May 14 2011
Official Website for Massimo Villata
Is Anti-gravity the Answer to the Elusive Dark Energy?
Villata poses a new theory which assumes that both matter and antimatter have positive mass and energy density, which gets particles attracting particles and antiparticles attracting antiparticles through the force of gravity. This new theory will in essence remove dark energy from the cosmic expansion equation. Villata shows that the theory of general relativity predicts that the gravitational interaction between matter and antimatter is mutually repulsive (anti-gravity), and can potentially explain the observed accelerated expansion of the Universe without the need for dark energy.
Read Massimo Villata’s theory in depth here.
Jun 10, 2011 @ 01:21:21
Hi Massimo,
I have referenced your work on a site I have only just set up. It is a site which deals with some of the biggest problems in astrophysics.
http://astronomiconography.blogspot.com/2011/06/massimo-villatas-cpt-gr-paper.html
Regards.
Jun 13, 2011 @ 12:06:46
Hi Bart,
thanks for the nice post.
Cheers, massimo
Jul 01, 2011 @ 03:06:51
Hi Massimo,
I would like to pay your attention on our paper which was published in EPL, V. R. Shaginyan et al 2011 EPL 94 69001, on the web: http://arxiv.org/abs/1007.4317. There we attempted to explain existing asymmetry suggesting that Universe behaves like a non Fermi liquid and baryon asymmetry appears as a consequence, not requiring any modification of a standard model of particles as well as a standard cosmological model.
If antigravity exists than our approach rather naturally introduces voids separating clumps made of either solely matter or antimatter. If something like spontaneous symmetry breaking is not considered, I do not see how antigravity can overcome the Coulomb force from symmetric initial conditions (of course provided that in pre-inflation epoch fine structure constant and newton’s constant were the same as today).
I understand that you think that antigravity may be the reason why these clumps are not colliding and subsequently annihilating. Another possibility that voids must be location/made of antimatter is also intriguing though it is not clear to me why voids made of antimatter being adjacent to clumps of matter do not interact and annihilate with the matter.
Would be glad to hear your opinion.
Cheers,
George
Jul 01, 2011 @ 12:48:26
Hi George,
thank you very much for bringing your paper to my attention; I’ll read it soon.
Regarding your question on antimatter voids, you should consider that repulsive gravity between galaxy clusters/filaments made of matter and antimatter hidden in the voids makes them well separated, and that the distance between them increases with time. I’m currently studying how this applies to the surrounding well observed voids.
Cheers, massimo
Jul 08, 2011 @ 15:25:35
Hi again George,
I read the paper and found it very interesting, even though, unfortunately, I don’t have the needed specific background to understand it completely. As far as I can tell, it sounds correct and looks fascinating. We should just discover whether antimatter is present or not in cosmic voids…
Best wishes, massimo
Jul 08, 2011 @ 20:15:09
What are your thoughts on the “Dark Flow” theory posited by Laura Mersini-Houghton which theorizes that a parallel universe or universes are pulling on galaxies which make them appear to be flowing in one direction?
Jul 11, 2011 @ 10:59:01
“Dark Flows” in the Universe, i.e. large-scale peculiar bulk motions of galaxy clusters in addition to the well-known Hubble flow appear to be unexplained by simple cosmological models. One explanation has been given by Laura Mersini-Houghton’s theory, in terms of the existence of other universes beyond our own. This theory is certainly fascinating, even if it may sound a bit too exotic. I think that, before claiming the existence of something unobservable, we should square with what we already know (or believe to know…). On one hand, we have the commonly accepted Lambda-CDM concordance model for the cosmic acceleration, which appears at the same time too exotic (based on an unidentified “dark energy”) and too simplistic (this unknown but dominant component of the Universe would uniformly permeate it). And fails in explaining dark flows. On the other hand, if the accelerating engine is not dark energy, but antimatter as source of antigravity (as it comes out from my analysis of general relativity) located in cosmic voids, we have an inhomogeneous distribution of acceleration sources that can cause strange, otherwise unexplained, galaxy-cluster motions, even though at very large scales the effect on the Universe expansion would be very similar.
Aug 24, 2011 @ 02:25:15
Hello Massimo,
I have read your recent article in EPL on antigravity. I am interested in the physical principles that support such antigravity, but at this point I think your theory still has some shortcomings. Here is a link to my comment on your paper:
http://arxiv.org/abs/1108.4543
Please, feel free to reply!
