Graphite bricks six feet long sit glowing at 2,400 degrees in a Boston suburb, hotter than half the surface of the sun, and the way you switch the power on is to lower a panel into the light and the way you switch it off is to pull it back out

By Luis Reyes – AutoNation

Anything hot enough gives off light. You have seen it in a campfire, on an electric stove burner, in the orange end of a blacksmith’s iron before it goes back on the anvil.

Keep pushing the temperature and that glow gets brighter fast. Much faster than the temperature itself climbs, in fact. Double the absolute temperature of an object and it does not emit twice the light, it emits roughly sixteen times as much, because the emission scales with the fourth power of temperature.