Gravitational Lensing in Action
This illustration shows a phenomenon known as gravitational lensing, which is used by astronomers to study very distant and very faint galaxies.
Lensing clusters are clusters of elliptical galaxies whose gravity is so strong that they bend the light from the galaxies behind them. This produces distorted, and often multiple images of the background galaxy.
But despite this distortion, gravitational lenses allow for greatly improved observations as the gravity bends the lights path towards Hubble, amplifying the light and making otherwise invisible objects observable.