Presenting .. Your Nine Planets!

The Classic Pneumonic!

Mercury	Venus	Earth	Mars	Jupiter	Saturn	Uranus	Neptune	Pluto
My	Very	Educated	Mother	Just	Served	Us	Nine	Pickels

Rough Size Scale :

Info Chart for the Planets :

Categories	Mercury	Venus	Earth	Moon	Mars	Jupiter	Saturn	Uranus	Neptune	Pluto
Mean Distance (AU)	0.387	0.723	1.0	384,400 km ~30 E-Diam	1.523	5.203	9.555	19.218	30.110	39.341
Period of Revolution	88 days	224.7 days	365.3 days	27.3 days	687 days	11.86 yrs	29.46 yrs	84 yrs	165 yrs	248 yrs
Equitorial Diameter (km)	4,880	12,100	12,756	3,476 ~1/4 E-Diam	6,794	143,200	120,000	51,800	49,528	~2,330
Atmosphere Components	Almost none	Carbon Dioxide	Nitrogen Oxygen	Almost none	Carbon Dioxide	Hydrogen Helium	Hydrogen Helium	Helium Hydrogen Methane	Hydrogen Helium Methane	Methane +?
Moons	0	0	1	0	2	16	18	15	8	1
Rings	0	0	0	0	0	3	1,000 (?)	11	4	0
Inclination of orbit to ecliptic	7 deg	3.4 deg	0 deg	5.2 deg	1.9 deg	1.3 deg	2.5 deg	0.8 deg	1.8 deg	17.1 deg
Eccentricity of the Orbit	0.206	0.007	0.017	0.055	0.093	0.048	0.056	0.046	0.009	0.248
Rotation Period	59 days	243 days	23 hrs 56 min	27.3 days	24 hrs 31 min	9 hrs 55 min	10 hrs 40 min	17.2 hrs	16 hours	6 days 9 hours
Inclination of axis *	near 0	177.2 deg	23.45 deg	6.68 deg	25.2 deg	3.08 deg	26.73 deg	97.92 deg	28.8 deg	120 deg

If the axis is inclined more than 90 degrees, the planet is more "upside down", and thus rotates around retrograde compared to its orbit.

Chart info taken from an Nasa graphic.

The following sets of data charts can be found on the SEDS website - an excellent resource!

The BIGGEST Solar System objects :


                   Distance   Radius    Mass
 Name       Orbits (000 km)    (km)     (kg)
---------  ------- --------  -------  -------
Sun                           697000  1.99e30
Jupiter    Sun       778000    71492  1.90e27
Saturn     Sun      1429000    60268  5.69e26
Uranus     Sun      2870990    25559  8.69e25
Neptune    Sun      4504300    24764  1.02e26
Earth      Sun       149600     6378  5.98e24
Venus      Sun       108200     6052  4.87e24
Mars       Sun       227940     3398  6.42e23

The Smallest Moons in the Solar System:

There are 13 moons whose radius is less than 20 km:


                   Distance   Radius    Mass
 Name       Orbits (000 km)    (km)     (kg)
---------  ------- --------  -------  -------
Deimos     Mars          23        6  1.80e15
Leda       Jupiter    11094        8  5.68e15
Adrastea   Jupiter      129       10  1.91e16 *
Pan        Saturn       134       10     ?   
Phobos     Mars           9       11  1.08e16 *
Calypso    Saturn       295       13     ?   
Cordelia   Uranus        50       13     ?

The Brightest objects in the Solar System:

There are 12 major bodies brighter than magnitude 6 (as viewed from Earth). All of these can be seen with the unaided eye or with binoculars. The more negative the magnitude number, the brighter the object. For comparison .. Big Dipper stars are about +2 to +4 in magnitude.


                   Distance   Radius
 Name       Orbits (000 km)    (km)     Vo
---------  ------- --------  -------   ---
Sun        ?              0   697000 -26.8
Moon       Earth        384     1738 -12.7
Venus      Sun       108200     6052  -4.4 
Jupiter    Sun       778000    71492  -2.7 
Mars       Sun       227940     3398  -2.0 
Mercury    Sun        57910     2439  -1.9 
Saturn     Sun      1429000    60268   0.7 
Ganymede   Jupiter     1070     2631   4.6 
Io         Jupiter      422     1815   5.0 
Europa     Jupiter      671     1569   5.3 
Uranus     Sun      2870990    25559   5.5 
Callisto   Jupiter     1883     2400   5.6

Weight on the other planets? See this Exploratorium link

Chronology of Solar System Discovery

Prior to 1600 From the dawn of history until the beginning of the 17th century the known universe consisted of only 8 bodies:
Earth, Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn plus the "fixed" stars. In Europe, the prevailing view was the Ptolemaic system with the Earth at the center and the other bodies revolving around it.

The 17th Century In 1610 Galileo first turned a telescope on the heavens and the universe exploded. By the end of the 17th century, 9 new bodies had been discovered and Copernicus's heliocentric theory was widely accepted. The total number of known bodies had more than doubled to 17: Callisto, Europa, Ganymede, Io, Titan, Iapetus, Rhea, Dione, Tethys (these are mostly the moons of Jupiter and Saturn).

The 18th CenturyOnly 5 new bodies (not counting comets) were discovered in the 18th century (all by William Herschel) bringing the total to 22: Uranus, Oberon, Titania, Enceladus, Mimas.

The 19th CenturyThe number of bodies in the solar system increased dramatically in the 19th century with the discovery of the asteroids (464 of which were known at by 1899) but only 9 more "major" bodies were discovered. The number of major bodies rose to 31 (almost double the 17th century total). These included Neptune in 1846.

The 20th Century So far, in 20th century 40 more major bodies (and thousands of comets and asteroids) have been discovered (27 by the Voyager probes) more than doubling the count again to 73. Pluto was found in 1930 by Tombaugh, and its moon Charon in 1978 by Christy. Since Pluto has been discovered, it has not yet made an orbit of the Sun, thus we don't know its orbital parameters to a great deal of accuracy. (Neptune has not made a trip around either, but it will by about 2010, since we have so much of an orbit, we have some good "numbers" for Neptune.)