The stargazers at the Harvard-Smithsonian Center for Astrophysics have released a huge three-dimensional map of outer space, a core part of its six-year survey of the skies. Encompassing four billion light-years cubed, the researchers hope to use the map to retrace the movements of the universe through the last six billion years. Using the latest Sloan Digital Sky Survey (SDSS-III), the center says the data will help improve their estimates for the quantity of dark matter in space and the effect that dark e