The Prime Meridian is 120 years old today. That's the imaginary north-south line through Greenwich which divides the world into western and eastern hemispheres, and from which longitude and universal time are measured. It passes less than a kilometre from my house. And we'd be lost without it.
Noon was once simply the time when the sun was directly overhead. The advent of rail travel in the 19th century forced many countries to standardise time based on a national meridian. The UK adopted Greenwich Mean Time in 1880, while the French preferred their own meridien through Paris instead. A global standard was clearly required, so in 1884 US President Chester Arthur invited delegates from around the world to Washington to attend the first (and last) International Meridian Conference.
There were an infinite number of possible meridians, each stretching from the North to the South Pole, and any one of these could have been chosen. However, the Greenwich Meridian was pre-eminent because it had already been adopted by the UK and USA and was therefore being used by 72% of the world's shipping. The French backed down, but only in return for the rest of the world agreeing to think about adopting their system of metric measures. The crucial conference vote was taken on 13 October, with France and Brazil abstaining and only San Domingo in opposition. And so time began at Greenwich (latitude 51°28'38"N, longitude 0°).
To celebrate today's anniversary I'm taking you on a week-long journey up the zero degree line of longitude from Greenwich to the M25, stopping off at all the places where the meridian has been marked in some way. There are plaques and monuments, sundials and statues, and an awful lot of random everyday objects that just happen to lie on this most special of lines. Plus it's a great excuse for a walk through East London. Do join me.
Marking the meridian
There were an infinite number of possible meridians, each stretching from the North to the South Pole, and any one of these could have been chosen. However, the Greenwich Meridian was pre-eminent because it had already been adopted by the UK and USA and was therefore being used by 72% of the world's shipping. The French backed down, but only in return for the rest of the world agreeing to think about adopting their system of metric measures. The crucial conference vote was taken on 13 October, with France and Brazil abstaining and only San Domingo in opposition. And so time began at Greenwich (latitude 51°28'38"N, longitude 0°).
