What is 0° longitude?

0° longitude is like the starting line for measuring how far east or west you are on Earth.

Imagine you're playing a game where everyone starts at the same spot on a giant map. That starting spot is 0° longitude, it’s like the middle of the map, but only for the left-to-right direction (east and west). It runs from the North Pole all the way to the South Pole, just like a straight line on your playground.

When you move east from 0° longitude, you're going in one direction, like walking towards the right side of your map. When you move west, you're going the other way, like walking towards the left side of your map.

This starting line is special because it passes through a place called Greenwich, which is near London, England. That’s why 0° longitude is also known as the Prime Meridian.

So, if someone says they are at 0° longitude, they're right where the game starts, just like you when you begin playing on your playground!