Massive black hole 'taking a nap' after overeating becomes most relatable scientific discovery ever

Scientists have found a massive black hole that is "napping" after stuffing itself with too much food in perhaps what is the most relatable space discovery ever.

Much like a post-Christmas dinner snooze that a lot of us will have done recently, the black hole is lying dormant in its host galaxy due to its overeating.

The black hole was found in the early universe - only 800 million years after the Big Bang - by an international team of astronomers, led by the University of Cambridge who used the NASA/ESA/CSA James Webb Space Telescope and published their findings in the journal Nature.

When it comes to the black hole size-wise, we're talking 400 million times the mass of our Sun - so one of the most massive black holes discovered by Webb.

To put this into context, black holes make up roughly 40 per cent of the total mass of their host galaxy, in contrast, the majority of black holes are around 0.1 per cent of their host galaxy mass.

iStock

And the black hole continues to eat (or accreting we should say) but it's not at the rate you would assume, it's actually fairly low - 100 times below its theoretical maximum limit which explains its slumber.

When you put together the fact that this is a massive black hole found in the early universe which is currently dormant, it defies how experts believe a black hole grows.

But there is a reason for this, and scientists reckon it is because black holes tend to experience short periods of rapid growth, and then become dormant for a long while.

What makes this find even more exciting is the fact that a napping black hole is harder to spot due to being less luminous, if it had been growing it may have been easier to find as the gas in the accretion disc becomes extremely hot, starts to glow, and radiates ultraviolet energy.

Collapsed remnants of dead stars form black holes, according to the standard model and accumulate matter up to a point called the Eddington limit. This is where the gravitational pull of the black hole gets overpowered by the pressure of radiation on matter.

“Even though this black hole is dormant, its enormous size made it possible for us to detect,” said lead author Ignas Juodžbalis from Cambridge’s Kavli Institute for Cosmology. “Its dormant state allowed us to learn about the mass of the host galaxy as well. The early universe managed to produce some absolute monsters, even in relatively tiny galaxies.”

Given the size of the black hole that was spotted, it seems the standard models cannot provide answers to how these are created and increase in growth, possible explanations could include that black holes are simply "born big" or they could have periods of activity and inactivity.

“It’s possible that black holes are ‘born big’, which could explain why Webb has spotted huge black holes in the early universe,” said co-author Professor Roberto Maiolino, from the Kavli Institute and Cambridge’s Cavendish Laboratory. “But another possibility is they go through periods of hyperactivity, followed by long periods of dormancy.”

Computer simulations were conducted by Cambridge researchers with help from colleagues in Italy to find out how the black hole grew so rapidly in the early universe.

Their research concluded that black holes being able to exceed the Eddington limit is the most probable case and with this, causes the black hole to grow quickly in a short period of time, and then become dormant for a longer period.

Time-wise, experts say that black holes like the one they recently discovered would have eaten for an estimated five to 10 million years, and went to sleep for about 100 million years.

Now that's a lot of food and a lot of napping...

“It sounds counterintuitive to explain a dormant black hole with periods of hyperactivity, but these short bursts allow it to grow quickly while spending most of its time napping,” said Maiolino.

Due to the inactivity time being significantly longer compared to the short bursts of growth, this also explains why astronomers were able to spot the less luminous black hole while it was sleeping.

"This was the first result I had as part of my PhD, and it took me a little while to appreciate just how remarkable it was,” said Juodžbalis. “It wasn’t until I started speaking with my colleagues on the theoretical side of astronomy that I was able to see the true significance of this black hole.”

Plus, experts believe there's more where that black hole came from, especially if black holes in the early universe were mainly napping.

“It’s likely that the vast majority of black holes out there are in this dormant state – I’m surprised we found this one, but I’m excited to think that there are so many more we could find,” said Maiolino.

Elsewhere, a massive group of black holes discovered in centre of ancient star cluster.

How to join the indy100's free WhatsApp channel

Sign up to our free indy100 weekly newsletter

Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.