Scientists offer new theory to explain the origin of monsters of the cosmos.
When astronomers use telescopes to look back in time—toward objects in the universe whose light is only now reaching earth after billions of years—they see something odd. Black holes, big ones, that already existed when the universe was still very young.
This is strange because from what physicists have understood, it takes time for a black hole to eat enough surrounding matter to grow so massive—so it seemed those black holes should not have had time to get so big.
“The analogy I’ve used is that if you saw a child that was only five or six years old, but already weighed as much as an adult human,” said Hai-Bo Yu, an associate professor of physics and astronomy at University of California, Riverside.
Yu and two other scientists with UC Riverside and the University of Chicago came up with a surprising possible explanation: Those black holes could have formed with the help of dark matter.
“This ties together two great mysteries in astrophysics—early supermassive black holes and dark matter—very neatly,” said UChicago postdoctoral researcher and study co-author Yi-Ming Zhong.
In the early days of the universe, visible matter existed as clouds of gas particles that would grow into denser objects, such as stars and galaxies. These clouds could collapse and form a seed black hole, i.e., the baby stage of a supermassive black hole. However, in this scenario, the scientists said, the seed would not have enough time to grow into the most massive black holes observed in the early universe, if it eats at a “normal” pace.
But alongside the ordinary matter in these clouds was a halo of dark matter, a mysterious form of matter that we can tell is there because of its gravity pulls on visible things in the universe. The scientists wondered if dark matter could serve as an ingredient that helps create supermassive black holes.
“This ties together two great mysteries in astrophysics—early supermassive black holes and dark matter—very neatly.”
— Yi-Ming Zhong, UChicago postdoctoral researcher and study co-author
According to their simulations, if particles of dark matter in those halos were colliding with each other, such activity could tip the balance of the system towards collapse. That’s because the particles could spread heat to one another as they collided, making the central halo unstable. They also found the dark matter collisions would dissipate the halo’s angular momentum—the quantity that describes the spinning of a body—which further tips the system towards collapse.
Such a collapse usually takes a long time. However, the presence of ordinary matter at the halo center adds extra mass that deepens the gravitational potential there, thus expediting the heat spread. “The presence of ordinary matter could shorten the collapse timescale by two orders of magnitude,” said graduate student and co-author Wei-Xiang Feng.
These “seed” black holes would have been much massive than those typically formed by the collapse of ordinary gas—akin to the baby in the analogy being born already weighing 100 pounds. From there, it could grow through the “normal” process of eating nearby matter.
The scientists are investigating further implications of this theory, such as the origin of supermassive black holes in our own Milky Way and many other large nearby galaxies. It could also be an indication about the nature of dark matter itself; it’s difficult to directly observe whether or not dark matter particles can collide among themselves, but if this theory pans out, it could serve as evidence that they can.
A way to test this theory might become possible as the next generation of more powerful telescopes begin taking data. For example, the Giant Magellan Telescope will be probing the growth of black holes in the universe.
“This system has very novel and interesting dynamics, so we’re exploring further,” said Zhong. “Plus, it’s intriguing that we can address two mysteries with one theory.”
For more on this research, see Dark Matter Halo Collapse: How a Supermassive Black Hole Originates.
Reference: “Seeding Supermassive Black Holes with Self-Interacting Dark Matter: A Unified Scenario with Baryons” by Wei-Xiang Feng, Hai-Bo Yu and Yi-Ming Zhong, 16 June 2021, Astrophysical Journal Letters.
Funding: U.S. Department of Energy, NASA, Kavli Foundation, John Templeton Foundation.
Or if the dark matter in the halo undergoes a state change and releases heat.
The problem is that dark matter does not interact, except possibly by self annihilation (which remains to be observed).
There is no trigger or low temperature mechanism for a state change.
Forget about dust and gas. They are the result of a collision of galaxies, one of which is old. Nothing is formed from dust and gas – it is space debris. Black holes, stars and planets are formed as a result of the gradual Great Synthesis:
Self promotion, of pseudoscience no less.
This article talks about dense gas clouds forming galaxies and stars, and the suggested role Dark Matter played. First of all, how in the world could dense clouds of anything form from the enormous expansion of the Big Bang, which is expanding at about 45 mi/sec even now. What kind of tiny particles could gather into clouds against that kind of expansion? Another way our universe could have been created from a view of String Theory is described in this YouTube. https://www.youtube.com/watch?v=IaxfuKXdhkg&t=6s
I don’t think you are serious in your questions, since you post self promotion of pseudoscience movies.
– The expansion rate differs with the inner energy state of the universe, so is not really the problem given the observed rates [“Scale factor (cosmology)”, Wikipedia}.
– “Even here in our own Solar System, dark matter might be present, but even its gravitational effects are totally negligible, contributing less than the dwarf planet Ceres does to all the orbits of the planets, moons, asteroids and Kuiper belt objects.
And yet, without dark matter, the Universe as we know it wouldn’t exist the way it does. Stars would be extremely rare entities in the Universe, and large galaxies with Sun-like stars and Earth-like planets would be all but impossible. Dark matter enabled the Universe to give rise to us, and without it, we wouldn’t be here. Here’s the cosmic story that every one of us should be thankful for.”
[ https://www.forbes.com/sites/startswithabang/2019/11/28/why-humans-should-be-thankful-that-our-universe-has-dark-matter/?sh=531c56206f8b ]
Please. Since we don’t know what Dark Matter is of even if it exists it can be used to explain anything. Figure out what it is first then you can use it, but not until then. Right now it is Fairy Dust that can be used to solve every problem.
Your opinion is not relevant for the science. We know what dark matter id and what it does, and it is most definitely not used in explaining everything. It has nothing to do with star processes, say.
Same paper as presented here by the other university press release:
And so my earlier comment bears repetition:
Unfortunately self-interacting collisional dark matter gas that can collapse by transporting heat away do not match cosmological observations.
“But what about alternative dark matter models like warm dark matter (WDM) and self-interacting dark matter (SIDM)? As we briefly touched in the beginning, they are partly conceived to resolve the cusp-core problem. In fact, WDM and SIDM are also mass-dependent like the DC14 model, but not in exactly the same way. So, how do they fare in predicting the velocity function and the Tully-Fisher relation for galaxies? Figure 3, our last figure of the day, shows exactly this. Despite doing better than the NFW profile, both WDM and SIDM are not able to fit the velocity function and Tully-Fisher relation as well as we expect.”
[ https://astrobites.org/2015/06/12/the-labor-of-outflows-against-dark-matter-halo/ ]
Relics of previous universes.
I already proposed in chapter 5 in paper that black hole are made up of dark matter