
This description ignores the relatively negligible gravitational effects of other planets (because of mass) and stars (because of distance).
An object, a concentration of mass, is hurled away from a star a result of some energetic event. This can have three different results. Objects that receive an initial energy above a certain threshold escape the star’s gravity and experience some alternative fate (unknown to us for the purposes of this discussion).
Here is another way to explain the energy exchange.
At some point the initial energy is all used up and the planet begins to fall back toward the star. As it falls to the star it accelerates acquiring momentum (which is another way of saying that it is reacquiring the energy it gave up in overcoming gravity). In the course of returning to the star it acquires enough energy to allow it to avoid falling into the star.
[1] The mass of the object must also be a part of the equation. Couldn’t there still be objects way beyond what we presently consider the boundaries of our solar system that will in fact someday come back as additional planets?[1] The mass of the object must also be a part of the equation. Couldn’t there still be objects way beyond what we presently consider the boundaries of our solar system that will in fact someday come back as additional planets?