xilihutu
[个人文集]
论坛管理员
性别: 
加入时间: 2007/03/29
文章: 9279
来自: 美国
经验值: 298871
|
|
|
作者：xilihutu 在 驴鸣镇 发贴, 来自 http://www.hjclub.org
LCROSS是NASA今年6月18日发射去绕月飞行的卫星，LCROSS由LRO携带去月球为人类建立永久工作站找水，两个半月后（应该是这个8月底）LCROSS 最终会高速坠落月球（哭）。
而后，LRO 会试图为登月找寻安全着陆地点和可用资源，然后继续飞行去火星...
今天， LCROSS 将镜头对准了地球:
而且发现了：
据说这光谱图可以探测生命的痕迹：
| 引用: |
This spectrum covers part of the ultraviolet and visible range of light. The big dips in the line are due to absorption of light from certain molecules; these dips are like fingerprints for specific atoms and molecules. You can see that LCROSS clearly detected ozone (O3) and water, which you might see on any old planet. But it also saw a feature that is from free oxygen (O2) — it’s subtle but it’s definitely there — and that’s something you don’t see just anywhere. Why not?
O2 is pretty unstable; plop some of it in a random planet’s atmosphere and in a few weeks it’ll be gone, combusted, combined with other molecules to make carbon dioxide or rust or something like that. The only reason we have a lot of it in our air (more than 20% of the Earth’s atmosphere is O2) is because we have life in the form of plants. They make it as fast as animals and chemical reactions use it up, keeping it in equilibrium.
In fact, looking for free oxygen is one way scientists may eventually look for life on planets orbiting other stars. It’s an incredibly difficult observation, but not impossible, and in the future better technology may allow us to search for the elusive dip in a spectrum that tells us that aliens are breathing (or whatever aliens do) there.
Incidentally, the forest of little dips in the spectrum may be due to vegetation itself, which would be a direct detection of life. I’ll take that, too. |
http://blogs.discovermagazine.com/badastronomy/2009/08/04/lcross-detects-life-on-earth/
作者：xilihutu 在 驴鸣镇 发贴, 来自 http://www.hjclub.org |
|
|
从月球卫星LCROSS看回来
