Brilliant Blunders: From Darwin to Einstein - Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe (31 page)

Ryle presented his results on May 6, 1955, when he was giving the prestigious Halley Lecture (named after the famous seventeenth-century astronomer Edmond Halley). Without ever mentioning Hoyle by name, referring only to “Bondi and others” as the originators of the steady state model, Ryle’s verdict was unambiguous: “If we accept the conclusion that most of the radio stars are external to the Galaxy, and this conclusion seems hard to avoid, then there seems to be no way in which the observations can be explained in terms of a steady state theory.”

Ryle continued his attack a week later, when at the May 13 meeting of the RAS,
he and his student John Shakeshaft were delighted to close by saying, “We must conclude that the remote regions of the Universe differ from those in our neighborhood, a result which is not compatible with steady-state cosmological theories, but which may well be accounted for in terms of evolutionary theories.”

Confronted with this serious challenge, Gold and Bondi, who attended the RAS meeting, found themselves on the defensive. Gold decided to craftily remind the audience that Ryle had been wrong before. He pointed out that he was
“glad to see that there is now agreement that many of these sources are likely to be extragalactic,”
as he himself had suggested four years earlier, when “Mr. Ryle . . . considered that such a suggestion must be based on a misunderstanding of the evidence.” He then added that based on the information presented, it was “very rash to regard the great majority of weak sources as extremely distant.” He cautioned that if the sources were not all the same, but, rather, there was a wide range of intensities among the intrinsic radio signals, then Ryle’s counting of weak sources could represent a confusing mix of faraway sources with nearby ones.
Bondi was also skeptical of the interpretation of Ryle’s results. In his view, the uncertainties that still existed in the counts did not allow for conclusive inferences. To drive home this point, he reminded his audience that earlier attempts aimed at determining the geometry of the universe based on galaxy counts resulted in totally disparate conclusions.

It goes without saying that Hoyle himself did not agree with Ryle’s interpretation. Rather than engaging in long arguments, however, he decided to wait for superior observational data to surface and refute Ryle’s finding. To the surprise of many astronomers, such contradictory results have indeed emerged. Australian radio astronomers showed in 1957 that Ryle’s earlier survey was seriously flawed: The map of radio sources that Ryle had produced was so blurred that blends of two or more radio sources were often counted as one. The consequences were clear to the Australian astronomers: “Deductions of cosmological interest derived from the analysis are without foundation.”

Hoyle did not bother to rejoice. The year 1957 witnessed the publication of the celebrated B
²
FH, and he was deeply engrossed in the synthesis of the elements rather than in steady state cosmology. It had not escaped him, though, that forging most of the nuclei in stellar cores (instead of in a big bang) could also be seen as supporting (at least partially) a steady state perspective. In the same year, Hoyle was also elected as Fellow of the Royal Society, an honor that put him on par with Ryle in terms of his academic status. But Ryle did not give up. He and his team continued to introduce significant upgrades both to their instrumentation and to the data reduction and
analysis. Their efforts resulted in the production of the third generation of the Cambridge catalogue of radio sources (known as the
3C Catalogue
).

By the early 1960s, Ryle’s group had at its disposal even an entirely new radio observatory, funded by the Mullard electronics company. The intellectual skirmishes between Ryle and Hoyle continued, culminating in one particularly unpleasant incident. Hoyle later described this traumatic experience in his autobiographical book
Home Is Where the Wind Blows
. It all started with what appeared to be an innocent phone call from the Mullard company in early 1961. The person at the other end of the line invited Hoyle and his wife to attend a press conference at which Ryle was expected to present new results that were supposed to be of great interest to Hoyle. When they arrived at the Mullard headquarters in London, Hoyle’s wife, Barbara, was escorted to a seat in the front now, while Hoyle was led to a chair on stage, facing the media. He had no doubt that the announcement would be related to the counting of radio sources according to their intensity, but he couldn’t believe that he would have been invited if the results were to contradict the steady state theory. In his words:

Was I being uncharitable in thinking that the new results Ryle would shortly be announcing were adverse to my position? Surely, if they were adverse, I would hardly have been set up so blatantly. Surely, it must mean that Ryle was about to announce results in consonance with the steady-state theory, ending with a handsome apology for his previously misleading reports. So, I set about composing an equally handsome reply in my mind.

