Here's why:

* Gravity is a force: It's an attraction between objects with mass. It's not something that moves.

* Velocity describes motion: Velocity is a measure of how fast something is moving and in what direction.

What you might be thinking about:

* Earth's orbital velocity: Earth orbits the Sun at a speed of roughly 30 kilometers per second (18.6 miles per second). This is a result of the gravitational force between the Earth and the Sun.

* Acceleration due to gravity: This is the rate at which objects fall towards the Earth. On Earth's surface, it's approximately 9.8 meters per second squared (32 feet per second squared). This means that for every second an object falls, its downward velocity increases by 9.8 meters per second.

In summary:

Gravity is a force, not something that moves. Earth has a velocity due to its orbit around the Sun, and objects near Earth accelerate due to gravity.