UCI celestial census indicates that black holes pervade the universe

August 8, 2017, University of California, Irvine
There are a lot more black holes in the Milky Way than previously thought, according to a new UCI study by (from left) James Bullock, chair and professor of physics & astronomy; Manoj Kaplinghat, professor of physics & astronomy; and Oliver Elbert, physics & and astronomy graduate student. Credit: Steven Zylius / UCI

After conducting a cosmic inventory of sorts to calculate and categorize stellar-remnant black holes, astronomers from the University of California, Irvine have concluded that there are probably tens of millions of the enigmatic, dark objects in the Milky Way - far more than expected.

"We think we've shown that there are as many as 100 million black holes in our galaxy," said UCI chair and professor of physics & astronomy James Bullock, co-author of a research paper on the subject in the current issue of Monthly Notices of the Royal Astronomical Society.

UCI's celestial census began more than a year and a half ago, shortly after the news that the Laser Interferometer Gravitational-Wave Observatory, or LIGO, had detected ripples in the space-time continuum created by the distant collision of two black holes, each the size of 30 suns.

"Fundamentally, the detection of gravitational waves was a huge deal, as it was a confirmation of a key prediction of Einstein's general theory of relativity," Bullock said. "But then we looked closer at the astrophysics of the actual result, a merger of two 30-solar-mass black holes. That was simply astounding and had us asking, 'How common are black holes of this size, and how often do they merge?'"

He said that scientists assume most stellar-remnant black holes - which result from the collapse of massive at the end of their lives - will be about the same mass as our sun. To see evidence of two black holes of such epic proportions finally coming together in a cataclysmic collision had some astronomers scratching their heads.

UCI's work was a theoretical investigation into the "weirdness of the LIGO discovery," Bullock said. The research, led by doctoral candidate Oliver Elbert, was an attempt to interpret the gravitational wave detections through the lens of what is known about galaxy formation and to form a framework for understanding future occurrences.

"Based on what we know about star formation in of different types, we can infer when and how many black holes formed in each galaxy," Elbert said. "Big galaxies are home to older stars, and they host older black holes too."

According to co-author Manoj Kaplinghat, UCI professor of physics & astronomy, the number of black holes of a given mass per galaxy will depend on the size of the galaxy.

The reason is that larger galaxies have many metal-rich stars, and smaller dwarf galaxies are dominated by big stars of low metallicity. Stars that contain a lot of heavier elements, like our sun, shed a lot of that mass over their lives. When it comes time for one to end it all in a supernova, there isn't as much matter left to collapse in on itself, resulting in a lower-mass black hole. Big stars with low metal content don't shed as much of their mass over time, so when one of them dies, almost all of its mass will wind up in the black hole.

"We have a pretty good understanding of the overall population of stars in the universe and their mass distribution as they're born, so we can tell how many black holes should have formed with 100 solar masses versus 10 solar masses," Bullock said. "We were able to work out how many big black holes should exist, and it ended up being in the millions - way more than I anticipated."

In addition, to shed light on subsequent phenomena, the UCI researchers sought to determine how often black holes occur in pairs, how often they merge, and how long it takes. They wondered whether the 30-solar-mass black holes detected by LIGO were born billions of years ago and took a long time to merge or came into being more recently (within the past 100 million years) and merged soon after.

"We show that only 0.1 to 1 percent of the black holes formed have to merge to explain what LIGO saw," Kaplinghat said. "Of course, the black holes have to get close enough to merge in a reasonable time, which is an open problem."

Elbert said he expects many more gravitation wave detections so that he and other astronomers can determine if black holes collide mostly in giant galaxies. That, he said, would tell them something important about the physics that drive them to coalesce.

According to Kaplinghat, they may not have to wait too long, relatively speaking. "If the current ideas about stellar evolution are right, then our calculations indicate that mergers of even 50-solar-mass will be detected in a few years," he said.

