Old idea spawns new way to study dark matter

This composite image shows the microlensing event OGLE-2005-SMC-001 as a distant star brightened (left) and dimmed (right) over the summer of 2005, with views taken from two very distant vantage points. The two images in the top row were taken on Earth -- by the 1.3-meter SMARTS telescope at Cerro Tololo Inter-American Observatory in Chile -- and the two in the bottom row were taken by the Infrared Array Camera on the Spitzer Space Telescope, which is orbiting the sun some 25 million miles away. An international team of astronomers led by Ohio State University combined the data from both telescopes in a new way, in order to study dark matter in the outskirts of the Milky Way. Credit: Composite image by Subo Dong, courtesy of Ohio State University.