Milky Way is a typical galaxy and, most likely, did not arise as a result of the collision of other galaxies. A popular hypothesis was denied Australian scientists who studied UGC 10738 – a galaxy, which, like the Milky Way, has fat and thin discs. Astrophysicists presented their findings in the article published in the Astrophysical Journal Letters magazine.
According to hypothesis, thick and thin discs appeared due to an ancient catastrophe and are not typical of spiral galaxies. The thin disk contains 85 percent of stars, and the thick consists mainly from old stars formed in the early stages of the formation of the Galaxy. However, scientists conducted observations using VLT (Very Large Telescope) and found that similar structures are also available at UGC 10738, located 320 million light years from the Earth. This indicates that the Milky Way is most likely formed by the usual way.
The sun is in the thin disk of the Milky Way and 1.5 percent consists of elements heavier than helium. In the stars in a thick disk, the number of elements heavier helium is 3-10 times less. The difference in the ratio of elements is a decisive characteristic for thick and thin disks. Such structures were observed in a large number of galaxies, but it remained unknown, whether they have the same feature that the Milky Way disks.
Data obtained using VLT confirmed that the distribution of stars by age in UGC 10738 is similar to the distribution in our galaxy. So, the Milky Way and UGC 10738 evolved in a similar way, which refutes the former representations of astronomers.