Alternate location for prime meridian

Hi!

What would have been the ramifications of a different location for the prime meridian, say Jerusalem? One of the reason I'm asking is that if the international date line hovers around 180 degrees longitude, it's going to have to go through countries in all likelihood when you get the prime meridian far away from Western Europe.

From what I gather, the zero meridian was not really fixed on Greenwich until the early 1900's, or rather, every country with some naval power had its own reverence point with its own maps showing longitudes in reference to this point. Famously when Jules Verne wrote "20.000 leagues under the sea" in 1870, Captain Nemo always lets professor Arronax choose whether he wants to know the position according to the longitude of Greenwich, Paris or Washington. (Mostly, he continues with "In your honor, I will use the Paris meridian, according to which we are now at ....") For the captain, as for pretty much any trained sailor switching meridians was an easy thing to do. You just added or subtracted a fixed number. It's not that much more complicated then switching from US eastern time to US standard time to Greenwich Mean Time. Certainly a lot easier then switching from miles to kilometers or from Celsius to Fahrenheit.

In short, longitude was never given as an absolute number, rather as a relative number to a reference point. It was only when the British Admiralty maps became the prevalent standard that everybody ended up using the maps and therefore the corresponding median.

So how to get to a different meridian? Stop the UK from becoming such a naval power, or simply from becoming so great explorers and mapmakers.... At least until navigation becomes so fine-tuned as it became between 1800 and today. With a combination of better navigation aids, sextants, clocks and maps, and a less naval UK, we might well be using the meridian of Madrid, Lisbon or even Newfoundland right now.

I like the idea of the Ferro meridian being the Prime Meridian instead of Greenwich.

In the European Age of Discovery, the prime meridian was well to the west of Europe, so that all of Europe would conveniently be on the same side of it.

Another possibility is the Florence meridian, so that the 180 degrees meridian passes between Chukotka and Alaska rather than through Chukotka.

Of course, many other meridians become possible if Britain is not the preeminent world power in the late 19c. A Paris, Amsterdam, Rome, etc. meridian might be used instead of London.

https://en.wikipedia.org/wiki/International_Meridian_Conference

A Prime Meridian is a necessity for globally coherent time zones - and the problem becomes acute when you have continental sized nations with transcontinental railways.


Given the 800 pound gorilla that the British Empire was (in terms of maritime and Imperial matters, anyway), GMT is pretty much guaranteed to be a major, probably THE major, system. Might the French insist on using their own system? Maybe. Might the US use a Washington meridian? That would be interesting.

But seriously, GMT and the Greenwich meridian ARE going to be what most of the world uses. But there might be a small handful of others used enough to worry about.