Why is space cold if there’s no matter in it?

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Why is space cold if there’s no matter in it?

In: Physics

16 Answers

Anonymous 0 Comments

The heat can’t travel because the matter holds the heat. With no matter to move it, the heat cannot move to heat- leaving it cold.

Anonymous 0 Comments

I can’t give a thorough answer, but matter holds and conducts heat, which is why you can feel heat. For instance, part of the reason that earth is warm is because of the greenhouse gases creating a sort of bubble around earth that keeps the heat bouncing around inside, creating our atmosphere. Beyond that barrier everything is different and it gets very cold. Everything is open and flows freely. And back to the first thing, matter is what holds heat or energy. That’s why when the air is more humid, there is more water in there, it can feel hotter than it really is, because the water is such a great conductor of the heat. Likewise when it’s cold, which is why you sweat to cool off (as the water/sweat evaporates off you it pulls the energy with it). I’m sorry this is a very complicated answer, I hope someone else can provide a better one

Anonymous 0 Comments

In reality there isn’t such a thing as “cold” just less hot. (Similar to how black is just no light)

Heat is the movement of atoms and molecules. So if you have no matter, you can’t have any heat.

Anonymous 0 Comments

The movie-depiction of “everything freezing to death in space” in a second is not true. And yes, space aint cold – exactly because its so empty. So, Overheating is a far bigger issuein space, because that vaccum cant transmit heat easily, you cant get rid of the heat (on spacestations / -suits) energy easily.

Anonymous 0 Comments

It’s cold *because* there’s very little matter to hold onto energy. Cold is just a lack of thermal energy.

Anonymous 0 Comments

Yea its a case of lack of molecules (hence space) heat dosnt transfer through a vacuum very well
In the sunlight temps scorch in shaded non lit areas cold.
Ironically the space station has more of a cooling problem than heating as the heat generated from the astronauts and electronics dosnt dissipate very well and large heat sinks are required to dissipate heat generated

Anonymous 0 Comments

Any matter in space will radiate away it’s heat energy until it reaches a temperature a bit above absolute zero. So space isn’t cold, it’s just that the things in space tend to become cold over time.

Anonymous 0 Comments

Most answers here are plain wrong. Space being cold is entirely unrelated to it being mostly empty. Temperature is, informally, the average speed the molecules move at; the amount of said molecules is irrelevant.

So, why is space cold? The main reason is that it is not; humans and the things around us are just pretty hot. The average temperature of the universe is much lower than Earth or the Sun might suggest. Those two are just exceptions, which we rely on to survive.

But lets also talk about what happens if you would be dropped into space without protection from temperature (while somehow still being able to breath and not in vacuum). First, this depends on where “space” is supposed to be here: if I drop you “near” the sun in astronomical terms, lets say around Earth’s orbit, then one side of you will actually heat up quite a bit due to the Sun. The other one will slowly cool down due to thermal radiation leaving your body (this also happens on the solar side of you, but is totally overwhelmed by the sun). In short, one side gets cooked, the other frozen, but slowly. If you are far away from the sun (say, Pluto), then both sides do not get much sunlight and cool the same.

If somehow you have no protection from vacuum on your skin (yet do not die from lack of breathing), then another effect kicks in and cools you down much more rapidly: water evaporating. Just like wet skin or clothes on a hot day, water cools you when evaporating. However, in vacuum, water starts boiling already at 0°C! Thus your surface is more like a hot plate rather than just a bit warm, relatively speaking. Evaporation is extremely rapid under those conditions, untill the water gets down to 0°C (it actually starts freezing when left in vacuum, even in a chamber on earth that normally has room temperature). If you had a drop of water (or e.g. blood or any other liquid that mostly consists of it) on your skin, it would even look like water on your oven. But note that your skin substitutes for some pressure, i.e. holding blood and sweat in, thus making your insides not boil, only liquids that leave your body.

Anonymous 0 Comments

Because you can expand the definition of “cold” and “hot” to include heat radiation.

If you put something in space, it will radiate away its heat after a while, until it has a certain temperature that’s very cold.

You can do this at home easily: hold the back of your hand close to a hot cup of tea without touching it: you will feal the warmth. This warmth is not transmitted through the air, but through infrared radiation.

Now take a chilled drink and hold the back of your hand close to it. You will feel the coldness of it. This is also not the air, but the “absence” of infrared radation coming from the drink, as well as the infrared radiation from your hand that takes away the heat.

Since there’s nothing in space to radiate heat onto you, you will radiate your heat away and become very very cold.

Anonymous 0 Comments

In space hot bodies transfer their heat to colder bodies through heat radiation. If you were floating in space you’d be giving your energy away to everything you can see around you (mostly empty space).