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Definition of: planet
Our photo definition of planet 
(plan′it) noun
1. Astron. One of the non–self–luminous bodies of the solar system revolving around the sun as their center of motion. Those within the Earth's orbit, Mercury and Venus, are called inferior planets; those beyond it, the superior planets, are Mars, the asteroids or planetoids (known collectively as minor planets), Jupiter, Saturn, Uranus, Neptune, and Pluto.
2. In ancient astronomy, one of the seven heavenly bodies (the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn) that have an apparent motion among the fixed stars.
3. One of these bodies considered in relation to its supposed influence on human beings and their affairs. [<OF planete <LL planeta <Gk. (asteres) planētai wandering (stars) <planaesthai wander]
| NAME | Symbol | Distance from sun: millions of miles | Mean diameter: miles | Period of sidereal revolution | Period of rotation | No. of satellites | Mass: Earth considered as 1. | Escape velocity: in miles per second. |
| Mercury | ☿ | 36 | 3,000 | 88 days | 88 days? | 0 | 0.0543 | 2 |
| Venus | ♀ | 67 | 7,600 | 225 ” | 20–30 d. | 0 | 0.8136 | 6.3 |
| Earth | ⊕ | 93 | 7,918 | 365.25 d. | 23 h. 56 m. | 1 | 1.0000 | 6.95 |
| Mars | ♂ | 142 | 4,200 | 687 days | 24 h. 37 m. | 2 | 0.1069 | 3.1 |
| Jupiter | ♃ | 483 | 87,000 | 12 years | 9 h. 50 m. | 12 | 318.35 | 37. |
| Saturn | ♄ | 886 | 72,000 | 29.5 ” | 10 h. 14 m | 9 | 95.3 | 22. |
| Uranus | ♅ | 1780 | 29,600 | 84 ” | 10 h. 45 m. | 5 | 14.58 | 13. |
| Neptune | ♆ | 2790 | 27,700 | 165 ” | 15 h. 48 m. | 2 | 17.26 | 15. |
| Pluto | ♇ | 3670 | 4,000 | 248 ” | ? | 0 | .1? | ? |
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