Proof of dark matter

As widely reported today, scientists claim that they have found direct proof of dark matter, the mysterious stuff that makes up the vast majority of our universe. Dark matter was first proposed in the 1930s when astronomers noticed that the motion of galaxies and clusters of galaxies they observed did not jibe with the visible mass. Since then, dark matter and dark energy have theoretically been implicated in the expansion of the universe. Using NASA's Chandra X-ray Observatory and other telescopes, scientists observed galaxies colliding at 10 million miles per hour, pulling apart normal matter and dark matter. Link to NASA press release, Link to News@Nature, Link to New Scientist, Link to Good Math, Bad Math