E. Mediavilla

A distant quasar appears as four points of light arranged in a cross. This is how the gravity of a galaxy lying along our line of sight distorts the view: it acts like imperfect glass, multiplying the image. Each point is the same object, but its light travels different paths.

You don't hold a ruler right up to an invisible disk; you measure it across the entire universe. Light from a distant quasar, a blazing gas swirling around a supermassive black hole, passes through a lensing galaxy on its way to us.