Cosmic Rays Still Mysterious 100 Years After Discovery [1]

Space.com
By SPACE.com Staff,Date: 01 August 2012 Time: 07:01 AM ET

Little is know about the ultra high-energy cosmic rays that regularly penetrate the atmosphere. Recent IceCube results challenge one of the leading theories, that they come from gamma ray bursts. CREDIT: NSF/J. Yang

Cosmic rays continue to puzzle scientists a century after the fast-moving particles were discovered.

Austrian scientist Victor Hess first cottoned on to the existence of cosmic rays [2] after a high-altitude balloon flight on Aug. 7, 1912. In the 100 years since, researchers have learned a lot about these highly energetic particles, which constantly bombard Earth from outer space. But important questions remain, including where exactly they come from.

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