You might wonder: in an age of digital mapping, do we still need the concept of meridians? Absolutely.
While modern geodesy uses a 3D ellipsoid model (like WGS84) rather than a perfect sphere, the underlying graticule of meridian longitude remains the standard. As we map other planets—Mars, Venus, the Moon—we arbitrarily assign them a prime meridian (for Mars, it passes through the Airy-0 crater). The same logic of converging north-south lines applies across the solar system. meridian 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. You might wonder: in an age of digital
Your smartphone doesn’t "look up" longitude; it calculates it using atomic clocks on 31 satellites. Each satellite constantly broadcasts its position and precise time. Your receiver compares the time difference between several satellites to triangulate your longitude and latitude to within centimeters. As we map other planets—Mars, Venus, the Moon—we
Today, we take longitude for granted, but it powers virtually every aspect of modern life.