Antipodes


In geography, the antipode of any spot on Earth is the point on Earth's surface diametrically opposite to it. A pair of points antipodal to each other are situated such that a straight line connecting the two would pass through Earth's center. Antipodal points are as far away from each other as possible.
In the Northern Hemisphere, "the Antipodes" may refer to Australia and New Zealand, and Antipodeans to their inhabitants. Geographically, the antipodes of Britain and Ireland are in the Pacific Ocean, south of New Zealand. This gave rise to the name of the Antipodes Islands of New Zealand, which are close to the antipode of London. The antipodes of Australia are in the North Atlantic Ocean, while parts of Spain, Portugal, and Morocco are antipodal to New Zealand.
Approximately 15% of land territory is antipodal to other land, representing approximately 4.4% of Earth's surface. Another source estimates that about 3% of Earth's surface is antipodal land. The largest antipodal land masses are the Malay Archipelago, antipodal to the Amazon basin and adjoining Andean ranges; east China and Mongolia, antipodal to Chile and Argentina; and Greenland and the Canadian Arctic Archipelago, antipodal to East Antarctica. There is a general paucity of antipodal land because the Southern Hemisphere has comparatively less land than the Northern Hemisphere and, of that, the antipodes of Australia are in the North Atlantic Ocean, while the antipodes of southern Africa are in the Pacific Ocean.

Geography

The antipode of any place on the Earth is the place that is diametrically opposite it, so a line drawn from the one to the other passes through the centre of Earth and forms a true diameter. For example, the antipodes of New Zealand's lower North Island lie in Spain. Most of the Earth's land surfaces have ocean at their antipodes, this being a consequence of most land being in the Land Hemisphere.
The antipode of any place on Earth is distant from it by 180° of longitude and as many degrees to the north of the Equator as the original is to the south ; in other words, the latitudes are numerically equal, but one is north and the other south. The maps shown here are based on this relationship; they show a Lambert azimuthal equal-area projection of the Earth, in yellow, overlaid on which is another map, in blue, shifted horizontally by 180° of longitude and inverted about the Equator with respect to latitude.
Noon at one place is midnight at the other and, with the exception of the tropics, the longest day at one point corresponds to the shortest day at the other, and midwinter at one point coincides with midsummer at the other. Sunrise and sunset do not quite oppose each other at antipodes due to refraction of sunlight.

Mathematical description

If the geographic coordinates of a point on the Earth's surface are, then the coordinates of the antipodal point are. This relation holds true whether the Earth is approximated as a perfect sphere or as a reference ellipsoid.
In terms of the usual way these geographic coordinates are given, this transformation can be expressed symbolically as
that is, for the latitude the magnitude of the angle remains the same but N is changed to S and vice versa, and for the longitude the angle is replaced by its supplementary angle while E is exchanged for W. For example, the antipode of the point in China at is the point in Argentina at .

Etymology

The word antipodes comes from the Greek: ἀντίποδες, plural of ἀντίπους, "with feet opposite ", from ἀντί + πούς. The Greek word is attested in Plato's dialogue Timaeus, already referring to a spherical Earth, explaining the relativity of the terms "above" and "below":
The term is taken up by Aristotle, Strabo, Plutarch and Diogenes Laërtius, and was adopted into Latin as antipodes. The Latin word changed its sense from the original "under the feet, opposite side" to "those with the feet opposite", i.e. a bahuvrihi referring to hypothetical people living on the opposite side of the Earth. Medieval illustrations imagine them in some way "inverted", with their feet growing out of their heads, pointing upward.
In this sense, Antipodes first entered English in 1398 in a translation of the 13th century De Proprietatibus Rerum by Bartholomeus Anglicus, translated by John of Trevisa:
The modern English singular antipode arose in the 16th or 17th century as a back-formation from antipodes. Most dictionaries suggest a pronunciation of for this form.

