Heat is atoms vibrating and bumping into each other. The way heat typically transfers and dissipates on earth is atoms bump into other atoms, transferring the energy to those. But this requires things to be in physical contact. If there is nothing to touch, heat can’t be dissipated the normal way. This is how thermoses work; there is a vacuum in between layers of metal, heat can’t cross the vacuum which makes it harder for heat to escape.
The glow you see from something “glowing hot” is black body radiation . Basically everything emits light at a wavelength dependent on how hot it is. Things that aren’t yet “glowing hot” are just emitting light that is at a lower wavelength than we can see, like infrared. That’s how some night vision googles work: they can detect the difference in infrared light emitted by something at body temperature and something at room temperature.
Black body radiation carries energy, cooling the thing that emitted it and warming whatever ends up absorbing it. In space, this is the only way to dissipate heat. Satellites often have large heat radiators designed to dissipate heat in this way as efficiently as possible, but it’s still much, much harder than on earth, because you basically have a hot thing you want to cool down but you’ve put it in a vacuum thermos.
They don’t. Not very well anyway. It’s a major engineering challenge to relocate the heat away from crew areas and towards areas that are very large and pointed away from the sun.
On earth we take advantage of the huge amount of stuff around us to move heat around and get things the temperature we want. Take some ambient temperature gas, manipulate it just right and you can move the heat from one part to another. Put that next to a hot room and the room tries to equalize with the gas. Move the gas back to the start and repeat and you’re moving heat around. It works because we have stuff to use as a heat sink.
In space, that doesn’t work. There’s nowhere to move it. You need to rely on things emitting a little bit if light proportional to their temperature. Glowing with heat is something everything does, it’s just usually not visible when you or I do it. It’s how thermal cameras work.
So things in space cool down by gently glowing. It’s not very fast and is nowhere near as efficient as dumping hot water on the ground.
On top of all the other explanations is that deeper realization that can bend your mind a little. Space isn’t hot or cold, it is a void outside of that definition. In the same way you cannot see out the back of your head and that you are not aware of there being a deficiency of sight in that direction. It’s a non-event.
Also when it comes to heat radiations, on the right wave length we are all glowing all the time. That’s now heat vision works. Very neat to think about.
This doesn’t make sense to me, heat doesn’t radiate and diffuse in space?
How do craft “cool down” after leaving the atmosphere? Why aren’t they always glowing hot?
(not an engineer or scientist or even smart)
Heat is atoms vibrating and bumping into each other. The way heat typically transfers and dissipates on earth is atoms bump into other atoms, transferring the energy to those. But this requires things to be in physical contact. If there is nothing to touch, heat can’t be dissipated the normal way. This is how thermoses work; there is a vacuum in between layers of metal, heat can’t cross the vacuum which makes it harder for heat to escape.
The glow you see from something “glowing hot” is black body radiation . Basically everything emits light at a wavelength dependent on how hot it is. Things that aren’t yet “glowing hot” are just emitting light that is at a lower wavelength than we can see, like infrared. That’s how some night vision googles work: they can detect the difference in infrared light emitted by something at body temperature and something at room temperature.
Black body radiation carries energy, cooling the thing that emitted it and warming whatever ends up absorbing it. In space, this is the only way to dissipate heat. Satellites often have large heat radiators designed to dissipate heat in this way as efficiently as possible, but it’s still much, much harder than on earth, because you basically have a hot thing you want to cool down but you’ve put it in a vacuum thermos.
Nice explanation!
Thank you. I’ve decided that the wings on the TIE fighter are heat radiators, not solar panels as I previously surmised.
They don’t. Not very well anyway. It’s a major engineering challenge to relocate the heat away from crew areas and towards areas that are very large and pointed away from the sun.
On earth we take advantage of the huge amount of stuff around us to move heat around and get things the temperature we want. Take some ambient temperature gas, manipulate it just right and you can move the heat from one part to another. Put that next to a hot room and the room tries to equalize with the gas. Move the gas back to the start and repeat and you’re moving heat around. It works because we have stuff to use as a heat sink.
In space, that doesn’t work. There’s nowhere to move it. You need to rely on things emitting a little bit if light proportional to their temperature. Glowing with heat is something everything does, it’s just usually not visible when you or I do it. It’s how thermal cameras work.
So things in space cool down by gently glowing. It’s not very fast and is nowhere near as efficient as dumping hot water on the ground.
Thank you for your answer
On top of all the other explanations is that deeper realization that can bend your mind a little. Space isn’t hot or cold, it is a void outside of that definition. In the same way you cannot see out the back of your head and that you are not aware of there being a deficiency of sight in that direction. It’s a non-event.
Also when it comes to heat radiations, on the right wave length we are all glowing all the time. That’s now heat vision works. Very neat to think about.