The Beginning and End of the Universe

This episode, exploring theories of how the universe came into being, outlines the realisation of Edwin Hubble that the universe is expanding, and the discovery of the residual radiation that gave weight to the Big Bang theory.[1] It also highlights some lesser known theorists including Georges Lemaître, who first theorised that there was a big bang, Ralph Alpher, who stated that the light from this should be detectable, and Cecilia Payne, who calculated that hydrogen and helium were the dominant elements in the universe.[2] The episode concludes at the Large Hadron Collider, where physicists create matter in a similar manner to the Big Bang.[1]

This episode explores the theories of the big crunch, the big rip and the big freeze, that are postulated by physicists as possible fates for the universe.[3] Al-Khalili indicates that the difficulty in understanding this is our limited ability to comprehend something of such immensity both physically and philosophically.[4] So, rather than suggesting an answer, he provides the historical background for how we came to know what we know, such as how elements are forged inside stars and how gravity provides the key to the fate of the universe, and what we don't know, such as the nature of dark matter and dark energy.[3]