Milky Way's Core May Contain Less Dark Matter Than Estimated, MIT Study Finds

Stars at the Galaxy's Edge Move More Slowly Than Expected, Suggesting a Lighter Galactic Core

MIT physicists have discovered that stars at the edge of the Milky Way galaxy are moving more slowly than expected, suggesting that the galaxy's core may be lighter and contain less dark matter than previously thought.
The findings are based on the analysis of data from the Gaia and APOGEE instruments, which track the location, distance, and motion of stars throughout the Milky Way.
The team plotted each star's velocity against its distance to generate a rotation curve, a graph that helps scientists understand the distribution of visible and dark matter in a galaxy.
The rotation curve remained flat out to a certain distance, then started to decline, indicating that outer stars are rotating slower than expected.
The team translated the new rotation curve into a distribution of dark matter that could explain the outer stars' slowdown, and found that the resulting map suggested a lighter galactic core than expected.