LAST UPDATED: March 25, 2020 by Ryan M
I spent quite a bit of time trying to answer this question so a 10-year-old could understand it. In the end, I was at about 2,000 words and wasn’t even close to finishing my answer. The best I can do is direct you to Richard Feynman answering this question in the wonderful video below. If you have a good concise answer, let me know and I’ll use it.