Explore further: Spiral arms allow school children to weigh black holes

More information: Oliver D. Elbert et al. Counting Black Holes: The Cosmic Stellar Remnant Population and Implications for LIGO, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx1959

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CubicAdjunct747
2.3 / 5 (9) Aug 08, 2017
there's your dark matter. now move on to something more important and stop wasting time on it. Get to work on plasma shielding for spaceships, fusion reactors aboard space ships, particle generators aboard spaceships, and of course warping of spacetime so the spaceship can travel.
javjav
4.6 / 5 (11) Aug 08, 2017
Cubic why do you think dark matter can be explained with this calculations ? A trivial calculation can demonstrate that you are wrong. The Milky Way has 100 billion stars, and dark matter needs to be more than than 5 times all that mass. With these numbers, 10 million black holes is nothing, even if they all had 30 solar masses ( which they don't ) it would not be significant , much less than 1% of dark energy could be explained with this theory. In fact they don't even mention dark matter in all the article.
CubicAdjunct747
2 / 5 (4) Aug 08, 2017
perhaps you are right, but i still question that dark matter needs to be 5 times all the mass in the galaxy. Even so, its a wasting of time to study. So dark matter turns out to be some particle we dont know about, even less influencing than neutrinos, we still have plenty of particles to start doing engineering with and make useful. So many people get wrapped up in finding physics at so improbable levels as to be very wasteful. My point is we should turn that wasted energy into something to get us off this planet and star bound, then we can continue to explore these kind of things for real rather than just from our armchair earth.
Gigel
3.7 / 5 (3) Aug 08, 2017
Well, dark energy is one of the things we think exist and come close to travel at speeds greater than those of light. Non-local speeds, but still... So studying something we don't know much about may help us fly to other stars.
CubicAdjunct747
3 / 5 (8) Aug 08, 2017
MOND will prove dark matter to be false, its as simple as that. THink of the wasted time spend on studying "dark matter" that could have been used for higher end engineering.
JongDan
5 / 5 (1) Aug 08, 2017
perhaps you are right, but i still question that dark matter needs to be 5 times all the mass in the galaxy.

Well unless someone can scribble up a theory of gravity that explains why objects as big as galaxies exhibit gravitational forces five times larger than one would expect from scaling, then yeah it needs to be.
cantdrive85
1.5 / 5 (8) Aug 08, 2017
perhaps you are right, but i still question that dark matter needs to be 5 times all the mass in the galaxy.

Well unless someone can scribble up a theory of gravity that explains why objects as big as galaxies exhibit gravitational forces five times larger than one would expect from scaling, then yeah it needs to be.

Gravity is not responsible for these phenomena. The plasma that galaxies are composed are driven by electrodynamic properties.
Benni
1.7 / 5 (6) Aug 08, 2017
"UCI celestial census indicates that black holes pervade the universe"

OK, so you say, but we're still waiting for the first picture so as to prove by OBSERVATION these things actually exist, and don't start with the tired INFERRED GRAVITY crap.
Da Schneib
4.2 / 5 (5) Aug 08, 2017
perhaps you are right, but i still question that dark matter needs to be 5 times all the mass in the galaxy.
This is something you should know about. The amount of dark matter required is determined by measuring the dynamics of galaxies and the dynamics of galaxy clusters, and the visible mass of galaxies. The visible mass only accounts for 1/5 of the mass needed to explain both these sets of dynamics. The mathematical theorem that shows this is called the "virial theorem," and it's not a theory; it's a mathematical theorem, subject to a proof (which theories are not). So we know for certain there has to be five times as much mass as we can see.

That's the long and short of it. "Dark matter" is just a label put on that extra mass we can't directly see, but that we know has to be there. MOND has a very, very high mountain to climb to account for this. If it were half, or even twice, that would be easy, but half an order of magnitude is really, really tough to account for.
Maggnus
4.5 / 5 (8) Aug 08, 2017
MOND will prove dark matter to be false, its as simple as that. THink of the wasted time spend on studying "dark matter" that could have been used for higher end engineering.


Most scientists do observations and then come up with explanations, not decide the explanations and then find evidence to support it.

MOND appears to be unsupportable, in that observations have constrained the parameters set by the proponents to the point that it has fallen from real consideration. it was an interesting theory and while it is not technically dead, it is certainly unlikely.
javjav
not rated yet Aug 08, 2017
Cubic, maybe dark matter could help those spaceships you want, we just don't know. In principle , you can think that there is not enough dark matter density around you for using it as fuel. But think about this: the faster you go (in the right direction ) the higher dark matter density that you will find in your reference frame. You will need an initial impulse, but once you are fast enough then you could get a lot of dark stuff on the way, whatever it is. If it can be used as fuel or not remain to be seen, but you want to know it, don't you ?
Osiris1
5 / 5 (2) Aug 08, 2017
I really do not care about Cubie's dark matter point. I DO care about his OTHER point. With all those stellar outlaws running about, Steven Hawking's advice to start looking for a new home before we have to or it is way too late, like when one of these outlaws decides to wander a bit too near to OUR system. We are already looking for a 'planet nine' out there in the Oort cloud, suppose it is something Bigger and farther out and reallly reallly dark?

