Why protons don't weigh 100 tonnes

摘要

Imagine looking up at the sky and seeing protons the size of planets. You'd be mighty impressed at such a sight, if you weren't pinned to the ground because you weighed as much as a blue whale. We all know the universe isn't like this - but we don't know why. Nothing in the known laws of physics says that the universe can't be built in either of these ways.