In 2006, subsequent to several discoveries of several large outer Solar System objects beyond Pluto (one of which was found to be even larger than Pluto) it was decided that a planet should be defined as an object which (a) orbits the sun, and (b) is massive enough not only to coalesce itself into a nearly spherical shape, but also to gravitationally dominate its region of the solar system. Using this new definition, there are eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was re-classified as a “minor planet”. Nevertheless, for historical reasons, Pluto is still found with the 8 planets on the JPL Planetary Ephemeris.
See the complete Solar System planetary classification discussion.
Description of Menu Items
|Orbits & Ephemerides||Provides access to orbital data for all planets.|
|Physical Parameters||Table of selected physical parameters for the planets and dwarf planets.|
|Gravity Fields||Visualize and download the gravity fields of several planets, the moon, and a few small-bodies.|
|Observational Data||Provides sets of observations that are currently being used in the creation and improvement of modern planetary and lunar ephemerides.|
|Discovery Circumstances||Discovery circumstances for the planets.|