An accident or lack of logistics? Sometimes the math fails, even for those where the technology did not yet allow geolocation. Thousands of photos were taken there, now it turns out they were taken 102 meters further from the real point.
The Zero Meridian, as the point that divides East from West and is a reference for times and locations, is not located where, for just over two centuries, scientists believed it was located.
Today, in the middle of 2023, scientists assure that this change in the Greenwich Meridian point is a consequence of gravity, the shape of the Earth and satellites.
What is the Greenwich Meridian?
In the 17th century, England was experiencing a period of political and economic splendor. Hers dominated the Atlantic and led the commercial and military interests of the rest of the powers. King Charles II founded the Royal Observatory in 1675, urging those in charge to solve one of the main problems of navigation: determining longitude, that is, an imaginary line (meridian) that marked the east-west distance equally to all its navigators (today known as the Greenwich Meridian).
Latitude (north-south) was always easy to establish thanks to the position of the sun, a star or the Earth’s equator, but the same was not true of longitude. Each culture had chosen to establish an easily located city or geographical point to use as a reference in their travels by sea.
It was not until John Harrison and the H4 watch that we approached the point that had been sought for years. Especially when in 1772 Captain Cook took a copy of the H4 on his second trip to the Pacific. Thanks to Harrison’s clock, Cook was able to prepare nautical charts of Australia and New Zealand. With this he definitively demonstrated that longitude could be measured with a clock and without the need for complex knowledge of astronomy.
However, that is where the problem began, not the solution. Because after a few years, it showed that the Greenwich Meridian was not where it should be and his problem had to do with gravity.
Where is the Greenwich Meridian really located?
The exact location of the Greenwich Meridian is marked on a path near the forest in the park that surrounds the observatory and is located more than 100 meters away from the one established in 1884.
This position, marked by common agreement between more than 25 countries more than two centuries ago, was universally recognized to have more accurate global navigation as well as standardize maps and time zones, such as the Greenwich Mean Time zone.
The cause of this inaccuracy is due to the fact that at the time of measurement, the telescope used is slightly inclined due to the type of terrain, shape of the Earth and the effect of gravity, which does not happen with satellites and GPS systems. which have been used since 1984.