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If the vacuum of space couldn't kill you and you had no suit... (lemmy.ca)
submitted 2 years ago by to c/asklemmy@lemmy.world
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...in what proximity would you have to be to the sun and how fast would you have to be spinning (like a rotisserie chicken) so that your light side didn't burn and your dark side didn't freeze; rotating just enough to keep a relatively stable temperature?

Absolutely absurd, I know but this question somehow popped into my head and won't leave. ๐Ÿ˜†๐Ÿ”๐Ÿ”ฅ๐ŸงŠ

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[โ€“] 63 points 2 years ago (2 children)

Outside of all the assumptions to make this work, the real issue is that the "dark side" doesn't cool you like you're thinking. Getting rid of heat in space is actually a hard problem to solve as a vacuum is a great insulator. Heat has to be radiated away, and that takes time and lots of surface area.

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  • [โ€“] 15 points 2 years ago* (last edited 2 years ago) (3 children)

    Interesting and does make sense. Where does this image of stuff freezing instantly as it "enters" space vacuum come from?

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  • [โ€“] 6 points 2 years ago

    Probably because many pop science articles will mention that the background radiation of the universe is at about 2-3 degrees above absolute zero. Plus things like the night side of mars being freezing, pluto being a frozen rock, comets being made of ice etc...

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  • [โ€“] 5 points 2 years ago (3 children)

    Depends on the entry I suppose. A liquid being sprayed out you'd imagine would do exactly that (assuming it's not being heated by sunlight), but that's probably because spraying means it's a lot of tiny droplets, all with very little heat energy individually and lots of surface area to lose it. A big block of something like hot metal wouldn't suddenly freeze, but cool as fast as its surfaces could radiate the internal heat.

    This is going strictly as a thought experiment, the math or physics is probably different to some degree.

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  • [โ€“] 8 points 2 years ago (1 child)

    Boiling/freezing depends on pressure as well as temperature, I think water would actually turn into steam if sprayed into space. There's a story of a spacesuit technician being accidentally exposed to a vacuum and he says his last memory is feeling the saliva bubble on his tongue.

    https://www.spacesafetymagazine.com/aerospace-engineering/space-suit-design/early-spacesuit-vacuum-test-wrong/

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  • [โ€“] 4 points 2 years ago

    It will do both. The initial boiling will draw heat away from the other molecules, eventually freezing them. So I suppose it wold depend on how fine the spray pattern is as well as the beginning temperature as to how much goes to gas vs. solid.

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  • [โ€“] 6 points 2 years ago

    I think an additional effect is that, the drop in pressure causes any liquids exposed to it to vaporise, which is an exothermic process, and it's a race to see whether it boils off entirely or the inner part freezes to solid from the drop in temperature through conduction. So the immediate surface of your body would either dry out or flash freeze but the inner part take a while to solidify.

    Why there is any ice in space and it doesn't just sublimate away over time I'm not sure.

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  • [โ€“] 1 point 2 years ago (1 child)

    What I had in mind was stuff like people getting shot into space in sci-fi, stuff like that. Theyre usually shown to freeze in the matter of seconds. So I guess thats unrealistic, though its a little sad because that means its a much more painful death by suffocation

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  • [โ€“] 5 points 2 years ago

    Yes, that's correct. Scenes like from Total Recall or Mission to Mars are totally wrong. It will be more like the opposite of drowning but about as bad. I'm trying to remember if The Expanse got it right in the several examples, they usually do pretty good hard science. It may have been a combination, since anyone seeing someone NOT freeze will say it looks fake.

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  • [โ€“] [S] 1 point 2 years ago

    This is exactly what I am curious about. I'm fully aware of the mountain of assumptions needed to make this work lol. I guess its the "its ~-200ยฐC out here but I'm not frozen" thing that makes my head spin a bit.

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