The sun itself doesn't actually move across the sky. It's the Earth's rotation that makes it appear to move.

Here's why:

* Earth's Spin: Our planet rotates on its axis, completing one full rotation roughly every 24 hours. This rotation causes us to see the sun move from east to west throughout the day.

* Perspective: As the Earth spins, different parts of the planet face the sun. This creates the illusion that the sun is moving across the sky.

Imagine a spinning carousel: If you're standing on the carousel, you might feel like the horses are moving around you. Similarly, we feel like the sun is moving because we're on the rotating Earth.

The sun's actual movement: The sun does move, but on a much larger scale. It's part of our solar system and orbits the center of the Milky Way galaxy, taking millions of years to complete one orbit.