Does anyone know what hadronic matter is, and why it is important? I was reading something about it, and I thought it looked interesting, so if anyone knows something about it, I would appreciate the input. Thank you!
Hadronic matter is ordinary matter, like you and me. Hadrons are subatomic particles that feel the strong force; the most common hadrons are the proton and neutron. They make up the nucleus of the atoms that make us up, and the great amount of our mass. The electrons only contribute less than 1/1800th of the mass.
The importance of hadronic matter in cosmology is what it can't do. It can't account for all the gravitation we infer from the motions of the galaxies. So there must be something non-hadronic that does this. This is the famous "dark matter".