Comment on The sun is a deadly laser...

• Mesophar@pawb.social ⁨3⁩ ⁨weeks⁩ ago

  Are you dissipating heat in a vacuum, though? Pressure shenanigans aside, would someone’s body heat slowly, continually build up, or would they freeze?

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  • Tar_alcaran@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    If you could somehow prevent yourself from dying due to lack of pressure, you would radiate about 650W more than you generate.

    That’s using the Stefan Boltzmann law, at normal body temp, perfect blackbody and 1.5m2 of skin. And then assuming 2000kcal a day.

    You’d cool down pretty quickly.

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    • ivanafterall@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      So how long do I have? Also, if you guys could hurry with the answer…?

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      • Tar_alcaran@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

        I can’t really find a good number for how cold you can get and not die, so let’s say 20 degrees. That gives 16 degrees.

        Meat has a specific heat of about 3.5kJ per kilo per degree, so say you weigh 70kg, that’s about 4 million joules to lose before you die.

        At 650 joules per second, you’ve got slightly over 10 minutes.

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      • Fedizen@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

        RIP

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    • Mesophar@pawb.social ⁨3⁩ ⁨weeks⁩ ago

      Good to know! I didn’t realize humans would radiate heat so much, I wrongly assumed it was more convective and relied on atmosphere

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  • ExperiencedWinter@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    en.wikipedia.org/wiki/Black-body_radiation

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  • rockerface@lemmy.cafe ⁨3⁩ ⁨weeks⁩ ago

    Heat buildup is actually a problem in space, yeah. You need heat sinks on long term space flights.

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  • DaddleDew@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    You constantly radiate heat. The warmer you are, the faster you radiate it away. In space this does not stop.

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    • craftrabbit@lemmy.zip ⁨3⁩ ⁨weeks⁩ ago

      Have you ever looked up at a clear summer night sky? Your face will feel cold. Colder than when looking at the ground. That’s because there’s not as much stuff radiating heat at you up there.

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  • hemko@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago

    It would be pretty warm at earth if the planet didn’t radiate some of the heat away

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