A New Zealand researcher appears to have solved the mystery of the vanishing South Pacific island which shows on Google Earth and world maps but does not exist.
A research ship cruised through the Coral Sea, east of Australia, bearing down on Sandy Island. The digital scientific databases used by the researchers showed the island to be 15 miles long, north to south, and about three miles wide. Manhattan-sized.
But when the ship reached the place where the island should have been, the researchers saw only open ocean. The water was nearly a mile deep. Sandy Island simply wasn’t there. Or, it turned out, anywhere.
How could an island supposedly discovered in 1876, and appearing on many maps ever since, vanish? Did it sink beneath the waves like the mythical Atlantis? Or was it always a figment of some mariner’s imagination?
The bizarre and complicated story of ghostly Sandy Island is a cautionary tale about what we know and don’t know in the 21st century — and how, even with satellite technology and modern surveying instruments, the ocean can still spring a surprise.
Last October, Maria Seton, a young scientist at the University of Sydney, led a 25-day expedition to the Coral Sea aboard the Australian national research vessel RV Southern Surveyor. The researchers wanted to understand the tectonic evolution of that corner of the Pacific. They gathered magnetic and gravity data to map the sea floor and collected rock samples from the bottom at depths up to two miles.
They noticed that multiple scientific data sets, including the General Bathymetric Chart of the Oceans, showed Sandy Island clearly in a remote area west of New Caledonia. But the chart used by the ship’s master indicated only open water. Seton and her fellow sailors realized something didn’t add up.
“We had a cached version of Google Earth for the area — we had no Internet — and saw that the ‘island’ was depicted as a big black blob. This also made us very suspicious,” she said.
Seton’s “undiscovery” of the island prompted a story in the Sydney Morning Herald that went viral. This was big news in the world of cartography; experts were puzzled, and some wondered if Sandy Island had been eroded away by the waves, like some ephemeral coral atolls. Google and National Geographic quickly removed Sandy Island from all of their maps.
Seton, meanwhile, dug into the mystery and has now published an obituary of Sandy Island in EOS, the journal of the American Geophysical Union.
Her research showed that the island appeared on the 1908 edition of a British admiralty map, which indicated that Sandy Island had been discovered in 1876 in French territorial waters by the whaling ship Velocity. The location and shape of the island on the 1908 map corresponds to what can be seen in the modern, erroneous databases.
The island was repeatedly “undiscovered” over ensuing decades, but it remained a shadowy presence in the cartographic world. Some maps labeled it “ED,” for “existence doubtful.” French hydrographic maps deleted Sandy Island once and for all in 1974.
But the island kept popping up in other places. The island was clearly marked, for example, on a 1982 U.S. Defense Mapping Agency map. “Ile de Sable,” it says, giving the French name. There’s a cryptic annotation: “Reported 1876. Reported to be about 4 miles east, 1968.”
“[I]nconsistencies in this data set exist in some of the least explored parts of our planet, a function of both human digitizing errors and errors in the original maps from which the digitizing took place,” Seton wrote in EOS.
The errors then migrated to other databases used by scientists such as the Global Self-consistent, Hierarchical, High-Resolution Shoreline Database (GSHHS), Seton found.
The phantom island has been blamed on an error by the crew of a whaling ship from 1876, the Velocity, which originally recorded the land mass, known as Sandy Island, midway between Australia and the French-governed New Caledonia. Though the island has existed on maps for hundreds of years, a group of Australian scientists went searching for it in the Coral Sea last month and could not find it.
Shaun Higgins, a pictorial librarian at Auckland Museum who was intrigued by the mystery, now believes he has also solved the case.
He says the ship’s master aboard the Velocity reported a series of “heavy breakers” and some “sandy islets” on an admiralty chart and that the unusual features spotted by the crew were copied over time as an island.
“But what we do have is a dotted shape on the map that’s been recorded at that time and it appears it’s simply been copied over time.”
Asked whether there may be other “undiscovered” islands, Mr Higgins said: “There certainly could be. It opens up the possibilities.”
The missing island has regularly appeared in scientific publications since at least 2000 and appears on Yahoo Maps as well as Bing Maps. Though the island would fall in French territory, official French maps did not show it.
Google said last month it welcomed feedback on maps and “continuously explore(s) ways to integrate new information from our users and authoritative partners into Google Maps”.
Sandy Island now appears to have been taken off its map.
“As far as I can tell, the island was recorded by the whaling ship the Velocity,” Mr Higgins told ABC radio.
“My supposition is that they simply recorded a hazard at the time. They might have recorded a low-lying reef or thought they saw a reef. They could have been in the wrong place. There is all number of possibilities.”