Regards, Marcoen
Aug 24, 2011 @ 11:20:49
Dear Marcoen,
thanks for your message and Comment on arXiv.
I have your Annalen 2010 paper on the EPT on my desk for several weeks, but, because of its length and complexity, I have not found the time to read it in detail. At first glance, your theory is fascinating, and I think that our two different approaches to antigravity can be complementary rather than conflicting: your approach (which is still in a protoscientific stage) appears to be incompatible with general relativity, while mine is the (hopefully correct) extension of general relativity to incorporate antimatter and antigravity. However, as soon as I can get rid of some urgency accumulated during the recent two-week vacation, I’ll take the chance of your Comment both to reply to it and to watch your theory in more detail.
Cheers, massimo
Sep 07, 2011 @ 10:31:14
Hi Marcoen,
my Reply to your Comment is at http://arxiv.org/abs/1109.1201.
Best wishes for your interesting Elementary Process Theory.
Cheers, massimo
Sep 08, 2011 @ 23:45:52
Dear Massimo,
Thank you for clarifying your point of view. From your reply I understand that you take a pragmatic approach to theory development, and that your main interest was/is a workable theory to explain observations at the astronomical level. That puts your extension of general relativity in an entirely different perspective, at least for me. That is to say, when taken as emergent at macroscopic scale, I believe your theory may indeed be useful – I wish you succes in your further research.
My primary interest is more in the fundamental physics at supersmall (Planck) level, where classical physics is known to break down and where philosophical questions become more important; from that perspectiveI wrote my original comment.
Let’s keep in touch!
Regards, Marcoen
Sep 13, 2011 @ 10:11:11
Thanks for your further comment Marcoen, with which I fully agree.
Surely we will keep in touch.
massimo
Sep 14, 2011 @ 13:11:03
Dear Massimo,
In your paper 1103.4937 “CPT symmetry and antimatter gravity in general relativity” you assert that particles must gravitational repulse by antiparticles. But there are particles which are own antiparticles. For example photon. It means that photon is matter and antimatter simultaneously.
So, the question is what is the gravitational interaction between photons: repulsion or attraction?
And we know (experimental) that photons are attractive by the sun gravity, the sun consists of matter.
Regards, Sergey
Sep 14, 2011 @ 15:55:00
Dear Sergey,
thanks for your message.
Yes, this is one of the main arguments against antigravity, but the answer is rather simple.
You can find it in the very recent paper at http://arxiv.org/abs/1109.1201.
My best regards,
massimo
Sep 15, 2011 @ 13:03:45
Dear Massimo,
As I understand you assert that there are retarded photons and advanced photons (antiphotons). And you assert that we cannot detect advanced photons.
But annihilation an electron and a positron gives two photons and in according to symmetry one must be advanced photon and other must be retarded photon. But we can detect both photons in experiments. So, we can observe advanced photons.
Sergey
Sep 16, 2011 @ 11:15:39
Dear Sergey,
we can not detect advanced photons from astrophysical sources, since we can not use them as detectors. The situation is different in laboratories, where a detector may also be an emitter, so that advanced photons can be detected at the source. Concerning the property of photons from an annihilation process of being retarded or advanced, the situation can be very complex (quantum field theories do not help in this sense) and can not be discussed here in few lines.
Cheers, massimo
Sep 20, 2011 @ 11:54:44
xDear Massimo, thanks for the link to your latest article,which is excellent and explains a number of the issues I raised. With regard to the discussion as to whether antimatter follows FIT or BIT, I think that when Matter split from (Partitioned) Antimatter at Big Bang, Matter became subject to FIT at the Macroscopic level and BIT at the Quantum level,whilst antimatter became subject to BIT at the Macroscopic level and FIT at the Quantum level. Thus there was very likely a form of Entanglement which connected and still connects both parts of the universe. This may explain the origin of mass and should Gravity be subject to BIT,could explain why it has so far evaded direct detection. Also Entropy may be conserved in the universe as a whole(Matter + Antimatter), I also consider bi-directional time to be the explanation for the double slit experiment(a photon travels through one slit in BIT and the other in FIT.) Would these ideas agree with your paper or would there be a conflict?
Sep 20, 2011 @ 14:13:34
Dear Julian,
thanks again for exposing your ideas. Some of these resemble some of my insights, while on other issues I have not yet reflected. The problem, as always, is to pass from the speculative level to theoretical construction.
