Atmospheres

[Wanderer]

Originally posted by capnq:

quote:

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You are not going to go to another galaxy and find that suddenly the laws of physics stop applying or get changed

There are a number of science fiction stories where this assumption turns out to be false.

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I think it's more than an assumption - although we might not have travelled to other parts of the universe, we have observed them with all manner of telescopes and not noticed any glaring differences.

For example the WMAP probe (whose first results were published Last week) read temperatures differing by just millionths of a degree in the cosmic background radiation from different directions. Were the rules of physics different in different regions of the universe we'd expect to see a lot more variety.

Of course, science fiction gives you the liberty to create your own rules, thank goodness.

A side note concerning the atmosphere: oxygen is actually toxic for humans above a certain partial pressure. The figure US Navy divers came up with was 1.6 bar. That is, if you breathed in pure oxygen at more than 1.6 times atmospheric pressure (or normal air at more than 8 times atmospheric pressure) you'd experience dizziness, vomiting, black-outs and, eventually, death. This is why divers don't usually carry 100% O2 in their tanks as it limits them to staying within 6m of the surface... one man's meat is another man's poison.