Cosmic Scale
Betelgeuse
Red supergiant · 550 light-years
How big is Betelgeuse?
Betelgeuse is about 1.1 × 10⁹ km across.
See Betelgeuse in 3D, at true scale
Betelgeuse is the red shoulder of Orion and the most famous star waiting to explode. It is only about 10 million years old but is already near the end: a supergiant, unstable, shedding its outer layers.
At a glance
| Diameter | 1.1 × 10⁹ km |
|---|---|
| Mass | 3.28 × 10³¹ kg |
| Diameter compared with Earth | 83,400 × Earth |
| Distance | 550 light-years |
| Surface | 3,600 K |
| Brightness | Around 100,000 Suns |
Good to know
- In 2019–2020 it dimmed so much that people noticed by eye; it had coughed out a cloud of dust that blocked its own light.
- When it does explode it will be visible in daylight for weeks — but it is far too distant to harm Earth.
- It was the first star other than the Sun to have its surface imaged.