Here's why:

* Gravity: The Sun's immense gravity is the dominant force in our solar system. It holds all the planets, asteroids, and comets in its gravitational pull.

* Orbits: Comets travel in elongated, elliptical orbits around the Sun. Their orbits are much larger than the orbits of planets like Earth.

* Earth's Influence: While Earth's gravity does affect objects near it, it's not strong enough to influence the path of comets.

So, while comets may appear to be moving past Earth from our perspective, they are actually following a path dictated by the Sun's gravity.