Circumnavigation – literally, "navigation of a circumference" – refers to travelling all the way around an island, a continent, or the entire planet Earth.
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In principle, if a person walks completely around either Pole, they will have crossed all meridians, but this is not generally considered a "circumnavigation." A basic definition of a global circumnavigation would be a route which covers at least a great circle, and in particular one which passes through at least one pair of points antipodal to each other.[1] In practice, different definitions of world circumnavigation are used, in order to accommodate practical constraints depending on the method of travel. Since the planet is a sphere, a trip from one Pole to the other, and back again, would technically be a circumnavigation, but practical difficulties generally preclude such a voyage.
For the wealthy, long voyages around the world, such as was done by Ulysses S. Grant, became possible in the 19th century, and the World Wars moved vast numbers of troops around the planet. However, it was later improvements in technology and rising incomes that made such trips relatively common.
The nautical circumnavigation record is currently held by a wind powered vessel.
The map on the right shows, in red, a typical, non-competitive, route for a sailing circumnavigation of the world by the trade winds and the Suez and Panama canals; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route roughly approximates a great circle, and passes through two pairs of antipodal points. This is a route followed by many cruising sailors, going in the western direction; the use of the trade winds makes it a relatively easy sail, although it passes through a number of zones of calms or light winds.
In yacht racing, a round-the-world route approximating a great circle would be quite impractical, particularly in a non-stop race where use of the Panama and Suez Canals would be impossible. Yacht racing therefore defines a world circumnavigation to be a passage of at least 21,600 nautical miles (40,000 km) in length which crosses the equator, crosses every meridian and finishes in the same port as it starts.[2] The map on the left shows the route of the Vendée Globe round-the-world race in red; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route does not pass through any pairs of antipodal points. Since the winds in the higher latitudes predominantly blow west-to-east it can be seen that there is an easier route (west-to-east) and a harder route (east-to-west) when circumnavigating by sail; this difficulty is magnified for square-rig vessels.
For current sailing records, see article : Around the world sailing record. For around the world sailing records, there is a rule saying that the length must be at least 21,600 nm calculated along the shortest possible track from the starting port and back that does not cross land and does not go below 63°S. It is allowed to have one single waypoint to lengthen the calculated track. The equator must be crossed.[3]
The current wind powered circumnavigation record of 48 days 07 hours 44 minutes 52 seconds was established by a voyage of the maxi-multihull sailing yacht Groupama 3 which was completed on 20 March 2010. The voyage followed the North Atlantic Ocean, Equator, South Atlantic Ocean, Southern Ocean, South Atlantic Ocean, Equator, North Atlantic Ocean route in an easterly direction.
Since the advent of world cruises in 1922, by Cunard's Lanconia, thousands of people have completed circumnavigations of the globe at a more leisurely pace. Typically, these voyages begin in New York City or Southampton, and proceed westward. Routes vary, either travelling through the Caribbean and then into the Pacific Ocean via the Panama Canal, or around Cape Horn. From there ships usually make their way to Hawaii, the islands of the South Pacific, Australia, New Zealand, then northward to Hong Kong, South East Asia, and India. At that point, again, routes may vary: one way is through the Suez Canal and into the Mediterranean; the other is around Cape of Good Hope and then up the west coast of Africa. These cruises end in the port where they began.
The current mechanically powered circumnavigation record of 60 days 23 hours and 49 minutes was established by a voyage of the wave-piercing trimaran Earthrace which was completed on 27 June 2008. The voyage followed the North Atlantic Ocean, Panama Canal, Pacific Ocean, Indian Ocean, Suez Canal, Mediterranean Sea route in a westerly direction.
Since the development of commercial aviation many thousands of people have flown around the world. Some regular routes, such as the old Pan American Flight One (and later, although briefly, United Airlines Flight One), circled the globe, and today planning such a trip through various connections is quite simple.
The first flying man-made airship to circumnavigate the world was the LZ 127 Graf Zeppelin, which did so in 1929.
Aviation records take account of the wind circulation patterns of the world; in particular the jet streams, which circulate in the northern and southern hemispheres without crossing the equator. There is therefore no requirement to cross the equator, or to pass through two antipodal points, in the course of setting a round-the-world aviation record. Thus, for example, Steve Fossett's global circumnavigation by balloon was entirely contained within the southern hemisphere.
For powered aviation, the course of a round-the-world record must start and finish at the same point and cross all meridians; the course must be at least 36,787.559 kilometres (22,858.729 mi) long (which is the length of the Tropic of Cancer). The course must include set control points at latitudes outside the Arctic and Antarctic circles.[4]
In ballooning, which is totally at the mercy of the winds, the requirements are even more relaxed. The course must cross all meridians, and must include a set of checkpoints which are all outside of two circles, chosen by the pilot, having radii of 3,335.85 kilometres (2,072.80 mi) and enclosing the poles (though not necessarily centred on them).[5]
The first person to fly in space, Yuri Gagarin, became also the first to complete an orbital spaceflight on spaceship Vostok 1, in 1961. Early NASA space missions included only sub-orbital spaceflights.
According to AdventureStats by Explorersweb, Jason Lewis completed the first true human-powered circumnavigation of the globe while National Geographic (http://www.nationalgeographic.com/adventure/best-of-adventure-2007/achievements/colin-angus-julie-wafaei.html) lists Colin Angus as being the first to complete a global circumnavigation. While neither Lewis or Angus met the criteria of Guinness World records, each completed continuous human powered journeys around the planet. [6] David Kunst was the first verified person to walk around the world between 20 June 1970 and 10 October 1974. Guidelines issued by Guinness World Records in March 2007 state that a human powered circumnavigation must travel a minimum of 36,787.559 km (the distance of the Tropic of Cancer), cross the Equator, and each leg must commence at the exact point where the last finished off. To date no one has completed a human-powered circumnavigation according to the guidelines set by Guinness.[7][8][9]
People have both bicycled and run around the world,[10] but the oceans have had to be covered by air travel, making the distance shorter than the Guinness guidelines. To go from North America to Asia on foot is theoretically possible but very difficult. It involves crossing the Bering Strait on the ice and around 3000 km roadless swamped or freezing cold area in Alaska and eastern Russia. No one has so far travelled all of this route by foot.