A scientist looked at 'little red dots' in the early Universe and found a black hole that shouldn't exist

There's something strange going on in the early Universe.

The James Webb Space Telescope has peered so deep into the cosmos, it's effectively been able to look back in time to show what the Universe was like just after the Big Bang.

It's found numerous objects astronomers call little red dots (LRDs).

These are compact red dots that appear James Webb Space Telescope data, and observations show they're common in the early Universe, within the first two billion years after the Big Bang.

But we don’t yet know exactly what they are.

Initially, astronomers believed little red dots could be massive galaxies.

This caused a problem for standard theories of cosmology. How could such heavy objects exist so early in the Universe’s history? 

Pierluigi Rinaldi is a postdoctoral research fellow at the Space Telescope Science Institute (STSci) who studies black hole formation and galaxies in the early Universe.

We spoke to him to find out more about what these little red dots could be.

What do we know about little red dots?

Researchers started finding that little red dots had very strongly characterised emission signatures typical of active galactic nuclei (AGNs), which are objects harbouring supermassive black holes at their centre.

When we observe the light from a galaxy, we can split it into a spectrum, a kind of cosmic fingerprint that reveals information about the galaxy’s stars and gas – such as what it’s made of and how its material
is moving.

In an AGN, some of the spectral lines are broad, which tells us that gas is spinning around a black hole.

We observed these broad lines in little red dots, which hinted that many little red dots might contain these large, active black holes.

What is the Virgil Galaxy? 

I discovered Virgil together with another early-Universe object called Cerberus, so I named it Virgil, after The Divine Comedy.

If you look at the light we observe from Virgil at different wavelengths, you find that in the ultraviolet, visible and near-infrared, it’s a completely normal, star-forming galaxy.

But, as soon as you add mid-infrared wavelengths, Virgil changes character completely, like Jekyll and Hyde.

When looking at mid-infrared light, it appears Virgil contains an enormous, active black hole. 

What makes Virgil’s black hole so unusual?

First, there’s no sign of the black hole in ultraviolet and visible wavelengths, which is quite unusual.

Virgil’s AGN is also surprisingly massive. Black holes like this can be a sort of dark puppet master within
a galaxy, regulating how the galaxy evolves.

For our current models of cosmology to work, we must explain how such an ‘overmassive’ black hole could have been created so early in the Universe’s history. 

What might cause these ‘overmassive’ black holes?

We’re still far from understanding how these early black holes formed and many think we may be missing an important piece of the cosmic puzzle.

One idea involves a hypothetical class of objects known as black hole stars or quasi-stars.

In this picture, some of the tools we commonly use to estimate black hole masses in the nearby Universe may not apply to little red dots at high redshift, leading to masses that appear unexpectedly large. 

How would that work?

In the quasi-star scenario, little red dots are envisioned as black holes embedded within extremely dense cocoons of gas.

Radiation produced near the black hole can become trapped inside this envelope, scattering many times before escaping.

This process could alter the appearance of the emitted light and the shapes of spectral lines we observe, potentially causing standard methods to overestimate the true black hole mass.

This idea remains speculative, but if correct it would significantly change how we think black holes grew in the early Universe.

What’s next for your team?

We can try to understand Virgil better by taking deeper data at mid-infrared wavelengths, or – and this is much more difficult – find similar objects by observing large patches of the sky in the mid-infrared.

JWST’s mid-infrared instrument (MIRI) is less sensitive than its other instruments, so these observations take a long time, and JWST’s observing time is finite. 

This speaks to something important. After four years, JWST has delivered great results, but there’s a hidden part of the Universe we can only access with mid-infrared observations.

Having this data is extremely important, not just for little red dots but also for characterising the early Universe. 

This interview appeared in the March 2026 issue of BBC Sky at Night Magazine