"It’s hard to know just when a star will explode when you’re on the outside. Betelgeuse might go up tonight, or it might not be for 100,000 years. We’re just not sure....The post also talks about Betelgeuse shrinking. That claim is from observations made over the course of many years. Those data indicate the star is shrinking, but it’s unclear what they mean. While it may mean the star is in fact shrinking, starspots (sunspots on another star) may be fooling us, for example. Also, red supergiants aren’t like marbles, with a clean, sharp surface. They are balls of gas, extended and bloated, so there is no real surface. It’s therefore entirely possible the astronomers aren’t even really measuring the surface of the star at all, and it’s just the highly extended atmosphere that’s changing." - bob