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Cosmic hole defies dark matter theories

点击量:   时间:2017-11-16 08:02:18

FROM an intergalactic pile-up comes the disturbing suggestion that mysterious dark matter is even more puzzling than we thought. The massive galaxy cluster Abell 520, some 3 billion light years away, is thought to have formed from a collision between smaller clusters. When astronomers examined the wreckage, they found that Abell 520 has a massive dark core, empty of bright galaxies (www.arxiv.org/abs/0706.3048). Some of the core is made up of hot gas,