| Planet | Distance from Sun (AU) | Speed (m/s) |
|---|
The speed of the planets in their orbits is influenced by the gravitational pull of the Sun. The closer a planet is to the Sun, the greater the Sun's gravitational force on it, and the faster the planet moves in its orbit. Conversely, the farther a planet is from the Sun, the weaker the gravitational force, and the slower the planet's speed. This phenomenon is described by Kepler's laws of planetary motion.
Mars comes closest to Earth approximately every 26 months. This event is called "Mars opposition." During opposition, Mars and the Sun are on directly opposite sides of Earth. Depending on the specific details of the orbits, Mars' closest approach to Earth may occur days before or after opposition. The distance at closest approach can vary between 54.6 million kilometers to about 100 million kilometers.
The planets of the solar system orbit the Sun in elliptical paths, with the Sun at one focus of the ellipse. The shape of the ellipse and the speed of the planet's orbit vary depending on the planet's distance from the Sun and its mass. Understanding the principles of these orbits allows scientists to predict planetary positions and to plan missions to other planets.