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The prime meridian of the Moon lies directly in the middle of the face of the Moon visible from Earth and passes near the crater Bruce. The prime meridian of Mars was established in 1971 [35] and passes through the center of the crater Airy-0, although it is fixed by the longitude of the Viking 1 lander, which is defined to be 47.95137°W. [36]
Figure 1. This BLM map depicts the principal meridians and baselines used for surveying states (colored) in the PLSS.. The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.
The intersection of this plane with Earth's surface defines two geographical meridians (either one east and one west of the prime meridian, or else the prime meridian itself and its anti-meridian), and the intersection of the plane with the celestial sphere is the celestial meridian for that location and time.
Eratosthenes in the 3rd century BC first proposed a system of latitude and longitude for a map of the world. His prime meridian (line of longitude) passed through Alexandria and Rhodes, while his parallels (lines of latitude) were not regularly spaced, but passed through known locations, often at the expense of being straight lines. [1]
The International Meridian Conference was a conference held in October 1884 in Washington, D.C., in the United States, to determine a prime meridian for international use. [1] The conference was held at the request of U.S. President Chester A. Arthur . [ 1 ]
Ultimately the outcome was as follows: there would be only one prime meridian, the prime meridian was to cross and pass at Greenwich (which was the 0°), there would be two longitude direction up to 180° (east being plus and west being minus), there will be a universal day, and the day begins at the mean midnight of the initial meridian. [4]
From 1884 to 1974, the Greenwich meridian was the international standard prime meridian, used worldwide for timekeeping and navigation. The modern standard, the IERS Reference Meridian, is based on the Greenwich meridian, but differs slightly from it. [1] This prime meridian (at the time, one of many) was first established by Sir George Airy ...
Together, a meridian and its antimeridian form a great circle that passes through the geographic poles. 2. The 180th meridian in particular, i.e. the meridian of longitude that is exactly 180 degrees both east and west of the Prime Meridian, with which it forms a great circle dividing the Earth into the Eastern and Western Hemispheres.