Dark Matter Theory Triumphs In Sweeping New Study
“It’s a revolutionary breakthrough that dark matter can reproduce both the relationships between luminosity and galactic speeds and the stellar mass function in galaxies simultaneously, as this new study accomplishes for the first time. By incorporating advanced techniques and more detailed physical models and the interplay between different components, relations that has only been observed, never explained, are finally seen to emerge. If we can throw our cosmic ingredients into a simulation and get out the Universe exactly as we observe it, that’s as big a success for our theories and models as one can ask for.”
On the largest scales, dark matter has been undoubtedly the most successful theory in modern cosmology for explaining a huge variety of observations. From the motions of galaxies in clusters to the separation of mass and light when they collide, from the correlations between galactic positions to the fluctuations in the CMB, from the bending of starlight to the formation of large-scale structure, it’s clear that the Universe needs dark matter. But individual galaxies have always been the most difficult test for dark matter. In particular, there have been empirical correlations – or relationships between two different observables – that have never had an underlying explanation successfully presented. One of the most difficult has been the Tully-Fisher relation, which relates the luminosity to the rotational speed of spiral galaxies. But a new simulation, at long last, has finally cracked that nut by incorporating not only gravitation and dark matter, but the relationship between baryons and dark matter.
The way a galaxy forms stars over its history matters tremendously for what we get today, and by simulating it all together, it adds up to one stunning conclusion: success for dark matter in an entirely new way!