Superclusters

Superclusters are currently the largest structures known in the universe. Stars and clusters of stars group together into galaxies that can contain anywhere from a few million to a few trillion stars. Galaxies collect into groups known as clusters of galaxies. On a larger scale superclusters are clusters of clusters of galaxies. As clusters of galaxies group into superclusters they leave empty spaces called voids between the superclusters. Superclusters and voids typically extend for hundreds of millions of light-years.