The Astrophysics Spectator

Home

Topics

Interactive Pages

Commentary

Other Pages

Information

Planets

Solar System Planets Compared to Earth

The table below gives the basic orbital and physical characteristics of the eight major planets in terms of the values for Earth. The values given in this table are based on the numbers given in Yoder (1995).[1]

Orbital and rotation periods are sidereal measurements, which are measured relative to a fixed position on the sky. In the case of the orbital period, the fixed positions are quasars, while in the case of the rotation period, the fixed position is the first point of Aries (Vernal Equinox). The sidereal day for Earth is 23.93447 hours, or 86164.09 seconds, which is 3 minutes 55.91 seconds short of a solar day.

The mean distance of each planet from the Sun is given in Astronomical Units (AU), which is defined as the mean distance of Earth from the Sun.

Pluto is left off of this list because it has more the characteristics of a trans-Neptunian minor planet than of either the giant planets (of course) or the terrestrial planets. The recently-discovered trans-Neptunian planetoid 2003 VB_12 (unofficially named Sedna) is left off for the same reason.

The second and third columns show the R3 proportional to T2 relationship found by Johannes Kepler. The density column shows that the four terrestrial planets, Mercury, Venus, Earth, and Mars, are fundamentally different in composition from the four giant planets.

Planetary Characteristics

Mean Distance
from Sun

Sidereal
Orbital Period

Mass

Sidereal
Rotation Period

Density

Surface
Gravity

Escape
Velocity

AU

Pe

Me

days

ρe

ge

Ve

Mercury

0.387

0.241

0.055

58.807

0.984

0.38

0.380

Venus

0.723

0.615

0.815

243.687

0.951

0.90

0.926

Earth

1.000

1.000

1.000

1.000

1.000

1.00

1.000

Mars

1.524

1.881

0.107

1.029

0.713

0.38

0.449

Jupiter

5.203

11.857

317.828

0.415

0.241

2.64

5.382

Saturn

9.537

29.424

95.161

0.445

0.125

1.14

3.227

Uranus

19.191

83.749

14.536

0.720

0.230

0.92

1.911

Neptune

30.069

163.727

17.148

0.673

0.297

1.15

2.106

[1] Yoder, Charles F. “Astrometric and Geodetic Properties of Earth and the Solar System.” In Global Earth Physics: A Handbook of Physical Constants edited by T.J. Ahrens, 1–31. AGU Reference Shelf, No. 1. Washington: American Geophysical Union, 1995.

Ad image for The Astrophysics Spectator.