Science joke

Okay, so I just came up with this, and I'm really proud of it. That will probably only continue for the next five minutes, so I'll hurry up and tell it:

So Stephen Hawking, Albert Einstein, and Niels Bohr all end up in this weird alternate universe where famous people (dead and living) get together for the sake of being material for great jokes. After years of walking into different bars and crossing that famous road, they finally all run into each other.

Upon meeting each other, they are all suddenly beset by an impulsive urge to engage in a footrace. For the sake of impartiality, they enlist Sir Isaac Newton as the official. Sir Newton spends two minutes jamming ball and powder into his 1700s pistol, and then he fires it in the air, signaling the beginning of the race.

Stephen Hawking wheels into a black hole and pops out at the finish line.

Albert Einstein grabs an anvil and yells that because E=Mc^2, he just performed the equivalent of beating everybody in the footrace.

Niels Bohr...it's hard to tell what happened with Bohr. Witnesses of the race say that he lost by a mile, but Bohr contends that he won while nobody was watching.

In order to settle the dispute, the three famous physicists all come up to Sir Newton to see what he says, being the father of physics and everything.

Sir Newton opens his mouth to answer, but only blood comes out. He had been suddenly struck by the ball he had fired into the air minutes earlier, because as we all know, what goes up must come down.