This map shows the antipode of each point on Earth's surface—the points where the blue and yellow overlap are land antipodes; most land has its antipodes in the ocean. This map uses the Lambert azimuthal equal-area projection. The yellow areas are the reflections through Earth's center of land masses of the opposite Western Hemisphere.
The same map, from the perspective of the Western Hemisphere. Here the blue areas are the reflections of the Eastern Hemisphere.

In geography, the antipode (/ˈæntɪˌpd/ or /ænˈtɪpəd/) of any spot on Earth is the point on Earth's surface diametrically opposite to it. A pair of points antipodal (/ænˈtɪpədəl/) 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.[note 1]

In the Northern Hemisphere, "the Antipodes" may refer to Australia and New Zealand, and Antipodeans to their inhabitants.[2] 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.[3] Another source estimates that about 3% of Earth's surface is antipodal land.[4] 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.[5] 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 (or vice versa); in other words, the latitudes are numerically equal, but one is north and the other south.[5] 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 (ignoring daylight saving time and irregularly shaped time zones) 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 (latitude and longitude) of a point on the Earth's surface are (φ, θ), then the coordinates of the antipodal point are (−φ, θ ± 180°). 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

x° N/S y° E/W    x° S/N (180 − y)° W/E,

that is, for the latitude (the North/South coordinate) the magnitude of the angle remains the same but N is changed to S and vice versa, and for the longitude (the East/West coordinate) the angle is replaced by its supplementary angle while E is exchanged for W. For example, the antipode of the point in China at 37° N 119° E (a few hundred kilometres from Beijing) is the point in Argentina at 37° S 61° W (a few hundred kilometres from Buenos Aires).

Etymology

The word antipodes comes from the Greek: ἀντίποδες (antípodes),[6] plural of ἀντίπους (antipous), "with feet opposite (ours)",[7] from ἀντί (antí, “opposite”) + πούς (poús, “foot”). 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":

For if there were any solid body in equipoise at the centre of the universe, there would be nothing to draw it to this extreme rather than to that, for they are all perfectly similar; and if a person were to go round the world in a circle, he would often, when standing at the antipodes of his former position, speak of the same point as above and below; for, as I was saying just now, to speak of the whole which is in the form of a globe as having one part above and another below is not like a sensible man.

— Plato[8]

The term is taken up by Aristotle (De caelo 308a.20), 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:

Yonde in Ethiopia ben the Antipodes, men that haue theyr fete ayenst our fete.

(In Modern English: Yonder in Ethiopia are the Antipodes, men that have their feet against our feet.)

The modern English singular antipode arose in the 16th or 17th century as a back-formation from antipodes. Most dictionaries suggest a pronunciation of /ˈæntɪˌpd/ for this form.[9][10][11]

Historical significance

Pomponius Mela, 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.[note 2]

The Terrestrial Sphere of Crates of Mallus (c. 150 BCE), 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."[13]

In the Early Middle Ages, Isidore of Seville's widely read encyclopedia presented the term "antipodes" as referring to antichthones (people who lived on the opposite side of the Earth), as well as to a geographical place; these people came to play a role in medieval discussions about the shape of the Earth.[14] 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.[15][16][17][18]

The antipodes being an attribute of a spherical Earth, some ancient authors used their perceived absurdity as an argument for a flat Earth.[19] 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.[20]

The author of the Norwegian book Konungs Skuggsjá, from around 1250, discusses the existence of antipodes. He notes that (if they exist) 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 (who, on his way home in 1292, sailed south of the Malay Peninsula). 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 40,075 kilometres (24,901 mi). 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 40,008 kilometres (24,860 mi). Any other closed great circle route starting on the equator and traveling at an angle between 0° (an equatorial route) and 90° (a polar route) would be between 40,075 and 40,008 kilometres (24,901 and 24,860 mi). 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 17,395 km (10,809 mi), or roughly 87% of an average antipodal distance. The current world record holder for the longest commercial flight, Singapore Airlines, utilizes Airbus A350 XWB (with a range of 17,965 km (11,163 mi), or almost 90% of an average antipodal distance) 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 AucklandLos AngelesLondon marathon, at 19,240 km (11,960 mi) over Los Angeles (18,360 km (11,410 mi) directly) - 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.[21][22]

A hypothetically perfect antipodal flight would be Tangier Ibn Battouta Airport, Morocco (IATA: TNG), to Whangarei Aerodrome, New Zealand (IATA: WRE), whose designated locators are 10,800 nautical miles (20,001 km) apart,[23] the maximum possible distance, but their actual runways cross in projection. However, with only a length of 3,599 ft (1,097 m), Whangarei's runway is too short to accommodate any current (as of 2015) 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: