Don’t panic, but we are moving at a speed of 250,000 miles per hour on a head on collision course towards our nearest galaxy, Andromeda. And by ‘we’, I mean the Milky Way Galaxy.



We know that there are hundreds of billions of galaxies in the universe all moving through space at very, very high speeds. As such, collisions between galaxies is a common occurrence throughout the universe.


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So, what happens when two galaxies with hundreds of billions of stars each and possibly a super massive black hole at the centre of each, collide with each other?



You might think that the whole affair would be a highly disastrous one which would cause the destruction of most, if not all the stars of both the galaxies, but you would be wrong. In fact, galactic collisions are so tame that you wouldn’t even notice it happening.


Let me explain exactly what happens by taking the example of our own scheduled collision.



Milky Way Vs Andromeda


As I mentioned at the start, our galaxy is headed towards Andromeda which will lead to a galactic collision in roughly 4 billion years. Even though we wouldn’t be alive to see it, it’s still nice to understand what would happen.



Again, as I mentioned, the collision won’t be like that of a Hollywood action movie but it will be more serene. But, you might be thinking how that is possible if there are more than 100 billion massive glowing hot balls in both the galaxies.



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The reason for that is, though the number of stars is very high, they are also spaced out over unfathomable distances. In fact the nearest star to our sun is Alpha Centauri which is 93 million miles away!



So, you can imagine when two galaxies collide, their constituents (the stars), just hit empty space and not other stars in a galactic fireworks show, like you would imagine.



That being said, both the galaxies do get a big makeover.



A Galactic Makeover


Even though the collision itself isn’t destructive, it causes a massive change in the structure of both the galaxies involved. There is a huge amount of mass in each galaxy owing to all the stars, dust, gases, and black holes. 



We also know that whatever has mass, also has a gravitation pull. Therefore when two galaxies merge, it gives both of them a titanic makeover in terms of size, shape and structure of their constituents.



It is highly likely that all the solar systems, including our own, will be literally flung into totally new regions of the resultant galaxy. This won’t change anything within our solar system though, as gravity of the sun will hold everything intact.



Also, the merger itself would take around 2 billion years to complete after gravity does it work slowly merging the two massive black holes at the centre of both the galaxies. The new galaxy will likely be a single elliptical galaxy and we even have a name for it - Milkomeda.

Here’s a simulation video of what the whole thing would look like: