TECH

Greenwich Prime Meridian Line Is In The Wrong Place According To Modern GPS, Astronomers Explain Why

13/08/2015 12:52 BST | Updated 13/08/2015 12:59 BST

If you have ever taken a selfie at the Royal Observatory in London while standing astride the Prime Merdian line you may be disappointed to know that we actually got the location wrong.

For years, visitors have been puzzled by why GPS systems never show zero longitude when standing on the imaginary line.

prime meridian

Astronomers say the famous line equally dividing the eastern and western hemispheres is supposed to be 102 metres to the east, running close to a nearby bin. Oops.

So, maybe the astronomical error is not such a disaster, at least as far as selfies are concerned.

The revelations were made in a study published in the Journal of Geodesy.

The reason for this discovery is simple: today's technology is better at calculating longitude than astronomers in the 19th century.

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“With the advancements in technology, the change in the prime meridian was inevitable,” said Ken Seidelmann, an astronomer at the University of Virginia and co-author of the study.

In 1884 the International Meridian Conference involving 25 nations, called for the marking of a Prime Meridian line to make global navigation easier.

To identify where this line would fall, they used a telescope and a "clock-star."

However, due to local terrain and gravity, their measurements were not as accurate as those that have been made by the GPS systems we have been using since 1984.

In order to avoid future confusion, Dr Marek Kukula, the Royal Observatory’s public astronomer told The Independent that we may need to have a new line called the “GPS Meridian.”

“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,” he explained.

“I think having a marker in the park would be brilliant, to update the story of the Greenwich meridian line into the 21st century. At the moment the nearest thing there is to a marker is a litter bin.”