The universe 13 billion years ago was not at allas it is seen by scientists today. The latter believe that at that time an active process of star formation was taking place in the vast expanses of space. New lights were born and attracted closer to each other under the influence of gravitational forces. This led to the formation of the first star clusters, then small (dwarf galaxies), which collided with each other and formed larger galaxies, such as our Milky Way.
Evidence of the Milky Way's collisionGalaxies called Gaia Enceladus appeared in 2018, when data from the telescope of the European Space Agency indicated that some stars are not quite in place. Scientists have discovered that the interior of the Milky Way is filled with the “debris” of another galaxy, which was four times smaller than ours when it was alive. However, until today it was not known when this collision could occur.
See also: Something unknown like a bullet punched a hole inside the Milky Way
Scientists from the Canary Institute of Astrophysics believe that they were able to solve this mystery.
How the Milky Way was formed
During the study, they were able to find out the exact location and brightness of one million stars of our galaxy within 6500 light years from the Sun with the help of the Gaia space telescope.
The stars were divided into two categories: blue (poor in metals) and red (rich in metals). It turned out that all the luminaries are equally ancient, but the "blue" move chaotically. This feature has become evidence that the Milky Way really once swallowed the less extensive galaxy.
Focusing on the age of the stars, scientists determined the time of the collision of galaxies. According to their calculations, it happened 10 billion years ago.
The primitive Milky Way formed stars onover three billion years. The smaller galaxy went the same way, but it was chemically poorer and had less mass. So she was absorbed, the study says.
The researchers note that the merger process itself took place over several million years.
The merger is not a one-step, but a gradual process that has a huge impact on star clusters, the study authors say.
Scientists have created a 3D animation that demonstrates this merging process. The video can be viewed below.
According to researchers, the heat released bymerger, and a large amount of galactic gas eventually led to the formation of the modern form of the Milky Way. However, this was not the first case of such a merger, noted investigated. Over the history of its existence, the Milky Way has swallowed up many other smaller galaxies. After about 5 billion years, our own galaxy will have the same fate. It will be absorbed by the neighboring Andromeda galaxy.
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