Historical significance

, the first Roman geographer, asserted that the earth had two habitable zones, a North and South one, but that it would be impossible to get into contact with each other because of the unbearable heat at the Equator.
, showing the region of the antipodes in the southern half of the western hemisphere
From the time of St Augustine, the Christian church was skeptical of the notion. Augustine asserted that "it is too absurd to say that some men might have set sail from this side and, traversing the immense expanse of ocean, have propagated there a race of human beings descended from that one first man."
In the Early Middle Ages, Isidore of Seville's widely read encyclopedia presented the term "antipodes" as referring to antichthones, as well as to a geographical place; these people came to play a role in medieval discussions about the shape of the Earth. In 748, in reply to a letter from Saint Boniface, Pope Zachary declared the belief "that beneath the earth there was another world and other men, another sun and moon" to be heretical. In his letter, Boniface had apparently maintained that Vergilius of Salzburg held such a belief.
The antipodes being an attribute of a spherical Earth, some ancient authors used their perceived absurdity as an argument for a flat Earth. However, knowledge of the spherical Earth was widespread during the Middle Ages, only occasionally disputed — the medieval dispute surrounding the antipodes mainly concerned the question whether people could live on the opposite side of the earth: since the torrid clime was considered impassable, it would have been impossible to evangelize them. This posed the problem that Christ told the apostles to evangelize all mankind; with regard to the unreachable antipodes, this would have been impossible. Christ would either have appeared a second time, in the antipodes, or left the damned irredeemable. Such an argument was forwarded by the Spanish theologian Alonso Tostado as late as the 15th century and "St. Augustine doubts" was a response to Columbus's proposal to sail westwards to the Indies.
The author of the Norwegian book Konungs Skuggsjá, from around 1250, discusses the existence of antipodes. He notes that they will see the sun in the north in the middle of the day and that they will have seasons opposite those of the Northern Hemisphere.
The earliest surviving account by a European who had visited the Southern Hemisphere is that of Marco Polo. He noted that it was impossible to see the star Polaris from there.
The idea of dry land in the southern climes, the Terra Australis, was introduced by Ptolemy and appears on European maps as an imaginary continent from the 15th century. In spite of having been discovered relatively late by European explorers, Australia was inhabited very early in human history; the ancestors of the Indigenous Australians reached it at least 50,000 years ago.

True trip "around the world"

To make the longest distance trip around the planet a traveler would have to pass through a set of antipodal points. All meridians can be crossed in one hemisphere—indeed, by walking around one of the poles—but such trips are shorter than a maximum circumnavigation. On the other hand, the greatest straight line distance that could in theory be covered is a trip exactly on the Equator, a distance of. The Earth's equatorial bulge makes this slightly longer than a north-south trip around the world along a set of meridian lines, which is a distance of. Any other closed great circle route starting on the equator and traveling at an angle between 0° and 90° would be between. In all of these cases, after half of the world has been traversed, every subsequent point will be antipodal to one already visited.

Air travel between antipodes

There are no non-stop scheduled flights between any two antipodal locations by commercial airline service. There is currently no commercial aircraft capable of travelling between antipodes at full load non-stop ⁠— ⁠the current world record holder Boeing 777-200LR's maximum range is rated at, or roughly 87% of an average antipodal distance. The current world record holder for the longest commercial flight, Singapore Airlines, utilizes Airbus A350 XWB for its non-stop Newark-Singapore route. There are also regulations regarding pilot's work time, requiring changes in the global protocols for relief crew members on long-haul flights. Among flights with fuel stop and crew-change stop but still same flight number, Air New Zealand previously had the world's longest active plane route - the Auckland–Los Angeles–London marathon, at over Los Angeles - until the airline cancelled this route late in 2019.
In the same year, Qantas completed separate non-stop flights taking 19-20 hours to encompass the 16,013 km from New York and 17,016 km from London, both to Sydney, Australia with a limit of 49 passengers on the Boeing 787 Dreamliner and who underwent medical tests on the flight. The London-Sydney direct routes are said to be the world's most profitable ultra-long haul flights annually. Whether further such flights will be made after two more such experiments was still in question due to global travel restrictions as a result of the COVID-19 pandemic.
A hypothetically perfect antipodal flight would be Tangier Ibn Battouta Airport, Morocco, to Whangarei Aerodrome, New Zealand, whose designated locators are 10,800 nautical miles apart, the maximum possible distance, but their actual runways cross in projection. However, with only a length of, Whangarei's runway is too short to accommodate any current commercial jet airliner, especially one with the required range. Traveling between them would presently need at least two plane changes, in London and Auckland.
Other near-antipodes major city pairs include:

Earth

Around 71% of the Earth's surface is covered by oceans, and seven-eighths of the Earth's land is confined to the land hemisphere, so the majority of locations on land do not have land-based antipodes. About 15% of the earth's land has an antipodes on land. Rough calculation shows that, of the 29% of the earth that is covered by land, if 15% of that has antipodes on land, then about 4% of the earth's surface has antipodes that are both land surfaces. Spilhaus estimates this at about 3%.
The two largest human inhabited antipodal areas are located in East Asia and South America. The two largest monolithic antipodal land areas are most of Chile and Argentina along with eastern and central China and Mongolia, and most of Greenland along with a part of Antarctica. The Australian mainland is the largest landmass with its antipodes entirely in ocean, although some locations of mainland Australia and Tasmania are close to being antipodes of islands in the North Atlantic Ocean. The largest landmass with antipodes entirely on land is the island of Borneo, whose antipodes are in the Amazon rainforest.

