In geography, a is an imaginary half-circle that runs from the North Pole to the South Pole. Unlike lines of latitude (which are parallel circles that never touch), all meridians are the same length and intersect at the poles.
Every map you use, from paper charts to Google Maps, relies on this grid.
In the age of sail, determining longitude was the greatest scientific challenge of the era, requiring the invention of highly accurate clocks (chronometers). Today, while we have to do the heavy lifting, the concept of meridian longitude remains essential for: meridian longitude
Coordinates are marked as E (East) or W (West). For example, New York City sits at approximately 74° W, while Tokyo is at roughly 139° E. The Connection Between Longitude and Time
While the ground beneath our feet feels solid and stationary, we navigate our planet using a complex, invisible grid. At the heart of this system is . Often paired with latitude, longitude is the crucial coordinate that tells us exactly how far east or west we are from a starting point. What is a Meridian? In geography, a is an imaginary half-circle that
When we talk about "meridian longitude," we are referring to the angular distance of a place east or west of a specific reference line known as the . The Prime Meridian: Point Zero
Meridian longitude is more than just a line on a map; it is a mathematical triumph that synchronized the world’s clocks and opened the door to global exploration. Whether you are checking the time or ordering a package from across the globe, you are using the legacy of the meridians. In the age of sail, determining longitude was
Pilots and captains use these coordinates to chart paths across featureless oceans.
We apply similar coordinate systems to map the surfaces of Mars and the Moon.
In 1884, the International Meridian Conference met in Washington, D.C., and established the (passing through the Royal Observatory in Greenwich, London) as the world's official Prime Meridian. It is designated as 0° longitude . How Longitude is Measured Longitude is measured in degrees, minutes, and seconds: