New map of the universe reveals its history for the past six-billion years

This image shows the positions of the 900,000 luminous galaxies used in four Sloan Digital Sky Survey studies described during the 2012 annual meeting of the American Astronomical Society. 

Each green dot represents one galaxy. 

The image covers a redshift range from 0.25 to 0.75, a time when the universe was between 7-billion and 11-billion years old. 

Credit: David Kirkby (University of California, Irvine) and the SDSS-III Collaboration