system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to heat in a vacuum? why is space cold and earth (with an atmosphere) warm?
gpt
Heat doesn't really exist in a vacuum.  Space is cold because there's almost nothing there, and almost nothing holds almost no energy.  If there is an object with temperature in a vacuum (such as a human being), the heat stays where it is until it very slowly radiates away.