Who won the race? (Image: Universal History Archive/UIG/Bridgeman)
Peary or Cook? The bending of sunlight has helped to reveal who bent the truth in a century-old debate about which explorer was the first to the North Pole
WHEN Robert Scott reached the South Pole in January 1912, . It was holding up a tent left behind by Roald Amundsen five weeks earlier. Inside was a note for Scott. There could be no dispute about who had got there first.
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On the other side of the world at the North Pole, any marker left behind soon drifts away with the sea ice, so it was harder for early explorers to prove they had reached it. Frederick Cook was the first to claim he had got there, in April 1908. The feat was briefly celebrated on his return to the US in 1909, but then his honesty suffered a public knock: Cook’s previous claim of climbing North America’s highest mountain, Mount McKinley, in 1906 was denied by his climbing companion. Matters weren’t helped by the fact that Cook’s detailed records of the Arctic expedition had been left behind in Greenland.
Instead, the official plaudits – and even a government pension – went to his one-time friend turned rival, Robert Peary, who claimed to have reached the pole in April 1909. Doubts remained, however, especially after a re-examination of the records in 1988 revealed suspicious elements in Peary’s story. For example, the pages of his log book are mysteriously blank for the two days he claimed to be at the pole, 6 and 7 April 1909. His navigational readings are written on paper slips that were inserted later.
It has also emerged that Cook’s former climbing companion may have been paid by representatives of Peary to discredit Cook, and that because the team member who was carrying them ended up travelling back on Peary’s ship – and Peary refused to take the records aboard.
So the debate about who got there first continues more than a century on, as Wayne Davidson found out in 1997 when he met a group of explorers from New Zealand. “They were divided into a Cook gang and a Peary gang,” he says, “and they argued all the way to the North Pole.” That led Davidson to wonder whether his own Arctic observations might be able to resolve the argument.
Davidson is a meteorological observer based in Resolute on Cornwallis Island in Nunavut, Canada, which, at a latitude of almost 75° north, is deep inside the Arctic Circle. His particular interest is refraction in the atmosphere. This is essentially the same as what happens at the surface of a pond or a piece of glass: when a ray of light goes through regions with different optical properties, it gets bent.
We rarely think about this happening in the air, says Davidson, but it is everywhere and it distorts our view of the world. “The horizon and everything around us is constantly shifting,” he says.
Under some conditions, refraction can even turn things upside down. When a warmer layer of air sits above a cooler layer it can bend light so strongly around the curvature of Earth that it creates a type of mirage called a Fata Morgana. In the Arctic, this can lead to an apparent wall of ice rising before an explorer.
Usually the effect is more subtle. As the sun sinks close to the horizon, it appears a little bit squashed. That’s because to reach your eye, light from the lower edge of the sun has to travel through denser air closer to the ground, bending it more than light from the upper edge (see diagram). This is what Davidson has been recording for many years. “I’m the only one in the world to specialise in refraction of the sun disc,” he says.
The amount of flattening depends on the angle of the sun in the sky, along with fickle atmospheric conditions, but Davidson believes that his database is large enough to test the observations of Peary and Cook. These explorers used a sextant to measure the height of the sun above the horizon, which along with the date and time (supplied by a chronometer) enabled them to calculate their latitude. They took the position of the top and bottom of the sun to get an average – and in the process they happened to measure the size of the sun disc.
Peary’s readings, as written on those infamous inserts, put the sun at 6.7 degrees from the horizon. According to Davidson’s database, at that angle the atmosphere should squash the sun’s vertical diameter to something between 31.19 and 31.49 arc minutes. Peary’s record gives values ranging from 31.58 to 32.17 arc minutes. Only one of Peary’s numbers is plausible, with the others impossibly large. The biggest is even larger than the undistorted diameter of the sun, 32 arc minutes. Atmospheric refraction doesn’t magnify the sun.
As an experienced surveyor, Peary should have been able to get readings with an error margin of no more than 0.2 arc minutes, says Davidson. “So I’m having trouble with this guy now. Someone good at surveying would have noticed such unusually inflated measurements, prompting an immediate rejection. This suggests he made no observations there.”
Soon this sign will go with the floe (Image: B&C Alexander/ArcticPhoto)
But if you are going to cheat, why insert impossible readings? Davidson speculates that after the expedition, someone with access to Peary’s archive but limited navigational knowledge made up the numbers. In any case, the strange readings cast doubt on Peary’s reliability.
Does this mean redemption for Cook? Hardly. One of his measurements has the sun disc at 26.5 minutes. This is way outside the range in Davidson’s database, suggesting that Cook was very sloppy in his measurements. “He had huge variations far greater than I ever measured. After all he was a physician, not a physicist.”
There is a glimmer of consolation. In one of Cook’s observations, he records seeing the sun when it was actually 5 degrees below the horizon. This may sound like another mistake, but in fact such extreme refraction can happen far out on the flat Arctic ice. So while some think that Cook didn’t even venture far out on the ice, this suggests otherwise.
Overall, it seems that neither Peary’s nor Cook’s claims can be believed. “I’d say neither of them made it to the pole,” says Davidson. He isn’t the first to make this suggestion. Explorer Wally Herbert, who carried out the 1988 re-examination, concluded that Peary missed the pole by about 100 kilometres, taken off course by the drift of the ice. Herbert wasn’t entirely disinterested, however: if neither Peary nor Cook got there, it would mean Herbert himself was the first person to reach the pole on foot, in 1969.
Davidson’s findings at least add another line of evidence, though the Cook and Peary camps will no doubt keep squabbling. Instead of wrangling about the past, perhaps we should instead look forward to another record that will be up for grabs some time later this century: the first person to reach the North Pole by kayak.
This article appeared in print under the headline “Pole position”
