Elisa Portaluri

Light from a distant quasar, the bright core of a galaxy, passes by a massive galaxy and bends, like a flashlight beam through uneven glass. If the lens and source align almost perfectly, we see not one quasar but several copies.

At night, a telescope looks at a star but sees it as a quivering blob. Earth's atmosphere is constantly rippling, and light passing through it bends like a flashlight beam through water.