Why Does the Universe Expand?

Five hundred years ago, Nicolaus Copernicus proposed that the Earth might be one of several planets orbiting the Sun, rather than the centre of the universe. He compared the geocentric model to a monstrous form assembled from parts of different bodies, like the Creature Mary Shelley brought to life three centuries later in Frankenstein — each part appearing human on its own, but as a whole a grotesque patchwork.