Every so often, there is a revolution in our understanding of the universe. Obvious milestones are Copernicus suggesting that the Earth might go round the Sun instead of vice versa, Newton's law of gravity explaining the movements of the planets in quantitative terms, and the discovery that the cosmos is expanding and started with the Big Bang. It would be fascinating to know what contemporary scientists had in the way of immediate reactions to these earlier breakthroughs, but, if this knowledge is available at all, it doesn't seem to be collected in easily accessible form. We are currently in the middle of a new revolution, which started in 1980 when Alan Guth proposed the idea of "inflation": the universe, according to what has now become the mainstream theory, began as a vacuum fluctuation and then expanded exponentially to a macroscropic size during a tiny fraction of second. This time, however, Alan Lightman and Roberta Brawer had the excellent idea of interviewing a couple of dozen of the world's leading cosmologists in 1988, when things were still fluid and undecided. Origins
collects together the results of the exercise.
I am impressed at how accurately most of the interviewees are calling it, given that there was no hard evidence for inflation when the interviews were carried out. They really like the idea, but they hedge their answers with many caveats: they can see it doesn't quite work yet, and will need to be further developed. Most of them justify their preferences in terms of esthetic judgements. The idea is beautiful, and ties together several important things that previously were unconnected loose ends. In particular, it explains why there are no magnetic monopoles (this had really been bothering the theoreticians), why the universe is so homogenous, and why space is almost flat. This last point, however, brings out an interesting difference between the theoreticians and the observers; several of the observers stubbornly say that they don't yet see clear evidence for flat space, and they'll wait until they do, even if that's what inflationary theory is predicting. Though the comments from John Huchra, at the time the world's greatest expert on observing galaxies, are startlingly exact. He is already half expecting to see evidence of dark energy, ten years before it was identified, and he confidently gives an age for the universe of 13 billion years, when most of the others are leaving a large margin for possible error.
It's amazing to get a glimpse of how the pluralistic scientific society works. All these people know each other and talk frequently: their conversations are full of X said this, of course Y answered with that, Z had this clever angle that suddenly made me think about it in a new way. I have never had such a concrete feeling of watching science develop right under my eyes. And even if your interest in cosmology is minimal, the book is worth reading for the anecdotes. Roger Penrose, while still a student, gave one of his professors a paper written in his newly invented tensor notation;
the professor's look clearly indicated that he was concerned about Penrose's sanity. David Schramm never studied at all at high school, and spent all his time on the sports field (he was a state wrestling champion) or chasing girls. My favorite is Andrei Linde sitting with his phone in the bathroom talking about chaotic inflation in whispers because his family has gone to bed, and then waking up his wife with the news that he's just figured out how the universe began.
What a great book! And what a shame that someone doesn't do one of these every time a new scientific breakthrough happens!