A black hole that may have outgrown its own galaxy
Webb has weighed the black hole inside one of its puzzling Little Red Dots. It appears to be heavier than the young galaxy around it.
Since the James Webb Space Telescope began work, it has kept finding small, intensely red points of light in the very early universe. Astronomers call them Little Red Dots, and nobody has settled what they are. I find that delightful.
One of them now has a measured weight. The object, known as QSO1, sits behind the galaxy cluster Abell 2744, whose gravity magnifies it. Astronomers used Webb to measure the mass of the black hole inside directly and got about 50 million times the mass of the Sun. The light we see left it when the universe was less than a billion years old.
Why that is strange
The usual picture is that galaxies and their central black holes grow up together. In QSO1 the black hole seems to outweigh the galaxy that hosts it. That hints the black hole got big first. It is a little like finding a yolk bigger than its egg.
One idea being tested
A study published in Physical Review Letters on 12 June 2026, and reported by Space.com on 9 November 2026, asks whether QSO1 could be built around a primordial black hole, one formed in the first moments after the Big Bang instead of from a dying star. The researchers say the Webb data leave that possibility open. They do not claim to have shown it.
This is early work on a single object, and other explanations for Little Red Dots are still in play. I don’t know which is right. Nor does anyone else yet. I will be following it.
To get a feel for the sizes involved, set my instrument below near 50 million Suns.
- Width of the event horizon
- 25 million km
- The black hole at the centre of our galaxy. Its horizon is about 18 Suns wide.
- Width of the dark shadow it casts
- 66 million km
- About 2.6 times wider than the horizon itself, because the hole also swallows light that passes close by. This is the black disc in the picture.
- Stretch across your body at the horizon
- Under 0.001 g
- Far too gentle to notice. You would cross the horizon without feeling a thing.
- One hour for you, hovering there
- 3.3 hours far away
- Time runs slower deep in gravity. The closer you hover to the horizon, the faster the rest of the universe ages.
- Longest possible fall from horizon to centre
- 67 seconds
- By your own watch. Firing rockets to resist only makes it shorter.