14 DAY TRIAL // In 1884, an international delegation convened in Washington DC decided that the north-south line marking zero degrees longitude, a.k.a. the Greenwich Prime Meridian, should run through the Airy Transit Circle at the Royal Observatory in Greenwich, England.
Fast forward to present day, and this is no longer the case. Au contraire, the Greenwich Prime Meridian now runs about 334 feet (102 meters) east of the Royal Observatory. Check out the image below to see its exact position. Kind of bizarre, right?
Well, the good news is there's no reason to panic. The Greenwich Prime Meridian moved to the east not because Earth was deformed in a freak collision with an asteroid without our noticing. It wasn't meant to pass through the Royal Observatory to begin with.
When its path was established back in 1884, scientists relied on whatever telescope observations were available at the time, NGA explains. As new technologies emerged, however, researchers found that Earth's zero longitude wasn't drawn quite in its proper place.
“With the advancements in technology, the change in the prime meridian was inevitable,” explains Ken Seidelmann, an astronomer at the University of Virginia. “Perhaps a new marker should be installed in the Greenwich Park for the new prime meridian,” he adds.
True, a slight deflection in the natural direction of gravity at Greenwich also had a say in the matter, but it was chiefly new technologies to measure Earth's rotation that ultimately brought about this shift.
