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JPL Solar System Dynamics

The planets in order of increasing semimajor axis are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Although the IAU recently removed Pluto from the list of planets, it is included with the planets on most of our web-pages.

Orbit Diagrams

Plots showing the inner region of the solar system (just beyond Jupiter) and outer solar system region (just beyond Pluto) are available.

Physical Parameters

Selected physical parameters such as mass, bulk density, mean radius, and geometric albedo are available for the planets. These parameters are presented in a table with references.


Planetary ephemerides are available using JPL's HORIZONS system. Although the HORIZONS system will be sufficient for the vast majority of ephemeris requests, JPL planetary and lunar ephemeris files (e.g. DE406) are also available. The use of these ephemeris files is recommended only for professionals whose needs are not readily met by the HORIZONS system. Alternatively, you may use the NAIF SPICE toolkit and planetary ephemerides in SPK format from JPL's NAIF web-site.

Orbital Elements

Approximate positions of the major planets and Pluto may be found by using Keplerian formulae with their associated elements and rates. Such elements are not intended to represent any sort of mean; they are simply the result of being adjusted for a best fit. As such, it must be noted that the elements are not valid outside the given time-interval over which they were fit.

Such orbital elements should not be used to compute high accuracy ephemerides. See the Ephemerides section (above) for information on what is available for planets.
Please consult our page detailing the approximation of planetary positions using Keplerian elements for more information.

Gravity Fields for the Outer Planets

Gravity field data used in our planetary satellite orbit determination models for the outer planets (Jupiter, Saturn, Uranus, and Neptune) is given in a table with references.

Optical and Radar Astrometry

Optical and radar astrometry as well as spacecraft measurements used in the planetary ephemerides are available on this site.

Additional Data

Visit the JPL Solar System page for more information about the planets.

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