Betelgeuse’s mysterious ‘Great Dimming’ may have been triggered by a wandering black hole

In late 2019, the star Betelgeuse dimmed by about 60%. While it’s impossible to say with certainty exactly what caused it, new research suggests that a wandering companion may have played a role. By swinging close to the giant star, the interloper may have raised a tidal bulge, causing the surface of Betelgeuse to dim. While this scenario can’t explain the full amount of dimming observed, it may have triggered other effects on the star that made the problem worse, researchers propose in a new paper.