All the best,
massimo
Sep 22, 2011 @ 12:42:23
Thanks for your reply Massimo. One other question that I have is this. Assuming the scenario of a mirror antimatter universe and that Dark Matter is one and the same, why is it that there appears to be 5 times as much Dark Matter compared to matter(from a gravitational perspective)? Is it possible that the Repulsive force between matter and antimatter is in fact the square of what would be the Newtonian force(if we were dealing only with matter/matter or antimatter/antimatter attraction?
Sep 26, 2011 @ 11:51:46
Dear Julian,
we do not know what dark matter is, and there are even doubts whether there is, at least at some level (see e.g. http://arxiv.org/abs/1106.0847v1). However, if it exists, I see no reason why it should not exist also the one that goes backwards in time, i.e. the “dark antimatter”. The next question we should thus respond in the scenario of repulsive gravity between matter and antimatter, which already seems to eliminate the embarrassing presence of dark energy, is whether and how much dark matter is still required.
Sep 26, 2011 @ 14:07:39
Dear Massimo, thanks for your reply. What I was hinting at in my question, was that if my scenario was valid, and that Gravitation propagates in BIT(in the matter part of the universe) but in FIT in the antimatter part, there would seemingly be two available channels to carry the repulsive force, thus magnifying it’s effect and making it appear that Dark Matter is much more abundant than Ordinary Matter in the universe.
Regards,Julian
Sep 26, 2011 @ 14:28:36
Thanks Julian, ok, it is more clear now.
Cheers, massimo
Sep 27, 2011 @ 12:11:04
Massimo, thanks for the link to Dragan’s paper, which I have read. I should say that I regard the phenomenon of Dark Matter as real and not just a gravitational inbalance that can be explained in other ways. The thing that convinces me are the excellent pictures of the Bullet Cluster where Dark Matter is virtually visible and of discrete form(and clearly separated from ordinary matter.)
Going back to the Double Slit experiment for the moment and my explanation of the photon utilising both the BIT and FIT channels simultaneously, it occurs to me that this idea could be very important not only for Gravity and Repulsion, but also as a way of explaining Entanglement.
Sep 27, 2011 @ 16:18:53
Julian, yes, I see your point, and partly agree, even though I should have more time to address it in detail.
Oct 05, 2011 @ 11:48:53
Dear Massimo, with regard to Big Bang do you think this was the point of origin for both forms of time? If so does the expression T(unified) = T + ~T describe this? T is FIT and ~T is BIT.
Also could conservation of entropy in the universe as a whole be expressed as S + ~S = K? Where ~S denotes anti-entropy.
Julian
Oct 06, 2011 @ 16:47:43
One other point Massimo. According to what I said before concerning 2 channels carrying the repulsive force between matter and antimatter, I would say that the Repulsive force would be equal to
G.-G = -G^2 (Minus G squared)
Julian
Oct 10, 2011 @ 10:29:27
Dear Julian,
what the “Big Bang” is and whether it actually occurred is a fascinating mystery. I have my own ideas, but before making them public, I still have to think about it. Your T(unified) would be constant, since while T increases ~T decreases, as it would happen to S. As regards the two channels and -G^2, I find it odd, it should be demonstrated.
Cheers, massimo
Oct 10, 2011 @ 15:38:08
Dear Massimo. Thanks for getting back to me. Regarding Big Bang I don’t agree with the matter/antimatter mutual annihilation, leaving a small surplus of matter. That is why I proposed “Partition” between matter and antimatter at Big Bang. If Dark Matter is this “Partitioned “antimatter we would then need to account for it being times or so more abundant than ordinary matter(in gravitational terms). This could be due to the repulsive force being the square of the equivalent matter/matter attraction etc,(and we can detect this force only indirectly on ordinary matter).
Regarding T(unified) I agree that just before Big Bang it would be constant or lack the Arrow of Time. That is why I think that Big Bang was the start of both forms of time, or possibly Big Bang was caused by Time splitting.Thus the Infinite universe scenario is not necessarily correct and Big Bang may have been a unique event. I don’t hold with the Multiverse concept at all.
With regard to the channels, Gravity applies only between matter/matter and antimatter/antimatter as separate systems(or in my scenario,they are Partitioned) Thus Gravity does not apply to matter/antimatter interaction, only Repulsion applies. However Repulsion works in both directions(but Gravity does not) and that is why I say the effect is magnified(squared).
