Q: How many science fiction writers does it take to change a lightbulb?
A: Two, but it's actually the same person doing it. He went back in time and met himself in the doorway and then the first one sat on the other one's shoulder so that they were able to reach it. Then a major time paradox...
An unexplained Mass!
I'm so sorry.
Anyway I'm me and I like maths and physics, but I don't know that much yet. I'm always open to people pointing me towards interesting resources for learning, and I love to discuss anything, well most things anyway. I'll always try to get the facts.