Chandra Resolves Why Black Holes Hit the Brakes On Growth (phys.org)
- Reference: 0181098724
- News link: https://science.slashdot.org/story/26/03/24/2334230/chandra-resolves-why-black-holes-hit-the-brakes-on-growth
- Source link: https://phys.org/news/2026-03-chandra-black-holes-growth.html
> Astronomers have an answer for a long-running mystery in astrophysics: why is the growth of supermassive black holes so much lower today than in the past? A study using NASA's Chandra X-ray Observatory and other X-ray telescopes found that supermassive black holes are [2]unable to consume material as rapidly as they did in the distant past . The results [3]appeared in the December 2025 issue of The Astrophysical Journal .
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> [...] The team ran tests of the three main possible scenarios currently being considered for the slowdown of black hole growth. These options were: could the decline in black hole growth be caused by less efficient rates of consumption, or by smaller typical black hole masses, or by fewer actively growing black holes? Their analysis of the data, extending over billions of years of cosmic history, led them to the conclusion that black holes are indeed consuming material less rapidly the later they are found after the Big Bang. The researchers expect this trend of slower-growing black holes to continue into the future.
[1] https://slashdot.org/~alternative_right
[2] https://phys.org/news/2026-03-chandra-black-holes-growth.html
[3] https://iopscience.iop.org/article/10.3847/1538-4357/ae173d
Almost as if... (Score:5, Insightful)
> unable to consume material as rapidly as they did in the distant past
It's almost as if time slowed down around them the more they eat...
Re:Almost as if... (Score:4, Interesting)
>> unable to consume material as rapidly as they did in the distant past
> It's almost as if time slowed down around them the more they eat...
While funny and insightful the time dilation occurs primarily above half the speed of light while gravitational pull occurs at all speeds. Natural objects only statistically reach these speeds on a significant basis within a low number of its horizon size widths which is a couple of AU while the gravitational pull is significant at over light years to tens of thousands of light years and significant for attracting and concentrating gas even if weak compared to the galactic gravitational field. Because we know black holes grow, time dilation is more of a weak plug in the drain of the bathtub of material it attracts with gravity.
Its important to note that the summary does not state a reason why we have super massive black holes extremely early in the universe, such as observations of red dots that are ultra massive stars a hundred thousand or even a million suns that direct collapse into the very large category of black holes without needing to feed at all. Despite that, the paper still applies because it does not focus on size but instead growth rate under many parameters including growth rates where the observed brightness to theoretically maximum brightness is decreasing.
Proximity To Matter? (Score:2)
Following the big bag wouldn't there have been a lot higher density of matter for a black hole to consume? It seems obvious that in order for a black hole to grow it needs access to matter and presumably as it consumes all of the matter close to it - it would slow down over time. I'm not an astrophysicist, so I am just going to assume I am just missing something obvious that would make an astrophysicist roll their eyes and chuckle politely.
Re: Proximity To Matter? (Score:2)
Before the âoebig bangâ has no meaning in this context, although there are some fans to be made in comparing black holesâ(TM) interiors to early stages of the big bang. The main thesis of this article seems to be predicated on the expanding universe theory making material less available over time for obvious reasons (expansion and distributions having occurred), at least according to the article summary. I will have to defer reading the article in 10th until later, so I have to save the link
Re: Proximity To Matter? (Score:3)
The issue is probably that the big bag won't fit in the overhead bin. Pull some of the matter out of the big bag and it might be able to be squished enough to fit.
Other black holes pack more slowly now, so everything fits.
If you insist on packing so much matter into the big bag so quickly, you're going to have to gate check it.
Chandra is a marvel (Score:4, Interesting)
Let's bear in mind that Chandra has been in orbit for over 25 years. Not quite as long as Hubble, but from the same era. Unlike Hubble, it was not made for servicing or upgrades - it's the same hardware that Columbia launched in 1999. At over 20 tons, it was the heaviest payload every launched by the shuttle. And folks reckon it has at least ten more good years of operation ahead of it.
