Winnie-the-Pooh came to a village far away from Hundred Acre Wood in which, as he had heard, stood a great jar of the very best honey to be found anywhere. Bears and honey, oh boy. The jar of honey was very famous. Everyone far and wide was saying — because they had had it heard being confirmed by everyone all the time — that this honey is especially very special because it is invisible. And so many other inhabitants of the woods and meadows came to look at The Jar, even from very far places no-one had ever heard of. Many of the rich visitors even hoped to be able to get a taste of this famous invisible honey. The jar was famously called “The Jar Full of Invisible Hunny”. Winnie-the-Pooh wanted to later take his friends, Christopher Robin and Piglet, to also see this Jar Full of Invisible Hunny. Maybe Christopher could buy some of the famous invisible hunny for Winnie-the-Pooh? But it must be very very expensive, so Winnie-the-Pooh thought he should first have a look.
Winnie-the-Pooh (copyright A.A. Milne and E.H. Shepard; credit: Winnie The Pooh 2011 51st Disney’s classic).
Winnie-The-Pooh was very impressed by the great size of The Jar of Invisible Hunny and really wanted to get a taste of this very best honey. But no-one was allowed to look into the The Jar, and when someone did manage to sneak a glance in, they confirmed that it is truly The Jar of Invisible Hunny. Being a clever bear albeit with a very slow mind, Winnie-The-Pooh thought, after some time of looking at The Jar Full of Invisible Hunny, that he might learn a little more about this invisible hunny by knocking on the side of The Jar. He went up to The Jar, embraced it to show his gratitude of being near it, and quickly, so no-one noticed, knocked. The sound he received made him raise his eyebrows – the clanking he heard in return sounded as if The Jar was empty!
Somewhat disconcerted and very thoughtful, Winnie-the-Pooh sat back and looked at The Jar supposedly Full of Invisible Hunny. After some time (the Sun had moved from the left to the right) of very intense thinking, a thought slowly and unstoppably formulated in the bears mind: might it be that The Jar Full of Invisible Hunny is (supposedly) full of “Invisible Hunny” because there is no hunny inside The Jar? Very bothered with his new very Uncomfortable Thought, Winnie-the-Pooh got up and walked around the village and spoke to anyone who would be willing to listen to him. And every time Winnie-the-Pooh explained the Uncomfortable Thought, the listener stopped listening, calling the bear a very impolite bear who should stop having such Uncomfortable Thoughts, behave as everyone else and just accept that The Jar Full of Invisible Hunny is FULL of Invisible Hunny. This has been confirmed by many who have had it confirmed with utmost certainty by others, and there is no question about The Jar Full of Invisible Hunny being FULL of Invisible Hunny. EVERYONE knows this!
No-one believed Winnie-the-Pooh. Some even suggested that the bear be removed from the village and put into a hole as the bear’s Uncomfortable Thought might spread to those dimm wits with lesser minds. After all, the village wants everyone to come because the visitors bring affluence. Winnie-the-Pooh became very unhappy, and sat down again in moonlight as the Moon started to climb up its ladder. By the time Winnie-the-Pooh had to look straight up to see the Moon, a plan had formulated in the bear’s mind:
"If I am not allowed to taste the invisible hunny, I can at least see if I can remove the Uncomfortable Thought from my thoughts and become like everyone else, by dropping a small stone into The Jar Full of Invisible Hunny. If the stone falls through to the bottom or The Jar ever more rapidly, as if it were falling outside of The Jar Full of Invisible Hunny, then the Jar Full of Invisible Hunny is a jar without hunny in it and my Uncomfortable Thought would become a Bother. But if the stone falls into The Jar Full of Invisible Hunny and stops for a while before sinking down slowly to the bottom of The Jar Full of Invisible Hunny then The Jar Full of Invisible Hunny is indeed full of invisible hunny."
The Winnie-the-Pooh Test
Winnie-the-Pooh became very proud of himself because he had managed to have such a great idea for such a complicated test, but he became very worried about the possible outcome of this ultimate experiment.
So when everyone was sleeping and the Moon had climbed down on the other side, Winnie-the-Pooh collected a little stone, cleaned it in a nearby stream, borrowed the same ladder and climbed up the Jar Full of Invisible Hunny. Looking around to make sure no-one saw his very secret and surely forbidden experiment, Winnie-the-Pooh dropped the little stone into the jar. It fell right through landing on the jar’s bottom with a clanking sound. The Jar Full of Invisible Hunny was completely empty.
