Cosmic Scale
NGC 3918
Planetary nebula · About 4,900 light-years
How big is NGC 3918?
NGC 3918 is about 0.22 light-years across.
See NGC 3918 in 3D, at true scale
NGC 3918 is the glowing gas around a dying star in Centaurus. In a small telescope it looks like a blue planet, which is why John Herschel named it the Blue Planetary. Hubble shows a bright inner shell, a fainter outer shell and thin jets.
At a glance
| Diameter | 0.22 light-years |
|---|---|
| Diameter compared with Earth | 1.6 × 10⁸ × Earth |
| Distance | About 4,900 light-years (uncertain) |
| Size | About 0.2 light-years across |
| Constellation | Centaurus |
| Nickname | The Blue Planetary |
Good to know
- It is so bright that it outshines its own central star, which no telescope has clearly picked out.
- Its central star is around 25 times hotter than the Sun's surface.
- Thin jets of gas shoot out of both ends of the cloud.
- Next smaller: Egg Nebula · 0.14 light-years
- Next larger: IC 418 · 0.26 light-years