We were walking round the back of the O2 in Greenwich today and saw this artwork marking the Greenwich Meridian. I wondered why there seemed to be several different lines marked on the ground, one of which had some white metal or plastic extensions (containing a light, I assumed) stretching over the edge of the path and over the water. Behind the fence in what is now the back of a hotel I could see some stores let into the ground with names of different countries, and assumed (correctly it seems) that these are poorly-maintained markers from the millennium just a few years ago.
The Greenwich Meridian web site is very useful here. It turns out that there are many different possible meridian lines. The one that is usually marked is the Airy Transit Circle, the main one that runs through the Greenwich Observatory, though it’s not the line shown as 0 degrees longitude on a GPS device, and it actually no longer has any connection at all with the UTC time standard.
As well as the Airy Meridian, three other Lines were marked [round the back of the Millennium Dome] – the Bradley Meridian, roughly 6 m to the west and still used by the British Ordnance survey, along with the rather spurious ‘Halley’ and ‘Flamsteed’ Meridians.
This article explains in some detail why when you visit the ‘Prime Meridian’ at the Greenwich Observatory, your GPS locator does not read 0 degrees of longitude – you’d need to move some 100 meters East:
If you’re feeling overly joyous and need a downer, read this account of the doomed Millennium Tree Project.
The prime meridian hasn’t fared particularly well in my neighbourhood either. I hadn’t even realised it had been marked out in an artwork in Hither Green, but it’s all but vanished now.
There was a stone marking the place where it crosses Lee High Road (close to where the photo above was taken) but I went looking for it yesterday and couldn’t find that either – possibly because they’re digging the road up. I hope it gets put back.
All of which leads me to think that meridian lines are really quite silly, arbitrary things. A bit like New Year’s Eve or Millennium night itself…