system
Given the following post, respond as if you're commenting on Reddit:
human
If the vacuum of space is a poor conductor of heat, how do stars give off so much of it?

Mostly interested on if this principle could be used in spacecraft to get rid of excess heat?
gpt
Heat transfer happens through 3 primary methods: Conduction, convection and radiation.

As the name implies, the property "conductivity" only applies to the first of these three methods. In space, there is no heat conduction (or convection for that matter), so we say that the conductivity of vacuum is very low (essentially 0).

Stars give off their heat through the third method: radiation. Stars emit massive amounts of electromagnetic radiation (visible light, infrared, UV, etc... the spectrum depends on the temperature of the star).

Radiation is also the only way for a spacecraft to shed its excess heat. Unfortunately, radiation is not very effective at doing so (but since stars are so large, they still emit a lot of heat that way), but it's the only practical solution available.