Alex McColgan

It would also explain the brightness, point-source morphology, and reddish color.

To top it all off, their emissions show broad Balmer lines, which suggests there is a lot of gas spinning at thousands of kilometres per second around something central.

Orbiting gas moves both towards and away from us at extreme speeds.

This exaggerates the spectral lines in each direction, broadening their profile.

The faster the orbital velocity of the gas, the wider that broadening becomes.

And this is exactly what we would expect from a massive black hole feeding on lots of gas.

So far, things were looking good for the black hole theory.

That was… until researchers noticed something vital was missing.

You see, as far as we know, active black holes always emit X-rays from their accretion disks, but when astronomers measured the little red dots, they found no trace of X-rays at all.

This was a devastating blow to a promising theory.

As if that weren't enough, there was one more problem.

The black hole seemed too big for the galaxies they were in.

In the local universe, black holes are usually around 0.1% of the mass of the galaxy around them.

This is such a consistently observed relationship, we think galaxies and their black holes must co-evolve together using some kind of feedback loop mechanism that keeps them in tight check with each other.

But when researchers started looking at little red dots, they noticed they...

had much higher black hole to galaxy mass ratios than we're used to, closer to 10%.

It was almost as though the black hole had somehow grown to full size before the surrounding galaxy had the chance to catch up.

Both the starburst galaxy and active black hole theories had their merits, but neither could fully explain what was going on with these little red dots.

Astrophysicist Fabio Pacucchi at the Harvard-Smithsonian Center for Astrophysics explained the dilemma perfectly.

If they, little red dots, contain black holes, those black holes are enormous for such small galaxies.