The night sky is an endless source of wonder and mystery. For thousands of years it has been at the heart of scientific and philosophical inquiry, from the first star catalogues etched into ancient Mesopotamian clay tablets to the metres-wide telescopes constructed in Chile’s Atacama Desert today. On a clear night it is hard not to look up and pick out familiar constellations, and to think of the visionary minds who pioneered our understanding of what lies beyond. The Princeton Professor of Astrophysics reveals how it only becomes more beautiful and exciting the more we discover. She takes us from the very basics – why Earth orbits the sun, and how our moon works – right up to massive, strange phenomena like superclusters, quasars and the geometry of spacetime.