In late 2019 and early 2020, Betelgeuse blew its top.

Literally.

Around that time the famous bright star marking the right shoulder of Orion suddenly started dimming, dropping to about half its usual brightness. I still remember going outside and staring wide-eyed in awe of the star; it was substantially dimmer even by eye.

Despite a lot of people freaking out that this meant it was about to go supernova — it wasn’t, it isn’t , and a lot of us spent a lot of time putting out fires on the internet about that — this was still an extraordinary event, and a lot of astronomers who study red supergiants were pointing their telescopes at Betelgeuse to try to figure out what happened.

Observations from the Very Large Telescope were stunning , showing that the entire southern hemisphere of the star had dimmed. Mind you, Beteleguse is about a thousand times bigger than the Sun — replace the Sun with it and it would extend out past Jupiter! — so this was a massive event.…