Dark matter is slowing the Milky Way’s rotation, according to new research.
According to physicists from the University of Oxford and University College London (UCL), dark matter is slowing down the spin of the Milky Way’s galactic bar.
For more than 30 years, scientists have hypothesized that the Milky Way’s galactic bar is slowing down. Now, researchers from the University of Oxford and the University College London (UCL) have proof.
The galactic bar is the Milky Way’s central region, which is home to billions of stars.
The researchers saw the Hercules stream, a massive group of stars that revolves around the Milky Way’s centre at the same speed as the galactic bar, using the European Space Agency’s (ESA) Gaia Telescope.
The stars travel further out as the speed of the bar slows.
The spinning bar acts as a gravitational trap for the stars, similar to how rocks in the asteroid belt follow Jupiter’s orbit.
According to study published in the Monthly Notices of the Royal Astronomical Society, astronomers discovered that stars have a “chemical fingerprint.”
This element is found in heavier metals, indicating that the stars have moved away from the galactic center, where the stars and gas have more elements.
The scientists was able to prove that the galactic bar has slowed by at least 24% since it initially formed – roughly 13 billion years ago – using the data.
According to the researchers, this reveals a lot about the nature of dark matter, which acts as a counterweight to spin.
“Astrophysicists have long assumed that the spinning bar at the center of our galaxy is slowing down, but we have uncovered the first proof of this happening,” said co-author Dr Ralph Schoenrich of UCL Physics & Astronomy.
“Dark matter must be the counterweight slowing this spin.
“Until now, we’ve only been able to infer dark matter by mapping galaxies’ gravitational potentials and eliminating visible matter’s contribution.
“Our finding gives a novel form of dark matter measurement—not of its gravitational energy, but of its inertial mass (dynamical response), which slows the bar’s spin.”
“Our result gives a novel perspective for restricting the nature of dark matter, as different models will modify this inertial pull on the galaxy bar,” said co-author and PhD student Rimpei Chiba of the University of Oxford.
“We discovered the same thing.” Brinkwire Summary News.