Why does time only ever move in one direction? We talk to philosophers of physics Jeremy Butterfield and David Wallace, as well as the eminent Roger Penrose about the puzzle time poses to physicists and what it has to do with the Big Bang and the second law of thermodynamics.
On the fourteenth day of advent, we consider the night sky...which isn't actually black, but permeated by the faint afterglow of the Big Bang.
There are some interesting answers to this question, including that we live in a bubble multiverse!
On the twelfth day of advent we celebrate Stephen Hawking's contribution to cosmology.
On the sixth day of advent we find out why gravitational waves are so important in revealing the secrets of the Universe.