Dr. Charles Keeton, Rutgers University
"A Ray of Light in a Sea of Dark Matter"
Abstract: In the 1930s, Einstein used his theory of relativity to predict that the bending of light by a star's gravity could create multiple images of a more distant star. Today there are many observed cases where the gravity of a distant galaxy bends the light from an even more distant quasar. This "gravitational lensing" provides a unique opportunity to study the invisible dark matter thought to surround all galaxies, and even to detect galaxies we cannot see. The search for invisible galaxies with gravitational lensing will provide important clues about the nature of the exotic substance that pervades the universe.