The concept of dark matter was formulated in the 1930s and aims to respond to scenarios in which objects have a stronger gravitational force than visible matter would allow. In theory, the more mass an object has, the greater its gravitational force. Astronomical observations revealed, however, galaxies to rotate much faster than their gravity should allow based on their visible mass, which led Fritz Zwicky to suggest the existence of dark matter, something that is not seen, but that exists and that contributes to this behavior. Now, researchers have discovered 150 galaxies that have a ‘modified gravity’, reinforcing other hypotheses.
The great challenge to Zwicky’s concept was to find the dark matter itself. Several teams of scientists have tried to observe it in space or even recreate it, but without success.
The discovery of modified gravity in the 153 galaxies points, however, to a new approach, suggesting that our current gravity models and Physics as we know it need minor adjustments. Modified Newtonian Dynamics’ MOND emerges as the most likely hypothesis for these galaxies, explains the publication New Atlas. This model, proposed in 1982, indicates that at low accelerations, the effects of gravity are stronger than Newton’s laws describe. As a side effect, the movement of objects thus depends not only on their own mass, but also on the other nearby masses, due to the EFE (from external field Effect, external field effect in free translation).
The discovery of modified gravity indicates that EFE is there and the researchers conclude that galaxies with the effect of strong external fields moved more slowly than galaxies with weaker external fields. This conclusion is described in the MOND and surprised the researchers: “The external field effect on the rotation curve must be quite small (…) We spent months checking several systems. In the end, it became clear that we had a clear and solid detection ”, explains Federico Lelli, co-author of the study.