What if dark matter is just regular matter that's not very well lit up? What do you think?
There are a variety of ways that we measure the amount of dark matter that is out there. One is to use gravitational lensing to estimate the mass of an entire galaxy or galactic cluster, and then to estimate ordinary matter based upon the luminosity of the visible stars which astronomy observations lead us to infer constitute the vast majority of baryonic matter, and then to adjust slightly for non-luminous sources of ordinary matter like neutrinos, interstellar gas, planets, stellar black holes, MACHOs etc.What if dark matter is just regular matter that's not very well lit up? What do you think?