The northern states. The adjacent image shows an instrument which uses the absorption of light by atoms in that hot tube as a means of detecting them. This process is very, very sensitive and can detect specific atoms in the parts per billion range in environmental samples. This impulse is collected via the optic nerve and passed to your brain which has learned how to interpret this signal as sight. So there are lots of forms of electromagnetic radiation that we may want to detect that can't be seen by our eyes since we only see photons of wavelengths from about 400 to 700 nm.
Chemiluminescence is light given off because of a chemical reaction.
Here is a movie showing a chemical reaction that occurs at room temperature. The reaction that takes place produces energy that does not take the form of heat. Instead it yields highly excited chemicals products which give off energy in order to stabilize themselves. The result is chemiluminescence . Furthermore, that process of light causing changes in electronic structure that we saw with Rhodopsin also has implications for other kinds of matter.