system
Given the following post, respond as if you're commenting on Reddit:
human
What happens to light that is absorbed by a black object?

When photons enter my prized lump of coal, do they just bounce around in there indefinitely? Are they absorbed by electrons undergoing quantum leaps?
gpt
A material is made up of lots of charges. Roughly speaking there's a more-or-less static "lattice" of positive nuclei, the electrons bound to those nuclei, some electrons shared in covalent bonds, and in some materials, electrons freely floating between the nuclei (like metals). All of these charges mean that there's a rather complex electromagnetic field already present within the material. You can think of it as many many photons real or virtual flitting about exchanging momentum between particles.

When a photon encounters a material, that electromagnetic field of the material, what we often call an "effective" EM field, can absorb the photon and do a number of different things with it. In transparent materials, an energy proportional to the energy of the incoming photon will pass through the material at a speed slower than c, to perhaps emit or reflect at the other side.

In "opaque" materials, the energy might go into vibrating the lattice a little bit more. This vibration is a kind of random motion that we will often just lump all together and call heat. (think of it kind of like the photon is a very small mallet hitting a gong)

In "reflective" materials, which tend to have free electrons moving about unbound to nuclei, these free electrons respond with an equal-and-opposite photon of their own. Emitting a "new" photon according to the laws of reflection while they are absorbing the "old" photon that comes in.