Why isn't the green which meridian straight?

Answer 1

Because a straight line up and zooms right off the surface of the earth.

Since the earth is a sphere (ball) only curved lines can stay on the surface.

The meridian may not be a straight line, but it's the shortest possible distance

between its ends, and you can prove it:

The ends of the meridian are the north and south poles. Take a globe and a rubber band.

When you stretch a rubber band between two points, it always follows the shortest path.

Stretch the rubber band between the north and south poles of the globe. Make sure it goes

across Green Which, and you'll see that it exactly follows the Prime Meridian.

Answer 2

The Greenwich Meridian isn't perfectly straight because it follows the Earth's natural geographic features, which are not always aligned in a perfectly straight line. Additionally, the Greenwich Meridian was established to pass through specific points to define 0 degrees longitude, rather than following a strict straight line.