《那些古怪又让人忧心的问题》第110期:地球扩张(3)

t = 1 Month

1个月后

After a month, the Earth would have expanded by 26 kilometers-an increase of 0.4 percent-and its mass would have increased by 1.2 percent. Surface gravity would have gone up by only 0.4 percent, rather than 1.2 percent, since surface gravity is proportional to radius.4

1个月后，地球的直径增加了26千米——增长了0.4％——它的质量增加了1.2％。而地表的重力也只是增加了0.4％，而不是1.2％，因为地表的重力与地球半径成正比。4

You might notice the difference in weight on a scale, but it's not a big deal. Gravity varies by this much between different cities already. This is a good thing to keep in mind if you buy a digital scale. If your scale has a precision of more than two decimal places, you need to calibrate it with a test weight-the force of gravity at the scale factory isn't necessarily the same as the force of gravity at your house.

你可能会在称体重时发现一些异常，但也不是什么大问题。在不同的城市你的体重偏差的量差不多也是这么多。如果你买的是电子秤的话你最好记住这一点。如果你家的秤精确到小数点后两位，那么你就需要用一个测试砝码来校准它——不过秤的生产厂家那里的重力和你家的重力一般是不同的。

While you might not notice the increased gravity just yet, you'd notice the expansion. After a month, you'd see a lot of cracks opening up in long concrete structures and the failure of elevated roads and old bridges. Most buildings would probably be OK, although those anchored firmly into bedrock might start to behave unpredictably.5

虽然直到此时你可能还没注意到重力变大了，但你一定会发现地球在扩张。1个月后，你会在长混凝土结构上发现许多裂缝，一些高架桥和旧的大桥会相继断裂。绝大多数建筑不会倒塌，但那些地基深入基岩的房子的处境就有些不可预料了。5

At this point, astronauts on the ISS would start getting worried. Not only would the ground (and atmosphere) be rising toward them, but the increased gravity would also cause their orbit to slowly shrink. They'd need to evacuate quickly; they'd have at most a few months before the station reentered the atmosphere and deorbited.

此时此刻，国际空间站上的宇航员们要开始着急了。不仅是地面（以及大气）在朝他们扑来，不断增大的引力也在使空间站的轨道高度不断下降。他们需要尽快撤离空间站。最多几个月时间，空间站就会脱离轨道坠毁。

t = 1 year

1年后

After a year, gravity would be 5 percent stronger. You'd probably notice the weight gain, and you'd definitely notice the failure of roads, bridges, power lines, satellites, and undersea cables. Your pendulum clock would now be ahead by five days.

1年后，重力变强了5％。这时你应该会注意到体重增加了，你也绝对会注意到道路、桥梁、输电线、卫星、海底电缆相继出了问题。而你家的那台单摆钟比正常时间快了5天。

What about the atmosphere?

那么大气层呢？

If the atmosphere isn't growing like the land and water are, air pressure would start dropping. This is due to a combination of factors. As gravity increases, then air gets heavier. But since that air is spread out over a larger area, the overall effect would be decreasing air pressure.

如果大气层不像陆地和海洋那样扩张，那么气压会开始下降。这是许多因素共同作用的结果：随着重力增加，空气也变得更重。但由于空气分散于一个更大的面积上，总体效果就是气压下降了。

On the other hand, if the atmosphere is also expanding, surface air pressure would rise. After years had passed, the top of Mount Everest would no longer be in the “death zone.” On the other hand, since you'd be heavier-and the mountain would be taller-climbing would be more work.

另一方面，如果大气层也一起扩张，那么表层的气压也会随之上升。几年后，珠峰顶端将不再是“死亡区”。但反过来说，你的体重增加了，山也更高了——于是爬山就更累了。