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.

A quick tour to some of Hawking's most significant achievements.

Some of the Universe's most important secrets are hidden in the shape of a beautiful undulating curve: the power spectrum of the cosmic microwave spectrum. This article explains how.

Find out all you need to know about the cosmic microwave background in this comprehensive overview.

To understand the why the cosmic microwave background tells us so much about the Universe, you first need to understand what created it: sound waves travelling through the early Universe.

The cosmic microwave background is the earliest light we can see in the Universe. So important is this baby picture of the Universe, it's been involved in two Nobel Prizes. Why?

Find out what gravitational waves will tell us about the Universe: from understanding its birth to figuring out whether black holes have hairs.