Unfortunately, what Hoyle found utterly unthinkable did happen. When Ryle appeared, rather than making a brief announcement, as advertised, he launched into a technical, jargon-filled lecture on the results of his larger, fourth survey. He finished by claiming confidently that the results now showed unambiguously a higher
density of radio sources in the past, therefore proving the steady state theory wrong. The shocked Hoyle was merely asked to comment on the results. Incredulous and humiliated, he barely mumbled a few sentences and rushed away from the event. The media frenzy that followed in the subsequent days disgusted Hoyle to the point that he avoided phone calls for a week and was absent even from the following RAS meeting on February 10. Even Ryle realized that the press conference had crossed the border of common decency. He called Hoyle to apologize, adding that when he agreed to the Mullard event, he “had no idea how bad it would be.”

On the purely scientific front, however, despite these disturbing failures in etiquette, Ryle’s arguments grew increasingly compelling, and by the mid-1960s, the vast majority of the astronomical community agreed that the proponents of the steady state theory had lost the battle. (
Figure 30
shows, from left to right, Gold, Bondi, and Hoyle, attending a conference in the 1960s.)
The discovery of extremely active galaxies, in which the accretion of mass onto central, supermassive black holes releases sufficient radiation to outshine the entire galaxy, cemented the evidence against a steady state universe. These objects, known as
quasars,
were luminous enough to be observed by optical telescopes. The observations allowed astronomers to use Hubble’s law to determine the distance to these sources,
and to show convincingly that quasars were indeed more common in the past than at present. There was no escape from the conclusion that the universe was evolving and that it had been denser in the past. At that point, the floodgates opened, and the challenges to the steady state model kept pouring in. In particular, in 1964 scientists Arno Penzias and Robert Wilson made a discovery that to all but its diehard supporters represented the last nail in the coffin of the steady state theory.

Figure 30

Penzias and Wilson were working at the Bell Telephone Laboratories in New Jersey with an antenna built for communication satellites. To their annoyance, they were picking up some sort of pervasive background radio noise: microwave radiation that appeared to be the same from all directions. After failing to explain away this disturbing “hiss” as an instrumental artifact, Penzias and Wilson finally announced the detection of an intergalactic temperature excess of about 3 Kelvin (3 degrees above absolute zero). Lacking the necessary background, Penzias and Wilson did not realize initially what they had found. Robert Dicke of Princeton University, however, recognized the signal immediately. Dicke was in the process of building a radiometer to search for the relic radiation from the big bang, previously predicted by Alpher, Hermann, and Gamow. Consequently, his correct interpretation of the results of Penzias and Wilson literally transformed the big bang theory from hypothesis into experimentally tested physics. As the universe expanded, the incredibly hot, dense, and opaque fireball cooled down continuously, eventually reaching its present temperature of about 2.7 Kelvin.

Since then, observations of the cosmic microwave background have produced some of the most precise measurements in cosmology. The temperature of this radiation is now known to four significant figures to be 2.725 K, and its intensity changes with wavelength precisely as expected from a thermal source—confirming the predictions of the big bang. Even in the face of this overwhelming, contradictory evidence to the steady state theory, Hoyle was never convinced. He proposed that instead of representing a relic of the big bang, the cosmic microwave background is produced by some extragalactic
iron “whiskers,” which absorb and scatter the infrared light of galaxies at microwave wavelengths. These iron whiskers were supposed to have condensed from metallic vapors—for instance, in the material ejected by supernova explosions.