Oct 11, 2011 @ 00:46:01
Massimo, I should add that Gravity takes place either with matter/matter or antimatter/antimatter. Repulsion involves matter/antimatter and hence a far greater overall mass. Also I am not sure if I clarified how we are able to detect the implied gravitational effect of Dark Matter(comprised of partitioned antimatter only) if it is anyway repulsive to matter. Let us say for the moment that Dark Matter resides beyond the perimeter of the Galaxy (As in Bullet Cluster, for example) then Dark Matter is strongly repelling the ordinary matter situated within the galaxy. This will increase the velocity of stars near the edge of the Galaxy resulting in greatly increased Relativistic mass. Thus the gravitational effect of Dark Matter is not being detected. What is being detected is it’s indirect effect on matter by virtue of the Repulsion.
Oct 27, 2011 @ 18:13:23
Hi Mr Villata,
I want to annonce you that your article has reached the “Baut” forum and a discussion is going on about this article . As expected a number of members disagree with your article saying antimatter cannot have antigravitational properties . One of the arguments is the Pound-Rebka experiment , or the thought experiment where a proton/antimproton annihihalition takes place at a height h above surface of earth .
I’m currently won for the idea about antigravity and want some reply about the discrepancy with the above mentionned thought experiment or experiment .
Oct 28, 2011 @ 11:11:42
Hi Frank, thanks for your message.
I don’t see how the Pound-Rebka experiment could disprove antigravity. Remember that antimatter can emit advanced photons, which are repelled by matter, see http://arxiv.org/abs/1109.1201. The same argument applies to the thought experiment. This will be clarified in my forthcoming paper.
Cheers, massimo
Oct 28, 2011 @ 17:56:13
Hi Mr Massimo , thanks for the reply .
In order to be more specific , the discussion is about this article ( see Appendix A) which derives that antmatter should “fall down” .
http://johanw.home.xs4all.nl/PhysFAQ/ParticleAndNuclear/antimatter_fall.html
Is it possible to look at the formulas in detail and derive the “flaw” ?
This experiment is closely related to the Pound Rebka experiment .
Nov 02, 2011 @ 13:07:58
The main problem with this thought experiment (which represents the famous Morrison argument against antigravity) is in the statement: “…they will measure a different energy that we did at the top of the tower, because the photons will be blueshifted. The photons will gain energy as they fall in a gravitational field.”. This would be true if all the photons were retarded ones, whereas, most likely, half of them would be advanced ones, being emitted by antimatter. These latter would not be blueshifted but redshifted, and the total “energy gain” will be zero. Moreover, this conceptual experiment is also too simplistic, and other, second-order effects may affect it.
Jan 09, 2012 @ 15:01:22
Congratulations on a very interesting paper. Below are some questions from an interested but non-expert reader.
1. If AEGIS produces a results showing anti-hydrogen falls at the same rate as hydrogen , will that have any implications about CPT invariance? That is, I’m wondering if there is a productive path for your line of reasoning even if AEGIS produces a completely conventional result.
2. Does electronic binding energy (photons) always have positive mass even with anti-particles? Does nucleon binding energy (gluons) always have positive mass?
3. How accurate a result does AEGIS need to produce? Is it important to get to a 0.01% error or better, or will 1% be sufficient to test your theory?
4. Does the original Dirac notion of a positron as a hole in a sea of negative energy have any validity in the context of your theory?
5. Does your theory apply equally to quarks as electrons?
Jan 10, 2012 @ 08:47:02
Elaborating on question 2 above, it seems like there are three types of binding energy which can have inertia in the E=mc^2 sense: electronic (off mass shell virtual photons), inter-nucleon (pion exchange) and intra-nucleon (quark binding via gluons). When one creates an anti-atom, how does your theory treat the various types of binding energy?
Jan 11, 2012 @ 13:23:30
Dear Charles, thanks for your interest.
1. From my analysis of the equations of general relativity, it seems that CPT invariance implies gravitational repulsion between matter and antimatter. However, if the experiments will show the opposite, it will be necessary to understand which of the basic assumptions is wrong; for instance, general relativity as it is, i.e. based on the existence of matter alone, could not be able to predict the behavior of antimatter directly, that is under the same assumptions.
2. In my theory, any form of matter/antimatter/bosons etc. has positive energy density and mass (if not zero). What can change sign is the gravitational charge, i.e. the energy-momentum four-vector, which is PT-odd.
