How do you explain Einstein’s Theory of Special Relativity when you don’t allow yourself to use the word “relativity”? Or “gravity”? Or “Einstein”? Or pretty much everything else you find in a science textbook?
That’s the challenge Randall Munroe (creator of XKCD) gave himself in an essay for the New Yorker, where he limited his explanation to the one thousand most commonly used words in the English language:
People have known for a long time that you can’t say how fast something is moving until you’ve said what it’s moving past. Right now, you might not be moving over the ground at all, but you (and the ground) are moving very fast around the sun. If you say that the ground is the thing sitting still, you’re not moving, but if you say that the sun is, you are. Both of these are right: it’s just a question of what you say is sitting still.
Some people think that this idea about moving was the space doctor’s big idea, but it wasn’t. This idea had been around for hundreds of years before him. The space doctor’s idea came up because there was a problem with the old idea of movement.
Oh, it just gets better from there.
It’s the sort of explanation you’ll find many times over in Munroe’s latest book, Thing Explainer: Complicated Stuff in Simple Words, which will be released next week.
(Image via Shutterstock)