Why is space cold if there’s no matter in it?
In: Physics
Cold is just the lack of heat. They aren’t two opposing forces; heat is the force, cold is what you get when heat is missing.
Without anything to warm it up (the sun, hot molten planetary core, a radiator), everything gets cold. That’s the natural way of things. Areas completely devoid of any sources of heat whatsoever sit at absolute zero.
Heat travels through particles (picture warm particles “vibrating” with warmth, so much so that they make their close neighbours vibrate too, which makes *their* neighbours vibrate). This means you need a lot of particles at a reasonable density in order for things to be warmer.
Space has so few particles that the heat that exists in the universe has no way to travel. The few particles that do exist out in the void of space are very spread out, and unable to transmit warmth to their neighbours.
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