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Competitive_Way_5485 t1_j4u3hrp wrote

Reply to comment by TheJasonKientz in What happens to the energy of sound in space? by full_hammer

Ok, i understand. But how do we Communicate in the Vacuum of Space from Earth to Moon. How do the Signals move without any chance to form a Wave? And why do we freeze in Space?

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gab_r95 t1_j4u45u9 wrote

The signals are electromagnetic waves (light, microwave, radio...). They don't need a medium, and actually in a vacuum they go as fast as possible (speed of light). We freeze in space by radiating the energy away (thermal infrared).

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Jai84 t1_j4uhxzz wrote

Also, (I see people going back and forth on this a lot, but here’s my understanding….) you wouldn’t freeze super fast like you see in movies. There might be ice forming on your skin, but in general there’s not really any matter (there’s an infinitesimal amount even in the “vacuum of space”) for your body to interact with, so the only heat your body is loosing is from slow radiation. I’m assuming you’re also gassing off water vapor and other things into the vacuum from your skin, eyes, mouth, lungs, etc. which would cause a loss in temperature locally I think? I haven’t done a lot of research in this, but I think the general understanding is you’d take awhile to actually “freeze up”. You’d be dead and floating around and looking stiff because there’s minimal forces acting on your limbs etc., which could give the impression you’re frozen.

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Jarlentium t1_j4uk8n8 wrote

Yeah decompression is what will kill you not freezing

And spacecraft don't have freezing issues, they have overheating issues because there's no medium to transfer heat out of the ship

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Poopster46 t1_j4usgbv wrote

> I’m assuming you’re also gassing off water vapor and other things into the vacuum from your skin, eyes, mouth, lungs, etc. which would cause a loss in temperature locally I think?

Absolutely. Due to the extremely low pressure in space, any liquid water would immediately evaporate, as the boiling point is inversely related to pressure. This will cause your surface temperature to drop. But as soon as that's over, your core temperature would probably offset that again.

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Thundahcaxzd t1_j4u4794 wrote

Sound is molecules bumping into each other, so it needs a medium. Electromagnetic radiation such as light or radio or microwaves etc are something else entirely and dont need a medium.

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TheJasonKientz t1_j4xlz53 wrote

The other answers about communicating are correct, we use radio wave which are light and which do not require a medium to propagate.

We freeze in space because there are no molecules in the air (there’s no air) bumping into our skin. On earth, air molecules are constantly bumping into you and transferring the energy they have picked up from the suns rays or from other air molecules. When this happens your badly stays warm.

But if you go to the top of a mountain, even in a sunny day it’s really really cold because the air is very thin. Actually you might be warm on the top of the mountain if you were in the sun because the suns rays would heat you up but if you were in the shade you’d get real cold. Even the back side of you body, the part not facing the sun would get real cold.

This is what happens in space as well. Things that are in direct sunlight are very hot and things that are in the shade are extremely cold. Because the only natural heat source when there is no air are the rays from the sun.

The James Webb Space telescope is over 200 degrees Fahrenheit on the sun lit side and is less that -350 degrees Fahrenheit on the dark side. There is almost a 600 degree difference. All because there is no air.

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