Mass curves spacetime: light from the background galaxy bends around the lens by an angle α = 4GM/c²b. Perfect alignment → an Einstein ring; slightly off → a double image + arcs.
—
Drag the background source (bright blob) or adjust the Mass slider → the ring/images change instantly · pick a "Scenario" · click a structure/concept for details
Canvas is not enabled in your browser.
Light curve over time (microlensing) & magnificationsource brightnessmagnification μ