Even today, in the era of electronic mail, faxes, and international flight, it is still possible for two individuals or groups to work independently, unknown to each other, and to come to the same conclusion simultaneously. This nearly happened in the case of the meteorite impact theory.13 In 1974, geologist Jan Smit began to study the K-T boundary at Caravaca, Spain, for his doctoral dissertation, focusing on the disappearance of the microscopic foramin-ifera there. At the start, he thought their sudden exit at the boundary was only apparent, caused by an erosional gap that made a gradual extinction appear falsely sharp. But the sudden extinction persisted even in sections without visible gaps. Smit decided to see whether there were invisible, chemical changes.
In the spring of 1977, he sent off to the Dutch interuniversity laboratory in Delft a set of 100 K-T samples for neutron activation analysis, asking the scientists there to determine the concentrations of various elements. Because there was no reason for him to do so, Smit did not include iridium on his list of elements to be studied. When the results came back, the thin boundary clay turned out to have concentrations of nickel, cobalt, chromium, arsenic, antimony, and selenium that were orders of magnitude higher than in the limestones on either side. Smit published his finding that the extinctions were rapid, and, as he describes it, "began to speculate about extraterrestrial causes."14 What Smit did not know was that the iridium levels of his samples had actually been available in the analysis records, but, since they had not been requested, were not reported to him. On that may have hung the priority for the meteorite impact discovery—otherwise we might be discussing the Smit theory rather than the Alvarez theory. Serendipity thus can also work in reverse: A scientist may be unlucky and miss having the chance to make a critical observation.
Two years later, after a lengthy bout with mononucleosis, Smit was bowled over to read in the New Scientist that scientists at Berkeley had discovered high iridium concentrations in the Gubbio boundary clay.15 Smit sent his Caravaca samples to Jan Hertogen in Belgium, who had the equipment to analyze them for iridium. At 28,000 ppt, iridium in the Caravaca K-T boundary clay turned out to be five times higher than at Gubbio! This prompted the head of the Neutron Activation Department at the interuniversity laboratory in Delft to go back over the archived data from the earlier analysis—the unreported iridium peak came in at 26,000 ppt.
Smit and Walter Alvarez met at the Copenhagen K-T conference in September 1979 and, finding themselves alone in giving credence to the meteorite impact theory, soon became fast friends, and they have remained so. At first, Smit preferred the supernova explanation for the K-T mass extinction, but subsequent discussions with an astronomer colleague soon convinced him that the iridium levels were too high. In December 1979, he received a preprint of the paper that the Alvarez team had submitted to Science. One month later, he and Hertogen submitted a paper to Nature based on their Caravaca findings, noting that "the impact of a large meteorite may have provided the iridium" and caused the K-T mass extinction." The paper appeared in May 1980, one month before the original Alvarez paper. Thus Smit got into print first, which would have allowed a less scrupulous person to claim priority. He knew, however, that the chronology of events required that he give credit for the discovery to the Alvarezes, which he did. But it was a near thing. And Smit had not only supernovae, but meteorites, on his mind. But in science, as an excellent practitioner like Smit knows full well, there is no second prize.
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