Stupid(?) Astrophysics question: (Score:2)
Shouldn't the super-fast rotation of massive black holes counteract at least some of their gravity vertical to it's axis? Could that - at least hypothetically - eventually cause a black hole to break apart into bits of regular non-black-hole matter, if it spins fast enough?
Sorry if I'm sounding silly here, I'm a 5th-grader when it comes to astrophysics but perhaps someone with knowledge could offer some insight?
Re: (Score:2)
Black holes can evaporate via some weird physics (and Stephen Hawkings' pop explanation is apparently wrong even as a simplification and he knew it...), but normal physical processes do not apply.
A black hole can't break apart. Any energy you add to the black hole to attempt it would only make the black hole gain mass.
Re: (Score:2)
> Shouldn't the super-fast rotation of massive black holes counteract at least some of their gravity vertical to it's axis? Could that - at least hypothetically - eventually cause a black hole to break apart into bits of regular non-black-hole matter, if it spins fast enough?
> Sorry if I'm sounding silly here, I'm a 5th-grader when it comes to astrophysics but perhaps someone with knowledge could offer some insight?
While I'm not an astrophysicist, my understanding is that physics, along with everything else, breaks down inside the event horizon, so no matter how fast the black hole is spinning, once something reaches that event horizon, the only way back out is via the radiation we sometimes see escaping black holes. It's not coming back out as regular matter unless something catastrophic happens that I'm not sure we've ever seen observational data to prove is possible.
Re: (Score:2)
You can do the calculations yourself. To break apart, a rotating object has to reach its escape velocity at its outer perimeter. Otherwise, the gravity would pull back anything that was trying to break apart. A black hole by definition has all its mass within its event horizon, and the event horizon is defined as the surfaces where the escape velocity equals the speed of light. That means that a black hole would have to rotate so fast that its equator surpasses the speed of light to break apart.
Re: (Score:2)
In which frame of reference? Wouldn't the value of c vary on each side of the event horizon?
This is a bit silly (Score:2)
I mean, the language in the summary merely rephrases the question, without really explaining anything. And the body in the article says, in black and white, that the reason is because there is less material available for the black holes to swallow. Nice that they have found out, but hardly an unexpected answer.
Duh, have you seen gas prices lately (Score:1)
[It's the economy, stupid.]
The real truth (Score:1)
With recent budget cuts, they actually just sent someone named Chandra to a Chinese buffet and observed that you do get pretty full at some point. It's actually somewhat logarithmic.
I love news that says... (Score:2)
The reason that stuff happens is because it happens. Brilliant work!
Simple explanation: (Score:2)
As the universe expands, black holes don't suck as much as they used to.
Editor: rewrite (Score:2)
What is the word "resolved" doing in the headline?
DNRTFA (Score:3)
I'm guessing:
1) The cloud of material surrounding the black hole normalizes over time just like a planetary disk. At some point, pretty much everything that can intersect with the black hole already has, and only random collisions create new infalling material.
2) When the black hole does feed, it produces a lot of high energy activity just beyond the event horizon, which pushes material away before it can cross.
Re: (Score:2)
> I'm guessing:
> 1) The cloud of material surrounding the black hole normalizes over time just like a planetary disk. At some point, pretty much everything that can intersect with the black hole already has, and only random collisions create new infalling material.
> 2) When the black hole does feed, it produces a lot of high energy activity just beyond the event horizon, which pushes material away before it can cross.
They outline and reference many parameters affecting growth but we can summarize:
3)Early in the universe a greater density and unconsolidated small galaxies, clouds, and clusters ensured a higher collision rate bringing in new material. While later in the development of the universe the consolidation under gravity meant less available mass and less perturbation effects that is helpful in bring new shipments of food.
Re: (Score:2)
From the article, the reason is "This is probably because the amount of cold gas available for them to ingest has decreased since cosmic noon."