The death of Orion's Betelgeuse. The eventual destruction of Betelgeuse will mark the end of a star that has already lived an eventful life. Once a massive, blue-white O-type star, Betelgeuse has since expanded into a red giant, fusing helium into carbon and oxygen. This dramatic transformation has made Betelgeuse one of the largest known stars, with a diameter over 700 million miles, large enough to engulf the orbits of Mercury, Venus, Earth, and Mars if placed at the center of our solar system