Sloan Digital Sky Survey

The Sloan Digital Sky Survey (SDSS) is one of the most extensive and ambitious astronomical surveys undertaken by modern astronomers. In its first two stages, lasting from 2000 to 2008, SDSS mapped almost 30 percent of the northern sky using a dedicated 2.5 meter telescope at the Apache Point Observatory in New Mexico. The survey used a 120-megapixel camera to image over 350 million objects, and collected the spectra of hundreds of thousands of galaxies, quasars, and stars. Notable SDSS discoveries include some of the oldest known quasars and stars moving fast enough to escape from our galaxy. SDSS data has also been used to map the distribution of dark matter around galaxies through observations of weak gravitational lensing and to study the evolution of structure in the universe through observations of how both galaxies and quasars are distributed at different redshifts. The third phase of the survey is scheduled to end in 2014, and is expected to yield many exciting scientific discoveries.