As far as I understand, the stability of the Solar system means that planets do not collide and will not in near future. The only thing that is stated on Wikipedia is that scientists are concerned about what already is in the solar system: they observe something with Jupiter's satelites Io and Europa and how Europa changes the orbit of Io. That, to me, looks like we are an isolated system and we are not.
So, here is my first question: Is it possible, that as a result of well, something, some large object (the size of Jupiter, let's say, because the Lyapunov stability of linear systems implies that Earth size object does not matter) swims into our galaxy?
Now, if that first question has a positive answer, is it possible that it takes a position close enough to Earth so that it changes the orbit of Earth (like satellite Europa does to satellite Io)?
In case that is, is it possible that Earth will become this large object's satellite? If is possible, what would happen to the Moon? Are there any examples of this in galaxy: Object A is a satellite of object B and has its own satellite namely, object C. Obviously then, C would be a satellite of B as well, but we are looking for stronger thing.
Now, we come to real deal. In case everything I suggested above is true, would we survive such a scenario, and how would(in short) the change of Earth's orbit change the life on it? Since Life as we know it very much depends on the position of Earth.
Thanks for your answers, hints and links to what happens and why. All of this came like a nightmare to me, and now I end up typing and asking, is this possible?