Professor Jim Al-Khalili explores how studying the atom forced us to rethink the nature of reality itself. He discovers that there might be parallel universes in which different versions of us exist, finds out that empty space isn’t empty at all, and investigates the differences in our perception of the world in the universe and the reality.

The final part of Professor Jim Al-Khalili’s documentary series about the basic building block of our universe, the atom.

Al-Khalili explores how studying the atom forced us to rethink the nature of reality itself, encountering ideas that seem like they are from science fiction but in fact are a central part of modern science. He discovers that there might be parallel universes in which different versions of us exist and finds out that empty space is not empty at all, but seething with activity.

The world we think we know – the solid, reassuring world of our senses – turns out to be a tiny sliver of an infinitely weirder and more wonderful universe than we had ever conceived in our wildest fantasies.