Pretty much everything that is either capturing or releasing energy is giving off a spectrum of EM radiation. Usually it is mostly in the IR range, but you really just need sensitive enough equipment to get all sorts of EM noise.

Not "pretty much everything" but actually everything. The only way an object wouldn't emit radiation is if it was at absolute zero, which is something that exists literally no where in the universe.

That said, this light is not the result of just radiating heat and must have a different source.