Cosmic Scale
Black hole sizes compared: from Gaia BH1 to TON 618
The size of a black hole is the size of its event horizon, which grows in step with its mass. A black hole of a few Suns is a city wide; the giants in the cores of galaxies would swallow the Solar System.
See black holes in 3D, at true scale
| # | Name | Diameter | × The Sun |
|---|---|---|---|
| 1 | Gaia BH1 Dormant black hole | 56.8 km | 0.000 |
| 2 | Cygnus X-1 Stellar-mass black hole | 125 km | 0.000 |
| 3 | Gaia BH3 Dormant black hole | 195 km | 0.000 |
| 4 | Sagittarius A* Supermassive black hole | 2.5 × 10⁷ km | 18.2 |
| 5 | M87* Supermassive black hole | 3.8 × 10¹⁰ km | 27,600 |
| 6 | NGC 4889 Ultramassive black hole | 0.01 light-years | 89,100 |
| 7 | Holmberg 15A* Ultramassive black hole | 0.03 light-years | 170,000 |
| 8 | TON 618 Ultramassive black hole | 0.04 light-years | 280,000 |
| 9 | Phoenix A* Ultramassive black hole | 0.06 light-years | 424,000 |
Black holes
Phoenix A*
Phoenix A* is the black hole at the heart of the Phoenix Cluster, and current estimates put it near 100 billion Suns — possibly the most massive known.
TON 618
TON 618 is an ultramassive black hole powering a quasar so bright that we can see it from over ten billion light-years away.
Holmberg 15A*
Holmberg 15A is the brightest galaxy of its cluster, and its centre is strangely empty of stars — the signature of a huge black hole that scattered them away during past galaxy mergers.
NGC 4889
NGC 4889 is a giant elliptical galaxy in the Coma Cluster, hosting one of the largest black holes ever weighed: about 21 billion Suns.
M87*
M87* was the first black hole ever photographed.
Sagittarius A*
Sagittarius A* is the supermassive black hole at the centre of the Milky Way, 26,700 light-years away.
Gaia BH3
Gaia BH3 is a black hole of 33 Suns found in 2024 from the wobble of a star orbiting it every 11.6 years.
Cygnus X-1
Cygnus X-1 is a black hole of about 21 Suns locked in a 5-day orbit with a blue supergiant star.
Gaia BH1
Gaia BH1 is the closest known black hole to Earth, found not by any glow but by watching a Sun-like star swing around something invisible.