What Is The Greenwich Meridian?

The Greenwich Meridian also known as the Prime Meridian is an imaginary line roughly coinciding with 0 degree longitude and 51 degrees 28 N latitude; the line passes through Greenwich where the Royal Observatory is located, near London in the UK and hence is referred to by the name of the place.

The Greenwich Meridian first established in 1851 by George Airy, a British astronomer was officially declared as the separating line between the Eastern and Western hemispheres in 1884 at the International Meridian Conference held in Washington D.C. in the United States. The time at any place on Earth is denoted in terms of the Greenwich Meridian while the location is denoted keeping the Meridian and the Equator as the base.

The Greenwich Meridian passes through 8 countries and 3 continents namely the UK, France, Spain, Algeria, Mali, Burkina Faso, Togo, Ghana and Antarctica.  The line opposite to the Greenwich Meridian, 180 degree longitude also known as antimeridian, roughly coincides with the International Date Line and passes for the major part through the Pacific Ocean.