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Asked by to Simon on 17 Mar 2014. This question was also asked by .
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Simon Albright answered on 17 Mar 2014:
Do you mean when our galaxy and the andromeda galaxy collide?
There are people working on that. Galaxy collisions have happened and we also have computer simulations that look at it.
Roughly speaking everything will get mixed up, sloshed around, half the planets will probably get pulled out of their orbits, maybe even destroyed, and basically we’ll have a pretty bad time of it. That’s what I think anyway, but it’ll take a very long time before it happens and the whole process will actually take billions of years to happen.
If a star came near enough to interrupt our orbit for example we’d know it was coming probably thousands of years before it arrived, and it would slowly change our orbit as it got nearer. Nothing on a galactic scale happens quickly. It takes a few hours at light speed to reach Pluto, so everything else takes a really long time!
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Comments
Thomas commented on :
“Nothing on a galactic scale happens quickly.” Although this is generally a true statement, there is one specific case when things happens rather fast: a supernova explosion.
Matter is transferred from a big star to a dead one for a long time (galactic slow-mo) until there is so much at the surface of the dead star that it gets all compressed together and ignites and then WOOSH! Within 1s, all of that burns out in nuclear reactions and releases of lot energy, light and new elements in the universe… and goes to sleep again.
Clara commented on :
But when Simon’s talking about galactic timescales, he’s not talking about stars exploding, so I think that comment stands.
Either way, I hope we’re pretty good at space-travel by the time Andromeda gets anywhere near us and we can find ourselves a nice new galaxy to play in!