Galactic Collision Challenges Dark Matter Theories

Science : Astronomer Arthur Eddington’s prophetic quote about the universe still holds: It is stranger than we can imagine. And new images from NASA’s Chandra X-ray Observatory combined with views from two ground-based optical telescopes have produced one of the biggest cosmic mysteries yet. A collision between giant galactic clusters seems to have separated the galaxies from their dark matter cores. The find threatens to turn current thinking about dark matter on its ear.