Dark matter may slow the rotation of the Milky Way’s central bar of stars
A cosmic analog of tree rings hints at how the bar’s spin slowed over time
![illustration of the milky way galaxy](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2021/06/062121_ec_milkyway_feat.jpg?fit=1030%2C580&ssl=1)
The Milky Way (illustrated) contains a central bar of stars (yellow) that rotates along with the galaxy. Researchers reported evidence that the bar is being slowed by the presence of dark matter.
R. Hurt/JPL-Caltech/NASA, ESO