1·Eleven point two kilometers per second, at which satellites can be freed from the gravitation of the earth, is called "escape speed".
卫星以11.2千米每秒的速度前进可以脱离地球引力，这被称为“逃逸速度”。
2·A body that has very little matter has very little gravitation.
一个天体所含的物质很少，它的引力也很小。
3·Secondly, the strength of gravitation depends on the distance between the bodies.
其次，引力的强度还取决于天体之间的距离。
4·For example, the earth has more matter than the moon, so the earth's pull or gravitation is stronger than the moon's.
比如，地球比月球含的物质多，所以地球的拉力或引力就比月球大。
5·This is called gravitation, or gravity.
这叫引力。
1·And that is a rather deep purely mathematical consequence of understanding gravitation in this way.
以这种方式理解万有引力，是纯数学的一个十分深刻推论。
2·Science has shown us through measurement, observation and experimentation that there are four forces in the Universe: electromagnetism, strong interaction, weak interaction and gravitation.
科学早就通过测量、观察和实验告诉我们宇宙中有四种力：电磁力、强相互作用力、弱相互作用力和万有引力。
3·Everybody knows that. It's the property of gravitation.
这就是万有引力的性质，我们都很了解了。
4·But it does mean that our attempts to understand the world are reduced to the kind of thing that Newton did in case of gravitation.
但是这并没有意味着我们试图理解世界的热情有所减少，诸如牛顿对万有引力的研究一样。
5·One biographer credits him with "discovering gravitation," and where would we be without that?
传记作家把“发现万有引力”归功于他，如果他没有发现这一事实，我们会变成什么样呢？