New discovery may change understanding of universe
www.chinaview.cn 2008-11-20 01:14:42   Print

    NANJING, Nov. 20 (Xinhua) -- Chinese and foreign experts on Thursday announced the discovery of an unexpected surplus of high-energy, cosmic ray electrons, which could change the current understanding of the universe.

    Dr. Chang Jin, an astrophysicist at the Purple Mountain Observatory in China's eastern Jiangsu Province, along with his foreign counterparts, made the discovery using the Advanced Thin Ionization Calorimeter (ATIC).

    That's an instrument sent on helium balloons to measure the composition and energy spectra of cosmic rays from 35 kilometers above Antarctica.

    The electrons, about 300 to 800 giga electron volts, were believed to be from a previously unidentified source close to the Earth's solar system.

    According to Chang, the electron excess cannot be explained by the standard model of cosmic ray origin, in which electrons are accelerated in sources such as supernova remnants and then propagate through the galaxy.

    Chang believed that the surplus possibly resulted from the annihilation of dark matters.

    "One such predicted particle has annihilation characteristics that would produce a very good fit for the ATIC results," said Chang. "If true, this would be a major advance in our understanding of dark matter and its role in the universe."

    His theory is shared by Lars Bergstrom, an expert in dark matter study with the Stockholm University in Sweden.

    Other experts believed that even if the surplus didn't result from dark matter, the finding would be helpful in resolving the enigma of cosmic rays.

    Chang said further research in dark matter would be continued.

    "The ATIC team plans to build a new instrument to further study this source," he said. "The research has just started. We have a long way to go for further data."

    Chang worked on the project for seven years and flew to Antarctica three times to confirm the result.

    Details of his finding are in the latest issue of the journal, Nature.

Editor: Yan
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