* Meteoroid: A small, rocky or metallic body in space that orbits the Sun. They range in size from dust particles to boulders.

* Asteroid: A larger rocky body that orbits the Sun, typically found in the asteroid belt between Mars and Jupiter.

* Comet: A celestial body composed mostly of ice and dust that orbits the Sun in a highly elliptical path.

* Satellite: An object that orbits a larger object, such as a planet or moon.

The key here is the size range, "from grain of sand to boulder," which is characteristic of meteoroids.