We really do need to research and build some working fusion reactor that would also make a really good rocket, like sustainable 1g acceleration. We also need to discover a really good conductor of very large amounts of power. The second will likely be enabling technology of the first, as this conductor wound into a coil would create sufficient magnetic field strength in a small space to enable fusion 'burns' in many fusion devices, not just tokomaks.

With that power, we have freedom to go forth where man has never gone before!
Benni
1 / 5 (7) Aug 08, 2017
The visible mass only accounts for 1/5 of the mass needed to explain both these sets of dynamics.
..........and this is BS & you can't prove differently Schneibo, it's why you need Zany Zwicky's INFERRED GRAVITY or the whole pathetic theory falls apart.
krizo888
not rated yet Aug 08, 2017
perhaps we are but bugs being blown against a giant screen door
Molecular hydrogen
1 / 5 (3) Aug 09, 2017
Have a look at this for a drive
https://m.phys.org/news/2016-11-physics-violated-em-leaked-nasa.html
Gigel
not rated yet Aug 09, 2017
With all those stellar outlaws running about, Steven Hawking's advice to start looking for a new home before we have to or it is way too late, like when one of these outlaws decides to wander a bit too near to OUR system.


Stellar outlaws, hehe! Forget about them, it's Earth outlaws we should mind. A nuclear war could bring our species to extinction. We should find new homes before we get close to that! And that means fast!

Too bad space research lost momentum with the end of Cold War. It was a really good, useful and fun way to improve ourselves. Plus an excellent purpose for the whole society, which now seems to be running purposelessly in all directions as on a brownian motion.
Benni
1 / 5 (4) Aug 09, 2017
the faster you go (in the right direction ) the higher dark matter density that you will find in your reference frame


.......and guess what else you run into? Micron sized particles of real matter which exist at a density of about a dozen per cubic kilometer, the kinetic energy impact of which will tear apart your spaceship long before you even reach 1/10 the speed of light. Your spaceship won't survive long enough to make it to the nearest star no matter what size dust deflector you put on the front of your spaceship.
Benni
1 / 5 (3) Aug 09, 2017
August 9, 2017, 9:06 am 1 IMP-9 rwooten

Whats'a matter you two, Kinetic Energy too deep a subject for you to comprehend?

So you two imagine you know how to put together a hulled craft that will travel near the speed of light & not be torn apart by interstellar dust particles......I'd guess you believe in a lot of other things you've never seen as, BHs, DM, God.
jonesdave
5 / 5 (4) Aug 09, 2017
August 9, 2017, 9:06 am 1 IMP-9 rwooten

Whats'a matter you two, Kinetic Energy too deep a subject for you to comprehend?

So you two imagine you know how to put together a hulled craft that will travel near the speed of light & not be torn apart by interstellar dust particles......I'd guess you believe in a lot of other things you've never seen as, BHs, DM, God.


This is the idiot that didn't realise that visible light from the Sun can actually provide heat. Take no notice of what he says. The bloke is a loon.
jonesdave
5 / 5 (4) Aug 09, 2017
Come on, Benni the burke; how about explaining how light between 400-700 nm doesn't heat anything (say rock) up? Never mind pretending that you actually understand science, with somebody who might never have come across your rubbish before - tell us how you managed to screw that one up. Yes, dear? Give it up. You know nothing, as is bleeding obvious from everything you post. Go back to your electric suns, and comets, and whatever other woo you believe in. Just give the rest of us a break from your scientifically illiterate nonsense. OK?
Shootist
5 / 5 (1) Aug 09, 2017
there's your dark matter. now move on to something more important and stop wasting time on it. Get to work on plasma shielding for spaceships, fusion reactors aboard space ships, particle generators aboard spaceships, and of course warping of spacetime so the spaceship can travel.


Not enough. We'd see lensing events everywhere if there were enough singularities to make up the missing mass, so I'm told.
javjav
5 / 5 (2) Aug 10, 2017
Benni, in a case like this the dust particles are an easily solvable issue. Just put it into perspective: if you go 10% light speed then they only come from the front. So just shot a decent laser in front and thats it. Of course you need energy to feed it, but if you are going 10% light speed it means that you already found how to solve the "energy problem", which is the real problem in here and not the little dust particles

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