Winnie-the-Pooh returned the ladder to where he had gotten it from so as to have no-one raise suspicion and sat down. His tummy was by now rumbling away and also increasingly unhappy, because it was very hungry. So Winnie-the-Pooh first needed to get his tummy, his best pal, happy, and he decided to look for a non-empty pot of honey, or some condensed milk, or something else that would make tummy happy.
Winnie-the-Pooh left the village with The Jar Full of Invisible Hunny which he now knew was an empty jar. He reasoned with himself: “oh bother, there’s nothing I can do about the large jar empty of hunny. No-one listens to me and no-one cares about knowing the truth, I do not want to end up in a hole and my tummy will have none of it anymore”.
In The Dark Matter Crisis by Elena Asencio, Moritz Haslbauer and Pavel Kroupa. A listing of contents of all contributions is available here.
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The Cosmology Group at the Astronomy Lab of the Aristotle University of Thessaloniki is organising a conference on the above problem. The organisers are PhD student Asvesta Kerkyra with professor Leandros Perivolaropoulos and professor Christos Tsagas.
The conference will take place from June 3rd until June 6th on site in Aristotle University. Further information can be found at this link.
In The Dark Matter Crisis by Elena Asencio, Moritz Haslbauer and Pavel Kroupa. A listing of contents of all contributions is available here.
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Readers may be interested in two on-line meetings that are coming up:
1. Challenges of Modern Cosmology 2024 (CMC2024): January 18th
CMC2024 is an online discussion panel intended for listening, sharing and learning about challenges of modern cosmology and alternative theories. It will take place on the 18th of January 2024 from 12:00 to 17:00 (CET) and it will be publicly streamed on youtube. The panel will be divided in three sessions: current problems of modern cosmology, modified cosmology and gravity theories, and standard cosmological and gravitational tests. Each of these sessions will include from two to three 10 minutes talks followed by a 20 minutes discussion on the corresponding topic of the talk.
In order to join the discussion panel, registration is still possible until the 10th of January. The discussion can also be followed online without registration by searching for “CMC2024” on youtube or directly through. Before lunch break:
After lunch break:
Participation in social media to share comments or questions is also possible by using, for example, the X-hashtag #cosmos24.
2. Challenging the standard cosmological model: April 15th-16th
Scientific discussion meeting organised by Professor James Binney FRS, Dr Roya Mohayaee, Professor John Peacock FRS and Professor Subir Sarkar. See this link for the details and the registration for researchers in relevant fields.
In The Dark Matter Crisis by Elena Asencio, Moritz Haslbauer and Pavel Kroupa. A listing of contents of all contributions is available here.
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It seems that experts have a conference once a month somewhere on the globe to discuss why the local Universe seems to be expanding faster than the global Universe. Local expansion is obtained by using standard candles, the type Ia supernovae that explode in galaxies, by associating their distances to their recessional speeds. Global expansion is obtained by fitting the standard cosmological model to the cosmic microwave background (CMB) properties. This Hubble Tension is keeping hundreds if not thousands of astronomers and physicists busy in their jet-setting around the world to meet at repeating conferences at which the latest ideas on exotically complex, time or space-dependent dark energy descriptions are announced as possible solutions to the Hubble Tension. It keeps many bright people busy and some at a very elevated state of fame: “We have discovered a major new mystery of the Universe and only the very brightest of minds will be able to solve it.” Such minds can only be found in Ivy League Universities. I have been at a few such conferences (DMC Nr.77). I noted that it is not a problem for this group of scientists that the standard Einstein/Newtonian–inflation–plus–dark-matter–plus–dark-energy (the LCDM) model (I include here warm and fuzzy dark matter versions as these are extremely similar to the cold-dark matter version) does not conserve energy.
It is simply accepted that this model universe (which nearly everyone thinks is the real Universe) accelerates its expansion driven by a dark energy that no one understands and that creates more space and energy ever faster without an end.
Why is dark energy even needed? Well, assuming Einstein/Newtonian gravitation plus inflation plus dark matter leads to a model universe that would today globally expand too slowly. The only way to fix this overall expansion problem is to include an additional hypothetical process which pulls the model universe apart, and this is dark energy. The draw back of this fix is the above infinite-energy problem.
Interesting in this is also the systematic ignoring of the obvious solution to the Hubble Tension problem: the simple fact that our Local Group of Galaxies (about 10 million light years across) is located in a cosmological void of matter which is some 3 billion light years across. This region contains fewer galaxies than other regions and is observed in all surveys that have been done to date — see Figure 1.
