EDITOR'S PICK: See the International Space Station in real-time (on any computer) at:  http://liftoff.msfc.nasa.gov/ temp/StationLoc.html

Super clusters are groups of clusters composed of galaxies, which are in turn composed of many star clusters. These have a typical width of a few hundred million light years. The one we are located in is known as the Virgo Supercluster.

A star cluster, on the other hand, is a group of stars near each other in space and resembling each other in certain characteristics that suggest a common origin for the group. Stars in the same cluster move at the same rate and in the same direction. Two types of clusters can be identified—open clusters, also called galactic clusters due to their wide distribution in our  galaxy (the Milky Way), and globular clusters. More than one thousand open clusters have been cataloged in the Milky Way, most of which are found in the spiral arms of the galaxy. Typically, an open cluster contains from a few dozen to a thousand loosely scattered stars and exists in a region rich in gas and dust. Globular clusters are spherical groups of thousands to hundreds of thousands of densely concentrated stars. About 150 globular clusters are known in the Milky Way galaxy, and others have been found in nearby galaxies.