Sloan Digital Sky Survey

The Sloan Digital Sky Survey, the most ambitious astronomical survey project ever undertaken, will bring the modern practice of comprehensive and quantitative mapping to cosmography, the science of mapping the universe and determining our place in it. The Sky Survey will systematically map one-quarter of the entire sky, producing a detailed image of it and determining the positions and absolute brightnesses of more than 100 million celestial objects. It will also measure the distance to a million of the nearest galaxies, giving us a three-dimensional picture of the universe through a volume one hundred times larger than that explored to date. The Sky Survey will also record the distances to 100,000 quasars, the most distant objects known, giving us an unprecedented hint at the distribution of matter to the edge of the visible universe.