《那些古怪又讓人憂心的問題》第110期:地球擴張(3)

t = 1 Month

1個月後

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個月後，地球的直徑增加了26千米——增長了0.4％——它的質量增加了1.2％。而地表的重力也只是增加了0.4％，而不是1.2％，因爲地表的重力與地球半徑成正比。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.

你可能會在稱體重時發現一些異常，但也不是什麼大問題。在不同的城市你的體重偏差的量差不多也是這麼多。如果你買的是電子秤的話你最好記住這一點。如果你家的秤精確到小數點後兩位，那麼你就需要用一個測試砝碼來校準它——不過秤的生產廠家那裏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

雖然直到此時你可能還沒注意到重力變大了，但你一定會發現地球在擴張。1個月後，你會在長混凝土結構上發現許多裂縫，一些高架橋和舊的大橋會相繼斷裂。絕大多數建築不會倒塌，但那些地基深入基岩的房子的處境就有些不可預料了。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.

此時此刻，國際空間站上的宇航員們要開始着急了。不僅是地面（以及大氣）在朝他們撲來，不斷增大的引力也在使空間站的軌道高度不斷下降。他們需要儘快撤離空間站。最多幾個月時間，空間站就會脫離軌道墜毀。

t = 1 year

1年後

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年後，重力變強了5％。這時你應該會注意到體重增加了，你也絕對會注意到道路、橋樑、輸電線、衛星、海底電纜相繼出了問題。而你家的那臺單擺鍾比正常時間快了5天。

What about the atmosphere?

那麼大氣層呢？

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.

如果大氣層不像陸地和海洋那樣擴張，那麼氣壓會開始下降。這是許多因素共同作用的結果：隨着重力增加，空氣也變得更重。但由於空氣分散於一個更大的面積上，總體效果就是氣壓下降了。

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，如果大氣層也一起擴張，那麼表層的氣壓也會隨之上升。幾年後，珠峯頂端將不再是“死亡區”。但反過來說，你的體重增加了，山也更高了——於是爬山就更累了。