How Do Shadows Move Across Time Zones?

Imagine the sun is a giant flashlight held by a teacher walking around you. As the teacher moves, your shadow follows them, stretching and shrinking. Now picture that teacher walking all the way around the Earth. The sunlight hits different countries at slightly different times. When it is noon in London, the sun is directly overhead, so shadows are short. But in New York, which is to the west, the sun hasn't reached its peak yet, so shadows are still long and pointing east.

The Earth spins like a top once every day. This spinning motion makes it look like the sun is moving across the sky from east to west. Because of this movement, the shadow cast by any object also moves. It starts long in the early morning when the sun is low on the horizon.

Think of the Earth as a big ball with a giant stick (the sun's rays) shining on it. As the ball turns, the light hits different parts of the surface. This creates a wave of light and shadow that travels around the world every twenty-four hours. We call these areas time zones because they experience daylight at roughly the same moment.