Two scientists’ debate over whether the universe had a beginning – and how the elements were created
22 Dec 2021 Laura Hiscott
Taken from the December 2021 issue of Physics World where it first appeared under the headline "A tale of two scientists". Members of the Institute of Physics can enjoy the full issue via the Physics World app.
Laura Hiscott reviews Flashes of Creation: George Gamow, Fred Hoyle, and the Great Big Bang Debate by Paul Halpern
Scientists get stuff wrong all the time. Mistakes are an essential part of the pursuit of knowledge, so the history of science tends to be kind – immortalizing its pioneers in the names of their most successful equations and theories – rather than emphasizing their failures.
But if a scientist is publicly involved in a pivotal debate, and if it later transpires that they were wrong, they might become an unlucky exception and end up being remembered for where they went awry. Whether or not the universe had a beginning is certainly a big enough debate, and Fred Hoyle, the physicist who coined the term “the Big Bang” but didn’t believe in it, is one such scientist.
Hoyle’s most vocal opponent in the argument was the Russian-Ukrainian-American physicist George Gamow. It is their lives and research that are the subject of the new joint biography Flashes of Creation: George Gamow, Fred Hoyle, and the Great Big Bang Debate by Paul Halpern, a physicist at the University of the Sciences in Philadelphia and author of 17 popular-science books.
After recounting how Edwin Hubble announced in 1929 that more distant galaxies are flying away from us more quickly – implying that the universe is expanding – Halpern describes how two schools of thought emerged. According to one side, the universe must have started off in an extremely compressed state that exploded a long time ago and continues to evolve. The other theory, known as the steady-state hypothesis, held that the cosmos had always looked roughly the same, with new matter being gradually created to maintain its density and structure as it grew in size.
While many scientists advocated for each side of the argument, Gamow and Hoyle became the public faces of it, appearing on radio shows and writing articles in popular magazines to voice their views. In the early 1950s each published a book, Hoyle’s called The Nature of the Universe and Gamow’s The Creation of the Universe, whose titles neatly summed up their differences.
Though Gamow and Hoyle might seem to have been in polar opposition, their research was beautifully complementary when it came to understanding how the different elements formed. Gamow co-developed a theory that they were created within the first few minutes of the universe’s beginning, while Hoyle, believing in no such beginning, thought the elements were fused together in stars. In fact, the correct answer was a combination of both their ideas.
Stellar fusion alone could not account for the huge abundance of helium in the universe, but Gamow’s ideas failed to explain the formation of elements heavier than the unstable isotope beryllium-8. In a flash of brilliance, Hoyle inferred that beryllium-8 and helium-4 could reliably fuse into carbon-12 inside red giant stars if carbon-12 had an energy level at 7.65 MeV – the sum of the two smaller nuclei’s own energies.
The existence of the 7.65 MeV level was soon confirmed by experimental physicist William Fowler and his colleagues, gifting us that fairy-tale fact that I remember learning in school: we are all, quite literally, stardust. Hoyle would continue to collaborate with Fowler, along with physicists Margaret and Geoffrey Burbridge, to elucidate the formation mechanisms of elements heavier than carbon inside stars.
But, as a joint biography, Flashes of Creation tells much more than just the scientific work of Gamow and Hoyle. I found the description of the scientists’ early lives fascinating, particularly as they are set against a backdrop of political turmoil in Europe. In one memorable story, Halpern tells how Gamow and his wife attempted to escape their increasingly autocratic Russian homeland in 1932 by travelling 170 miles across the Black Sea in a kayak.
Their plans were scuppered by a storm, but they later managed to get out when Soviet officials allowed them to attend the seventh Solvay Conference in Belgium in 1933. Niels Bohr, who was a friend of Gamow, had strategically arranged for the French physicist and known communist sympathizer Paul Langevin to extend the invitation. Gamow would never return to his home country.
The book also portrays the scientists’ personalities and senses of humour entertainingly. For example, after completing a paper with his student and long-term collaborator Ralph Alpher, Gamow listed a third author, the physicist Hans Bethe, “in absentia”. Bethe had not been involved, but Gamow wanted the author list to read “Alpher, Bethe, Gamow” in reference to the Greek alphabet.
Elsewhere, Halpern refers to Hoyle’s “dagger-sharp wit”, and describes his coining of the term “Big Bang” as a mocking name for a theory that he considered ridiculous. Hoyle first used it during a BBC radio programme in 1949 and it’s clearly a catchy name; in 1993 the astronomy magazine Sky and Telescope ran a competition to come up with an alternative, but out of 13,099 submissions they found nothing better.
There is some uncertainty around whether Hoyle said “Big Bang” disparagingly. In Eight Improbable Possibilities, a book published this year by veteran science writer John Gribbin, the author asserts in a footnote that Hoyle told him he just wanted a snappy expression to contrast with “Steady State”. Whatever his feelings about the theory, Hoyle had the utmost respect for its main proponent, with his son quoted in the book as saying “I never heard my father say a bad word about Gamow.”
It certainly seems like they disagreed amicably, though they met only a few times in person. I enjoyed Halpern’s recounting of their meeting in the summer of 1956, when Gamow was working in California and Hoyle was doing research at Caltech. While driving around in Gamow’s white Cadillac, the two physicists talked about what they each thought the temperature of space was, based on their preferred theories. If only all disagreements could be had in such good humour.READ MORE
The debate was eventually settled after astronomers Arno Penzias and Robert Wilson observed an unexpected radio-wavelength hiss coming from all directions in space in 1964, and notified the experimental physicist Robert Dicke, who identified it as evidence of the Big Bang. But this wasn’t a perfectly jubilant triumph for Gamow. Halpern relates how Gamow was actually upset for some time, feeling that Dicke got too much credit for the discovery, while he and his collaborators didn’t get enough recognition for their earlier prediction that the Big Bang would leave this background radiation.
Later on, Hoyle also felt underappreciated, and was particularly hurt when he was overlooked for a Nobel prize. Fowler was awarded half the 1983 Nobel Prize for Physics for studies of the nuclear reactions that led to the formation of chemical elements – work that Hoyle had begun and continued in collaboration with Fowler and the Burbridges. Sadly, Hoyle’s son relates that “after 30 years of a very close friendship, he never had direct contact with Willy Fowler again”. This human side of science is a picture that the book paints beautifully and poignantly, ranging from friendship and camaraderie to clashes of personality and the desire for fair recognition.
It’s impossible to know the full story behind every discovery, so careers are often reduced to trivia
It’s understandable that scientists want to be acknowledged for their contributions, but it’s impossible to know the full story behind every discovery, so careers are often reduced to trivia. Perhaps the fact that the Big Bang was named by the person who most famously disputed it was simply too good not to become the most often-repeated anecdote about Hoyle. I must admit, until I read this book, that was pretty much all I knew of him. Of Gamow I knew even less. But as Halpern shows, there is much more to this story – and it’s a tale that’s well worth discovering.
2021 Basic Books $17.99hb 304pp
Laura Hiscott is the reviews and careers editor of Physics World
from physicsworld.com 22/12/2021
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