Prime Meridian - Earth

Earth

As of 2012 the most used prime meridian for the Earth is the IERS Reference Meridian (IRM). It passes about 5.3 arcseconds east of Airy's transit circle or about 102 metres (335 ft) at the latitude of the Royal Observatory, Greenwich, London. A current convention on the Earth uses the opposite of the IRM as the basis for the International Date Line.