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Aseyhe t1_j2q6qrm wrote

Reply to comment by ScootysDad in How do galaxies move? by modsarebrainstems

Superclusters are still expanding, they are just overdense regions that would eventually collapse if there were no dark energy. Assuming dark energy persists, only our Local Group will remain nearby.

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ScootysDad t1_j2r15zu wrote

That's a yes an no answer mostly because the space between the local clusters are too large. There's a region around the supercluster where objects are gravitationally bound to the center of gravity and outside of that radius the local clusters will eventually escape. Much like the orbital mechanic of our solar system. So from that region outward the dark force appears to dominate and expand the space.

Edit: With our current understanding of the universe, within the Supercluster the dark force responsible for the expansion of the universe is too weak to overcome the gravitational "force" within the bounded section of the supercluster.

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Aseyhe t1_j2r1iul wrote

If a cluster of galaxies is virialized (its constituents are orbiting stably), we call it a cluster, not a supercluster. Superclusters are expanding with the Hubble flow by definition. A supercluster could certainly have a virialized cluster at its center though!

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