Are galaxies stable?

Question

i mean will the stars leave each other?

Answer 1

On the time scale of our universe (..more than 13-billion years..) the majority of galaxies themselves are pretty stable although a lot of change goes on constantly inside them. Collisions between galaxies also sometimes occur. In fact our own Milky Way Galaxy is on a collision course with the Andromeda Galaxy.

Answer 2

Galaxies will run into each other and when that happens, a few stars will leave getting thrown out by the collision and the remainder will combine to form a single galaxy (or possibly remaining as two distinct galaxies depending on the collision).

But I don't think that is your question. Over time, stars will collide within the galaxy eventually forming larger and fewer masses, the black hole in the center of the galaxy will continue to grow. Some stars will be ejected from the galaxy using a gravity slingshot the same way that the pioneer spacecraft was ejected from the solar system. But we are talking 10-100 billion years for most of these effects to be noticable and by then all or nearly all of the stars in the galaxy will be burnt out.

It all boils down to Newton's law of gravity. As soon as you get a system with more than two objects, it is inherently unstable. But the time period is so long that there is nothing to worry about.

Answer 3

Galaxies, generally, are held together by their gravity. In fact, they're *so* well held-together, that astronomers are calling the force "dark matter", because they tend to rotate faster than the mass within them should allow.

Occasionally, galaxies "collide" - there's no true crash, it's kinda like when clouds collide - they more or less merge together. The stars are so far apart that the chance of any actually hitting each other are billions to one - but it probably does happen occasionally.... Anyway, after such a collision, there will likely be a few stars from each colliding galaxy that are flung out & away, but it's a very small percentage, and depends on the 'type' of collision - a glancing blow probably casts more stars out than a direct impact.

Answer 4

No , and Yes ---
Nothing , it would seem is "stable", and one day-- far into the future -- the sky will not be what it is now , for everything you see is really in motion, and will change, Even our Moon is slipping away from the Earth -- something like a inch per year-- getting further away ever so slightly til one day -- it will go into a orbit of its own around our solar system.

Answer 5

no Galaxy is stable.they are moving away from each other all the time at the speed of light. in about 2 billion years Andromeda will crash into our galaxy

Answer 6

There are billions of them, and some of them are billions of years old, which sounds pretty stable to me.

Answer 7

No it does hoever takes billions of years to change.