3. The currently planned 1% precision is more than enough.
4. No, it is useless in any case, even in quantum field theories.
5. Yes, but remember that it is a classical, not quantum, theory.
Regarding your second message, as said above, any form of energy is positive definite and does not change sign in antimatter, being PT-even, only the gravitational charge changes.
Jan 12, 2012 @ 02:33:34
Going back to the binding energy question, up and down quark masses are reported to be small in comparison to gluon binding energy in a proton. The sum of quark masses in a proton is thought to be on the order of 10 MeV , whereas the mass of a proton is about 1 GeV, so 99% of the inertia of a proton seems to be due to binding energy rather than mass of constituent particles.
I somehow feel that any complete theory showing a gravitational difference between matter and anti-matter must distinguish between composite entities (protons and atoms) and fundamental particles (electrons, quarks). But, as you say, your theory is classical and does not include quantum mechanics.
Regarding your answer to 4, it is refreshing to see someone describe the original Dirac notion of positrons as holes as “useless”. It never made much sense to me but my guess is that that Dirac’s original model of positrons is the source of thinking that anti-matter could have different gravitational properties from matter.
I take the orthodox view that matter and anti-matter will have identical gravitational properties, but I am nevertheless very interested in the AEGIS experiment since it tests assumptions which need to be tested.
I can’t help but remember the AEGIS experiment web page which asks the question “Does anti-matter fall down?”.
Jan 09, 2012 @ 17:26:27
I have been interested in the gravitational acceleration of antimatter for many years. I believe the discovery of antigravity (gravitational repulsion between matter and antimatter) will, like fire and the wheel, represent a one-time transformative event in the history of humanity. Consequently I try to keep up with experiments to determine the gravitational acceleration of antimatter like AEGIS as you mention in your paper “CPT symmetry and antimatter gravity in general relativity.”
I read your paper with interest but find myself confused. Perhaps you can clear things up for me. First a couple of facts. We know from experiments that 1) antimatter has a positive inertial mass and 2) antimatter moves forward in time. Agreed?
The Principle of Equivalence, the very basis of General Relativity, maintains that no experiment can determine if you are at rest in a gravitational field (say 1g) or are undergoing uniform acceleration of 1g in a gravity-free space. Now clearly, if matter and antimatter gravitationally repel one another, regardless of the reason (including PT-oddness) this is a violation of the Principle of Equivalence. Antimatter would fall UP on the Earth, but would fall just like matter on a 1g rocket. I would greatly appreciate it if you could explain why this would not be so?
Please don’t misunderstand me; I believe (for reasons I will not go into now) that AEGIS will find gravitational repulsion between matter and antimatter. I just do not believe that General Relativity predicts such a result. Gravitational repulsion between matter and antimatter should be a death blow to General Relativity – not a reaffirmation of the theory!
Jan 25, 2012 @ 13:26:09
Yes, antimatter has positive inertial mass, and in my theory I assume that it also has positive gravitational mass, just for consistency with the principle of equivalence, which states the equality between the two masses. Thus, in an antimatter world everything happens as in ours, and anti-apples fall onto anti-Earths. Only, an anti-apple on the Earth falls up. But even in this case the (reversed) gravitational acceleration can be indistinguishable from a rocket acceleration, as long as the rocket accelerates in the right direction. With regard to 2), we go forward in time, and then observe matter traveling back in time as antimatter going forward in time with us.
Best regards,
massimo
Feb 01, 2012 @ 04:54:32
You answer to 2) made me think matter/antimatter collisions look like normal matter traveling on two opposite time lines colliding (if time was multi-dimensional) and annihilating each other because you can’t have two particles at the exact same position in space when the timelines intersect.
Repulsive gravity as an alternative to dark energy (Part 1: In voids) | Alternative Energy – Solar PV – Heat Pumps – Renewables
Feb 01, 2012 @ 19:43:06
[...] Website of Massimo Villata (comments welcome): link [...]
Astral Universe » Repulsive gravity as an alternative to dark energy (Part 1)
Feb 01, 2012 @ 23:22:44
[...] Website of Massimo Villata (comments welcome): link [...]
Feb 22, 2012 @ 19:49:22
Dear Massimo,
Many thanks for your reply.