Cities

Exact or almost exact antipodes:
To within, with at least one major city :
Taiwan is partly antipodal to the province of Formosa in Argentina.
Other major cities or capitals close to being antipodes:
is approximately antipodal to Te Arai Beach about north of Auckland, New Zealand. This illustrates the old yet correct saying that the sun never sets on the British Empire; the sun still does not set on the Commonwealth of Nations.
The northern part of New Caledonia, an overseas territory of France, is antipodal to some thinly populated desert in Mauritania, a part of the former French West Africa. Portions of Suriname, a former Dutch colony, are antipodal to Sulawesi, an Indonesian island spelled Celebes when it was part of the Netherlands East Indies. Luzon, the largest island of the Philippines, is antipodal to eastern Bolivia. As with the British Empire, the sun set neither on the French Empire, the Dutch Empire, nor the Spanish Empire at their peaks.
Santa Vitória do Palmar, the most southerly town of more than 10,000 people in Brazil, is antipodal to Jeju Island, the southernmost territory of South Korea.
Hawaii is antipodal to parts of Botswana. The Big Island of Hawaii is antipodal to the Okavango Delta in Botswana, with the island's largest city, Hilo, antipodal to Nxai Pan National Park.
Desolate Kerguelen Island is antipodal to an area of thinly inhabited plains on the border between the Canadian provinces of Alberta and Saskatchewan and the US state of Montana. The only permanent settlement on Kerguelen Island, the research station Port-aux-Français, is antipodal to fields northeast of Senate, Saskatchewan. Other Canadian towns with antipodes on Kerguelen Island include: Consul, Nashlyn and Govenlock in the vicinity of Senate, and in Alberta Eagle Butte, Elkwater and Manyberries as well as the Red Coat Trail between Orion, Alberta and Etzikom. The northern part of Liberty County, Montana, especially the communities Goldstone, Fox Crossing and Sage Creek Colony, also have antipodes on Kerguelen Island.
St. Paul Island and Amsterdam Island are antipodal to thinly populated parts of the eastern part of the US state of Colorado. They are situated ca. south-south-east of Firstview and south-south-west of Granada, Colorado, respectively. Together with the northern part of Liberty County, Montana, they are the only three areas of the Contiguous United States with antipodes on land.
The north-eastern coast of Alaska from Utqiagvik, Alaska over Prudhoe Bay to the Canadian border, and the coasts of the Canadian territories of Yukon, Northwest Territories, and Nunavut, are antipodal to Antarctica.
The Heard Island and McDonald Islands, an uninhabited Australian territory, is antipodal to an area in central Saskatchewan, including the towns of Leask and Shellbrook.
Tigres Island, the largest uninhabited island of Angola, is approximately antipodal to Johnston atoll, which is the third largest uninhabited island of the United States.
Easter Island is antipodal to an area close to Desert National Park, from Jaisalmer, India. The only town on Easter Island, Hanga Roa, is antipodal to the village of Serawa northeast of Jaisalmer. Serawa is the only village in India to be antipodal to a human settlement. Its neighbouring villages Mokla and the northern part of Bhadasar also have antipodes on Easter Island. The small, rocky, uninhabited island of Sala y Gómez, east-northeast of Easter Island, is antipodal to an area in the city of Ajmer, India, just east of Ana Sagar Lake. All the rest of India has its antipodes in the sea.
Kiritimati, the largest island of Kiribati and the largest coral atoll in the world, is antipodal to Salonga National Park, which is the largest national park of the Democratic Republic of the Congo and the largest tropical rainforest reserve in Africa.
Serra da Estrela Natural Park, the largest natural park of Portugal, is antipodal to Kahurangi National Park, the second largest national park of New Zealand.
South Georgia Island is antipodal to the northernmost part of Sakhalin Island.
Lake Baikal is partially antipodal to the Straits of Magellan.
The Russian Antarctic research base Bellingshausen Station is antipodal to a land location in Russian Siberia.
Rottnest Island, off the coast of Western Australia, is approximately antipodal to Bermuda.
Cocos Islands, an Australian external territory in the Indian Ocean, is almost antipodal to Nicaragua's Corn Islands.
Flores Island, the westernmost island of the Azores, is nearly antipodal to Flinders Island between Tasmania and the Australian mainland.
Point Nemo, the point in the South Pacific Ocean most distant from any other land, is precisely opposite a desolate piece of desert in western Kazakhstan.
By definition, the North Pole and the South Pole are antipodes.
Null Island,, at the intersection of the prime meridian and the equator, has its antipodes at, at the intersection of the antimeridian and the equator. This point lies northeast of Nikunau in the Gilbert Islands and southwest of Baker Island, a United States territory.
As can be seen on the purple/blue map, the Pacific Ocean is so large that it stretches halfway around the world; parts of the Pacific off the coast of Peru are antipodal to parts of the same ocean off the coast of Southeast Asia. For example, the island of Ko Chang—which is the second or third largest island in Thailand—is nearly antipodal to San Lorenzo Island, which is the largest island of Peru.

