英语听力：探索发现 科学新发现：我们的大气层-6（在线收听） |
In contrast, Jupiter and Saturn are all atmosphere. Unlike Earth, Jupiter doesn’t really have a solid surface that you could stand on and then have your head up in the atmosphere looking at the clouds. It’s just a giant, giant gas ball. Only one other planet shares the Earth’s thick atmosphere and rocky surface—our nearest neighbor, Venus. But even here there are striking differences. Dr. David Crisp has spent 20 years studying Venus’ acrid air.
Imagine you’re at the surface of the planet Venus. You’re at pressures that are high enough to crush a nuclear submarine. The pressures there are about ninety times the pressure of the Earth’s surface.
This pressure is combined with extreme heat, nine hundred degrees Fahrenheit, hot enough to melt lead. Clouds drift over the baked surface, but they are not water vapor. Venus’ clouds are made of concentrated sulphuric acid. Venus is a stark example of how extreme an atmosphere can be. But the real mystery isn’t why Venus is so hostile, but why Earth hasn’t followed the same path.
As planets go, Earth and Venus are essentially twins. They’re almost exactly the same size. They’re also very close together in the solar system. In spite of that, their environments evolved in dramatically different ways.
|
| 原文地址：http://www.tingroom.com/lesson/yytltsfx/2014/284446.html |