What happens if I star escapes its galaxy?

[Moky]

What would happen if by some force a star gets knocked away from its cluster or galaxy? Would it still float along on it's merry way or would something happen that destroys the star? What if that star had planets orbiting it? Would a solar system be able to survive out of a cluster or galaxy? I'm imagining it would be ok, but it's something I kinda want a solid idea on since it's been bothering me for about a year.

 

[FaithlessThinker]

Nothing, really. If we take our solar system, we are actually dependent only on the Sun for life, not on any other star in the Milky Way. So if we are going to take the sun and its planets and put it outside in free space, it will still sustain us.

The thing is, gravity acts everywhere in the universe. Even if the sun was to be put in free space, eventually it will gravitate towards a galaxy that has the highest gravitational influence on it. The same can be said of any star.

It's quite clear from astronomy that things don't "float" in space. No matter where they are, they are moving due to gravitational pull of more massive objects. And stars don't need to be in a galaxy to survive. They just happen to form galaxies due to gravity.

By the way, I'm not a qualified astronomer. It seems I may have missed something since I didn't consider the expanding universe part.

 

[Moky]

I know things don't float, but its was the only thing I was able to think of saying ^^' It might be a question that I can figure out the answer to without much searching, but I never like to assume I can answer a question I'm not qualified to answer. (And the fact that Google had nothing on this) I asked my high school Astronomy teacher, but either he didn't answer the question because of time constraints or he said what you said.

 

[sgrunterundt]

When galaxies collide stars are often ejected from their galaxies. Since galaxies are in general extremely thin (can be compared to a handful of ping pong balls spread across a continent) stellar collisions are pretty rare even when the galaxies collide and a planet system would be perfectly capable of surviving the process.

 

[SagansHeroes]

When galaxies collide stars are often ejected from their galaxies. Since galaxies are in general extremely thin (can be compared to a handful of ping pong balls spread across a continent) stellar collisions are pretty rare even when the galaxies collide and a planet system would be perfectly capable of surviving the process.

I can see how they COULD survive a galactic collision, however with a lot of the gas and dust in each galaxy heating up to extreme temperatures and two super massive black holes running through everything I imagine it would still be bad

 

[sgrunterundt]

I can see how they COULD survive a galactic collision, however with a lot of the gas and dust in each galaxy heating up to extreme temperatures and two super massive black holes running through everything I imagine it would still be bad

Certainly there are going to be planetary systems in the middle of things that get fried by radiation or worse.

 

[Moky]

The majority of stars would probably get away due to the distances between them.

 

[Plunder]

When two galaxies collide there are nearly no real collisions between starts itself. The space between 2 starts is simply too big. However the collision of gas clouds will trigger a lot of star formation (you can see it clearly when google for "whirlpool galaxy", all the red dots indicate new stars ) . Some of these new stars are heavy and will go supernova in the fairly short future =)

Asking what happens with one star leaving a galaxy, is about the same as asking what happens to one grain of sand that is blown away from the beach. ^.^

 

[Logic-Nanaki]

I know i read somewhere that there is a star traveling out from a galaxy, and that very fast alls0. i just cant seem to find it by google. maybe i'll have to re-read my collection of astronomy-magazines to find it. but i KNOW there is one. and it was nothing more special than a star just leaving it's gravitational bond with the galaxy it once resided.

 

[Pulsar]

I know i read somewhere that there is a star traveling out from a galaxy, and that very fast alls0. i just cant seem to find it by google. maybe i'll have to re-read my collection of astronomy-magazines to find it. but i KNOW there is one. and it was nothing more special than a star just leaving it's gravitational bond with the galaxy it once resided.

Yes, those are called hypervelocity stars. There are 16 known at the moment. Such hypervelocity stars are probably the result of a close encounter between a binary system and the central supermassive black hole: one star is captured by the black hole, and the other get "catapulted" out at extreme velocities.

Another, much more common mechanism by which a galaxy loses stars is tidal stripping, due to interactions with other galaxies. Those stars become part of the intergalactic medium, and it's unlikely that they get captured by another galaxy (space is big, really really big). This happens quite frequently in rich galaxy clusters: many intracluster stars (and planetary nebulae) have been discovered, e.g. in the Coma cluster. Some stars can even form in the intracluster medium, when a stripped molecular cloud collapses.

Do planetary systems survive? In the case of hypervelocity stars, probably not, the process is too violent. In the case of tidal stripping, possibly. However, if the star has a surrounding Oort cloud, it will get disturbed and the planets will be bombarded with comets.

 

[Anachronous Rex]

Do planetary systems survive? In the case of hypervelocity stars, probably not, the process is too violent. In the case of tidal stripping, possibly. However, if the star has a surrounding Oort cloud, it will get disturbed and the planets will be bombarded with comets.

I was under the impression that this also occurred in galactic mergers, no?

 

[Pulsar]

Do planetary systems survive? In the case of hypervelocity stars, probably not, the process is too violent. In the case of tidal stripping, possibly. However, if the star has a surrounding Oort cloud, it will get disturbed and the planets will be bombarded with comets.

I was under the impression that this also occurred in galactic mergers, no?

Yes, probably, in the regions where the interactions are strongest.

 

[Moky]

Thank you for the answers everyone ^^

 

[Predanator]

The big question is "how much does our galaxy shield our solar system from extragalactic radiation?" Star systems without that protection might be pretty crispy.