decay of particles from some higher energy scale. Background and comment are provided in the news story by Glanz (p. 1923).




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