9 (and now 8) Solar System planets

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Earth-Sun

distnce=1

Radius

Earth=1

Mass

Earth=1

Number

moons

orbital

inclination

orbital

eccentricity

obliquity

density

(gm/cm³)

links to . . .

332,800

9

--

--

--

1.41

Mercury:

0.39

0.38

0.05

0

7°

0.2056

0.1°

5.43

Venus:  

0.72

0.95

0.89

0

3.39°

0.0068

177.4°

5.25

Earth: 

1

1

1

1

0°

0.0167

23.45°

5.52

Mars: 

1.5

0.53

0.11

2

1.85°

0.934

25.19°

3.95

Jupiter: 

5.2

11

318

67

1.31°

0.0483

3.12°

1.33

Saturn:  

9.5

9

95

62

2.49°

0.056

26.73°

0.69

Uranus:  

19.2

4

17

27

0.77°

0.0461

97.86°

1.29

Neptune:

30.1

4

17

14

1.77°

0.0097

29.56°

1.64

39.5

0.18

0.002

5

17.15°

0.2482

119.6°

2.03

1 AU = 93 million miles, the radius of the Earth’s orbit.

Mass: the Sun is 1.3 million X the volume but only 330,000 X the earth's mass because its density is so low.

"Orbital inclination" is the tilt of a planet’s orbit to the ecliptic.

"Orbital eccentricity" (or orbital ellipticity) is how elliptical a planet’s orbit is (0 = circular, 1= a straight line). Mercury and Pluto, the inner and outermost planets, have the most inclined and most elliptical orbits.

"Obliquity" is the tilt of a planet’s axis to its orbital plane. A spinning body’s spin axis never changes the direction it points in space as it orbits its parent body (explained on page 42 in You and the Universe), the principle by which gyroscopes (a spinning body) direct and stabilize vehicles in flight.

The table of planetary data above is current as of March 2014. The number of moons of Jupiter, Saturn, Uranus, Neptune and Pluto increase as new surveys and telescopes are brought to bear.

On August 24, 2006, the IAU demoted Pluto to a dwarf planet because it did not meet the new definition of a  "planet;" i.e., an object that:

1) is in orbit around the Sun;

2) has sufficient mass to overcome its compressive strength and achievehydrostatic equilibrium;

i.e., a nearly round shape;

3) has cleared the neighborhood around its orbit of significantly sized bodies other than

its own satellites.

As of April 2014 there are five officially recognized dwarf planets in our solar system: Eris (a TNO larger than Pluto); Pluto a TNO in the Kuiper belt; Haumea (originally 2003 EL61, an elongated KBO longer than Pluto and with a moon); Makemake (2005 FY); and the asteroid Ceres.

This page and much of this 600-page website are from the Fine Art Book You and the Universe.