In spite of Hoyle’s valiant efforts, beginning in the mid-1960s most scientists stopped paying attention to the steady state theory. Hoyle’s continuing attempts to demonstrate that all the confrontations between the theory and emerging observations could be explained away looked increasingly contrived and implausible. Worse yet, he seemed to have lost that “fine judgment” that he had once advocated, which was supposed to distinguish him from “merely becoming a crackpot.” At an international symposium on the topic “Modern Cosmology in Retrospect,” which took place in Bologna, Italy, in 1988, he gave a talk entitled “An Assessment of the Evidence Against the Steady-State Theory.” In that downright anachronistic talk, Hoyle tried (unsuccessfully, I should add) to convince his audience that all the compelling pieces of evidence for the big bang—the existence of the cosmic microwave background; the implied need for a primordial synthesis of the light elements deuterium, helium, and lithium; and the counts of the radio sources—
could
all
still be explained by the steady state theory. Hoyle’s obstinate resistance to changing his views stood in stark contrast to the attitude adopted, for instance, by co-originator of the steady state theory Hermann Bondi. Recall that Bondi had insisted on being shown some fossil remains of what the universe was like in the past, if the universe was indeed evolving. In his own talk at the same conference in Bologna, Bondi admitted that such fossil evidence had indeed emerged, both in the form of the cosmic helium abundance, which had been shown to have most likely formed in the big bang, and in the cosmic microwave background, which beautifully matched the big bang predictions. Bondi therefore concluded graciously, “So my challenge of whether fossils could be found has had an answer long after I posed it.”

Hoyle, on the other hand, continued to advocate a somewhat modified version of the steady state theory (which he called “quasi–steady
state”). Even as late as the year 2000, at the age of eighty-five,
he published a book entitled
A Different Approach to Cosmology: From a Static Universe Through the Big Bang Towards Reality,
in which he and his collaborators, Jayant Narlikar and Geoff Burbidge, explained the details of the quasi–steady state theory and their objections to the big bang. To express their contemptuous opinion of the scientific establishment, they presented in one of the book’s pages a photograph of a flock of geese walking on a dirt road with the caption, “This is our view of the conformist approach to the standard (hot big bang) cosmology. We have resisted the temptation to name some of the leading geese.” By then, however, Hoyle had been out of the conventional cosmological wisdom for so long that very few even bothered to point out the shortcomings of the modified theory. Perhaps the best thing said about the book appeared in the review by Britain’s
Sunday Telegraph
, and it referred not so much to the contents of the book as to Hoyle’s fiery personality: “Hoyle systematically reviews the evidence for the Big Bang theory, and gives it a good kicking . . . it’s hard not to be impressed with the audacity of the demolition job . . . I can only hope that I possess one-thousandth of Hoyle’s fighting spirit when I, like him, have reached my 85th year.”

Hoyle’s blunder was somewhat different from those of Darwin, Kelvin, and Pauling in two important respects. First, there was the issue of the scale of the topic, in the context of which the blunder occurred. Darwin’s blunder involved only one element of his theory (albeit an extremely important one). Kelvin’s blunder concerned an assumption at the basis of a particular calculation (a very meaningful one). Pauling’s blunder affected one specific model (unfortunately for the most crucial molecule). Hoyle’s blunder, on the other hand, concerned no less than
an entire theory
for the universe as a whole. Second and more important, Hoyle did nothing wrong in proposing the steady state model—unlike Darwin, who did not understand the
implications of a faulty biological mechanism; Kelvin, who neglected unforeseen physical processes; and Pauling, who ignored basic rules of chemistry. The theory itself was bold, exceptionally clever, and it matched all the observational facts that existed at the time. Hoyle’s blunder was in his apparently pigheaded, almost infuriating refusal to acknowledge the theory’s demise even as it was being smothered by accumulating contradictory evidence, and in his use of asymmetrical criteria of judgment with respect to the big bang and steady state theories. What was it that caused this intransigent behavior? To answer this intriguing question, I started by asking a few of Hoyle’s former students and younger colleagues for their opinions.