The time we now use around the world is called Universal time, or UT. It was formalized a century ago — here's how it works.

Greenwich Mean Time (GMT) is the time measured on the Earth's zero degree line of longitude, or meridian. This runs from the North Pole to the South Pole, passing through the Old Royal Observatory ...

Enter: Greenwich Mean Time. The question is ... ‘Seventy percent of the world’s shipping companies were [already] using charts and data tables based on the Greenwich meridian.’ ...

Greenwich Mean Time (GMT) is the time measured on the Earth's zero degree line of longitude, or meridian. This runs from the North Pole to the South Pole, passing through the Old Royal Observatory ...