Establishing The Prime Meridian: Time To Talk About Time

People looking at the Shepherd Gate Clock on the wall outside the gate of the Royal Observatory at Greenwich in south London. (The Print Collector/Getty Images)

A meridian is an imaginary line that runs from the South Pole to the North Pole. The Prime Meridian is so named because it was arbitrarily chosen as the line of 0 degrees longitude, or the starting point for measuring time and distance around the planet, but who put it there and why?

Before The Prime Meridian

In the past, each major country had their own prime meridian and their maps were made using that as the starting point, but as society became more global, non-standardized navigation maps became problematic. Time zones could change even from one city to the next, so folks missed their trains and merchants literally missed the boat. Recognizing the need for the world to come to an agreement about time zones, U.S. President Chester A. Arthur called for representatives of the world's countries to come together for an International Meridian Conference, held in Washington, D.C. in 1884.