News FocusAstrophysics

Physicists Prepare to Catch Cosmic Bullets

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Science  21 Jun 2002:
Vol. 296, Issue 5576, pp. 2134-2135
DOI: 10.1126/science.296.5576.2134

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Researchers can't agree where the most energetic particles in the universe come from, or even how many of them strike Earth. Theories about the source abound, from the nearby descendants of quasars to ultramagnetic neutron stars to the annihilation of clumps of superheavy dark matter. Now physicists from 19 nations are building a giant observatory that they hope will end decades of confusion about the origins of particles called ultrahigh-energy cosmic rays, each of which can pack as much energy as a fastball from a professional baseball pitcher.