Meridian Longitude [best] <4K>

However, the true genius of the meridian system lies in its relationship with time. The rotation of the Earth is the fundamental basis for measuring longitude. As the Earth rotates on its axis once every 24 hours, it moves through 360 degrees. This means that the Earth rotates at a rate of 15 degrees per hour. Therefore, a difference of one hour in local time corresponds exactly to a difference of 15 degrees in longitude. This connection allowed sailors to determine their position at sea. By comparing the local time (determined by the position of the sun at noon) with the time at a reference point (such as Greenwich), they could calculate exactly how many degrees east or west they had traveled. Thus, accurate timekeeping was not just a matter of convenience; it was the key to survival on the open ocean, leading to the invention of the marine chronometer by John Harrison in the 18th century.

The conference established that the day begins at mean midnight on the Prime Meridian. meridian longitude

Let’s clear up a few frequent myths: