Cosmic Scale
Milky Way
Barred spiral galaxy · You are here
How big is Milky Way?
Milky Way is about 100,000 light-years across.
See Milky Way in 3D, at true scale
Our galaxy: a barred spiral of a few hundred billion stars, with a supermassive black hole at its centre and the Sun about two-thirds of the way out. The band of light across a dark sky is its disk seen edge-on from the inside.
At a glance
| Diameter | 100,000 light-years |
|---|---|
| Mass | 2.98 × 10⁴² kg |
| Diameter compared with Earth | 7.4 × 10¹³ × Earth |
| Stars | 100–400 billion |
| Sun's distance | 26,000 light-years out |
| Sun's orbit | 230 million years |
Good to know
- We have never seen it from outside; its shape is worked out from painstaking surveys taken from within.
- It is on course to merge with Andromeda in about 4.5 billion years.
- Its disk is warped, probably by the pull of the Magellanic Clouds.
- Next smaller: Whirlpool Galaxy · 76,900 light-years
- Next larger: Andromeda Galaxy · 152,000 light-years