英语听力文摘 English Digest 710 地平线有多远？（在线收听）

How Far Away Is The Horizon?

Here’s a neat question you may have never thought to ask. How far away is the horizon?

Flat Earth

Think about it. The Earth seems flat from our viewpoint, and if you are in a desert or out at sea you get a sense that the earth extends indefinitely in every direction. This isn’t correct, though; the planet is round, so at some point the ground must drop away. When it drops below your angle of vision, you can’t see it any more, and that’s what we call the horizon.

So how far can you see before the planet curves away? If you’re six feet tall, the answer is about three miles. Surprised? You aren’t alone. Try asking a friend next time you’re at the beach on a clear day to guess how far out across the ocean you are looking. She’s more likely to say twenty or fifty miles than just three.

Where Is The Horizon Line?

Now that we’re thinking about horizons, here’s another cool thing to think about. The horizon is three miles away on earth. But elsewhere in the solar system it’s closer or farther, depending on the size of the body you’re standing on!

Take the moon. The moon is two thousand, one hundred and sixty miles in diameter, only about one quarter the size of the earth.

So the curvature at its surface is much more noticeable, and the horizon is much closer. It’s only about 1.5 miles away.

One cool result? The surface bends so quickly on the moon that it’s possible to stand inside some of the largest impact craters and not know you’re in one. The walls of the crater are below the horizon on all sides!

地平线有多远？

这是一个你可能从未想过要问的问题。地平线有多远？

平地

想想看。从我们的角度来看，地球似乎是平的，如果你在沙漠或海上，你会感觉到地球在各个方向无限延伸。但这并不正确；地球是圆的，所以在某一点上地面一定会下降。当它低于你的视角时，你就看不到它了，这就是我们所说的地平线。

那么，在行星弯曲离开之前，你能看到多远？如果你身高六英尺，答案大约是三英里。惊讶你并不孤单。下次你在晴朗的天气里去海滩时，试着问问朋友，猜猜你在大洋彼岸看多远。她更可能说二十或五十英里，而不是三英里。

地平线在哪里？

既然我们在考虑视野，这里还有一件很酷的事情要考虑。地平线离地球三英里远。但在太阳系的其他地方，它更近或更远，这取决于你所站的身体的大小！

拿月亮来说。月球直径为两千一百六十英里，只有地球的四分之一大。

因此，它表面的曲率更加明显，地平线也更加接近。它只有1.5英里远。

一个很酷的结果？月球表面弯曲得如此之快，以至于站在一些最大的撞击坑里，却不知道自己身处其中。火山口的壁都在地平线以下！