The Great Conjunction

 

Near the end of December 2020, I saw Jupiter and Saturn very close in the sky just after sunset. I didn’t know this was called a great conjunction. The next one will happen in November 2040. And it will happen in a very different part of the sky: close to 120° away.

This is how it always works. People have known this for millennia. They just forgot to teach me about it in school. The time between great conjunctions is always roughly 20 years, and if you keep track of them, each one is...