what happens when galaxies collide

Scientists have found an answer to long unanswered question — What happens when two galaxies collide? Researchers say that what happens post-collision depends on the size of galaxies. If one giant galaxy collides with a dwarf galaxy then the collision stops smaller galaxy from forming new stars. While the rate of formation of stars increases in both the galaxies post-collision if they are similar in sizes. The study was based on analysis of 20,000 merging galaxies.

Andromeda, our nearest major galactic neighbor, is moving fast towards our galaxy Milky way at about 4,00,000 kilometers per hour and will collide with our galaxy in future, says Astrophysicist Luke Davies, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR). However, he further added that there are nearly four billion years left in the collision, but investigating such cosmic collisions lets us better understand how galaxies grow and evolve.

Previously scientists thought that when galaxy smash into each other the rate of production of stars increases by a significant amount due to more concentrated gas clouds which gives extra fuel for faster formation of stars. On the contrary, Dr Davis explained that when two galaxies of similar masses collide then they both increases their stellar birth rate. However, when one galaxy is significantly more heavier than other, then the bigger galaxy starts forming stars at a faster rate while the rate of production of stars decreases in smaller galaxy. This is due to the fact that the bigger galaxy gobbles up its companion’s gas leaving it without any fuel to form new stars.

Apart from unravelling the mystery of galaxy collision; the study has also pointed towards collision between Milky Way and Andromeda four billion years later.

Well, scientists believe that both they galaxies will start affecting star production rate as they come closer to each other, eventually merging up to form a new galaxy. In fact, scientists have given a new name to the galaxy that will form after the collision — ‘Milkdromeda’.

Below is the Andromeda–Milky Way collision simulation.

For the study, Dr Davies used Anglo-Australian Telescope in regional New South Wales.

The study appeared in the journal Monthly Notices of the Royal Astronomical Society

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Kanishk Singh, co-founder, and editor-in-chief at The TeCake, has forayed in the Science and Space for over five years, he enjoys his stint as an editor of several local magazines. He has written several editorials and high-level documentations.

Around the World

  • Anisetti Thammayya

    Congratulations to Luke Davies and his coworkers for their work on colliding galaxies. Very useful information to understand our infinite universe.

  • InternetCrazy

    I don’t think anything has moved in the void for an enormous period of time. Other than the bodies in satellite orbits. Meteors fly through, this is caused due to explosions on large planets, (maybe volcanos) breaching the gravitational orbit. There is not as many galaxies as stated.

    If a galaxy that huge moved we would already have known about it, and you would not be reading this article.

  • InternetCrazy

    I think when a galaxy exerts motion, the other galaxies force it back into equilibrium. Also if you were to enter the boundary between galaxies you would experience very weird events.

  • InternetCrazy

    So go to McDonalds and have a Milkdromeda.

  • Krishna Rao S.

    Fantastic research work, but an absolute waste of money and time. If another galaxy is to collide with ours, one thing is certain, we are all going to be dead and this bit of knowledge is not going to save us. That money could have been better spent on something that would put food on the table or bring about peace in some quadrant of the world.

  • InternetCrazy

    I think NASA and Roscosmo should build a high speed spaceship and send some of these guys to the area between galaxies. I think that’s where they came from in the first place. Maybe their theories would make sense there. I think Steve Hawkins should be captain of the first ship.