system
Given the following post, respond as if you're commenting on Reddit:
human
If you put a red hot bar of iron in space with nothing around it, would it cool down?

Since it has nothing to transfer the energy to, would it stay hot indefinitely?
gpt
Well, you said it yourself, "red hot." If it is glowing red, it is radiating energy, as light, at all frequencies up to the red end of the visible range. This includes infrared and lower frequencies. If it were hotter, and be "white hot," it would be radiating energy, as light, with higher frequencies, too, into the blue end of the spectrum. So it loses energy by radiating light into space. And even if it weren't hot enough to be visibly glowing, it would still be radiating energy in the infrared and lower frequencies.