astronomer using james webb space telescope They discovered supermassive black holes (objects up to millions of times the mass of the sun) when the universe was still in its infancy. How did they grow so big and so quickly?

new research in natural astronomy They argue that the early universe may have been created more easily than many researchers had assumed, by turning young galaxies into chaotic feeding grounds for newly formed tiny black holes.

“We have discovered that the chaotic conditions that existed in the early universe gave rise to small, nascent black holes that, in a frenzy of feeding on surrounding matter, later grew into the supermassive black holes we see,” Daxar Mehta, a doctoral candidate at Maynooth University in Ireland, said in a statement.

Mehta and his colleagues reached that conclusion by running a very vivid computer simulation of the first galaxy. In these digital universes, black holes that began as the remains of the first generation of stars could expand to about 10,000 times the mass of the Sun.

“Using state-of-the-art computer simulations, we have shown that the first generation of black holes, which were born just a few hundred million years after the Big Bang, grew at incredible speeds, reaching tens of thousands of times the size of the Sun,” Mehta added.

That doesn’t mean all early black holes became giants. But this study suggests that a surprising number of people might have been prepared to do so if they had landed in the right space neighborhood.

black hole nursery

When gas falls toward a black hole, it heats up and glows. If the glow gets strong enough, it can displace incoming gas. Astronomers call this balance point the Eddington limit, and for decades it has served as a kind of cosmic speed limit for black hole growth.

The Maynooth research team focused on the “seed of light” black hole. These are tiny black holes that were born when the first stars died. In many scenarios, these seeds start at a moderate mass and must be eaten steadily over a long period of time until they reach a supermassive mass.

But in their simulations, some seeds soared.

The researchers modeled black holes forming from early metal-free stars known as Population III stars, which are typically thought to be much more massive than most stars forming today. In the highest resolution runs, the simulations were able to resolve the structure to about a tenth of a parsec (roughly the scale of the inner region of a star cluster), giving them enough precision to track the flow of dense gas immediately around a small black hole.

More detailed simulations captured short, intense growth episodes that were undetectable with lower-resolution models.

Studies show that these growth spurts were short-lived by cosmic standards, lasting approximately 100,000 to 1 million years. But during the most intense bursts, some black holes pulled in gas up to 1,000 times more than the normal limit or short period in the simulations.

To put it more clearly, in the early universe, Let the black hole break the speed limit.

These binge-drinkers relied on environments that were dense, cold, and slow-moving enough to trap gas. But they also faced built-in shutoff devices. Heat injected by explosions from nearby stars, and possibly by the black hole itself, could blow away its surroundings, starving the black hole and ending its growth spurt.

listen nearby

Until now, one common way to explain these early giants was the idea that they were “heavy seed” black holes, objects that were born already massive, in some cases up to 100,000 times the mass of the Sun. Starting big makes the puzzle of early supermassive black holes easier to explain because there is less growth to account for.

The new simulation does not eliminate heavy seeds. However, this result weakens the assumption that heavy seeds are required.

“These small black holes were previously thought to be too small to grow into the massive black holes observed at the centers of early galaxies,” Mehta said. “What we have shown here is that although these nascent black holes are small, given the right conditions they can grow surprisingly fast.”

If that’s true, medium-sized black holes may have formed more widely in the early universe, acting as a stepping stone between stellar remnants and the supermassive beasts that anchor today’s galaxies. Simulations show that some black holes can grow to about 10,000 times the mass of the Sun, primarily by drawing in gas rather than merging with other black holes.

“This breakthrough solves one of the great mysteries of astronomy,” Louis Proulle, a postdoctoral fellow on the team, said in a statement. “This is why black holes that formed in the early universe were able to reach such supermassive sizes so quickly, as observed by the James Webb Space Telescope.”

This idea also suggests hearing rather than seeing through gravitational wave signals from early black hole populations.