Dark matter warps our galaxy

The edges of the disk of our galaxy are warped in different directions. Scientists have studied the halo of the Milky Way and came to the conclusion that dark matter, which surrounds our star system like a bubble, is responsible for this.

Dark matter warps out the Milky Way. Source: www.space.com

Milky Way is warped

The Milky Way galaxy, part of which is the Solar System, belongs to the spiral type. At first, people thought it was a flat disk. However, studies of the second half of the XX century have shown that it is warped like some other similar objects.  

In fact, the warp is significantly noticeable only at the ends of the disk of the Milky Way. One of them is bent “down”, and the opposite one is bent “up”, although both of these definitions are actually conditional. After all, these concepts exist only on the surface of the planets.

The reason for this remained unknown. However, in a new study, scientists have concluded that the halo of dark matter that surrounds the Milky Way is responsible for this phenomenon. The substance in it does not interact with the ordinary one in any way, so we can only judge it by the gravitational effect.

Warped dark matter

The starting point for the current research was the data of the Gaia telescope, published in the 2022 article. It provides data on the movement of approximately 2 billion stars. Some of them are not in the disk, but in the halo — an extremely sparse spherical shell that surrounds it. And their movements are strangely shifted to one side.

Scientists see the reason for this in the fact that there is another shell of dark matter around the halo of ordinary stars. And this giant bubble of invisible matter is tilted relative to the rest of the galaxy by about 20°. At least, this solution was suggested to researchers by modeling the evolution of our star system over 5 billion years.

They saw that this particular version of the simulation was most consistent with what they were observing. According to the authors of the article, the reason for such a strange shift could be the collision of the Milky Way with another galaxy, which occurred many billions of years ago.

As a result, the halo of the dark matter of the Milky Way tilted almost 50° relative to the axis of its disk, which caused the warp of the main system. So it slowly leveled off until it reached its current position.

According to www.space.com

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