The geographic location chosen to represent Universal Time is Greenwich, England. The choice is arbitrary and historical. Universal Time became an important concept when European ships began to sail the wide open seas, far from any known landmarks. A navigator could reckon the ship's longitude by comparing the Local Time (as measured from the Sun's position) to the time back at the home port (as kept by an accurate clock on board the ship). Greenwich was home to England's Royal Observatory, which was charged with keeping time very accurately, so that ships in port could re-calibrate their clocks before setting sail.
O lugar xeográfico escollido para representar a hora universal é Greenwich, en Inglaterra. A escolla é arbitraria e histórica. A hora universal tornouse un concepto importante cando os barcos europeos comezaron a navegar o mar aberto, lonxe de referencias coñecidas. Un navegante podía calcular a lonxitude do barco comparando a hora local (medida pola posición do Sol) coa hora no porto de partida (que marcaba un reloxo preciso a bordo do barco). Greenwich era a sede do Observatorio Real de Inglaterra, encargado de marcar a hora con moita precisión para que os barcos no porto puidesen volver a calibrar os seus reloxos antes de zarpar.