Meridian Longitude ⏰ 📌

For precise navigation, degrees are broken down:

Before Harrison, astronomers attempted to determine longitude using celestial events:

Meridians can define physical boundaries. For example, the 100th meridian west in the U.S. is considered a significant, though shifting, boundary between the humid eastern US and the arid west. Key Differences: Longitude vs. Latitude Longitude (Meridians) Latitude (Parallels) Direction North-South (connects poles) East-West (parallel to equator) Measurement North/South Distance Varies (0 at poles, max at equator) Consistent distance apart Reference Prime Meridian (Greenwich)

Longitude isn’t just about distance; it’s the foundation of how we measure time. Because the Earth rotates 360° every 24 hours, it moves . meridian longitude

The link between longitude and time is so fundamental that it literally divides our days. The world is divided into 24 primary time zones, each roughly 15° of longitude wide, corresponding to one hour of the Earth's rotation. The starting point is , which is effectively the mean solar time at the IERS Reference Meridian.

Meridians are not merely abstract lines on a map; they serve critical functions in daily life and science:

The international baseline used to separate the Eastern and Western Hemispheres. It establishes the basis for Coordinated Universal Time (UTC). 180∘180 raised to the composed with power For precise navigation, degrees are broken down: Before

: All meridians meet at the North and South Poles. This means the distance between meridians is greatest at the Equator and decreases to zero as they approach the poles.

Used in astronomy to identify when the center meridian of a celestial object (like Jupiter) is visible to an observer.

In geography and geodesy, a is an imaginary north-south line on the Earth's surface that connects both geographic poles and is used to measure longitude . Every point on a specific meridian has the same longitude, which represents the angular distance east or west of a starting reference line known as the Prime Meridian . The Prime Meridian and Global Grid The Prime Meridian , designated as 0∘0 raised to the composed with power Key Differences: Longitude vs

All 360 meridians converge into a single point. The distance between them shrinks to zero .

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Crucially, while latitude has a natural starting point (the equator at 0°), longitude has no natural zero. You can draw a meridian anywhere. Deciding where "0°" goes was one of the greatest political and scientific debates in history.