Greenwich Royal Observatory: How the Prime Meridian line is actually 100 metres away from where it was believed to be

Every year, hundreds of thousands of tourists from all over the world descend on the Royal Observatory in Greenwich to pose for a photograph astride the Prime Meridian, the famous line which divides the eastern and western hemispheres of the earth. There is just one problem: according to modern GPS systems, the line actually lies more than 100 metres to the east, cutting across a nondescript footpath in Greenwich Park near a litter bin. Now scientists have explained why – and it all comes down to advances in technology.According to a newly published paper on the discrepancy, which has existed for many years, tourists who visit the observatory at Greenwich often discover that they “must walk east approximately 102 metres before their satellite navigation receivers indicate zero longitude”.


http://www.independent.co.uk/news/science/greenwich-royal-observatory-how-the-prime-meridian-line-is-actually-100-metres-away-from-where-it-was-believed-to-be-10452386.html