Chandra Release - August 8, 2006

Visual Description: CL 0016+1609

The multi-panel graphic features a series of 6 galaxy clusters.  The dominant colors in this image are purple and white, on a black background.  The purple and white clumpy texture represents the Chandra X-ray Observatory emission from the galaxy clusters.  The shapes of the galaxy clusters are mostly spherical, with some variations in size and brightness.   These six galaxy clusters are a subset of the 38 that scientists observed with Chandra, with distances ranging from 1.4 to 9.3 billion light years from Earth, to help determine the Hubble constant. The Hubble constant is a critically important number that sets the expansion rate of the Universe, and is derived by measuring the speeds that the clusters are moving away from us and dividing by the cluster distances.