Winchester Science Centre – Space Lecture: The Euclid space telescope, with a planned launch in late 2020, will use its two instruments to observe the optical and infra-red light across nearly half the sky. It will image and measure the redshifts of millions of distant galaxies in order to catalogue them, their properties and their spatial distribution. From the apparent distortion of galaxy shapes we will measure the gravitational lensing caused by dark matter mass bending the space through which light travels. By looking at the tendency of galaxies to cluster, we will search for the remnants of giant acoustic bubbles from the early universe. Using them as a ‘standard ruler’, we will study the history of expanding space and therefore the history of cosmic gravity. With these two nearly independent measures of the topography of our space-time, we will attempt to unveil the nature of gravity, dark matter and dark energy.