Nullmeridian

Nullmeridian (schwarz)
Nullmeridian (black)

the Nullmeridian is perpendicularly to the equator more standing and of north - a semi-circle running to South Pole, from which the geographical length is determined eastward and the west. (Symbol: O for „the east “, English: E for „East “, and/or.W for „the west “.)

Since 1884 the Meridian running by the observatory in Greenwich is internationally recognized as Nullmeridian by the international Meridiankonferenz.

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Introduction

the length of the Nullmeridians is the half earth extent measured over the poles, thus approx. 20 003.9 km. With its in relation to lying Meridian, which cuts for example the Wrangelinsel with 180° (without additive E or W), that complements itselfNullmeridian to a great circle on earth. The legal date border runs today still partly (near Poland and into near-equator ones) exactly on 180° Greenwich.

The WGS84 Meridian zero is not bound no more to the earth's surface (keyword: Kontinentalverschiebung), butapproximately 300 m east the historical Greenwicher “tourist line” runs.

Before the definition on an international Nullmeridian in the year 1884 almost each European country possessed its own Nullmeridianen, usually the geographical length of the respective capital and/or. their observatory.

With the increasinginternational passenger traffic became however a standardization of the existing systems necessary. Besides it became ever more importantly to have an exact international time available (world time).

the international Meridian conference, Washington, 1884

Der Nullmeridian in Greenwich (auf dem Boden und am Gebäude markiert)
the Nullmeridian in Greenwich (on thatSoil and at the building marks)

on the international Meridian conference in October 1884 in Washington, D.C. with representatives from 25 nations the Meridian specified by Sir George Biddell Airy already 1851 as basis of the international coordinate system one introduced.

As possible internationalNullmeridian were discussed with that Washington conference primarily five possibilities:

In the conference process (see Web left) it turned out very soon that that would not find Paris Nullmeridian majority. The old ferrous Meridian becamebecause of its some decades before took place definition on exactly 20° W from Paris very fast as French “submarine” unmasked. The Azores and the Bering Strait separated above all, because they did not have no observatory and also by telegraph at that timewere tied up to the remaining world.

Thus finally the Greenwich Meridian became generally accepted as international Nullmeridian with large majority - during abstention of France - also.

The Greenwich Nullmeridian crosses eight states on land area:

as well as the Antarctic new swabia country and still more south the queen Maud country.

The middle Sonnenzeit at the Nullmeridian became relevant for the world time (GMT, “Greenwich Mean Time”), which only 1972 was replaced by the coordinated world time (UTC).

historical

  • first organization of the world into lengths and widths by Hipparch of Nikaia (190 - 120 v. Chr.): Rhodos (its astronomical observation place)
  • Claudius Ptolemaeus shifted it around 150 to the westernmost border of the well-known world: Isladel Meridiano (El Hierro or ferrous, the westernmost of the Kanari islands („Hesperiden “), and created thereby to in 20. Century inside used ferrous Meridian.
  • Arab astronomers put the Nullmeridian first by the west point of Africa, 1075 then to 10°to the west of Bagdad.
  • There were thereafter attempts of a transfer again and again, z. B. as 1432 the Azores and 1492 America were discovered.
  • In April 1634 by a congress of scholar of all seafaring nations the island ferrous was confirmed.
  • Starting from 1738 becomesin England the Meridian applied by Greenwich.
  • To Germany he is transferred 1885, to France around 1900. Austria Hungary uses it until 1918 parallel with the old ferrous Meridian.

see also

Web on the left of

 

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