Gravitational Lensing

This animation illustrates the result of a mathematical model calculation for gravitational lensing. The elliptical lensing mass is fixed and in successive frames the position of the more distant point source is moved relative to the center of the lensing mass. A large variety of lensing effects is observed, including an Einstein cross when the lens and source are almost exactly aligned. Usage: Click "Play" to begin and when the button turns red to continue. "Step" moves forward one frame, and "Back" moves backwards one frame. Click "Stop" to pause. "Home" returns to the beginning from any point.