This thread reminded me of a question I’ve been meaning to ask.
In 2004, there’s going to be a probe sent to Mercury. Given that Mercury has a (very thin) atmosphere, and that there appears to be ice in craters at the poles, it stands to reason that there is some small zone between ice and baking daylight where liquid water, and life, are possible, and worth searching for.
At least, I think it stands to reason. Am I missing something?
The thread linked above is what reminded me to ask the question, but here’s the more relevant link:
http://www.cnn.com/2001/TECH/space/06/08/mercury.orbiter/index.html
If there is any sort of primitive life on Mercury it’s gotta be some of the hardiest stuff around. The CNN article said the sun is 11 times brighter on Mercury than on Earth, so I’d think that there would be an equivalent rise in solar radiation across the spectrum. Just because there’s ice in places where the sun may not reach doesn’t mean it’s not being bombarded by anything else the sun spews out.
There’s also the point that locations where ice may be found on Mercury are probably also an extreme, temperature-wise. I don’t remember how cold the night side of Mercury gets (a little voice in my head is saying roughly -300 F) but given that its atmosphere is paper thin, planetarily speaking, I doubt it holds in enough heat to keep anything from freezing to death.
Mercury has almost no atmosphere, let alone one containing hydrogen and oxygen. Still, I don’t think this eliminates the small possibility of life such as bacterial thermophiles.
Waverly why must there be hydrogen and oxygen. Aren’t there bacteria here on Earth that live in molten lava that require none of these traits for survival. Why do we assume that an alien life form would need oxygen to live?
You are referring to the bacterial thermophiles that I mentioned. Lack of oxygen and nitrogen merely eliminates most [but not all] permutations of life as we know it.
Mercury’s atmopshere just consists of a tenuous wisp of solar wind that its gravity can temporarily hold on to. There isn’t enough pressure for liquid water to exist at the surface.
No liquid water, no life as we know it.
Of course, one can speculate endlessly about life as we don’t know it, but, that’s the point, it’s empty speculation, and it’s endless.
How can Mercury’s atmosphere be made up of solar wind? As I understand it, the solar wind is a stream of charged particles, not an actual gas that could form any kind of atmosphere.
Yesterday man – I think your sig should say the large print giveth…
Whaddaya think the particles are? 
The solar wind is a plasma of electrons and ions, and the gasses that Mercury captures from the solar wind usually remain in ionized form, and are trapped by Mercury’s magnetic field. The solar wind also blasts ions off Mercury’s surface, and these are a significant atmospheric constituent. I’m having a hard time finding a good source for the composition broken down by percentage, but my astronomy text here lists hydrogen and helium from the solar wind, plus sodium and potassium from Mercury’s soil. The composition probably varies over time as the solar wind varies, Mercury gets closer and farther from the Sun, etc.
Although bacteria have been found that live in boiling water, I don’t think any have been found that actually live in molten rock. (Lava can be at temperatures of over 1,000° Celsius.)