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MannyRayner

Manny Rayner's book reviews

I love reviewing books - have been doing it at Goodreads, but considering moving here.

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Un atome d'univers

Un atome d'univers - Dominique Lambert You probably know by now that I'm fascinated by cosmology and also by the relationship between science and religion. When you read books on those subjects, there's a name you start noticing after a while: Georges Lemaître. Before reading this book, I'd gathered that he was a Belgian scientist, active in the 20s and 30s, who was also a Catholic priest. He seemed to have made a substantial contribution to the Big Bang theory. That already sounded interesting. Why is it not generally known that the current mainstream scientific account of the universe's origin is to a large degree the work of a man of faith? I wanted more details.

Well, having now finished Lambert's chunky biography, I am better informed. What a strange, paradoxical man Lemaître was! Born in 1894, he seems to have been an unlikely cross between saint and geek. At age 9, he found himself drawn both to the Church and to science. Almost anyone else would have had to make a choice, but Lemaître decided he could have it all: become a priest and a scientist. His university education was interrupted by WW I, where he served in the artillery corps, reading books on math and physics when there was a pause in the action; he missed getting promoted to lieutenant after he annoyed his commanding officer by pointing out an error in the ballistics manual. After being demobilized, he entered a theological seminary and simultaneously continued his studies in mathematics, where he made rapid progress.

Einstein had just stunned the world by revealing his General Theory of Relativity, and Lemaître became an early adopter. He read all the material he could get his hands on, and was soon up to speed and exchanging letters with experts overseas. When a chance came up in 1923 to bid for a travel scholarship, he submitted a proposal based on his investigations of this new subject. After some deliberation, the jury declared him the winner. Lemaître, now a postgrad student, suddenly had a chance to meet the top people in the field. He spent time at the University of Cambridge, England, working with Eddington, who had carried out the first experimental test of General Relativity during the total eclipse of 1919. The next year, he went to the US, and got to know other relativity experts; he also worked with people like Shapley and Hubble, who were using the big telescopes that had just been built to get good pictures of other galaxies.

I must know less than I'd thought about the history of science, because I was quite surprised to read about the scientific community's picture of the universe circa 1924. We now take it for granted that the universe is full of galaxies, and every seven year old has probably seen pretty, high-definition pictures of the more photogenic ones. Back then, people called them "nebulae" (from the Latin for "clouds"), and there was intense debate about whether they were inside our own galaxy or outside it. A lot of people, including Einstein, leaned towards the notion that "nebulae" were inside our galaxy, which meant that our galaxy was the whole universe. Einstein had adjusted the equations of General Relativity accordingly, adding the notorious "cosmological constant" to provide an antigravitational force that kept the galaxy-universe static.

But Lemaître had now talked to all the key players, and he had both the ingredients and the mathematical ability to construct a better theory. In 1927, he published a paper which by all rights should be world-famous. He showed how you could combine Einstein's and de Sitter's solutions to the General Relativity equations to get a solution which described an expanding universe filled with galaxies, and he backed up his theoretical ideas with the cutting edge observational data he'd got from Hubble and Shapley. The "nebulae" were outside our galaxy, and their red-shifts showed most of them were moving away from us. Lemaître put the pieces together: we must be living in an expanding universe! He looked at the red-shift data and hypothesized a linear relationship between speed and distance. The further away a galaxy is, the faster it is receding.

Now, if you know anything at all about the subject, you'll recognize what I just said as "Hubble's Law". But Hubble published his own paper, which really is world-famous, in 1929! How come he got the credit? Lambert does a good job of trying to untangle this mess, which has become something of a cause celèbre in recent years. First, Lemaître wrote his paper in French, and published it in a Belgian journal. It's hard to say whether he refused to admit that this was less prestigious than, say, Nature, whether he undervalued his work and didn't realise how important it was, or whether he was simply naive; all three explanations are suggested to some degree. He would certainly have had reason to undervalue himself. People were unkind about his idea. When they first met in person, in 1926, Einstein told him that he was a good mathematician but a terrible physicist; though Lemaître discovered, to his surprise, that Einstein apparently hadn't heard about the red-shift data.

When Hubble published his own paper in 1929, Lemaître wrote to his mentor Eddington and said, with surprise, that this was pretty much what he'd published himself two years earlier. He'd sent Eddington a preprint, but it turned out that Eddington hadn't ever got around to reading it. Eddington wanted to make amends; he suggested that Lemaître publish an English translation. But there was a catch. Not wanting to get into a fight with Hubble, he asked Lemaître to leave out the crucial paragraph where he stated what was now officially Hubble's Law. Many people have suggested that Lemaître was somehow censored against his will, but this doesn't seem to be borne by the facts. He simply agreed to the request, and published an emasculated version of his ground-breaking paper. I know very few scientists who would have backed down this way without making a fuss.

I was quite shocked to see how much trouble Lemaître got into over his claim that the universe, now generally agreed to be expanding, also had a beginning. Many scientists, including Eddington, said they found the idea philosophically repugnant, and there was always an implication, occasionally stated openly, that Lemaître was somehow trying to use science to justify his religious beliefs. I wondered about this myself - it's impossible not to - but in fact it seems to have been the opposite of the truth. Lemaître was scrupulous about maintaining a distance between science and religion. He stressed that the "Big Bang" (a dismissive label made up by Fred Hoyle, who wanted to ridicule the idea), was an entirely natural account of the origin of the universe, and had nothing to do with his faith.

It is certainly easy to see why scientists might have attacked him, but the most bizarre twist came in 1951, when Pope Pius XII gave a public address where he said, in so many words, that science had now validated the Biblical story of Creation. Despite the fact that the idea had come from one of his own priests, moreover one who was now a member of the newly formed Pontifical Academy of Sciences and actually present in the room, Pius made no mention of Lemaître, and did not discuss the speech with him before presenting it. Apparently Lemaître's separation of science and faith was regarded as suspect; he couldn't be relied on to back the official position.

Squeezed between the scientific and Catholic communities and criticized from all sides, some scientists might have had nervous breakdowns or started drinking. Lemaître did no such thing; he just shifted his central area of interest from cosmology to the calculation of orbits, where he made many interesting discoveries and became a pioneer in the new field of numerical simulation. (If he is canonized some day, à la A Canticle for Leibowitz, I hope a loyal disciple has preserved a few relics of his machine code). He also made noteworthy contributions to the mathematics of spinors.

Four days before his death in 1966, Lemaître received news that Penzias and Wilson had discovered the Cosmic Microwave Background Radiation, the first piece of hard evidence showing that the Big Bang theory was correct. Lemaître's idea, which was almost ignored in 1927, is today regarded as one of the cornerstones of modern science.