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Why Greenwich Is the Centre of Time and Space?

Prime Meridian

Prime Meridian



National Maritime Museum, Greenwich

National Maritime Museum, Greenwich

Greenwich Prime Meridian

…The Centre of Time and Space…

…is awesome. I know; I’ve been there. And I didn’t need to rocket 220 miles into orbit to board the International Space Station. Neither did I have to tunnel down through 100 meters of rock under the France, Swiss border to the CERN project.

All I had to do was go to England.

The Centre of Space and Time is in a small London borough on the south side of the River Thames. It seems an inconsequential borough on first sight, but the district has a name that is recognisable throughout the world. The locality’s tourist offices don’t seem to realise this, and keep trotting out yawn-inducing facts to prove that they should be famous when they already are.

Does anybody care that this part of England used to be under Danish rule?

Does your heart rate increase when you are told that Queen Elizabeth 1st was born here in 1533?

Do you get all bubbly with excitement when you are told that Inigo Jones built a house there for Anne of Denmark?

Knowing that the Cutty Sark, the celebrated tea clipper is berthed there, or what’s left of her after the tragic fire, is a different story.

The region is, of course, Greenwich, the home of the Greenwich Meridian. The Greenwich Meridian is an imaginary line that runs from the North Pole to the South Pole and dissects the east of the globe from the west. The line runs through the National Maritime Museum at Greenwich and according to the museum…

…‘the line was recognised as Longitude Zero by the International Meridian Conference in 1884. Ever since, every point on Earth has been defined by its longitude from Greenwich and its latitude – distance North and South of the Equator’….

Greenwich by the way is not pronounced Green Witch, it is pronounced Grin Itch – you’ll just have to bear it.

* * *

There is a very sensible reason for the Meridian Line (Longitude 0˚) running from the North Pole to the South Pole. The puzzle is why it should run through Greenwich!

It doesn’t take a wise man to figure out that the world must be a sphere. If you live anywhere near an ocean you can deduce it for yourself. Stand on a high cliff or promontory overlooking the sea. Make sure there is nothing visible in front or beside you but the chilling vastness of water, and the curve of the Earth is obvious – Do make sure someone is holding you down, OK?

Mathematicians and astronomers such as Eratosthenes and Ptolemy calculated the circumference of the Earth and the position of the equator, centuries before Magellan proved that the Earth was a sphere by his circumnavigation. To be strictly accurate, the Earth is more of an Oblate Spheroid than a circle.

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Oblate Spheroid is a fancy name for telling you that the globe needs to pull its stomach in. Consider the Earth’s slightly molten interior (think of volcanoes) and remember that it rotates between the North and South Poles every 24 hours. The spin that this imparts makes the equator wider than any other part of the globe. (Wouldn’t it be wonderful if all you had to do to lose weight was stop spinning?)

It made sense for the early seafarers to use the equator as a prime reference point. The equator was labelled Latitude 0˚ (from the Latin ‘latitudo’ meaning broad or wide). From pole to pole was split up into 180 degrees - 90˚ to the north of the equator and 90˚ to the south of the equator.

Each degree, or line of Latitude, is parallel with the equator, and is measured in slices of a circle. Using lines of latitude and taking bearings from the stars and a reference point in their own locality or country, early mariners could be reasonably accurate in their North/South positions as they sailed the featureless oceans.

‘Reasonably accurate’ was fine during this period of time. The loss of life in the oceans would be an accepted way of life and death, not only would rafts, canoes or ships sink but they would literally become lost due to faulty navigation. How many adventurers, fishermen, explorers or whalers ‘accidentally’ discovered the Americas or Asia? It isn’t as if they could wave down a friendly school of Dolphins and ask directions, or ask a Right whale for guidelines.

Could this be when men got the reputation for never asking directions?

* * *

Although the equator, (Latitude 0 degrees˚ 0 minutes’ 0 seconds”) is an imaginary line, the Greenwich Meridian, (Longitude 0 degrees˚ 0 minutes’ 0 seconds”) is visible – inside the NationalMaritimeMuseum grounds at least. It is marked with a brass plate embedded into the ground.

I’ve straddled it, (see photograph,) with one foot in the east of the world and the other foot in the west. I’ve flown over the Equator and the tropics of Cancer and Capricorn, and straddled the imaginary line of the Arctic Circle, (I’ve decided to pass on the Antarctic Circle), but standing astride the Greenwich Meridian had me shaking my head at the folly of mankind.

Up until 1884 each country had its own Longitude meridian. Charts were printed using different Meridians, making navigation pure guesswork. A Captain would have to remember which countries meridian he was using, and stick to it.

The ‘Reasonably Accurate’ stage of navigation needed to change – or be changed. Over the centuries life became more complicated; countries became more advanced in their methods of killing off their neighbours. Soon after the ships-of-the-line had finished pounding other fleets with bigger and better cannonballs, and shortly after the introduction of James Watt’s steam powered ships and the industrial revolution, sanity began to prevail.

With the oceans becoming so crowded, it was imperative that a single means of calculating the East/West position be implemented. An imaginary line, much like the equator is an imaginary line, needed to be agreed upon.

In 1884 U.S. President Chester A. Arthur called for the International Meridian Conference to be held in WashingtonD.C. to select a single Prime Meridian to be suitable to all nations. 25 countries from Austria-Hungary to Venezuela attended the conference. Up until then, America had postulated three different meridians, running through the White House, the Capitol or the Naval Observatory. France had assigned the EiffelTower as their central location. The 25 countries included Belgium, Brazil, Italy, and Poland.

Each nation put forward their own choice of meridian, but mainly because the Port of London already had most of the world’s tonnage passing through it, and Britain’s naval dominance at the time, Greenwich, a major part of the port, was chosen. The vote for Greenwich was passed 22 – 1, with the Dominican Republic voting against, and France and Brazil abstaining. Apart from London being the centre of the British Empire, it helped that the USA – the force of the future - already used the Greenwich meridian.

Longitude split the earth into segments much like an orange - 360˚ all the way round the globe; 180˚ to the East and 180˚ to the West.

The line 180˚ to the East/West of the Greenwich Meridian (the continuation of the imaginary Longitude Zero), passed through a nearly empty Pacific Ocean. It was (and is) known as the International Date Line, and was another excellent reason for Greenwich being chosen - but that story needs to be told another time. Copyright johnmacnab 2011


John MacNab (author) from the banks of the St. Lawrence on January 29, 2011:

Thanks for the compliment Docmo. I've read a number of articles re Harrison but haven't got around to the book yet - The 'Time' part of Longitude Zero is going to be the next hub, hopefully.

Mohan Kumar from UK on January 29, 2011:

Nice hub, well told. Engaging to read with great info- your enthusiasm is infectious.

Have you read the book Longitude by Dava Sobel about John Harrison's time pieces?

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