Betelgeuse and the Crab Nebula: Stellar Death and Rebirth

What happens when a star dies? In 2019 Betelgeuse dimmed in brightnessprompting speculation that it could soon explode as a supernova. Although it likely won't explode yet, we can predict its fate by observing nearby Crab Nebula.

Betelgeuse it can be easily found by the red shoulder star of Orion. Variable star Betelgeuse usually competes with brilliant blue-white Rigel for the position of the brightest star in Orion. Betelgeuse is a young star, estimated to be several million years old, but due to its gigantic size, it lives a fast and furious life. This massive star, known as a supergiant, ran out of hydrogen fuel at its core and began fusing helium instead, causing the outer layers of the star to cool and swell dramatically in size. Betelgeuse is one of the few stars for which we have any detailed observations on the surface, due to its enormous size – somewhere between the diameters of the orbits of Mars and Jupiter – and its relatively close distance – about 642 light years. Betelgeuse is also a “runaway star”, its remarkable speed possibly caused by its merger with a smaller companion star. If so, Betelgeuse may actually have millions of years left! So Betelgeuse may not explode soon, but maybe tomorrow! We still have a lot to learn about this intriguing star.

Crab Nebula (M1) is relatively close to Betelgeuse in the sky, in the neighboring constellation Taurus. Its ghostly, web-like gas clouds were created by a massive explosion; supernova observed by astronomers in 1054! A telescope in the backyard allows you to see some details. Still, only modern telescopes discover a rapidly spinning neutron star found at its center: the last stellar remnant of that cataclysmic event. These gas clouds were created during the violent death of a giant star and are constantly expanding, enriching the Universe with heavy elements such as silicon, iron and nickel. These element-rich clouds are like the cosmic fertilizer that makes rocky planets like our Earth possible. Supernovae also emit powerful shock waves that help form stars. In fact, if not for a long-ago supernova, our solar system—like all of us—would not exist! You can learn more about the Crab Nebula from a video taken by NASA's James Webb Space Telescope: bit.ly/CrabNebulaVisual

Want to know more about the life cycle of stars? Explore stellar evolution with the Life of the Stars activity and handouts on the website bit.ly/starlifeanddeathpart of our SUPERNOVA! tools.

Originally published by Dave Prosper: February 2020

Last updated by Kat Trosch: December 2025