system
Given the following post, respond as if you're commenting on Reddit:
human
When you heat metal a lot, it glows. Where are those photons of the glow coming from?
gpt
The surprising thing is actually that the metal glows all of the time.  When you heat it, it shifts the peak wavelength of the emission to a wavelength that you can see.  If you put on infrared goggles, you would see it "glow" before you would see it with unaided eyes. When something heats up, the wavelength of emission gets shorter (higher frequency), which represents that it has more energy. This is called blackbody radiation, and happens with almost all normal objects around us, including the sun (why the sun is yellow!) and the Earth (glows in infrared!).