If the Sun generates so much heat, why do astronauts have to worry about freezing?

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I see a lot of videos and shows where, if a person gets thrown out of an airlock, they immediately freeze to death. Disregarding the usual Hollywood exarcebation, WHY is space “cold” if the Sun generates so much heat radiation that it warms our very planet every day? Shouldn’t space be “warm”, then?

In: Physics

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Anonymous 0 Comments

Warm and cold don’t really make sense in a vacuum like space

There aren’t many particles so the average kinetic energy of a given volume is extremely low so space is extremely cold, but since there aren’t many particles you won’t conduct heat away almost at all, it’ll have to slowly radiate away from you

The sun meanwhile is blasting a ton of light at you which will heat you up if you don’t reflect it away. This is why most things in space are white or reflective because overheating in space is a much bigger problem than freezing

If you were shoved out an airlock with a little oxygen mask so you didn’t immediately suffocate and die, you would end up overheating quite quickly(even if you weren’t in direct sunlight) because your body is a 100W heater and without air to conduct the excess heat away to you’ll begin to get warmer and warmer until you overheat and die.

Most of an astronauts spacesuit is insulation to protect them from the sun’s heat, and water cooling to keep them safe from their own body’s heat

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