gmt

[straughton]

What is the origin of Grenwich Mean Time? Why is the worlds time worked from here? If it is at all and i've got the whole thing wrong?! And why Grenwich? Many Thanks in advance!

[warpig1]

Have a look at this.

http://en.wikipedia.org/wiki/Greenwich_mean_ti me

[sddsddean]

More info here
http://www.bbc.co.uk/london/content/articles/2 005/04/21/longitude_feature.shtml

Basically it is called GMT as that is just where the Royal Observatory happened to be. Presumably, if the Observatory had been just outside Manchester, we could have given everyone Eccles Mean Time!

[vehelpfulguy]

May be worth you reading the book Longitude.

There are absolute points of reference for Latitude on the earth - the lines that go east west (such as equator, tropic of cancer, tropic of capricorn etc).

So a sailor can say they are so far north of the equator or so far south.

But there were no absolute points of Longitude (the lines that go north south). Where do you start counting from, there is no equivalent of the equator going north south.

So someone had to put a stake in the ground and say HERE is point zero.

Various countries had proposed it for their country (including France) but the UK had set up the royal observatory in Greenwich to map the stars in the sky to help sailors find the Longitude from the positions of the stars.

The genius Harrison was also trying to build a clock that would keep the accurate time on board a ship, in stormy seas and in all weathers, to help find Longitude. The clocks were sent to Greenwich for testing (they are still there).

Because the Uk "ruled" the sea we put the stake in the ground and said Greenwich is now point zero and you can all count from here. And they did.

The book
http://www.amazon.co.uk/Longitude-Dava-Sobel/d p/0007214227/sr=8-2/qid=1163456639/ref=pd_ka_2 /203-6550941-9975910?ie=UTF8&s=books

[Octavius]

Another site worth a look (in person):

http://www.nmm.ac.uk/server/show/conWebDoc.134 96