Although dark matter is a central part of the standard cosmological model, it’s not without its issues. There continue to be nagging mysteries about the stuff, not the least of which is the fact that scientists have found no direct particle evidence of it. Despite numerous searches, we have yet to d
Dark matter is a fundamental component of the standard cosmological model, but its mysteries remain unsolved. One of the biggest puzzles is the lack of direct evidence for the existence of dark matter particles, despite numerous searches. Some astronomers have proposed alternative theories, such as Modified Newtonian Dynamics or modified gravity models, to explain the observations. A recent study on galactic rotation appears to lend support to these alternative theories.
Rotation curve of the typical spiral galaxy M33 and the predicted one from the distribution of the visible matter . The discrepancy between the two curves is accounted for by adding a dark matter halo surrounding the galaxy. Of course, just adding a small term to Newton’s gravity means that you also have to modify Einstein’s equations as well. So MoND has been generalized in various ways, such as AQUAL, which stands for A Quadradic Lagrangian. Both AQUAL and the standard LCDM model can explain observed galactic rotation curves, but there are some subtle differences.This is where a recent study comes in. One difference between AQUAL and LCDM is in the rotation speeds of inner orbit stars vs outer orbit stars.