Our Milky Way galaxy revolves inside the Local Group of galaxies in a relatively quiet corner of space. The Local Group is called gravitationally bound galaxies, including the Milky Way, the Andromeda Galaxy and the Triangle Galaxy. Researchers count more than 50 galaxies in the Local Group, but with the discovery of new galaxies, their number is constantly growing. Moreover, the Milky Way and the Andromeda Galaxy are the largest galaxies of the Local Group. They are surrounded by a group of small galaxies, the largest of which are the Big and Small Magellanic Clouds. These satellites of the Milky Way are located at a distance of 150 to 200 thousand light-years from us.
Local Group – part of the space web
The closest galaxy cluster to the Local Group is the Virgo cluster, which is about 55 million light-years from us. In the Virgo cluster, there are more than 2,000 “island universes.” Compare this with the Local Group, which, according to confirmed data, includes about 50 galaxies, and according to unconfirmed ones – another 30. Moreover, the size of most galaxies in the Local Group is not comparable to the size of the Milky Way and the Andromeda Galaxy. However, this is not all – the Local Group is only a small, peripheral part of the supercluster of galaxies, which in total totals more than a thousand different galaxies. Together, these superclusters form a gigantic but by no means the only substructure of the Universe. Feel small.
According to Astronomy, most of the galaxies that make up the cosmic web – a network of superclusters of galaxies – exist in small groups that are scattered throughout the cosmos. Researchers believe that the galaxies of the Local Group arose more than 13 billion years ago, when the first clusters of matter grew into protogalaxies. A billion years after the Big Bang, when stars formed, the Local Group spanned 600,000 light-years. The fact is that, being close to each other, galaxies at that time united more often. It is possible that such mergers could create the Milky Way of 100 or more protogalaxies.
The satellites of the Milky Way – the Big and Small Magellanic Clouds – are located at a distance of 163 thousand light years from us. These are dwarf galaxies that the Milky Way engulfs in the future. This is not surprising, since our galaxy right now destroys and devours the spheroidal dwarf galaxy Sagittarius. In addition, after about 4 billion years, the Andromeda Galaxy and the Milky Way will collide to form a new, large galaxy, which will eventually become a giant elliptical galaxy.
Given the fact that astronomers’ observations are limited by the observable Universe, the study of the Local Group galaxies and the nearest Virgo cluster allows scientists to see the microworld – a kind of laboratory or mini-Universe. The substance, which astronomers call dark matter, accounts for 26% of all matter in the universe, but so far no one knows what it is. Using a technique called gravitational lensing, astronomers studied the halo of the Milky Way and excluded several alleged candidates. In the same way, scientists use nearby galaxies to study where black holes form. One way or another, the evolution of galaxies and the process of star formation, allows scientists to learn more not only about our own galaxy, but also about the whole Universe.