英语听力：探索发现 科学新发现：我们的大气层-24（在线收听） |
This is a genuine iron meteorite, this is believed to have once been part of the core of a long dead planet or asteroid, and this was found right here in this strewn field, this remarkable little shapes, indentations on the surface are called thumbprints or scientifically *, and that's a feature that's unique to meteorites, and these little markings are caused by the surface actually melting as it flew through the atmosphere, we don't find * on Earth rocks. The air is constantly at work, making meteorites rare and valuable.
The chances of meteorites surviving their journey through the atmosphere and being found are minuscule, if it wasn't for our atmosphere, we would have little particles raining down on us all the time, and some of them not so little.
The mesosphere's barrier of thin air is the final gift from our atmosphere, adding to the oxygen we breathe, water we drink and pressure we feel, but as we cross into the layers above, we leave life far behind. John Paul's air ships have only reached the upper stratosphere, K's jump point is below that, in the middle of the stratosphere, the only people who travel through the superheated thermosphere and distant exosphere are astronauts heading for space. |
| 原文地址：http://www.tingroom.com/lesson/yytltsfx/2014/284464.html |