Earth: Vital Statistics
Mean radius 6371 km (3981 miles)
Average distance from Sun 149.6 million km (93 million miles)
Closest to Sun (perihelion) 147.1 million km (91.5 million miles) about Jan. 3
Farthest from Sun (aphelion) 152.1 million k
How Planets Work
You are now the proud owner of an Acme planet, the finest planets in the galaxy. Whether it's a
rocky terrestrial planet, a gas giant, or an ice planet, your Acme planet is guaranteed to give you
billions of years of sati
Motions of the Earth
Rotation of the earth causes day and night. Before sunrise and after sunset some light is scattered
over the horizon by the atmosphere, giving us twilight. Civil twilight is defined as the time when
the sun is less than 6 deg
Rings and Resonances
All four of the large outer planets have rings. Ring systems obey very strict geometrical laws:
Orbits of ring particles must be almost perfectly circular. Otherwise collisions will
rapidly destroy the ring.
Averages 36 million miles from the Sun but ranges from 28.6 million at perihelion to 43.4
million at aphelion.
Revolution period 88 days
Apart from Pluto, has the most eccentric (non-circular) orbit.
Rotates on it
Fifth planet from the Sun
Average distance from Sun = 484 million miles.
5.2 times the average distance of Earth
3.4 times the average distance from Mars
Perihelion distance 460 million miles.
Aphelion distance 508 million mil
Orbit and Rotation
Averages 67.3 million miles from the Sun. With the most nearly circular orbit, this
distance varies only half a million miles on either side.
Revolves around the Sun in 225 days, rotates, BACKWARDS, in 243 days.
Atmosphere of Venu
Average distance from Sun: 886 million miles
Perihelion: 839 million; Aphelion: 933 million
Takes 29.46 years to orbit the Sun
Diameter 74,600 miles. Even more flattened at the poles than Jupiter.
Also more gaseous and rarified tha
Fourth planet from the Sun
Rather eccentric orbit. Average distance from the Sun is 142 million miles
Perihelion distance 128.6 million miles,
aphelion distance 160 million miles.
Takes 687 days to orbit the Sun.
Distance from Ea
Averages 236,000 miles from the earth.
Closest distance (perigee) is about 220,000 miles,
Greatest distance (apogee) is about 255,000 miles.
Diameter about 2160 miles, roughly 1/4 that of the earth
Mass 1/81 that of earth. Surfac