Dark matter seems to be more clumpy than predicted
The following piece of text is from a popular article "Hubble Uncovers an Unexpected Discrepancy: An Ingredient Missing From Current Dark Matter Theories?" in Scitechdaily. The article tells about the observations by the NASA/ESA Hubble Space Telescope and the European Southern Observatory’s Very Large Telescope (VLT) in Chile. The original article “An excess of small-scale gravitational lenses observed in galaxy clusters” by Massimo Meneghette et al is published in 11 September 2020 in Science (see this).
"The researchers then used the Universe simulator to build 25 simulated clusters and performed a similar analysis with the clusters. They did so in order to identify the sites of possible lensing and the locations that could create the greatest distortions. The two didn't match. There were significantly more areas that generated high distortion in the real-Universe galaxy than there were in the model. This would be the case if the distribution of dark matter were a bit more clumpy than the models would predict-the dark matter halos around galaxies were more compact than the models would predict."
Cold matter scenario seems to be in grave difficulties. There are a lot of problems met already earlier but put under the rug. Probably an unavoidable outcome of over-specialization. During the years I have commented on these failures in articles, which can be found also at my homepage (see this).
The basic problem is that a continuous distribution of dark matter is assumed. Galaxies and other structures would be formed by the gravitational attraction of seeds producing filament like structures. Seeds would have emerged by fluctuations in mass density.
In the TGD framework the situation is exactly opposite: the seeds for the formation of galaxies are present from the very beginning as what I call cosmic strings. The model explains galactic velocity distribution, providing a model for the formation of galaxies,stars, and planets, and for the linear structures formed by galaxies.
- Cosmic string-like objects carrying dark matter and energy - not possible in GRT space-time - thicken to flux tubes and generate ordinary matter much like the decay of the inflaton field. There is no need to explain how cold dark matter generates clumps, cosmic strings as clumps are there from the very beginning. Galaxies and other visible structures - also filaments - are generated along cosmic strings and flat velocity spectrum for stars rotating around the galaxy is an automatic prediction.
- Also the invisible portions of cosmic strings not net decayed to dark matter induce a lense effect. The simulation of the presence of cosmic strings requires in halo models the distribution of the dark matter to be more lumpy and that requires too compact dark matter halos.
- The observed lense effect can be even 10 times stronger than predicted by the halo model. TGD explanation could be in terms of cosmic strings whose thickening to flux tubes at tangles liberates energy as ordinary matter forming the galaxies and string tension lowers leading to a smaller lense effect. The portions of the flux tube still thin and with higher string tension can explain the anomalously large lense effect.
Universe seems too thin and two large clumps of dark matter are required to explain the distribution of galaxies in clusters
It has been found that the observerved clumping of the dark matter is 10 per cent smaller than the clumping required by LambdaCDM scenario to make possible the formation of galaxies. The Universe seems to be also thinner than expected. This what one learns from Quantamagazine telling about the findings of the Kilod-Degree Survey (KiDS) published in the article "KiDS-1000 Cosmology: Cosmic shear constraints and comparison between two point statistics" (see this). The group studied about 31 million galaxies from up to 10 billion light-years away.
Could the TGD view about dark matter and energy provide understanding? Dark matter and energy would be associated with long flux tubes emerging as cosmic string-like objects thicken and liberate energy transforming to matter. Dark matter and energy are associated with effectively string-like objects. Could this help to understand these findings?
The dark energy and matter assigned to string-like entities would generate the ordinary matter around themselves and serves as seeds possibly attracting more matter also created in this manner. How would the clumping in the TGD Universe differ from the clumping in the LambdaCDM scenario?
In LambdaCDM clumps are necessary for the formation of galaxies and other structures. In the TGD framework they are not needed, one-dimensional string-like networks present from the beginning and create galaxies by decaying to ordinary matter. In long enough scales the average density would be constant and there would be no clumps at all.
Can one understand why the Universe is too thin? Could it be the energy and mass of all cosmic strings have not been taken into account. Long cosmic strings have galaxies and other structures as tangles decaying to ordinary matter. What about the straight portions. Have they been taken into account in the survey?
For the TGD view about the formation of galaxies and start see for instance this.
For a summary of earlier postings see Latest progress in TGD.