Black holes do exist however I think we don't know enough about them to actually conclude something. I'm talking about the properties they have and the rules they follow.
Lately I've been intrigued by the concept of "dark matter" and "dark energy." Wiki those topics and just read the synopsis. It's the idea that something is holding our universe together. It's the foundation and structure that defines how fast a galaxy spins, where space gas accumulates, or how stars burn.
Gravity, light, energy, mass, wavelengths, etc. I think there's a few more "real world" phenomena that has yet to be discovered and it involves the 90% of our universe that we don't understand.
They're doing studies now to see if light exerts gravity.
