Meridians

{{pseudoscience}}
In general, a '''meridian''' refers either to a pathway, or to an imaginary line, arc, or circle that connects two fixed points on a body ([[human]] or celestial).

==Acupuncture==
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[[File:Drawing of the human body showing acupuncture meridians..JPG|thumb|165px|left|Acupuncture meridians]]
In acupuncture, the meridians are paths through which [[chi]] (life force) flows around the body. Traditionally, there are twelve meridians, each associated with an organ of the body: the meridians of the bladder, gallbladder, heart, large intestine, small intestine, kidneys, liver, lungs, spleen, stomach, pericardium, and "triple heater" (三焦 or ''san jiao''), also known as "triple burner" in English. "Triple heater" is by necessity a translation from the Chinese; as there is no such organ, there is no correct medical term for it.<ref group=note>Acupuncturists are aware of this, and say that this particular meridian does not associate with one organ, but instead three functions in the torso.</ref> Some texts list more than twelve meridians, but the twelve listed above are the traditional meridians in Chinese medicine.
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==Geography==
[[File:Magnetic meridians lat -64.44 long 137.44 1000x1000.png|thumb|165px|right|Meridians around the southern magnetic pole]]
In geography, a meridian is a line or arc of longitude, which runs due north to due south. There are two types of meridians.

===Terrestrial meridians===
A '''terrestrial meridian''' is an arc that runs from the North Pole to the South Pole. The meridians as shown on today's maps and globes were first established in 1851 by Sir George Airy, who used a point at the Royal Observatory in Greenwich, [[England]] as the reference point of 0<sup>o</sup> longitude, now known as the Prime Meridian or the Greenwich Meridian. There are 24 standard meridians that occur every 15 degrees. Each of these meridians roughly correspond to the border of one of the standard time zones.

The Greenwich Meridian, which passes through Greenwich, London, England, was chosen as the reference in 1884, at the International Meridian Conference in Washington DC.<ref>[https://adsabs.harvard.edu/full/1885MNRAS..45..261. The International Meridian Conference], ''Monthly Notices of the Royal Astronomical Society'', Vol. 45, p.261 (1885)</ref> Prior to this, there were various reference lines used. Chief were the Paris Meridian (now 2°20'14.025" E), through Paris, and the Ferro Meridian (17°39'46.02" W) through El Huerro (Ferro) in the Canary Islands, which was believed to be the westernmost point of the world, or later of the Old World (although the Azores are further west).<ref>{{wpa|Paris meridian}}</ref><ref>{{wpa|Ferro meridian}}</ref> The Paris Meridian is approximately 20 degrees east of the Ferro Meridian, give or take.

The Paris Meridian is also mentioned in Dan Brown's ''[[The Da Vinci Code]]'', where it is called the Rose Line and features on a treasure map. With a little jiggery-pokery, it can be viewed as the central axis of France, forming part of a mystic hexagram, at least according to [[Graham Hancock]]'s associate William Glyn-Jones.<ref>[https://grahamhancock.com/glynjonesw4/ The Meridian and the Hexagram: The Revelation of France's Foundation Plan], William Glyn-Jones, [[Graham Hancock|GrahamHancock.com]], 8th October 2008</ref> Glyn-Jones claims it forms a central axis of France, but it is impossible to exactly define the center of a country, owing to the vagaries of coastlines, fractal geometry, etc. The Paris Meridian is 2°20'14" E, while Bourges which Glyn-Jones takes to be the center is at 47°5'3.8400" N 2°23'47" E.<ref>[https://www.latlong.net/place/bourges-centre-val-de-loire-france-30163.html Bourges], LatLong.net</ref> Several towns, all in different places, likewise claim to be the geographical center, such as Bruère-Allichamps (46°46'09" N 2°26'39" E).<ref>[https://www.nytimes.com/1984/09/06/world/3-french-towns-go-to-extremes-to-be-the-center.html Three French Towns Go To Extremes To Be The Center], New York Times, September 6, 1894</ref> So any claim of ancient or mystical significance must take into account the vagaries of measurement.

All meridians intersect lines of latitude<ref group=note>Because our planet is an ''oblate'' spheroid, not a perfect sphere, ambiguity arises in the measurement of latitude. The normally-cited latitude is ''geodetic'', meaning referenced to the local vertical. ''Geocentric'' latitude is referenced to the exact center of the planet. The two latitudes nowhere differ by as much as a degree.</ref> &mdash; called '''parallels''' &mdash; at right angles. When used together, meridians and parallels are the basis of the coordinate system used by geographers.

===Guide meridians===
'''Guide meridians''', in combination with parallels called '''baselines''', are used by [[American]] geographers to establish private and public property boundary lines within 30 of the 50 states. This system was established in 1785 by the pre-constitutional U.S. government to make plats of lands located west of the Appalachian Mountains.  

The government adopted the standardized platting system to replace the British system of '''metes and bounds'''.  This older system, used in the original 13 colonies, is still used in those 13 states and in the states that were carved out of them (i.e., [[Vermont]], [[Tennessee]], [[Kentucky]], [[Maine]] and [[West Virginia]]). Metes and bounds relies on local landmarks to establish townships and individual lots. ([[Texas]] and [[Hawaii]], which were originally sovereign countries, continue to use the systems that were in place when the U.S. annexed them.)

A guide meridian and its corresponding baseline intersect at an established landmark within a state. From there, the land is divided into '''quadrangles''' (usually 24 miles by 24 miles), then into '''townships''' (usually six miles by six miles), then into square miles (640 acres), then into 40 acre plots.  Within cities, towns and villages, land is further divided into individual acres, and finally into individual lots.

Guide meridians are either named (like the Tallahassee Meridian in [[Florida]]) or numbered (like the Fourth Principal Meridian in [[Wisconsin]], northeastern [[Minnesota]] and northwestern [[Illinois]]).

==Astronomy==
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In astronomy, a meridian is an arc on the '''celestial sphere'''. The celestial sphere is an imaginary sphere which surrounds the [[Earth]], and whose center point coincides with the center point of the Earth. All imaginary points, arcs, and circles associated with Earth's geography &mdash; i.e., the poles, lines of latitude and longitude such as the equator, the Prime Meridian, and the Tropics of Cancer and Capricorn &mdash; are expanded outward to corresponding points on the celestial sphere. Astronomers use the celestial sphere to create star maps.

==See also==
*[[Chakra]]
*[[Ley line]]

==Notes==
{{reflist|group=note}}

==References==
{{reflist|2|80%}}

[[Category:Alternative medicine]]
[[Category:Astronomy]]
[[Category:Chinese medicine]]
[[Category:Energy therapy]]
[[Category:Geography]]
[[Category:Orientalist woo]]

Categories: Alternative medicine, Astronomy, Chinese medicine, Energy therapy, Geography, Orientalist woo