《那些古怪又讓人憂心的問題》第31期:小世界(2)
If the asteroid had a radius of 1.75 meters, then in order to have Earthlike gravity at the surface, it would need to have a mass of about 500 million tons. This is roughly equal to the combined mass of every human on Earth.
9． If you stood on the surface, you'd experience tidal forces. Your feet would feel heavier than your head, which you'd feel as a gentle stretching sensation. It would feel like you were stretched out on a curved rubber ball, or were lying on a merry-go-round with your head near the escape velocity at the surface would be about 5 meters per second. That's slower than a sprint, but still pretty fast. As a rule of thumb, if you can't dunk a basketball, you wouldn't be able to escape this asteroid by jumping.
如果你站在星球表面，那麼你就會感受到潮汐力。你的腳會感覺比頭更“重”一些，你的感覺就像是被拉伸了一樣：就像你躺在橡膠球的彎曲表面上，或者你躺在旋轉木馬的地上，並且頭靠近中心。星球表面的逃逸速度約爲每秒5米。這個速度比百米衝刺要慢，但其實還是挺快的。作爲經驗估算，如果你沒法扣籃，那麼你就不能通過豎直起跳的方式逃離這顆星球。However, the weird thing about escape velocity is that it doesn't matter which direction you're going. If you go faster than the escape speed, as long as you don't actually go toward the planet, you'll escape. That means you might be able to leave our asteroid by running horizontally and jumping off the end of a ramp.
但逃逸速度詭異的地方在於，無論你朝哪個方向前進，只要你跑得比逃逸速度快，並且你不是正衝着地面而去，那麼你就能逃出這顆星球。這意味着你可以通過水平跑動，並在坡道的盡頭起跳的方式離開這顆星球。
If you didn't go fast enough to escape the planet, you'd go into orbit around it. Your orbital speed would be roughly 3 meters per second, which is a typical jogging speed. But this would be a weird orbit.
如果你的速度沒有高於逃逸速度，那麼你就會進入環繞它的軌道中去。你的軌道速度大約在每秒3米左右，也就是平常慢跑的速度。只是這個軌道顯得有些奇怪……
