The Telegraph: The Greenwich Meridian Line was established as 0° longitude in 1884 and is marked at the Royal Observatory. However, anyone checking a GPS device at that location will find that the 0° meridian is 102 meters to the east. According to Ken Seidelmann of the University of Virginia and his colleagues, the discrepancy occurred because gravitational distortions weren't accounted for by the astronomers determining the line in 1884. The satellites used for GPS do.
