Cosmic Scale
Hercules A
Radio galaxy · 2.1 billion light-years
How big is Hercules A?
Hercules A is about 920,000 light-years across.
See Hercules A in 3D, at true scale
Hercules A is a giant elliptical galaxy whose central black hole, about 4 billion Suns, blasts out jets of particles at nearly the speed of light. The jets swell into radio lobes nearly a million light-years across.
At a glance
| Diameter | 920,000 light-years |
|---|---|
| Diameter compared with Earth | 6.8 × 10¹⁴ × Earth |
| Distance | About 2.1 billion light-years |
| Span | Nearly 1 million light-years |
| Black hole | About 4 billion Suns |
| Discovered | 1961, as a radio source |
Good to know
- It is one of the brightest radio sources in the sky.
- The jets are invisible to the eye; the drawing shows what radio telescopes see.
- Its host galaxy is about 1,000 times as massive as the Milky Way.
- Next smaller: Malin 1 · 650,000 light-years
- Next larger: ESO 383-76 · 1.8 million light-years