Figure 1: The local void: the y-axis shows, essentially, the ratio between the observed number of galaxies divided by the expected global-mean-value in the LCDM model and the x-axis shows the distance from our Local Group (one pc is about 3.3 light years and h70 is about one). The inset indicates the literature where the data come from. The observational data tell us that at distances further than about 1200 light years (400Mpc) an about constant average space density of galaxies is reached, but that at smaller distances we are seeing a significantly smaller number of galaxies per unit volume. This is the local void (also referred to as the KBC void after Keenan-Barger-Cowie, or the local hole already described by Tom Shanks and his collaborators since 2003. Note that the underdensity is much deeper than allowed by the LCDM model (the shaded region). This figure is from Kroupa (2015).
“Thus, the present 2MASS data suggest the presence of a potentially huge contiguous void stretching from south to north. Not only would this delineate further the limits for the cosmological principle but it would also show the possible presence of significant power on scales of >~300 h-1 Mpc in the galaxy power spectrum.”
In the above Mazurenko et al. (2023) work, a cosmological model was employed to calculate the growth of structures. The model is (yes, obviously) MOND-based and works without cold, warm or fuzzy dark matter (which by now everyone should know does not exist). This cosmological model leads to the growth, as cosmological time progresses, of density differences between different regions. It turns out that the type of under-density, such as is evident in Figure 1, arises naturally. The first-ever hydrodynamical simulations of structure formation in this “nuHDM model” was published by us in Bonn (Wittenburg et al. 2023).
These under-densities (and corresponding overdensities) develop in this MOND-cosmological model because the effective gravitational force is stronger allowing the tiny initial fluctuations observed in the CMB to grow to more pronounced structures than in the LCDM model. These same fluctuations produce a completely uniform and smooth model universe in LCDM when viewed on scales larger than some 600 million light years, while leading to a much more clumpy and irregular model universe in a MOND-based cosmological model on even larger scales. In two previous publications (2021 and 2023) our study in Bonn led by PhD student Elena Asencio and Indranil Banik have also shown that the very massive galaxy cluster El Gordo, observed to already exist at the redshift of 0.87, arises naturally in such a model. In the LCDM model this is quite impossible (the Bullet Cluster, by the way, is also a challenge for the LCDM model but is easy in MOND-cosmology, as explained by Elena in her publications). See DMC Nr. 84.
We thus have the following physical situation: The (correct — in the sense of not having cold or warm of fuzzy dark matter but a realistic gravitational law) MOND-cosmology grows large regions of matter underdensities (as well as major overdensities and massive galaxy clusters). Being in an underdensity, the observer finds that the galaxies in it are falling towards the sides of the underdensity, just like apples fall to the ground on Earth (Isaac Newton would probably have appreciated this — see Figure 2).
Figure 2: The image shows the schematic distribution of matter in space – (blue; the yellow dots represent individual galaxies). The Milky Way (green) lies in an area with little matter. The galaxies in the bubble move in the direction of the higher matter densities (red arrows – imagine these are apples). The universe therefore appears to be expanding faster inside the bubble.
This is the reason why the observer thinks the local Universe is expanding at a slightly faster rate than the global Universe. Given that the underdensity is observed to be there through a lack of galaxies (Figure 1), this solution to the “Hubble Tension” is straight-forward – it is in fact so trivial that the leading minds in cosmology (the elite) appear to be challenged in grasping it — it seems that the whole research community, as shepherded by the brilliant minds in Ivy League institutions, appears to be acting as if it were the Catholic Church some 400 years ago concerning MOND: MOND is a sacrilegious topic not to be talked about by those that want to matter, and any way, every one knows it is wrong and also not a theory (well, the wide-binary-star test of MOND lately causes some heated debate among the few people who have the skills to make calculations in MOND and will be addressed here in the near future).
In any case, given this explanation of the Hubble Tension in a MOND-based cosmological model, our model as published in Haslbauer et al. (2020)makes a prediction! The prediction is: in the model (which accounts for the underdensity — Figure 1 — and the Hubble Tension as published by Haslbauer et al. 2020, and which does not take into account any measurements of bulk velocities AT ALL), galaxies must be moving faster away from us the further they are, after subtracting the Hubble expansion. That is, the model predicts (before the measrurement) that the bulk flow speed of galaxies increases with increasing distance.
