Brilliant Blunders: From Darwin to Einstein - Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe (27 page)

Willy Fowler was also impressed with Hoyle’s prediction of the resonant level in carbon. In fact, he spent his following sabbatical in Cambridge to work with Hoyle. The collaboration between the two men and between them and the husband-and-wife team of astronomers Geoffrey and Margaret Burbidge led to one of the best-known works in astrophysics.
The 1957 landmark paper by Burbidge, Burbidge, Fowler, and Hoyle—often referred to as B
²
FH—gave a comprehensive theory for the synthesis of all the elements heavier than boron in stars. In a way, when Joni Mitchell sang “We are stardust,” she was simply giving a concise, lyrical summary of Hoyle’s 1954 paper and that of B
²
FH. The four researchers used extensive astronomical data on the abundances of heavy elements in stars and meteorites and combined those with crucial nuclear data from experiments and from the hydrogen bomb test on the Eniwetok Atoll in the Pacific on November 1, 1952, to support their theoretical calculations. They described no fewer than eight nuclear processes that synthesize the elements in stars and identified the different astrophysical environments in which these processes take place. B
²
FH pointed out correctly that the observational evidence that “there are real differences in chemical composition between stars” provides a strong argument in favor of a stellar synthesis theory, rather than having all the elements synthesized in the big bang.

This was a genuine tour de force. The massive, 108-page paper started with a romantic touch: two contradictory quotes from Shakespeare about the question of whether the stars govern humanity’s
fate. The first, from
King Lear,
reads: “It is the stars, the stars above us, govern our conditions.” This is followed by the words “but perhaps” preceding the second quote, from
Julius Caesar:
“The fault, dear Brutus, is not in our stars, but in ourselves.” The paper ended with a call to observers to make every possible effort to determine the relative abundances of different isotopes in stars, since those could truly be used to test the different nuclear reaction schemes.
Figure 22
shows a picture taken at the Institute of Theoretical Astronomy in Cambridge in 1967. Fred Hoyle is in the middle of the second row, with Margaret Burbidge to his left. Willy Fowler is in the middle of the front row, with Geoff Burbidge to his right.

Figure 22

There was one thing that the B
²
FH paper did not achieve. No matter how hard they tried, Hoyle and his collaborators did not manage to account for the abundances of the lightest elements by forming them inside stars. Deuterium, lithium, beryllium, and boron were just too fragile—the heat in stellar interiors was sufficient for these elements to be destroyed by nuclear reactions, rather than created. Helium, the second most abundant element in the cosmos, proved to be problematic too. This may sound surprising, since stars are clearly forming helium. After all, isn’t the fusion of four hydrogens into helium the main source of power for most Sun-like stars? The difficulty turned out to be not at all with synthesizing helium in general, but with synthesizing enough of it. Detailed calculations have shown that nucleosynthesis in stars would predict for helium a cosmic abundance of only about 1 percent to 4 percent, while the observed value is about 24 percent. This left the big bang as the lone source for the lightest elements, just as Gamow and Alpher had suggested.

You may have noticed that the story of the genesis of the elements—the “history of matter,” as Hoyle called it—contains in it some sort of “cosmic compromise.” Gamow wanted all the elements to have been created within a few minutes following the big bang (“in less time than it takes to cook a dish of duck and roast potatoes”). Hoyle wanted all the elements to be forged inside stars during the long process of stellar evolution. Nature chose a give-and-take: Light elements such as deuterium, helium, and lithium were indeed synthesized in the big bang, but all the heavier elements, and in particular those essential for life, were cooked in stellar interiors.

Hoyle got a chance to present his version of the history of matter even at the Vatican. Just a few months before the B
²
FH paper appeared in print, the Pontifical Academy of Sciences and the Vatican Observatory organized a scientific meeting on “Stellar Populations” at the Vatican. The two dozen invitees included some of the most distinguished scientists in astronomy and astrophysics at the time.
Both Fowler and Hoyle presented their results on the synthesis of the elements, and Hoyle was also asked to give
a summary of the entire meeting from a physical point of view. The Dutch
astronomer Jan Oort summarized from an astronomical perspective. At the opening of the meeting, on May 20, 1957, the participants met Pope Pius XII.
Figure 23
shows Hoyle shaking the Pope’s hand. Willy Fowler (with his back to us) stands to Hoyle’s right, and Walter Baade (facing us) is to the Pope’s right.

The rest, as they say, is history. The experimental and theoretical program at Kellogg Lab became, under Willy Fowler’s dynamic leadership, the hub for nuclear astrophysics. Fowler went on to win the Nobel Prize in physics in 1983 (together with astrophysicist Subramanyan Chandrasekhar). Many people, including Fowler himself,
felt that Hoyle should have also shared the prize. In 2008 Geoffrey Burbidge went so far as to say,
“The theory of stellar nucleosynthesis is attributable to Fred Hoyle alone, as shown by his papers in 1946 and 1954 and the collaborative work of B
²
FH. In writing up B
²
FH, all of us incorporated the earlier work of Hoyle.”

