Imagine holding a wine glass up to a candle (of course I had to pour a glass to try this.) The curved glass bends and distorts the flame, stretching it into arcs and rings of light. Now scale that up to the size of a galaxy, replace the glass with a trillion solar masses of matter, and the candle with an entire galaxy billions of light years away. What you get is one of the most beautiful and scientifically powerful phenomena in all of astronomy, a gravitational lens. Einstein's general theory