Cosmic Scale
Omega Centauri
Globular star cluster · 17,000 light-years
How big is Omega Centauri?
Omega Centauri is about 150 light-years across.
See Omega Centauri in 3D, at true scale
Omega Centauri is the largest globular cluster orbiting the Milky Way: around ten million ancient stars in a ball 150 light-years across. Its stars are not all the same age, which suggests it is the stripped core of a small galaxy the Milky Way swallowed.
At a glance
| Diameter | 150 light-years |
|---|---|
| Mass | 7.96 × 10³⁶ kg |
| Diameter compared with Earth | 1.1 × 10¹¹ × Earth |
| Distance | 17,000 light-years |
| Stars | About 10 million |
| Age | Around 12 billion years |
| Catalogued | 1677, Edmond Halley |
Good to know
- Near its centre stars are packed so closely that they sit only a tenth of a light-year apart.
- Evidence published in 2024 points to an intermediate-mass black hole hiding in its core.
- It is bright enough to look like a fuzzy star to the naked eye from the southern hemisphere.
- Next smaller: Pleiades · 86.0 light-years
- Next larger: Carina Nebula · 460 light-years