h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I was watching a programme on BBC Knowledge last night about Mars. IT was on about melting the ice in the core to ultimately create an atmosphere, life etc (like in 'Total Recall').....and my friend and I were having a debate what the temparature on Mars is (compared to the earth) and I reckon its a lot cooler....is it?

Also as a star gets older does it get hotter and then as its fuel supply diminishes it starts to cool and ultimately implode?????

Anybody?????................stay lucky.

Hmm, seems the guys doing that program has seen too much Totall Recall. If you´ve seen the ending scene in Total Recall, Arnolds eyes is about to pop out because of the low air pressure. Then when they get the atmosphere machine started, he returns to normal. But in real life, the reason why Mars has such little atmosphere is because of it´s small gravity. So setting off the atmosphere machine all the air would come out, and everything the Mars-gravity couldn´t hold back would just disappear into space. So it would only have normal air pressure for perhaps a few seconds before it would return to normal. So if the credits hadn´t started there in the movie, you would have seen Arnold again having his eyes popped out. And melting the ice in the core(is there even ice in the core?) wouldn´t create the right kind of atmosphere. There would be too much oxygen in the atmosphere, so we wouldn´t survive for long. And what about an ozone layer?

Stars die in different ways depending on their size. Our Sun is going to swell up and get all hot. That´s called a red giant. Then the inner planets will be within the sun, and the rest of the planets will get a lot hotter. Which means Mars might actually get a climate that could sustain life. But it won´t happen untill in 5 billion years. You can find more info on just about any site on astronomy.

Whew, a long message

Erm, actually, red is cooler than yellow so as the Sun goes into its Red Giant phase and swallows the Earth, it will be cooler than it is now in terms of surface temperature. It'll get hotter here because the surface will be getting closer and closer to us until we're consumed.

Blue stars are hotter than yellow stars and white stars are the hottest. After the Sun belches off its outer gas shells, leaving the core exposed, it'll be a White Dwarf - very hot, but also very small.



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