Greenwich prime meridian Thursday, 29th November 2007 by James
Turnbull The equator, or latitude 0, separates the northern and
southern hemispheres of the globe. Defined as the middle point
of the two geographic poles, there’s no way anyone could argue
about its location. However the meridian – longitude 0 – has no
scientific definition so could basically be anywhere you like on
the planet. The most widely accepted meridian was defined at the
Royal Observatory in Greenwich, London. However, even here the
meridian has shifted about a bit. 18th century astronomer James
Bradley’s meridian is still shown on UK maps today, but has
otherwise mostly been forgotten. The much more famous meridian,
which is now used as the base point for all the world’s time
zones, was defined by George Airy. Airy’s prime meridian was
chosen using the very scientific system of setting up his
equipment in the observatory as close as possible to Bradley’s
equipment, but without getting in the way! Two miles directly
north of Greenwich, o