The Daily Telegraph - Saturday - Review
The universe according to Hawking
Steven Poole is dazzled by the physicist’s final book, which tackles everything from black holes to Brexit
I256pp, John Murray, £14.99, ebook £9.99
f you look up at the sky at night, you will notice that it is mainly dark. This seems too obvious to mention, but it became a crucial piece of evidence for scientists in the mid-20th century who were worried about the greatest existential questions. If the universe is eternal and infinite, then the night sky should be a homogeneous blaze of light, from all the countless stars lying in every direction. The fact that it isn’t is one key part of the proof that the universe must have had a beginning at some finite point long ago.
The physicist Stephen
Hawking was one of the brilliant minds working on such cosmological puzzles, and made his name working on black holes. (He discovered what is now called the “Hawking radiation” that they emit.) At the time of his death, he was working on this collection of short scientific and philosophical essays, which has been completed by his colleagues and family. It is a fitting last message from a genius and spiky wit, who was at least more intellectually qualified for the role of cosmic guru than others – Yuval Noah Harari, say, or Jordan Peterson – jostling to claim that role today.
Hawking had a mischievous humour and a lovely line in self-deprecation. As he relates in an early autobiographical segment here, his undergraduate results at Oxford were on the borderline between a first and second-class degree, so he was called in for a chat. “In the interview they asked me about my future plans. I replied that I wanted to do research. If they gave me a first, I would go to Cambridge. If I only got a second, I would stay in Oxford. They gave me a first.” He later observes that, if we had a mini black hole that weighed about the same as a mountain, we could keep it in orbit around Earth and use it for free power for the whole planet. “People have searched for mini black holes of this mass, but have so far not found any,” he relates. “This is a pity because, if they had, I would have got a Nobel Prize.”
Not the least of the problems exercising that remarkable brain in his last months, it seems, was Britain’s imminent departure from the EU, to which Hawking often makes sarcastic mention. If he had studied with the physicist Fred Hoyle, he says, he would have found himself having to defend Hoyle’s “steady-state” theory of the universe, which was overturned by the new theory of the Big Bang. Doing that, Hawking says, “would have been harder than negotiating Brexit”.
The issue of Brexit, of course, is not in itself a scientific one, as much harm as it threatens to cross-border scientific collaborations. In a fondly awestruck preface, the physicist Kip Thorne points out that the “big questions” in this book fall into two types: the strictly scientific questions, and the more political or metaphysical ones. But the lines between the two can be fuzzy. One of the questions Hawking addresses, for instance, is the existence of God, which blends imperceptibly with the question of why we are all here. (I don’t mean why we are all here on this rain-sodden island, but how the universe came to exist.) “I don’t have a grudge against God,” he says, tartly putting the reader in mind of other high-profile scientists who do. But Hawking has no need of the God hypothesis. Perhaps, some suggest, God created the conditions and laws of the universe and then sat back to watch it run. Hawking objects that time itself began with the Big Bang, so beforehand “there is no time for God to make the universe in”.
Instead, he declares: “I think the universe was spontaneously created out of nothing, according to the laws of science.” A pedant might here note that the word “spontaneously” itself implies the existence of time in which something can suddenly happen, but if there is no time for God to make the universe, there is no time in which the Big
Bang can “spontaneously” take place either. But never mind: here is some physics about how all the positive and negative energy and universe add up neatly to zero. This means, Hawking concludes, that “if the universe adds up to nothing, then you don’t need a God to create it. The universe is the ultimate free lunch”. It appears that this might be the one case where you really can have your cake and eat it.
Hawking’s gift for vivid scientific storytelling is beautifully employed throughout: there is a terrific explanation of why exactly we live in three big dimensions of space, rather than two, four, or more, as well as exactly how time travel is allowed by the equations of relativity, and whether we could ever find out what is inside a black hole. Peering into the future, on the other hand, Hawking