At what longitude does the Prime Meridian lie?

1 Answer
Sep 15, 2017

The Prime Meridian is by definition #0^@# of longitude.

Explanation:

In the case of latitude, the equator, tropics and artic circles are clearly defined by the Earth's axis of rotation and axial tilt.

In the case of longitude a Meridian is a great circle through both poles. The Prime Meridian is the arbitrary circle which is designated the value of #0^@# of longitude.

In the past there have been many different Prime Meridians. Counties typically chose a great circle passing though a major city as the Prime Meridian.

Finally in 1884, the International Meridian Conference in Washington D.C. voted for the Greenwich Meridian to be the Prime Meridian.

Greenwich in South London, is the home of the Greenwich Observatory which the Prime Meridian passes through. If you visit the Greenwich Observatory there is a line painted on the ground indicating where the Prime Meridian passes.