How did Greenwich Mean Time start?

Answer 1

The history of GMT can be traced right back to the days of the old mariners, sailing their schooners and sloops. They knew how to work out latitude (how far north or south you are from the Equator which is 0 degrees lat) with sextants but it took an awful lot longer to work out longitude (how far east or west you are.) They couldn't use conventional clocks as they used pendulums and pendulums don't work at sea. Eventually some clever Englishman came up with a clock that didn't need a swinging pendulum. With this revolutionary new timepiece, the mariners could, for the first time, accurately work out how far east or west they were. As The British were the first to "crack" longitude, they decided to put 0 degrees longitude, right through London. It's at 0 degrees longitude that GMT (Grenwich MeanTime) is based. Travel east from 0 degrees longitude and the time advances; travel west from it and it's the opposite.