Seeing double - Looking at the Universe with gravity's eyes (Free Astronomy Public Lectures)

Presented by Dr Thomas E. Collett on Tuesday 14 November 2017.

Einstein's theory of general relativity predicts that light rays are bent when they travel past a massive object. In this talk, we will explore tests of this prediction and view some of the spectacular consequences of light bending: gravitational lenses. These gravitational lenses let us directly measure where the mass is in the Universe, and the results imply that the Universe is mostly made of an exotic substance called dark matter.