Figure 23

Why then wasn’t the Nobel Prize awarded to Hoyle? Opinions vary. Geoff Burbidge concluded, based on private correspondence, that a major reason for the exclusion was a perception (which he insisted was unjustified) that Fowler was the leader of B
²
FH. Hoyle himself apparently thought that he was denied the prize because of his criticism of the Nobel committee when it decided to award the Nobel Prize for the discovery of pulsars to Antony Hewish instead of to his graduate student Jocelyn Bell, who actually made the discovery. Others thought that Hoyle’s insistence on unorthodox views concerning the big bang, which we shall discuss in detail in the next chapter, might have played a role in his not getting the prize.

What were those dissenting views? What was the background for Hoyle’s opposition to the big bang?

During the years of World War II, Hoyle found himself working at the Admiralty Signals Establishment in Witley, Surrey. There he befriended two of his younger colleagues, Hermann Bondi and Thomas “Tommy” Gold, both of them Austrian-born Jews who’d escaped to England following the rise of Nazism. Ironically, prior to their work for the navy at Witley, the British government had interned the two men as enemy aliens because of their Austrian roots.

This is how Gold described his initial impression of Hoyle: “He seemed so strange; he seemed never to listen when people were talking to him, and his broad North Country accent seemed quite out of place.” Very quickly, however, his opinion changed:

I also discovered that I had misinterpreted Hoyle’s attitude of apparently not listening. In fact, he listened very carefully and had an extremely good memory, as I would find out later when he frequently had remembered what I had said much better than myself. I think he put on this air not to say, “I am not listening,” but instead “don’t try to influence me, I am going to make up my own mind.”

In their spare moments at the naval radar research facility, the trio of Hoyle, Bondi, and Gold started to discuss astrophysics,
and these collaborative exchanges continued after the war. In 1945
all three returned to Cambridge, and until 1949 they spent a few hours together every day at Bondi’s place. It was during that period that they started thinking about
cosmology
—the study of the entire observable universe, all treated as one entity. The Royal Astronomical Society asked Bondi to write what was then called a note, which was really a review article that would bring together an extensive body of knowledge.
Hoyle suggested cosmology as the topic, since in his view “the subject had been in abeyance for a long time.” To bring himself up to speed on the subject, Bondi immersed himself in the existing literature, including a sweeping 1933 article entitled “Relativistic Cosmology” by physicist Howard Percy Robertson. Hoyle, who had previously read the article, also decided to go through it again in more detail. They both realized that the almost encyclopedic essay rather dispassionately covered various possibilities for cosmic evolution without offering an opinion. In his typical nonconformist fashion, Hoyle immediately started thinking, “Has he [Robertson] really thrown his net wide enough? Are there any other possibilities?” At the same time, Gold was thrusting himself into more philosophical ideas about the universe. These were the seeds for the theory of
steady state cosmology,
which was put forward in 1948. As we shall soon discover, the theory had been a serious contender to the big bang for more than fifteen years before it became the focus of often-acrimonious controversy.

Bold ideas, unjustified anticipations, and speculative thought are our only means of interpreting nature . . . Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the scientific game.

—KARL POPPER

F
red Hoyle’s most enduring works were in the areas of nuclear astrophysics and stellar evolution. Yet most of those who remember him from his popular books and prominent radio programs know him as a cosmologist and co-originator of the idea of a steady state universe. What does being a cosmologist really mean?

The question “How close is the nearest planet to Earth?” is not a question in modern cosmology. Even a question on a larger scale, such as “What is the distance from the Milky Way to its nearest galaxy neighbor?” is not considered to be a question in cosmology. Cosmology deals with the average properties of our observable universe—the ones you obtain once you smooth out, over the range that our most powerful telescopes can reach. Even though galaxies tend to reside in small groups or in rich clusters, both held together by the force of gravity, once we sample large enough volumes, the universe appears to be very homogeneous and isotropic. In other words,
there is no privileged position in the universe, and things look the same in all directions. Statistically speaking, any cosmic cube with a side of five hundred million light-years or larger would look roughly the same in terms of its contents, irrespective of its location in the universe. (One light-year is the distance light travels in one year, or about six trillion miles.) This broad-brush homogeneity becomes increasingly more accurate the larger the scale, up to the “horizon” of our telescopes. Cosmology deals with precisely those questions that would yield the same answer independent of the galaxy we happen to be in or the direction in which we happen to point our telescope.