In 1998, astronomers using the 2.5-meter Sloan telescope at New Mexico’s Apache Point Observatory began scanning the sky and loading the images they captured into the freely available Sloan Digital Sky Survey database. Since then, astronomers have used that 100-terabyte-plus cache to map half a billion stars, galaxies, asteroids and quasars; create 3-D maps of our outer galaxy; and study the structure of the universe.
Last year, scientists used the SDSS’s enormous sample of stars to determine why some white dwarfs have unexpected traces of metal in their atmospheres. By comparing SDSS measurements of thousands of newly identified white dwarfs with those of other stars, they determined that the “pollution” is most likely planetary debris, including material that once contained water. Because the Milky Way contains so many polluted white dwarfs, scientists reasoned that rocky and watery planets may be more common than previously thought—thus, extraterrestrial life may be more likely to exist in our galaxy than scientists had previously guessed.
Check out the other nine most amazing databases in the world here.

140 years of Popular Science at your fingertips.
Each issue has been completely reimagined for your iPad. See our amazing new vision for magazines that goes far beyond the printed page
Stay up to date on the latest news of the future of science and technology from your iPhone or Android phone with full articles, images and offline viewing
Featuring every article from the magazine and website, plus links from around the Web. Also see our PopSci DIY feed
The 6th annual Invention Awards are here, from an inflatable tourniquet to a better lobster trap to spring-loaded hocket skates. This issue is all about the celebration of invention.
Plus: Making synthetic biology breakthroughs in a garage, building a constantly-moving ping-pong table, and a ridiculously overpowered barbecue.
Well it's about time. High speed computers and a 3D map of the galaxy. Sounds like a dream I had a while back. Virtual reality tours of the universe. You decide with a roll of your finger where you want to go. Who's on it?