If I launch a ball into the sky it would reach a distance after which it would return into the ground transforming the potential energy into kinetic energy as it hits the ground

This is similar to what happens at galactic scales, where material (like gases) from an outflow get expelled from the galaxy, they reach a distance where they turn back, and fall again into the galaxy, increasing their kinetic energy as they are attracted by gravity towards it

However, the presence of dark energy at galactic scales, causes outflows to be less bound to their galaxy (and could even reach a distance where the influence of gravity and dark energy are balanced, beyond which, it would be expelled from the galaxy to never return: Is there a distance from a gravitational source where the influence of gravity and dark energy are balanced out?). This then can make these outflows reach a greater distance before turning back into the galaxy.

Then, as the material would travel more distance towards the galaxy, and there would be a point in this trip where the influence of dark energy would be negligible (only leaving gravitational attraction), would the infalling material have more kinetic energy in this scenario (than in one without dark energy)?

  • 2
    $\begingroup$ Are you asking if a thrown/ejected object would return at a higher speed than it departed at? $\endgroup$
    – Sten
    Oct 21, 2023 at 14:29
  • $\begingroup$ Well I was asking if it would return with more kinetic energy than when it departed... which would probably mean more speed, yes @Sten $\endgroup$
    – vengaq
    Oct 23, 2023 at 10:09


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