What is Betelgeuse?

Betelgeuse in Orion - Photo by DAS Member, Jim Fouch — Betelgeuse in Orion – Photo by DAS Member, Jim Fouch

Not to be confused with Beetlejuice, the Michael Keaton character from the 1988 cult comedy-horror classic, Betelgeuse is one of the biggest and brightest stars in the night sky. It is a red supergiant, a type of star that is near the end of its life. Betelgeuse is enormous compared to our Sun. It has a diameter of about 1,400 times that of the Sun, meaning if it were placed in the center of our solar system, it would extend beyond the orbit of Jupiter. It is also about 15 to 20 times more massive than the Sun. However, because it is in the later stages of its life, it is much less dense than our Sun, with its outer layers spread out over a vast area.You can find Betelgeuse in the constellation Orion, where it shines as the bright, reddish star that marks the hunter’s shoulder. This massive star is about 10 million years old, which is quite young compared to the Sun, but because it is so large, it burns through its fuel much faster. Betelgeuse is located about 640 light-years away from Earth, which means that the light we see from it today actually left the star centuries ago!

How Do Stars Die?

Stars go through a life cycle just like living things, but their lifetimes are measured in millions or even billions of years. Smaller stars, like our Sun, will eventually expand into red giants and then shrink into white dwarfs, slowly cooling off over time. Larger stars, like Betelgeuse, take a more dramatic path. They grow into red supergiants, and when they run out of fuel, they collapse under their own gravity and explode in a huge event called a supernova. What happens next depends on the size of the star—some will leave behind a neutron star, while the biggest ones may form black holes.

Will Betelgeuse Go Supernova?

This four-panel illustration shows how the southern region of the rapidly evolving, bright, red supergiant star Betelgeuse suddenly become fainter for several months during late 2019 and early 2020. In the first two panels, a bright, hot blob of plasma is ejected from the emergence of a huge convection cell on the star's surface. In panel three, the outflowing, expelled gas rapidly expands outward. It cools to form an enormous cloud of obscuring dust grains. The final panel reveals the huge dust cloud blocking the light (as seen from Earth) from a quarter of the star's surface. NASA, ESA, and E. Wheatley (STScI) — This four-panel illustration shows how the southern region of the rapidly evolving, bright, red supergiant star Betelgeuse suddenly become fainter for several months during late 2019 and early 2020. In the first two panels, a bright, hot blob of plasma is ejected from the emergence of a huge convection cell on the star’s surface. In panel three, the outflowing, expelled gas rapidly expands outward. It cools to form an enormous cloud of obscuring dust grains. The final panel reveals the huge dust cloud blocking the light (as seen from Earth) from a quarter of the star’s surface.
NASA, ESA, and E. Wheatley (STScI)

Scientists believe that Betelgeuse is nearing the end of its life and will eventually explode as a supernova. In recent years, astronomers have noticed strange behavior from the star, including a dramatic dimming in 2019 and 2020. This dimming was caused by a cloud of dust ejected by the star, but it showed that Betelgeuse is undergoing changes. Other signs, such as changes in its brightness and surface activity, suggest that its core may be running out of fuel. However, while these clues tell us that Betelgeuse is evolving, they don’t give us an exact timeline for when it will explode.

When Will Betelgeuse Explode?

In everyday life, when we say something will happen “soon,” we might mean minutes, days, or weeks. But in astronomy, “soon” can mean thousands or even millions of years! While Betelgeuse is expected to go supernova, scientists can’t predict exactly when. It could happen tomorrow, or it might not happen for 100,000 years. Since Betelgeuse is relatively close to Earth (in cosmic terms), when it does explode, it will be a spectacular sight, possibly as bright as the full Moon and even visible during the day. The good news is that, because it is far enough away, the explosion won’t be dangerous to Earth.

Keep Looking Up!

Betelgeuse is a fascinating star that has captured the attention of astronomers and stargazers alike. While it is definitely on track to explode as a supernova, no one knows exactly when it will happen. Until then, we can keep watching and learning from this giant, unpredictable star. So next time you look up at Orion, take a moment to find Betelgeuse—you might be looking at a future supernova in the making!

Clear skies and happy stargazing!