All this time, astronomers believed that the closest tous the Andromeda galaxy is about three times more massive than the Milky Way. However, this assumption turned out to be erroneous. So, according to a recent study published in the journal Monthly Notices of the Royal Astronomical Society, the Andromeda galaxy is not so different from the Milky Way. These spiral galaxies will collide with each other after about 4 billion years. Due to gravitational attraction, Andromeda and the Milky Way will merge into a single galaxy, although earlier astronomers were confident that our galactic neighbor would absorb the Milky Way.
According to the researchers in the officialIn a press release, during the course of their work, they found that the mass of our closest galactic neighbor roughly corresponds to the mass of the Milky Way. According to calculations, the mass of the Andromeda galaxy is about 800 billion times the mass of the Sun. To determine the mass of the nearest galaxy to us, the researchers calculated the speed that a fast-moving star needs to pick up to avoid the gravitational attraction of the galaxy in which it is located. The speed required for a star to travel outside the galaxy is known as the object’s exit velocity. So, when a rocket is launched into space, its speed reaches 11 km / s, which allows it to overcome the gravitational attraction of the Earth. The Milky Way is a trillion times heavier than our small planet, therefore, to avoid its gravitational attraction, the speed of an object when leaving the galaxy should be at least 550 km / s.
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It should be noted that this is not the first time,when the galaxy’s weight is recalculated based on an analysis of the exit speeds of objects inside it. In 2014, astronomers used a similar technique to revise the mass of the Milky Way. According to the results, the amount of mysterious dark matter - matter that does not interact with the photons of light - in our galaxy is much less than experts expected.
Clash is inevitable
After about 4 or 5 billion years, the galaxyAndromeda will merge with the Milky Way. Despite the fact that our galaxy did not participate in any major collisions, astronomers have repeatedly observed the remains of previous mergers with dwarf galaxies.
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Like the 2014 work on massOf the Milky Way, the latest work of scientists suggests that in many earlier studies, the amount of dark matter in the Andromeda galaxy has also been overestimated. Astronomers studied the orbits of high-speed stars and found that the amount of dark matter in the galaxy is much less than they expected. The result means that all previous galaxy collision models are incorrect. In order to understand exactly what will happen during the merger, accurate computer models are needed. But no matter what the collision of galaxies will ultimately be after 4 billion years, researchers believe that their discovery “completely changes our understanding of the local galactic group.” But before we finally know the future of the Milky Way, we can find solace in the acquired knowledge - our galaxy will not be absorbed by Andromeda, as we once thought. This is great news.