So the evidence that we have that a quarter of the universe is dark matter -- this gravitationally attracting stuff -- is that galaxies, the speed with which stars orbiting galaxies is much too large; it must be embedded in dark matter.
我们有的证据 证明这¼是暗物质--- 这些以引力作用吸引的东西--- 是这些行星围绕星系运动的速率 过大；它一定嵌在暗物质中