A few years ago a researcher proposed a new theory of gravity that could explain the curious movements of stars in galaxies, going so far as to call into question the existence of dark matter. According to a recent study, the theory, although highly controversial, may indeed hold.
We were talking about it in November. Dark matter, this mysterious material component probably made up of elementary particles that are supposed to be distributed throughout the observable universe, would explain the movements of stars moving in galaxies since gravity alone is not enough. Physicists predict that dark matter accounts for about 27% of all the mass and energy in the observable Universe, but the detection of particles that prove its existence once and for all throws us off the hook. What if we were on the wrong track?
Starting from the principle that we will not be able to detect the slightest particle of dark matter, Erik Verlinde has decided to examine the problem in the other direction. He suggested that the problem was not a possible presence of dark matter, but that we don’t really understand how gravity works. He then proposed this: gravity is not a fundamental force of nature at all, but rather an emergent phenomenon — just as temperature is an emergent phenomenon that arises from the movement of microscopic particles.
In other words, gravity would only be a side effect and not the cause of what is happening in the Universe. Even better, with this new theory, we would no longer need dark matter. But how to prove it? Until then, the hypothesis could not be verified, but a few days ago a team of researchers from the University of Leiden, in the Netherlands, showed signs that the theory could indeed hold.
According to reports from The Royal Astronomical Society magazine, the team of researchers led by Margot Brouwer tested Verlinde’s theory by measuring the distribution of gravitational forces in a sample of 33,000 galaxies using the gravitational lensing effect predicted by the Einstein’s theory of general relativity. They then discovered that by applying the calculations of Verlinde’s emergent gravity theory, they could achieve the same results without having to resort to the idea of dark matter. Thus, Einstein’s theory of general relativity and that of Verlinde have the same relevance, at least in these measures.
This is just a very early test of Verlinde’s theory and it will take a lot more to throw or not trash more than a century of accepted thought about gravity and dark matter. These results are nevertheless very encouraging and could well lead us one day to consider the “theory of everything” which merges the observable effects of classical physics with the microscopic and strange world of quantum mechanics.