美国转移15名关塔那摩监狱囚犯 罗切特称在巴西遭遇抢劫 play pause stop mute unmute max volume 00:0003:15repeat repeat off Update Required To play the media you will need to either update your browser to a recent version or update

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What happens is that, first the dark matter forms the structure, the ordinary matter then follows the dark matter. The ordinary matter is hydrogen and helium at this stage. And the hydrogen and helium fall/ to the center of the dark matter halos that

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