What breaks our galaxy suspicious neighbors of the Milky Way

(ORDO NEWS) — The edges of the Milky Way are strangely distorted and deformed. Most likely, this is the influence of another galaxy.

Galactic Warp

Something mysterious is affecting the edge of our galaxy, causing a “galactic skew” to its outer edges, according to a study published in 2020 in the journal Astronomy of Nature.

The Milky Way is made up of approximately 250 billion stars that cluster in spiral arms and orbit around a supermassive black hole. But astronomers have noted strange dynamics taking place in the far reaches of the Milky Way, where the galactic disk is distorted by incomprehensible influences.

To find out the cause of the Milky Way’s outward warping, a team of researchers led by astrophysicist Eloise Poggio at the Italian National Institute of Astrophysics in Turin studied the motions of 12 million giant stars observed by the European Space Agency’s Gaia space telescope.

“Our Milky Way is a unique example of galactic deformation due to knowledge of its stellar distribution and kinematics ,” the scientists note in the study. “ However, the cause and dynamic nature of the deformation of our galaxy remains unclear due to the lack of kinematic constraints.”

In other words, scientists have just begun to model the external deformations of the Milky Way in detail, which, nevertheless, has taken several years. In 2019, the team created a fascinating 3D warp map of the galaxy based on measurements of 2,300 Cepheid variables, which are a special type of ultra-radiant stars.

Satellite galaxies warp the Milky Way

The sheer volume of data collected allowed Poggio and her colleagues to study the movement of millions of giant stars in order to trace the deformations of the galaxy: “We measured the rate of deformation by comparing the data with our models, ” she says.

Based on the obtained speed, the edge of the galaxy makes one revolution around the center of the Milky Way in 600-700 million years. This is much faster than we expected based on other models’ predictions.”

Suggested explanations for the deformation include a mismatch in the axial motions of the disk and center, or perhaps tidal forces from satellite galaxies of the Milky Way, which is more likely.

This discovery may be confirmed by other recent studies that reconstruct the past of the Milky Way and interactions with nearby galaxies that can attract materials and objects from our galaxy towards them or cause disturbances by colliding with them.

“The results of our study show that satellite galaxies play an important role in shaping the outer edge of the Milky Way, ” says Poggio.


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