Location is not, as the estate agents say, everything. We must also consider our place in history. — John D. Barrow

While we have no reason to expect that our position in the universe is special in every way, we would be equally misled were we to assume that it could not be special in any way.

Einstein had spent the previous thirty years showing how we could understand the behaviour of whole universes with simple maths. Gamow saw that those universes must have had a past that was unimaginably different to the present. What had stopped them both in their tracks was Gamow's suggestion that the laws of physics could describe something being created out of nothing.

Einstein showed us how to find all the possible universes that were consistent with the laws of physics and the character of gravity, how to reconstruct their pasts and predict their futures. But actually finding them was no easy task.