EVERYDAY SCIENCE

Detailed explanation-1: -The prime meridian is arbitrary, meaning it could be chosen to be anywhere. Any line of longitude (a meridian) can serve as the 0° longitude line. However, there is an international agreement that the meridian that runs through Greenwich, England, is considered the official prime meridian.

Detailed explanation-2: -The line in Greenwich represents the historic Prime Meridian of the World-Longitude 0º. Every place on Earth was measured in terms of its distance east or west from this line.

Detailed explanation-3: -Summary: Greenwich Meridian (Prime Meridian) The 0-degree line of longitude that passes through the Royal Observatory in Greenwich, England is the Greenwich Meridian. It’s also called the Prime Meridian. This line is the starting point for longitudinal lines that run north-south and converge at the poles.

Detailed explanation-4: -The indicated longitude is not exactly zero because the geodetic zero meridian on a geocentric reference ellipsoid (which is what GPS positioning yields, using the IERS Reference Meridian) is 102 metres east of this strip.