This is a fundamental concept in astronomy called the heliocentric model, which was first proposed by Nicolaus Copernicus in the 16th century.

Here's a simplified explanation:

* Earth revolves around the Sun: The Earth orbits the Sun in an elliptical path, completing one full orbit in approximately 365.25 days. This is what we experience as a year.

* Earth rotates on its axis: The Earth also spins on its axis, like a top, completing one rotation roughly every 24 hours. This rotation is what causes day and night.

The apparent movement of the Sun across the sky is actually a consequence of the Earth's rotation. As the Earth rotates, different parts of the planet face the Sun, creating the illusion that the Sun is moving.

It's important to remember that the Earth is just one of many planets that orbit the Sun.