Why prime meridian in greenwich

While there we stood directly on the Prime Meridian Line. So Neat just to be there. The tour in the Observatory seeing all the clocks from the beginning when it developed was so wonderful. Your email address will not be published. Skip to content. What is the Greenwich Meridian? Longitude lines like the Greenwich Meridian run north-south and converge at the poles. Really enjoyed this site. I learned so much more about what we saw. Since the location of this original prime meridian is defined by the location of the telescope, it cannot be wrong: it is always where the telescope is.

To understand how there can be two different prime meridians, both being in the correct location for their purposes, it's important to bear in mind that meridians and longitudes are a human invention, so there is essentially no right or wrong way to place them.

At the International Meridian Conference in , with multiple candidates to choose from, that honor was bestowed upon the longitude of the Airy Transit Circle in Greenwich. Apart from serving as a navigational reference point, the local mean time at the Greenwich Meridian now also served as the basis for the global time standard, Greenwich Mean Time GMT , before being replaced by UTC in the s.

The problem with the Greenwich Meridian of was that it was based on measurements from a telescope situated in a particular location, which did not take into account the actual shape of our planet.

The Earth is not a perfect sphere. It is slightly squashed at the poles and its mass is not distributed quite evenly. This means that measurements carried out at a particular location are not necessarily accurate for other locations. In addition, a study suggests that the astronomers who calibrated the telescope even did so on slightly false premises. They used a pool of mercury to identify the exact direction of Earth's gravity and, therefore, the planet's center.

Before this point, roughly ten other prime meridians were also in use, including ones through various other cities including Paris and Cadiz. Because all important scientific measurements are today made using GPS and not the original location of the Greenwich Meridian, the impact of the error is actually minimal.

Arguably, the main issues are confined to the Royal Observatory itself and how it plans to address the issue at the tourist site.

And where should we envisage the true Prime Meridian? Certainly, the new location is the more accurate line and the one that will be used in the future. The fact that the two lines are just m apart is testament to their hard work and ingenuity and so disregarding the old line would be disrespectful. Edition: Available editions United Kingdom.