In the cynical, dog-eat-dog world of journalism, few reporters can hope to be regarded by their peers as living legends. Any list of candidates for such exalted status would, however, undoubtedly include Bob Woodward and Carl Bernstein, the two Washington Post reporters whose investigation of the Watergate affair of 1972 led to the downfall of Richard Nixon, the US president.
It now seems that two other journalists could just as easily have won their place in history with the same story - had they taken it seriously. Last week it emerged that a reporter on the rival New York Times had lunch with a contact in August 1972 and was told of the involvement of the Nixon administration in the break-in at the Watergate Building in Washington, DC. The reporter, Robert Smith, knew that he was on to a big story as his contact was the acting director of the FBI, L Patrick Gray. Unfortunately, he was also on his last day at the newspaper and could only pass the bare bones of the story on to his editor, Robert Phelps. For reasons still unclear, Phelps did not pursue it - thus robbing both of them of a chance for journalistic glory. Meanwhile Woodward and Bernstein persisted with the story, followed up tip-offs from their own source (whom they famously referred to as "Deep Throat") and made history.
Many journalists will feel a sneaking sympathy for Smith and Phelps, aware of the big stories they have missed. Their blushes may well have been spared by the fact that the big story never came out. Scientists who miss big discoveries often have nowhere to hide, however, with even Nobel Prize winners being made to look flat-footed when nature finally gives up her secrets. Take the case of one of the biggest scientific stories of the last century, the discovery of the structure of the genetic molecule, DNA. As every schoolchild knows, DNA comes in the form of two intertwined spirals - the famous "double helix" - identified by the scientific world's answer to Woodward and Bernstein, the Cambridge University biochemists James Watson and Francis Crick.
Watson and Crick were always convinced that the key to understanding genetics lay with the structure of DNA. They were also pretty sure it was made up of a pair of interlocking strings of molecules - not least because organisms tend to do things in pairs. Their hunch was proved right by detailed X-rays of DNA, and they went on to win a Nobel Prize for their work - leaving another Nobel Prize winner nursing his dented pride.
If anyone could have beaten Watson and Crick to the greatest discovery in 20th-century biology, it was Linus Pauling of the California Institute of Technology, the world's leading expert on how atoms stick together in molecules. Just a few years before Watson and Crick's breakthrough, Pauling had solved the long-standing mystery of how proteins are put together. Using X-ray data, he had shown that these complex biomolecules contain spiral-like structures. It was a discovery which earned Pauling his own Nobel Prize - and led him to take on the challenge of DNA.
Watson and Crick were understandably alarmed by Pauling's entry into the race, and held their breath when he revealed his own theory about DNA's structure. To their astonishment, Pauling believed it consisted of three helix-like spirals wrapped round each other. They suspected he had made a mistake - and confirmed it by consulting the most authoritative textbook on the subject: General Chemistry, written by Pauling himself. Incredibly, it turned out that Pauling had made a major blunder over chemical bonds - the very subject on which he was the undisputed expert.
After DNA's true structure had been confirmed, Pauling came up with a variety of excuses for his shocking error; his biographer Thomas Hager believes it was a disastrous combination of hubris and haste. Simple incompetence has led more than a few scientists to miss major discoveries. When the 19th-century English mathematician John Adams claimed to have worked out that a new planet would be found in the constellation Aquarius, a simple search of the area would have proved him right. Unfortunately, the job was given to a Cambridge University astronomer named James Challis, who actually saw the planet in 1846 but failed to recognise it. Barely a month later, astronomers in Germany made no such mistake and were duly hailed as the discoverers of Neptune.
As in journalism, some scientific findings are so big they simply defeat the imagination of those who make them. In 1940 a Canadian physicist named Andrew McKellar noticed that features in the light of stars implied that the whole of space had a temperature of around minus 270°C - just a few degrees above absolute zero. A few years later, astronomers showed that if the universe began in a Big Bang, the whole of space would today have a temperature of a few degrees above absolute zero. Yet when McKellar's results were published, they were dismissed by one of the leading experts of the day as having only "a very restricted meaning" - and were promptly forgotten. It took another 25 years for astronomers to rediscover this primordial heat, and even then they nearly mistook what they found for the effect of pigeon droppings on their equipment.
Even the greatest minds can lack the confidence to accept what their own work is telling them. In 1917, Einstein applied his new theory of gravity to the entire universe - and found that the equations predicted an expanding universe. Horrified, he fiddled his equations to give the "right" answer of an unchanging universe. But in 1929, astronomers found the universe is indeed expanding. Einstein's original equations were right after all, and he had missed out on making arguably the greatest scientific discovery of all time.
It was a rare blunder by a scientist who seemed to get most of his tip-offs directly from the creator of the universe. Robert Matthews is a visiting reader in science at Aston University, Birmingham, England.