Countries

The following countries are opposite more than one other country.
CountryNo. of antipodal countriesAntipodal countries
New Zealand12Mainland: Spain, Portugal, Morocco, UK
Chatham Islands: France
Kermadec Islands: Algeria
Niue: Niger
Tokelau: Nigeria
Cook Islands: Chad, Central African Republic, Libya, Cameroon, Nigeria
France12Mainland: New Zealand
Southern & Antarctic Lands: Canada, United States
French Guiana: Indonesia
New Caledonia: Mauritania, Western Sahara
Wallis and Futuna: Niger
French Polynesia: Sudan, Egypt, Saudi Arabia, Eritrea, Ethiopia
Brazil9China, Japan, South Korea, Philippines, Malaysia, Indonesia, Brunei, Palau, Federated States of Micronesia
Indonesia8Ecuador, Peru, Colombia, Venezuela, Brazil, Suriname, Guyana, France
Peru7Vietnam, Cambodia, Laos, Thailand, Malaysia, Indonesia, China
United States7Mainland: France
Hawaii: Botswana, Namibia
Alaska: Antarctica
Palmyra Atoll & Kingman Reef: DR Congo
American Samoa: Niger, Nigeria
United Kingdom7Falklands: China, Russia
Gibraltar: New Zealand
South Georgia and the South Sandwich Islands: Russia
Pitcairn: Saudi Arabia, UAE
Bermuda: Australia
China6Argentina, Chile, Uruguay, Brazil, Bolivia, UK
Niger5Samoa, Tonga, United States, France, New Zealand
Antarctica5Greenland, Canada, United States, Russia, Norway
Malaysia4Ecuador, Peru, Brazil, Colombia
Argentina4China, Taiwan, Mongolia, Russia
Chile4China, Mongolia, Russia; Easter Island: India
Kiribati4Phoenix Islands : Nigeria; Line Islands: DR Congo, Central African Republic, Sudan
Russia4Antarctica, Chile, Argentina, United Kingdom
Australia3Mainland: Bermuda, Portugal
Heard Island and McDonald Islands: Canada
Christmas Island: Colombia
Ecuador3Malaysia, Singapore, Indonesia
Philippines3Brazil, Bolivia, Paraguay
Vanuatu3Mauritania, Senegal, Mali
Paraguay3Taiwan, Japan, Philippines
Mali3Fiji, Vanuatu, Solomon Islands
Colombia3Indonesia, Malaysia, Australia
Nigeria3New Zealand, United States, Kiribati
Canada3Antarctica, France, Australia
Taiwan2Paraguay, Argentina
Tonga2Algeria, Niger
Mongolia2Chile, Argentina
Tuvalu2Ghana, Ivory Coast
Fiji2Mali; Burkina Faso
Solomon Islands 2Guinea, Mali
Uruguay2China, South Korea
Bolivia2China, Philippines
Sudan2France, Kiribati
Mauritania2France, Vanuatu
Algeria2Tonga, New Zealand
Central African Republic2Kiribati, New Zealand
Saudi Arabia2France, UK
DR Congo2Kiribati, United States
Japan2 Brazil, Paraguay
South Korea2Uruguay, Brazil
Norway2 Antarctica, Russia
Portugal2Mainland: New Zealand
Azores: Australia

Countries matching up with just one other country are Morocco, Spain, Chad, Libya, Cameroon ; Egypt, Eritrea, Ethiopia ; Senegal ; the UAE ; Ghana, Ivory Coast ; Burkina Faso ; Guinea ; India ; Laos, Cambodia, Vietnam, and Thailand ; Singapore ; Brunei, Palau, Micronesia ; Venezuela and Suriname.
Of these, the larger countries which are entirely antipodal to land are the Philippines, Malaysia, Taiwan, Fiji, Vanuatu, Brunei, and Samoa. Chile was as well prior to its expansion into the Atacama with the War of the Pacific.

Extraterrestrial examples

In a number of cases on extraterrestrial bodies in the Solar System, unusual geologic features are located antipodal to major impact basins. It has been hypothesized that this results from focusing of some of the seismic waves produced by an impact at its antipode.