And the sensational thing about all of this is: this prediction has now been confirmed! Watkins et al. (2023) measure “the bulk flow in a volume of radii 150-200 h-1 Mpc using the minimum variance method with data from the CosmicFlows-4 (CF4) catalogue.” Figure 3 shows the measured bulk flow: For example, galaxies observed at a distance of 200/h Mpc (about 600 million light years) show a bulk velocity of about 420 km/s (after correcting for the Hubble expansion). The MOND-based cosmological model gives the same velocity if the Local Group (the green dot in Figure 2) is approximately 380 million light years (116 Mpc) away from the centre of the void and is moving with a velocity of about 220 km/s relative to the local bulk flow such that the Local Group moves with a total of approximately 627 km/s relative to the CMB.
Figure 3: The bulk flow of galaxies (the average speed of galaxies in a sphere, y-axis) is plotted versus the distance from the observer on the x-axis. The data from Watkins et al. (2023) are shown as solid black dots. The MOND-based cosmological model is shown as the dotted line assuming the local void has a Gaussian density profile, that the Local Group is located 116 Mpc (about 380 million light years) away from the void centre and that the Local Group is moving with 627 km/s relative to the CMB and about 200 km/s slower than the local bulk flow (within some 150 million light years). In other words, the Local Group’s velocity relative to the CMB has been reduced to 627 km/s by small-scale flows in the local region. Thus, the MOND-cosmology-based bulk flow (dotted black line) is in (stunning) agreement with the data in terms of its amplitude and shape, while the LCDM model predicts bulk velocities (solid red line) that are in major disagreement with the observations. Adapted from Mazurenko et al. (2023).
It thus turns out that once we have a better model of the observed Universe, then (i) the local billion light year underdensity, (ii) the Hubble Tension and, simultaneously, (iii) the high observed bulk velocities of the galaxies at distances of a few hundred million light years are automatically and simultaneously understood. This is trivial in the sense that it pops out of the MOND-based calculations, but it is highly non-trivial because no other known model has been able to achieve this.
What of the future? We now have an improved cosmological model, namely the “nuHDM” model. It accounts automatically for open star clusters, galaxies(e.g. Banik & Zhao 2022, Kroupa et al. 2023), the Hubble Tension, bulk flows as well as the significant density contrasts on scales of some billion light years (this text). But open questions remain:
This “nuHDM” MOND-cosmological model is very conservative by assuming a next-to-identical expansion history as the LCDM model. It thus assumes, like the LCDM model, inflation and dark energy, and assumes the CMB is the photosphere of the hot Big Bang. The one major issue therefore is that it is also not energy conserving. To achieve the same expansion history, the mass content of this model universe needs to be dominated by a sterile neutrino background, which effectively is a hot dark matter component that plays no role in galaxies and is less exotic by being related to the physics of the active neutrino. And it solves the missing mass problem in galaxy clusters. As shown in the first-ever hydrodynamical simulations of structure formation in the nuHDM model published by us in Bonn (Wittenburg et al. 2023), it seems to form galaxies too late and by the present time it is populated by too many hugely massive galaxy clusters, posing two additional problems. Further research on this model is needed reaching to much higher resolution. Given these open questions, a new, and bolder model of the Universe is being studied. I call it the Bohemian Model of Cosmology (it is hinted at in Kroupa et al. 2023). Currently we are testing if this model, which is based on radically moving away from the current Belief Canon of the Cosmological Community, stands up to the observational data, ranging from open star clusters to the largest probed cosmological scales.
To summarise: a major step towards an improved understanding of cosmologically relevant observations has been achieved, even though the majority of scientists are still far from accepting this. The real Universe is significantly better matched by a model based on Milgromian dynamics, from the scale of open star clusters to the billion light-year scale. The challenging prospects are to better understand the fundamental physics underlying Milgromian dynamics which appears to be related to the quantum vacuum, and to develop a model universe which conserves energy. It is quite possible that both of these are different aspects of the same solution. Today is truly an exciting time for young scientists to flex their cerebral muscles, perhaps comparable to the 1920s when quantum physics was being discovered to a large extend in Copenhagen and Goettingen.
In The Dark Matter Crisis by Elena Asencio, Moritz Haslbauer and Pavel Kroupa. A listing of contents of all contributions is available here.
We had a recent case where a submitted comment to The Dark Matter Crisis did not appear in the system, the comment being swallowed. The user had to use a different browser to submit the comment which we then approved. In case you submit a comment and it does not appear, try another browser and/or send us an
The Dark Matter Crisis 