[ Hypothesis of dark matter and dark energy with negative mass ]
[Abstract]
Gravity is the force conquering the structure of the universe. By recognizing the components of the universe, we are estimating the quantity of components composing the universe through size of gravity and gravitational potential energy (GPE). In this paper, it is being shown that the universe can be born and expanded through pair creation of positive energy (mass) and negative energy (mass) from zero energy condition. Also, GPE is composed by 3 units of U++, U–, and U-+ when negative and positive energy exists, U-+ (GPE between negative mass and positive mass) has positive values and is the component that makes repulsive gravitational effect. U-+ corresponds with the inner energy of the system and can be interpreted as dark energy. Also, situations in which U-+ has much higher value than |U–| + |U++| depending on the distribution of negative mass and positive mass is possible. This doesn’t mean that 72.1% of dark energy independently exists, but means that explanation from GPE occurring from 4.6% of negative energy, which is the same as 4.6% of positive energy, is possible. Moreover, 4.6% of negative energy is the energy which is inevitably required from zero energy, which is the most natural total energy value in the universe. This discovery implies that our belief that size of gravitational effect and size of components of the universe would always 1:1 correspond was wrong. We set up each model from the birth of universe to the present, and calculated GPE using computer simulation in each level. As a result, we could verify that “pair creation model of negative mass and positive mass” explains inflation of the early universe and decelerating expansion, and present accelerating expansion in time series.
http://3.bp.blogspot.com/-b9V5-xDBEUo/Ti7eygYn6FI/AAAAAAAAAM4/muaz4jPfFAQ/s1600/fig03.jpg
Negative mass is stable at the state of high energy. So the “problem of the transition of the energy level of minus infinity” does not occur, and thus positive mass and negative mass can exist in the same space-time
~~~~~
We set up each model from the birth of universe to the present, and calculated GPE using computer simulation in each level.
As a result, we could verify that “pair creation model of negative mass and positive mass” explains inflation of the early universe and decelerating expansion, and present accelerating expansion in time series.
This simulation is showing incredible results.
It not only explains the total energy of the universe, flatness, and the essence (Total zero energy, pair creation of negative energy and positive energy) of the process of birth of the universe, but it explains inflation, decelerating expansion in the early stage, accelerating expansion in the late stage, and dark matter through the only term, negative energy. Moreover, this negative energy is one that is essentially required by the Law of energy conservation.
Please see to below link!
1. Computer simulation : Dark energy – Accelerating expansion of distant galaxy due to negative mass
http://www.youtube.com/watch?v=71nMvwUhHwE
2. Computer simulation : Inflation, decelerating expansion and accelerating expansion with pair creation of negative mass and positive mass
http://www.youtube.com/watch?v=SRUqQM2FfNU
3. Paper1: The change of Gravitational Potential Energy and Dark Energy in the Zero Energy Universe.
http://vixra.org/abs/1110.0019
4. Paper2 : Hypothesis of dark matter and dark energy with negative mass :
http://vixra.org/abs/0907.0015
5. Big bang simulation from the Zero Energy State!
http://www.youtube.com/watch?v=vYEPbCpkLa8
Yours sincerely!
— Hyoyoung, Choi
Feb 23, 2012 @ 09:33:07
Dear Hyoyoung,
thanks for your interesting post.
Cheers, massimo
Mar 15, 2012 @ 16:26:10
Hi Massimo, do you think it is possible to reconcile QM to General Relativity using the FIT/BIT concept, rather than using String Theory as most physicists favour? If so, do you have any suggestions as to potentially useful mathematical expressions that can be adapted for this purpose?
Mar 19, 2012 @ 10:41:30
Hi Julian,
yes, I think that the consideration of the existence of the two time directions (and therefore of antigravity) is a fundamental step in the search for unification, but I have not many other ideas at the moment.
Best, massimo
Apr 22, 2012 @ 11:11:35
I have a potential alternative explanation for the seeming lack of antimatter galaxies etc. Suppose you tried to form a black hole of antimatter. The antimatter repels photons so rather than collapsing there would be a strong radiation pressure preventing collapse as photons are thrown out. It would basically look like a white hole.
This would mean that in the early universe only matter black holes could form whereas antimatter would be prevented from clumping too much. Now as I understand it these black holes are necessary for the galaxies and hence stars to form. Without them you’d just have cold, diffuse clouds of gas.
This might be what happened to antimatter, without black holes to shepherd it into galaxies you get no stars, no light just big cold voids.