Black Holes Could Be Dark Matter – And May Have Existed Since the Beginning of the Universe

How did supermassive black holes form? What is dark matter? In an alternative model for how the Universe came to be, as compared to the ‘textbook’ history of the Universe, a team of astronomers propose that both of these cosmic mysteries could be explained by so-called ‘primordial black holes’. In the graphic, the focus is on comparing the timing of the appearance of the first black holes and stars, and is not meant to imply there are no black holes considered in the standard model. Credit: ESA

Did black holes form immediately after the Big Bang?

How did supermassive black holes form? What is dark matter? In an alternative model for how the Universe came to be, as compared to the ‘textbook’ history of the Universe, a team of astronomers propose that both of these cosmic mysteries could be explained by so-called ‘primordial black holes’.

Nico Cappelluti (University of Miami), Günther Hasinger (ESA Science Director) and Priyamvada Natarajan (Yale University), suggest that black holes existed since the beginning of the Universe ­­and that these primordial black holes could themselves be the as-of-yet unexplained dark matter. The new study is accepted for publication in The Astrophysical Journal.

“Black holes of different sizes are still a mystery. We don’t understand how supermassive black holes could have grown so huge in the relatively short time available since the Universe existed,” explains Günther Hasinger.

At the other end of the scale, there might also be very small black holes, as suggested by observations from ESA’s Gaia, for example. If they exist, they are too small to have formed from dying stars.

“Our study shows that without introducing new particles or new physics, we can solve mysteries of modern cosmology from the nature of dark matter itself to the origin of super-massive black holes,” says Nico Cappelluti.

Two future missions in ESA’s space science program will investigate some of the most extreme phenomena in the Universe: Athena, the Advanced Telescope for High-ENergy Astrophysics, and LISA, the Laser Interferometer Space Antenna. Currently in the study phase, both missions are scheduled for launch in the early 2030s. Athena will be the largest X-ray observatory ever built, investigating some of the hottest and most energetic phenomena in the cosmos with unprecedented accuracy and depth. Meanwhile, LISA will be the first space-borne observatory of gravitational waves – fluctuations in the fabric of spacetime produced by the acceleration of cosmic objects with very strong gravity fields, like pairs of merging black holes. Credit: ESA – S. Poletti

If most of the black holes formed immediately after the Big Bang, they could have started merging in the early Universe, forming more and more massive black holes over time. ESA’s future gravitational wave space observatory, LISA, might pick up the signals of those mergers if primordial black holes exist. Small black holes might simply be the primordial black holes that have not merged into larger ones yet.

According to this model, the Universe would be filled with black holes all over. Stars would start to form around these clumps of ‘dark matter’, creating solar systems and galaxies over billions of years. If the first stars indeed formed around primordial black holes, they would exist earlier in the Universe than is expected by the ‘standard’ model.

The James Webb Space Telescope is a space observatory to see further into the Universe than ever before. It is designed to answer outstanding questions about the Universe and to make breakthrough discoveries in all fields of astronomy. Webb will observe the Universe’s first galaxies, reveal the birth of stars and planets, and look for exoplanets with the potential for life. Credit: ESA/ATG medialab

“Primordial black holes, if they do exist, could well be the seeds from which all black holes form, including the one at the center of the Milky Way,” says Priyamvada Natarajan.

ESA’s Euclid mission, which will probe the dark Universe in greater detail than ever before, could play a role in the quest to identify primordial black holes as dark matter candidates.

The upcoming NASA/ESA/CSA James Webb Space Telescope, a cosmic time machine looking back over more than 13 billion years, will further shed light on this mystery.

“If the first stars and galaxies already formed in the so-called ‘dark ages’, Webb should be able to see evidence of them,” adds Günther.

Reference: “Exploring the high-redshift PBH-ΛCDM Universe: early black hole seeding, the first stars and cosmic radiation backgrounds” by N. Cappelluti, G. Hasinger and P. Natarajan, Accepted, The Astrophysical Journal.
arXiv:2109.08701

AstronomyAstrophysicsBig BangBlack HoleEuropean Space AgencyPopular
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  • MB

    I’ve often thought that “extra” black holes could easily make up the dark matter that we have been seeking. But how does that tie in with the outward push that dark matter supposedly provides that causes the acceleration of the expansion of the universe? Correct me if I’m wrong….but black holes do anything but “push out”.

