 Here's Betelgeuse in early 2019. Normally, the star expands and contracts, brightening and dimming on a 420-day cycle. However, in October 2019, the star dimmed dramatically. Hubble captured signs of dense, heated material moving through the star's atmosphere in September, October and November 2019. Then in December, several ground-based telescopes observed the star decreasing in brightness in its southern hemisphere. By mid-February 2020, the star had lost more than two-thirds of its luminosity. The ultraviolet observations by Hubble suggest that the unexpected dimming was probably caused by an immense amount of super-hot material ejected into space. The material cooled and formed a dust cloud and blocked the sunlight coming from about a quarter of Betelgeuse's surface as seen from our line of sight. By April 2020, the star returned to normal brightness. The giant star is destined to end its life in a supernova blast. Some astronomers think the sudden dimming may be a pre-supernova event.