Earth Science

The Solar System

Planet Orbits in the Solar System

Study Tip
If you know the orbital period for a planet, can you find out the planet’s distance from the Sun? Does the same thing apply conversely? (Assuming you know the planet’s distance from the Sun, can you figure out its orbital period?)

Planetary Orbits

  • The planets’ orbits are elliptical.
  • Johannes Kepler discovered the relationship between a planet’s orbital period (how long it takes for a planet to make one orbit around the Sun) and its distance from the Sun.  
  • If the orbital period is known for a planet, its distance from the Sun can be found.
Study Tip
If you know the orbital period for a planet, can you find out the planet’s distance from the Sun? Does the same thing apply conversely? (Assuming you know the planet’s distance from the Sun, can you figure out its orbital period?)
Planetary Orbits
The size and shape of various planet orbits
Concept Check
  • Who is Kepler? What is an orbital period?
  • What shape are the planets’ orbits?