How does gravity affect the inner planets? (site 2)

The Sun's gravity pulls the planets in orbit around it, and some planets pull moons in orbit around them. The closer the planet is to the Sun, the greater the pull of the Sun's gravity, and the faster the planet orbits.

Because of gravity, the inner planets of our solar system have a shorter orbital period around the sun than the exoplanets do. For example, the sun's gravitational pull makes Mercury have a orbital period of 88 days, versus Neptune, who takes 165 Earth years to orbit the sun.