 We have seen how a mass like our Sun can bend light. It's not hard to extend this simple concept to what a galaxy of hundreds of billions of stars could do. Galaxies have a mass distribution with the maximum at the center trailing off to a minimum at the edges. This distribution acts like a lens for light passing through it. Here's the bottom of a wine glass with a configuration similar to a galaxy. You can see what it does to the graph lines as it passes over them. When we repeat the movement over a star, we see how it distorts the light into a circular pattern. We call a bending of light through gravitational fields, gravitational lensing. Here's how this lensing works on a galactic scale. A distant galaxy would be seen here on Earth directly if there were no intervening massive cluster to bend its light. But with such a cluster, the light from the distant galaxy gets bent. Light bent in our direction will continue on to Earth. Working back from the Earth's point of view, we see the distorted and magnified image. The amount of bending depends entirely on the structure of the lensing cluster. Magnifications can range from a factor of 2 to 40 times the size of the distant object. We'll see that under the right circumstances an object can be magnified by over a thousand times.