- cross-posted to:
- curatedtumblr@sh.itjust.works
- cross-posted to:
- curatedtumblr@sh.itjust.works
cross-posted from: https://feddit.uk/post/44126927
Goldilocks
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If that blows your mind then think about this: As the universe expanded after the Big Bang, it cooled from unimaginably high temperatures. In principle, this suggest that there could have been a very short window much later, tens of millions of years after the Big Bang, when the background temperature of the entire universe was capable of sustaining life everywhere. Some physicists have suggested this might have created a brief, universe-wide “habitable epoch,” though this remains theoretical.
I’m not an expert, so this is probably not a muture understanding, but it’s cool to imagine a universe where life was incredibly abundant.
Interesting theory, I’d never heard of it before. All of the sudden, “a long time ago, in a galaxy far, far away”, actually seems plausible (although this theory looks like it came well after SW in 2014).
The actual paper about it: https://lweb.cfa.harvard.edu/~loeb/habitable.pdf
but it’s cool to imagine a universe where life was incredibly abundant
There was probably nothing but helium, hydrogen and a tiny bit of lithium at that period.
Those are some of the best elements though.
They surely are popular…
The dark side of your body in space is freezing cold while the light side gets hot. You really need to rotate to get that even crispy layer.
Vacuum doesn’t have a temperature~
But you will if you sit in a vacuum for a while without a radiation source nearby, and it will be quite low.
Are you dissipating heat in a vacuum, though? Pressure shenanigans aside, would someone’s body heat slowly, continually build up, or would they freeze?
If you could somehow prevent yourself from dying due to lack of pressure, without blocking heat, 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. (~ 750 Watt) And then assuming 2000kcal a day (~100W)
You’d cool down pretty quickly.
You constantly radiate heat. The warmer you are, the faster you radiate it away. In space this is the primary way you lose heat.
In your living room you are constantly bombarded by radiated heat from all the objects that surround you, even if they’re just at room temperature, which lessens the effect. In space, not so much.
Someone who knows better might chime in, but as far as I know the trope of rapidly freezing out in space is exaggerated. You would definitely freeze eventually, but perhaps not as dramatically fast as portrayed in The Guardians of The Galaxy for example.
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.
Heat doesn’t work quite like that. In order for heat to transfer efficiently, there has to be “stuff” for it to transfer to. Vacuums are famous for lacking “stuff”.
You’re talking about conduction. I’m talking about radiation.
Sure, but radiation acts extremely slowly in the scenario of a person in the vacuum of space.
Yes it is. But it is the main way by which things cool down in space.
That’s how satellite electronics are cooled down. They have large heat sinks that slowly radiate heat away.
Infrared
Bonus: Making Infrared Cooling Paint From Grocery Store Items
Heat buildup is actually a problem in space, yeah. You need heat sinks on long term space flights.
It would be pretty warm at earth if the planet didn’t radiate some of the heat away
Yes. Like all multipliers the heat of the sun requires not only itself the thing that which is acting but also that which is to be acted upon. If you are a handsome wet rock, the distance you are to the sun effects how your heat is multiplied.
Is water wet?
No, water makes other things wet.
balmy is an understatement
