Something super-powerful is bending the disk of our Milky Way galaxy: scientists have a guess what it could be
Despite the fact that humanity has made remarkable progress in space exploration and modern technology allows us to look into the distant past of the Universe, we still have a rather poor understanding of our home galaxy, the Milky Way. A recent discovery has revealed that we were even wrong about the galaxy's shape.
This is stated in a study published on the arXiv preprint website. The research has yet to be peer-reviewed and approved by the scientific community.
It was only last century that humanity learned that the Milky Way is just one galaxy among billions, not the entire Universe. It is not surprising that it is still the subject of ongoing research.
The Gaia spacecraft in 2020 mapped the positions and motions of more than a billion stars, allowing scientists to better understand the external structure of our galaxy. It was thanks to the data from the spacecraft that the first evidence appeared that our galaxy may not be as flat as it was thought. Scientists also learned that our galaxy extends outward more than we thought.
The fact that the edge of the galaxy may have a wavy structure was of great interest to scientists. So they began to further study this phenomenon. According to Universe Today, it turned out that Gaia's data were not wrong at all, and the curvature of the outer edge of the galactic disk does exist. The first assumptions linked this phenomenon to ancient galactic collisions, such as the collision with the dwarf galaxy Sagittarius, which occurred about 6 billion years ago.
But a new study has revealed another reason for what exactly has warped our galaxy. Scientists believe that it is the tilted halo of dark matter.
It is known that most galaxies in the Universe are surrounded by a massive dark matter halo. Since this halo contains most of the mass of the galaxy, it can affect the structure of the galaxy over time. In particular, if it is tilted relative to the galaxy plane, gravitational effects can distort the galactic disk.
In order to understand whether this is a significant distortion and whether it is widespread in the Universe, the authors of the study used a supercomputer to simulate galactic evolution.
The data obtained showed that the inner region of the dark matter halo can be significantly tilted relative to the galactic plane. This can be caused by both galactic collisions and critical approaches of other galaxies, when the collision was avoided only by a miracle.
In this case, the change in halo orientation can persist for billions of years, so it is not surprising that it affects the structure of the galaxy itself.
Astronomers have also previously observed other galaxies with a distorted plane, and there is some evidence that about half of the spiral galaxies in the universe are distorted to some degree. This confirms the theory of the influence of a long-term and joint gravitational interaction between the galaxy and its curved halo.
Further observations and modeling are needed to confirm the scientists' version of the story, which will explain the details of the evolution of many galaxies, such as the Milky Way.
Earlier, OBOZREVATEL also talked about what will happen when the Milky Way crashes into Andromeda.