t = 300 years
300年后
It 8217;s a shame humans wouldn 8217;t live this long, because at this point, something really neat would happen.
我们人类活不到这一天真是遗憾，因为此时会发生一件非常赞的事情。
As the Earth grows, the Moon would, like all our satellites, gradually spiral inward. After several centuries, it would be close enough to the swollen Earth that the tidal forces between Earth and the Moon would be stronger than the gravitational forces holding the Moon together.
随着地球不断变大，月亮会像那些卫星一样轨道高度越转越低。几个世纪后，终有一天地球与月球之间的引潮力会超过月球聚拢自身的引力。
When the Moon passed this boundary-called the Roche limit-it would gradually break apart,9 and Earth would, for a short time, have rings.
当那个界限——叫作洛希极限——被跨越后，月亮会被撕裂9，而在短时间内地球会拥有一个美丽的光环。
If you liked it, then you should have moved a mass inside its Roche limit.
如果你喜欢它，就应该把一个物体移动到它的洛希半径内。10
1 The smoking gun that confirmed the theory of plate tectonics was the discovery of sea-floor spreading. The way sea-floor spreading and magnetic pole reversal neatly confirmed each other is one of my favorite examples of scientific discovery at work.
1． 板块构造学说的确凿证据是海床在不断延展。海床延展和地磁极倒转两者能够很好地互相印证，这是我最喜欢的科学发现管用的例子之一。
2 It turns out it 8217;s kind of dumb.
2． 事实证明这理论挺蠢的。
3 As it turns out, the ocean is expanding, since it 8217;s getting warmer. This is (currently) the main way global warming is raising the sea level.
3． 实际上海洋确实在扩张，因为海水在变暖，而这也是（目前）全球变暖导致海平面上升的主要原因。
4 Mass is proportional to radius cubed, and gravity is proportional to mass times inverse square of radius, so radius3 / radius2 = radius.
4． 质量正比于半径的三次方，而重力正比于质量乘以半径平方的倒数，所以半径的三次方除以半径的平方等于半径。
5 Just what you want in a skyscraper.
5． 造摩天大楼要的不就是这个嘛。
6 Although I wouldn 8217;t trust the elevators.
6． 虽然我可不敢再去乘电梯了。
7 Over decades, the force of gravity would grow slightly faster than you 8217;d expect, since the material in the Earth would compress under its own weight. The pressure inside planets is roughly proportional to the square of their surface area, so the Earth 8217;s core would be squeezed tightly.
7． 几十年后地球重力增加的速度会比你所期望的略快一些。因为不断增加的重量会压迫地球自身，地球内部的压强粗略正比于表面积的平方，因而地核会被压得十分紧密。
8 Although some radioactive elements, like uranium, are heavy, they get squeezed out of the lower layers because their atoms don 8217;t mesh well with the rock lattices at those depths.
8． 虽然一些放射性物质（比如铀）很重，但它们会被从地球内部挤出来，因为在那种深度下它们没法和岩石晶格很好地混合
9 Sorry, Moon!
9． 对不起啦，月亮！