World Wonders : The Greenwich Meridien.

The Prime Meridian is the meridian (line of longitude) at which longitude is defined to be 0°.

The Prime Meridian and its opposite the 180th meridian (at 180° longitude), which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.

Unlike the parallels of latitude, which are defined by the rotational axis of the Earth (thepoles being 90° and the equator 0°), the Prime Meridian is arbitrary. By international convention, the modern Prime Meridian passes through the Royal Observatory, Greenwich (at 51°28′38″N 0°00′00″E), in southeast London, United Kingdom, known as the International Meridian or Greenwich Meridian.

( adapted from http://en.wikipedia.org/wiki/Prime_Meridian )

Laser marking the Prime Meridian from the observatory.

- HISTORY OF THE ROYAL OBSERVATORY. -

The modern Greenwich Meridian, based at the Royal Observatory, Greenwich, was established by Sir George Airy in 1851.

By 1884, over two-thirds of all ships and tonnage used it as the reference meridian on their maps. In October of that year, at the behest of U.S. President Chester A. Arthur , 41 delegates from 25 nations met in Washington D.C. , USA, for the International Meridian Conference . This conference selected the Greenwich Meridian as the official Prime Meridian due to its popularity. However, France abstained from the vote and French maps continued to use the Paris Meridian for decades.

The Greenwich Meridian is now marked at night by a Laser beam emitted northwards from the observatory.( as above picture)

I went there last time... it was nice & quite interesting...

Here are a few pictures i search from the Internet...

The Prime Meridian in Greenwich.



The Greenwich Clock.

Okay! That's All For Now!!