Planetary Facts
The table below list a number of planetary facts for each planet. (If you are a detail-oriented person and would like to know more facts to, say win trivia games or impress friends at parties, please go and visit this planetary fact sheets site.) The table is a compilation that in some cases lists actual values, while other parameters are presented as a comparison to Earth (wherever you see the Earth value = 1), and some are presented both ways. For example, we give the diameter of planets in km and compared to Earth’s diameter. The reasons are twofold: 1) As Earthlings we have a very Earth-centric view and it is easier to relate many planetary comparisons to earthly existence. 2) Many numbers are so large in absolute values that we can’t really relate to them. That is the reason we neglect to tell you that the mass of Jupiter is 1898x1024 kg. For more information on the individual planets, click on the planet name; for definitions of individual parameters, click on those. You may be surprised to find our moon on this table; it is often included in traditional planetary comparisons. Everyone's favorite dwarf planet, Pluto is also included.
As we discuss aspects of the different planets, it will be helpful for you to come back to this table for reference.
Planetary Facts - Just the facts (Ratio to Earth Values) Link to site found here
| MERCURY | VENUS | EARTH | MOON | MARS | JUPITER | SATURN | URANUS | NEPTUNE | PLUTO | |
| Mass | 0.0553 | 0.815 | 1 | 0.0123 | 0.107 | 317.8 | 95.2 | 14.5 | 17.1 | 0.0025 |
| Diameter | 0.383 | 0.949 | 1 | 0.2724 | 0.532 | 11.21 | 9.45 | 4.01 | 3.88 | 0.186 |
| Diameter (km) | 4879 | 12,104 | 12,756 | 3475 | 6792 | 142,984 | 120,536 | 51,118 | 49,528 | 2370 |
| Density | 0.984 | 0.951 | 1 | 0.605 | 0.713 | 0.24 | 0.125 | 0.23 | 0.297 | 0.38 |
| Density (kg/m3) | 5427 | 5243 | 5514 | 3340 | 3933 | 1326 | 687 | 1271 | 1638 | 2095 |
| Gravity | 0.378 | 0.907 | 1 | 0.166 | 0.377 | 2.36 | 0.916 | 0.889 | 1.12 | 0.071 |
| Gravity (m/s2) | 3.7 | 8.9 | 9.8 | 1.6 | 3.7 | 23.1 | 9 | 8.7 | 11 | 0.7 |
| Rotation Period | 58.8 | -244 | 1 | 27.4 | 1.03 | 0.415 | 0.445 | -0.72 | 0.673 | 6.41 |
| Rotation Period (hours) | 1407.6 | -5832.5 | 23.9 | 655.7 | 24.6 | 9.9 | 10.7 | -17.2 | 16.1 | -153.3 |
| Length of Day | 175.9 | 116.8 | 1 | 29.5 | 1.03 | 0.414 | 0.444 | 0.718 | 0.671 | 6.39 |
| Length of Day (hours) | 4222.6 | 2802 | 24 | 708.7 | 24.7 | 9.9 | 10.7 | 17.2 | 16.1 | 153.3 |
| Distance from Sun | 0.387 | 0.723 | 1 | 0.00257* | 1.52 | 5.2 | 9.58 | 19.2 | 30.05 | 39.48 |
| Distance from Sun (106 km) | 57.9 | 108.2 | 149.6 | 0.384* | 227.9 | 778.6 | 1433.5 | 2872.5 | 4495.1 | 5906.4 |
| Orbital Period (days) | 88 | 224.7 | 365.2 | 27.3 | 687 | 4331 | 10,747 | 30,589 | 59,800 | 90,560 |
| Mean Temperature (C) | 167 | 464 | 15 | -20 | -65 | -110 | -140 | -195 | -200 | -225 |
| Surface Pressure (bars) | 0 | 92 | 1 | 0 | 0.01 | Unknown* | Unknown* | Unknown* | Unknown* | 0 |
| Number of Moons | 0 | 0 | 1 | 0 | 2 | 79 | 62 | 27 | 14 | 5 |
| Ring System? | No | No | No | No | No | Yes | Yes | Yes | Yes | No |
| Global Magnetic Field? | Yes | No | Yes | No | No | Yes | Yes | Yes | Yes | Unknown |
Update June 2018: Until a few days ago, the correct answer for the number of moons of Jupiter would have been 67, but then..
