Why Are There Superclusters?

So what's larger than a galaxy cluster? A supercluster, of course. Superclusters are collections of clusters connected by great cosmic filaments of dark-and-normal matter, whose gravitation mutually attracts them towards their common center-of-mass.

Why do galaxies form superclusters?

In models for the gravitational formation of structure with cold dark matter, the smallest structures collapse first and eventually build the largest structures, clusters of galaxies. ... The clusters themselves are often associated with larger, non-gravitationally bound, groups called superclusters.

How are superclusters formed?

It is believed that the process began after the Big Bang, when matter in the universe expanded out rapidly. Some matter clumped together to form stars. Then gravity took over and the stars formed galaxies, then groups, then clusters and, now, superclusters. The supercluster formation occurring now is at an early stage.