Solar System Data Table
Orbital data for the eight planets of our solar system. Use this table with the orbital period worksheet to verify Kepler's Third Law (T² = a³ in AU and years).
| Planet | Semi-major axis (AU) | Period (years) | Eccentricity | a³ | T² |
|---|---|---|---|---|---|
| Mercury | 0.387 | 0.241 | 0.2056 | 0.0580 | 0.0581 |
| Venus | 0.723 | 0.615 | 0.0068 | 0.3781 | 0.3782 |
| Earth | 1.000 | 1.000 | 0.0167 | 1.000 | 1.000 |
| Mars | 1.524 | 1.881 | 0.0934 | 3.540 | 3.538 |
| Jupiter | 5.203 | 11.862 | 0.0484 | 140.8 | 140.7 |
| Saturn | 9.537 | 29.457 | 0.0539 | 866.9 | 867.7 |
| Uranus | 19.19 | 84.01 | 0.0473 | 7068 | 7058 |
| Neptune | 30.07 | 164.8 | 0.0086 | 27190 | 27159 |
Notice how closely a³ and T² match for each planet—this is Kepler's Third Law in action. The small discrepancies are due to rounding and the fact that the law is slightly modified in the full Newtonian form (which accounts for the planet's own mass, though this effect is tiny for all planets except Jupiter).
Related:
Third Law |
Worksheet |
Ellipse Geometry |
Orbit Simulator
External: NASA Planetary Fact Sheet
External: NASA Planetary Fact Sheet