Meridians and longitude form the geographic coordinate system used to specify positions on Earth east and west of a reference meridian. Longitude is an angular measurement (in degrees) from the prime meridian; meridians are the imaginary north–south lines connecting the poles at constant longitude.
Furthermore, as climate change melts polar ice, new shipping lanes are opening in the Arctic. Navigating these requires precision longitude calculations near the poles, where traditional Mercator projection fails and navigators must rely on "grid navigation" aligned with meridians. meridian longitude
Telescopes use meridian circles to track celestial objects as they cross the local meridian (the line of longitude that passes directly overhead). This allows astronomers to measure the precise positions of stars, planets, and satellites. Spacecraft navigation also depends on knowing the longitude of landing sites and orbital paths. Spacecraft navigation also depends on knowing the longitude
Since 1884, the Prime Meridian has been defined as the line passing through the Royal Observatory in Greenwich, London, England. a self-taught English clockmaker.
The prize was ultimately won by , a self-taught English clockmaker. Harrison dedicated his life to inventing the marine chronometer —a highly precise watch that could keep perfect time despite temperature changes, humidity, and the violent motion of a ship. His invention revolutionized global navigation and saved countless lives. Meridians and Modern Time Zones