What is Prime Meridian Day?

Prime Meridian Day is the imaginary line that divides Earth into the Eastern and Western Hemispheres on November 1st. It's also a good time to learn more about the prime meridian.

You've obviously taken a map or globe and seen lines of latitude and longitude on a map or globe. These lines were designed to make it possible to find specific locations. To get a coordinate that is north or south of the equator, we use latitude lines. To give coordinates east or west of the prime meridian's prime meridian, lines of longitude are used. Hipparchus, a Greek astronomer, first used these lines of latitude and longitude to find a specific location. Hipparchus lived from 190 to 120 BC. Hipparchus lived from 190 to 120 BC.

Anywhere, the prime meridian (which is 0 degrees longitude) may have been set. However, for many years, governments of various nations disagreed on the prime meridian's location. For example, mapmakers in France branded the prime meridian in Paris, while the Chinese government released maps with 0 degrees longitude going through Beijing. The prime meridian's official location in Greenwich, England, wasn't until 1884 that governments from many countries decided on Greenwich, England, as the prime meridian's official location.

The prime meridian also serves for a few other purposes in addition to making travel more convenient. For example, it determines the Coordinated Universal Time. According to the Coordinated Universal Time, every country and region measures its time zones according to the Coordinated Universal Time. There are a total of 24 time zones around the world. One of the reasons for the prime meridian's presence is that it helps establish the International Date Line. This line is located at 180 degrees and marks the Earth's halfway point. You add a day to every day as you go west past the International Date Line. You subtract a day each day when you go east from the International Date Line.