    • Dave

      I agree. Black holes suck in, not push out. However, the term “singularity” is really just a placeholder because we have no clue what happens when that massive amount of matter gets smashed down under such immense gravity. Under the belief that information is never lost, just changed, I would assume there would be some state of “post-matter” that would be able to exit the black hole, simply because what’s left of it no longer interacts with it. They’d be like anti-gravitons that gives a lensed view of light, which is why we get the gravitational lensing effect but without the actual particle interaction that would then show the particle as if it were matter.

      Idonno. What do you think?

    • TheHeck

      The acceleration of the universe is credited to “dark energy” – a concept different from dark matter.

      “Dark matter” was coined to explain the fact that spiral galaxies can spin so rapidly without flying apart. So there must be some extra matter (or a different way in which gravity works at those scales) to explain that.

      “Dark Energy” is a theoretical concept that tries to explain why space-time is expanding. There is even less theoretical grounds for dark energy as there are for dark matter. In the end, it could also be that gravity behaves differently on a universal scale.

  • Plutarch Heavensbee

    These articles make my brain hurt. Next thing youre going to say there are dark Stars. Then you will say darl molecules. Then you will say there are signs of dark organic molecules. After that, you will start to say there is dark intelligent life. Cant you just jump to the end of the natural logical implications and stop boring me with your benality.

    • TheHeck

      The current hypothesis of dark matter is that it is composed of particles that don’t interact with each other, nor with “normal” matter. In that sense, dark matter won’t form molecules. They cannot form “dark stars” since there is no interaction between the particles to provide fusion. They could conceivably collapse in to a black hole if a sufficient density is achieved.

  • Lee berry

    As far as blacksphere’s go I think the super large ones in the center of galaxies are cores from second stars not first. But in saying that what could have happened when those Bsphere’s were becoming stars the point where the the gas ignited may have been extended and instead of lighting they may have kept growing as the amount of gas available when forming would have be much greater than appears today. In any case it’s fascinating to think about such things. Hopefully some answers will start to show themselves with this new Tele can’t wait hope all goes well.

  • Michael Johnson

    Would the correct title be”Dark Matter Could Be Black Holes”?

  • skierpage

    @MB the accelerating expansion of the universe implies (in most theories) the existence of a different kind of stuff, dark energy.

  • Graham Blank

    @Plutarch Heavensbee
    Tell me you don’t know what dark matter is without telling me

  • Matt

    It’s fascinating to think about these primordial black holes, all competing to harbor a galaxy first. What is the purpose life within a galaxy? What is the purpose of planets? Maybe the whole purpose of our universe, or every universe, is to harbor life. Those universes that successfully harbor life outperform the others somehow. Maybe that’s our purpose, to become interplanetary, to evolve and eventually take hold of this universe for an even greater purpose? What that purpose is we will not know until we are big enough to peek outside of this expanding universe.

    • TheHeck

      Why does there need to be a purpose?

      I know it’s an inherent psychological need to search for a meaning or purpose in everything, but if an asteroid crashes on your roof, is it for a purpose?

  • Dave

    I think they’re a little off the mark, but I do think dark matter and black holes have a correlation.
    Information, as they say, is never lost. It just changes. Applying that to a supermassive black hole, it means while stuff definitely goes into the black hole, information must somehow come out. I believe that dark matter is little more than the shadowed remnants of matter, smashed so completely that they are no longer effected by the black hole and are able to escape it’s gravity by simply not being able to interact with the matter that makes up the core of the black hole. From there it would spread out, like a cloud, from around the black hole, out to the farthest edges of the galaxy and somewhat beyond. It may even be that dark energy is simply the release of dark matter from black holes, perhaps pushing against or under the fabric of spacetime. This might explain why the space between us and other galaxies are moving apart so rapidly, but things in our general area seem to be staying pretty much where they are.

    I have more to this thought, but I think I’ll leave it like it is for now.

  • Fake_Judas

    Black holes suck if you’re thinking on one dimension. Since it’s all speculation let’s pretend the other end exits in to another universe and vice versa.
    Dark matter in, dark energy out.
    Also gives you a chance for the whole thing to start over once theres and imbalance of matter and energy in a given dimension.
    Please forward my noble prize once the math people work out how right I am.

    • TheHeck

      Your Dunning-Kruger medal is on the way.

  • BibhutibhusanPatel

    A basic difference is that supermassive blaçk holes do not had any dark matter or energy at the first moment of the big bang unless containing an èxceptional zero value,as èvery known form of matter or energy are to be observed.Another fact about SMBH is that they had relative great mass even at the begining point of time after Big Bang.

  • Angel

    El Big Bang nunca sucedió
    El universo fue luz desde el principio, y lo que llaman materia oscura,
    No es más que los residuos the energía y materia muerta universal a saber en qué estado, (algo así como el petróleo espacial)
    (Pues su Estado es oscuro)
    Y eso que llaman , agujero negro, no es más que un
    Virus universal de esa energía , que como en la vida real , necesita alimentarse de energía viva. Lo que provoca que devore todo lo que encuentre a su paso, algo así como Venom, (o un tifón espacial )
    y lo que llaman , expansión universal ,es la causa de que ,al desaparecer materia , queda un espacio vacante, lo que provoca que todo lo que está en el universo , busque una nueva posición o la oportunidad de crecer,
    Por , Ángel Castaner

  • HenryE

    It stands to reason that any primordial black holes would grow to immense size very, very quickly.

    Back then, the universe was much smaller and far more dense than it is today. Any black holes that developed soon after the Big Bang would have been pulling in matter and growing at an incredible rate. Even during the rapid expansion phase of the Universe’s existence there was a much greater concentration of matter available for the black holes to feed on, than we have today.

    While black holes are dark by definition, it does’t seem likely that they are composed of the elusive Dark Matter. Elusive because it doesn’t exist.

  • Gerald Nordley

    Black holes evaporate via Hawking radiation. The process depends on their mass, the smaller go sooner. The process is exponential; on the time scale of the universe, it’s as if they explode after a number of years. These explosions heat the cosmos, causing expansion. The rate of expansion could be telling us something about the mass spectrum of black holes formed after the big bang.

    • TheHeck

      Explosions heat the cosmos? Ummm… maybe open a space book instead of Facebook?

      The evaporation of a primordial black hole leaves tell tale signs of electromagnetic radiation, and that’s one of the things JWST will look for.

  • king rocker

    Why do people say black holes “suck in” and not “push out”? Aren’t you a bit short-sighted? They WILL evaporate, after all…

  • Ralph Clark

    Half the comments in this thread: “I believe ”

  • T Rajesh

    Multiverse could to be the right candidate for accelerating expansion of the universe. Maybe, immense gravity of some blackholes, of a different universe is pulling our universe outward.

    • TheHeck

      In that case, the expansion would not be uniform. What we have observed so far is a uniform expansion.

  • j

    If time and space ends at the center of a black hole, is that not homologous to the end of the universe at absolute zero; and the fate of all subject to entropy? In other words, is there a relationship in causality, between all matter converted to energy, in an infinitely expanded universe, and all matter converted to gravity in empty space?

    • TheHeck

      Matter never gets converted to gravity. Gravity, according to the GTR, is an effect of mass on space-time. Mass can get converted to energy, but not to gravity.

  • R45B

    Could primordial black holes not be left overs from a previous universe and already exist prior to the big bang?

    • TheHeck

      What would you expect to see, if that were the case? In other words, what’s the difference?

  • Plutarch Heavensbee

    Its almost as if anti-matter molecules could exist and dark stars could be a thing. Crazy.

  • Capt Sane

    I believe black spheres are white spheres inversed energetic muons that interact with normal matter in a baryonic molecular level.