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North Pole
A precise definition
See also: Polar motion
The Earth's axis of rotation and therefore the position of the North Pole has been widely acknowledged to be fixed (relative to the surface of the Earth) until, in the 18th century mathematician Leonhard Euler predicted that the axis might "wobble" slightly. By the early 20th century astronomers noticed a small apparent "variation of latitude, as determined for a fixed point on Earth from the star gazing. Some of this variation can be attributed to a wandering of the pole on the surface of the Earth, a series of meters. The wandering has several periodic components and an irregular component. The component with a period of approximately 435 days is identified with the eight months wandering predicted by Euler and called Now the Chandler wobble after its discoverer. The exact point of intersection of the axis of the Earth and the Earth's surface at a given moment is called the "instant center, but because of the oscillation" that can not be used as a definition of a fixed North Pole (or South Pole) where the meter-scale precision is required.
It is desirable to link the system of the Earth coordinates (latitude, longitude and altitude or topography) of fixed terrain. Of course, plate tectonics and isostasy given, there is no system in which all geographic features are fixed. Yet the International Earth Rotation and Reference Systems and the International Astronomical Union have defined a framework called the International Terrestrial Reference System.
Expeditions
See also: Arctic exploration, further north and the list of expeditions in the Arctic
Pre-1900
From the sixteenth century, many eminent personalities correctly believed that the North Pole was in a sea that, in the nineteenth century has been called the Polynia or Open Polar Sea. It was therefore hoped that passage could be found through the ice at times favorable year. Several expeditions have tried to find the way, generally with whaling, already commonly used in cold northern latitudes.
One of the first expeditions to go with the explicit intention of reaching the North Pole was that of British naval agent William Edward Parry, who in 1827 reached 8245 latitude. In 1871, the Polaris expedition, an American attempt on the Pole led by Charles Francis Hall, ended in disaster. An expedition led by 18791881 naval officer of the United States George Washington DeLong also ended in tragedy when their ship, the USS Jeannette was crushed by ice. More than half of the crew, including DeLong, have been lost.
Nansen ship Fram in the ice of the Arctic
In April 1895, the Norwegian explorer Fridtjof Nansen and Hjalmar Johansen Fredrik Striped Pole on skis after leaving Fram Nansen ship caught in ice. The pair reached the latitude of the North 8614 before abandoning the attempt and went to the south to reach Franz Josef Land.
In 1897, the Swedish engineer Salomon August Andre and two companions tried to reach the North Pole by hydrogen balloon NSNR ("Eagle"), but were stranded 300 km north of Kvitya, the northernmost part of the archipelago Svalbard, and perished on this lonely island. In 1930, the remains of the expedition were found by the Norwegian Shipping Bratvaag.
The Italian explorer Luigi Amedeo, Duke of Abruzzi and Captain Umberto Cagni of the Italian Royal Navy (Regia Marina) sailed the whaler converted Stella Polare Norway in 1899. On March 11, 1900 Cagni led a game on the ice and reached the latitude 86 34 April 25, setting a new record was broken after the 1895 Nansen of 35-40 kilometers. Cagni barely managed to return to the camp, remaining there until June 23. On 16 August the Stella left Polare Rudolf island towards the south and the expedition returned to Norway.
19001940
The American explorer Frederick Albert Cook claimed to have reached the North Pole on April 2.