I read a very interesting book on Emelia Earhart. It was the books reasoning (well researched) that she was lost due to her unfamilarity with her communications system (she would switch it between radio and telegraph every half-hour in case there was a failure with one of the systems) AND the lack of a common time frame. She was on one time (her last take off location), a telegraph ship near Howland Island was on Hawaii time (which was a 1/4 hour off of the other times!), and then there was Howland Island time. After the investigation they created the Greenwich Mean Time standard.
That’s interesting, but GMT goes back at least to the middle of the 19th Century. Originally GMT time zero ( 00:00 HR) indicated NOON on the Greenwich meridian. This allowed all the observations made by an astronomer in Europe during a single night to occur on the same day, GMT. One vestige of that is that the astronomical “Julian Day” still begins at noon, Greenwich time. January 1, 2000 12:00 TT is Julian Day 2451545.000000. (TT is Terrestrial Dynamical Time, used for astronomical calculations. It does not observe leap seconds either.) On January 1, 2000, TT was 64.184 seconds ahead of GMT (or UTC). TT and GMT agreed some time around 1900, ignoring the 12 HR offset of GMT prior to 1925.
In 1925 that was changed so that 00:00 HR GMT would be MIDNIGHT on the Greenwich meridian. GMT was the time zone used in the Nautical Almanac. The Nautical Almanac was a joint publication of Her Britannic Majesty’s Royal Greenwich Observatory and the United States Naval Observatory, until quite recently. Publishing the Almanac involved a lot of tedious calculation, especially in the days of logarithm tables. The two organizations split the observing and calculating chores. Britain closed the RGO about 20 years ago, and withdrew from publishing around the same time.
It was the Nautical Almanac that lead to the adoption of the Greenwich meridian as the Prime Meridian of the World. Other countries, especially France, published perfectly good almanacs, but the quality of the explanations and general accuracy and thoroughness of the US-British volume made it the choice of most mariners and lead to the adoption of the Greenwich Meridian at the Washington Conference of 1884.
https://en.wikipedia.org/wiki/International_Meridian_Conference