It's travelling at 3,000 or 4,000 kilometres per second.

它以每秒 3，000 到 4，000 千米的速度飞行。

Suddenly, an object the size of Mars comes towards our Earth, and crashes into the surface at a speed something like 15 kilometres per second.

突然，一个火星大小的物体朝地球飞来，并以大约每秒15公里的速度撞向地球表面。

Light itself, travelling at 300,000 kilometres per second is not going fast enough to escape the flow, and light itself will plunge into the black hole.

以至于连每秒行进 30 万千米的光线都再也无法从视界逃逸，就连光线也改变不了被黑洞吞没的命运。

It can do this because it is moving at a speed of almost 300,000 kilometres per second.

它之所以能做到这一点，是因为它以每秒近 30 万公里的速度移动。

Now, that's very close by cosmic standards, but light travels at only 300,000 kilometres per second, so that means that we're seeing the sun as it was in the past, actually eight minutes in the past.

从宇宙尺度上说，这算是非常近了，但因为光速只有每秒 30 万千米，所以我们看到的阳光其实来自过去的太阳，准确地说，是八分钟之前。