Orion, like all stars in the night sky, rises in the east and sets in the west due to the Earth's rotation.

Here's a breakdown:

* Earth's Rotation: The Earth spins on its axis, completing one rotation approximately every 24 hours. This rotation is what causes day and night.

* Perspective: As the Earth spins, it's like we're standing on a giant merry-go-round. Because of this rotation, everything in the sky appears to move from east to west.

* Apparent Motion: This apparent movement of celestial objects from east to west is why we see the Sun rise in the east and set in the west, and the same applies to stars like Orion.

Important Note: Orion itself doesn't actually move. It's our perspective from the rotating Earth that makes it *appear* to move across the sky.