Intersecting parallels: The Greenwich Meridian Glitch

Each night, a bright green beam cuts through the sky above Greenwich: a laser, marking the path of the Prime Meridian (the imaginary line – from the north pole to the south pole – from which all other lines of longitude are measured).

It is emitted from the Royal Observatory, high on the hill at Greenwich Park. Another (carved and gilded) representation of the line crosses the building’s forecourt.… Read more