1. Distance from the Sun:
* Kepler's Third Law of Planetary Motion states that the square of a planet's orbital period is proportional to the cube of its average distance from the Sun. This means that planets further away from the Sun take longer to orbit, and thus travel at slower speeds.
* Example: Mars, being farther from the Sun than Earth, orbits at a slower speed, taking almost twice as long to complete one revolution.
2. Mass of the Sun:
* The Sun's gravity is the force that keeps the planets in orbit. A more massive Sun would exert a stronger gravitational pull, causing planets to orbit at higher speeds.
* However, the Sun's mass is relatively constant, so this factor doesn't significantly impact the speed variations between planets.
In summary:
The primary factor influencing a planet's orbital speed is its distance from the Sun. The farther a planet is, the slower it orbits. The Sun's mass is also a factor, but its constant value means it doesn't significantly affect the speed differences between planets.
