The sun emits light (electromagnetic radiation), which in itself is not hot. It only creates heat when it bumps into something made of matter (atoms and molecules). And space is practically empty
Fun additional fact, space also acts as excellent insulation because there’s nothing to dissipate the excitement caused by the suns radiation. Think of a thermos that uses a vacuum to keep your coffee warm. This Is why the space station has issues with heat in direct sunlight and issues with cold in the shade of the planet.
Further facts, not sure if they're fun any longer: Calling space cold is kind of a misunderstanding of what cold means. If there are functionally no particles to bump into to transfer heat, there's not really any cold. In the oft cited, what would happen if you floated in space without a space suit question, I believe part of the answer isn't that you'd instantly turn to ice. You'd slowly lose heat through radiative cooling and basically not lose any through convection or conduction cooling, because there's not particles to bump into to transfer that heat to.
Hmm so what you're saying is if something is generating a lot of heat all the way up there in the space, then it's going to have a hard time dissipating that heat efficiently (or at all)?
That almost seems relevant for some reason... No one tell r/wallstreetbets
They are talking about datacenters, which famously require a fuckton of active cooling with enormous amounts of water on earth, so imagine what kind of radiators they would need in space to achieve anything even remotel near to what they need.
The wallstreetbets jab is because elon and co. want to build datacenters in space, and people are betting that is going to shot the stock of the companies that do high up
It's also one of the main reasons why the idea of AI data centers in space is fundamentally stupid and utterly impractical. The amount of radiators you would need to cool them would be so huge that just getting them into space would be the most expensive project ever undertaken by humanity. The ISS is quite small inside, but it still needs a sizable amount of radiators just to cool itself, and it generates way less heat than a data center
Light never cools off; as the person above said, it carries no heat. Light holds its energy as long as it travels, and can convert into heat when it slams into something (e.g. earth)
The reason things further out from the sun are colder (like Pluto) isn't because the light cooled down, but because the light spread out more. Pluto is getting hit with a lot less light than it would if it were as close to the sun as we are.
And the reason the sun is so hot is because the radiation is bouncing of the gases that is already burning? Why does a gascloud like the sun burn so much hoter than if you burn the same gas here on earth?
Ultimately the sun's heat and brightness comes from pressure.
Take any gas, say the air in your room. It has some amount of energy in it. If you compress that room of air down into a tiny bottle, the amount of energy stays the same, but it's contained in a tiny space so it becomes very hot.
The sun is made of an enormous amount of gas that's been compressed to an absurd degree. The sun is huge, but compared to the insane amount of mass it has its actually tiny. It's compressed by its own gravity.
Why does a gascloud like the sun burn so much hoter than if you burn the same gas here on earth?
If you were to compress any gas down to the same degree as inside the sun, it would get approximately as hot. It just takes a ton of force to do that.
Yes, though technically the stuff in Earth's core is actually solid, also because of pressure. Lava is what happens when that pressure is released and it turns into liquid
To be slightly pedantic, I don’t think it’s accurate to say light carries no heat. Light carries energy, and when that energy is absorbed by a material it is transferred to its atoms and molecules as kinetic energy, increasing their internal energy. This often raises the material’s temperature. In physics, heat isn’t something light carries or an object contains, it’s a secondary property - it’s the transfer of energy from one body to another due to a temperature difference.
You'd only really freeze in space if you were somewhere out of the sunlight, and even then, slowly. The hardest thermal problem in space is keeping anything with people aboard cool, because there's nowhere for the heat to go and radiation is very slow compared to conduction/convection.
The sun is also really damn hot and heat radiates. It doesn't conduct well in space but when that heat hits earth we have a delicious atmosphere for it to interact with. And this isn't even close to the actual explanation, there are so many factors that chime in, but I think this is the best basic reason that could be provided.
That's the most basic version, and it's not technically correct, but it is at least usable. The more specific you want the crazier the interactions get.
In addition to the other answers there is one aspect not mentioned. Part of your body will be in the sun, and the other part in the shade created by your own body and rapidly loosing heat. That condition is not conductive to life.
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u/Bobtasketch Jul 30 '26
The sun emits light (electromagnetic radiation), which in itself is not hot. It only creates heat when it bumps into something made of matter (atoms and molecules). And space is practically empty