Summary:
- Astronomers have finally solved the mystery of why Betelgeuse, a bright red star in the Orion constellation, suddenly dimmed in 2019-2020.
- The dimming was caused by a giant cloud of dust that formed in the star's atmosphere, blocking some of the star's light from reaching Earth.
- This dust cloud was likely formed by a large surface mass ejection, similar to solar flares on the Sun, which hurled material out into the star's atmosphere.