system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the vacuum of space have a temperature at all? What is it that has the temperature?
gpt
It’s the temperature that a perfect black body will heat up to if you left it in that spot. It has a temperature because light can heat up objects, but objects also emit light as they heat up. An area of space in our solar system will be receiving a certain amount of light from the sun, which will cause an object to heat up until it is hot enough that its own radiation balances with that its receiving from the sun. That temperature can be thought of as the temperature of that area of space.