Researchers celebrate a second sighting of gravitational waves

An instrument built in part by Stanford researchers detected gravitational waves for a second time. The observation proves the system works and improves our understanding of the universe. For physicists around the world, Christmas came one day late this year. On Dec. 26, scientists detected gravitational waves for a second time, further reinforcing Albert Einstein's theory of general relativity. Go to the web site to view the video. By proving a hundred-year-old theory, an international team of scientists has taken another step toward understanding the birth and evolution of the universe.