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The Greenwich Meridian Line isn't on the Meridian

The Greenwich Meridian Line isn't on the Meridian

The Greenwich Meridian Line isn't on the Meridian

We've been lied to all this time. Literally.

Scientists have been studying the position of the famous Greenwich Meridian Line - the primer meridian that marks zero degrees longitude which demarcates the eastern and western hemispheres of the world - and have discovered why GPS technology has not been aligning with the physical mark.

The actual Prime Meridian - which runs from the North Pole to the South Pole - lies 334 feet (100 metres) to the east of the line, cutting across a footpath and positioned close to a bin.

The reason for the error is that astronomers who originally calculated the position failed to take into account local gravitational distortions; modern GPS systems can make adjustments, thus revealing the true place of the meridian. A new study published in the Journal of Geodesy by Ken Sidelmann of the University of Virginia explains it in detail, with Sidelmann saying, “With the advances in technology, the change in the Prime Meridian was inevitable”.

Speaking to The Independent, The Royal Observatory's public astronomer Dr Marek Kukula said, “We’re forever telling this story, making the point that as we refine our measurements and get better technology of course these things change, because we want to have the best possible data. I think having a marker in the park would be brilliant to update the story of the Greenwich Meridian into the 21st Century. At the moment, the nearest thing there is to a marker is a litter bin."

The 'current' Prime Meridian is actually the third to have been made at the Observatory since it was chosen to be the zero marker in 1884: the Halley and Bradley Meridians predate it, but it turns out that they were all wrong.

The very first measurement was made using a large Transit Circle telescope built by Sir George Biddell Airy, which used 'clock stars' - celestial bodies that never rise or set. However, with gravity not as well understood in pre-Einstein days, they didn't get it quite right.

Good effort, but not quite good enough lads.

Greenwich Observatory

(Image: Rex)


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