2 The idea is that the matter we say does not have enough gravitational pull to keep galaxies together.
2 The idea is that the matter we say does not have enough gravitational pull to keep galaxies together.
这种概念源自我们所说的物质没有足够的引力把恒星束缚在星系内部。估计可见的黑暗物质仅占整个宇宙的5％。