The Universe in your hand: A journey through space, time and beyond
By Christophe Galfard
No one could accuse Christophe Galfard of being unambitious. In this marvellous handbook to the cosmos, he tackles all the big ideas – quantum mechanics, general relativity, string theory and parallel realities – seeking to explain them to a lay audience. For those prepared to provide a reasonable level of concentration, he mostly succeeds.
If anyone could do it, one suspects Galfard’s the man. He holds a PhD in theoretical physics from Cambridge University where he was Stephen Hawking’s graduate student from 2000 to 2006. Of course, knowing your subject is no guarantee that you can communicate it clearly. But Galfard is the co-author of the children’s primer on physics he wrote with Lucy Hawking, Stephen’s daughter, called George’s Secret Key to the Universe.
He begins with a promise – that he will try not to leave anyone behind.
This offering perhaps benefits from that experience. While the writing is clear and direct it does not talk down to the reader. He begins with a promise – that he will try not to leave anyone behind. His book contains one equation, E=mc2.
Throughout, Galfard’s sense of wonder at the scale and beauty of the Universe shines through.
He describes his work as a series of Gedanken experiments – exercises in pure thought and the techniques used by philosophers and theoretical physicists throughout history to project themselves into places and situations where they cannot physically travel.
In this way we visit the surface of our Sun in its death throes, experience the grip of a black hole, the spooky surface of an alien planet lit by twin stars and, perhaps the oddest place of all, the quantum universe of the very, very tiny.
Galfard acknowledges the risks in this approach.
“Some of what we have learnt throughout this journey may turn out to be wrong … Dark matter, dark energy, parallel worlds and realities are all ideas that may eventually be abandoned, but they are the most powerful ideas of our time, nonetheless,” he writes.