Unit: Solar System
I What’s out there?
A. Most of the matter is the solar system is contained in the sun (700x the mass
of everything else combined.) the relative masses of the components are:
SUN
Planets
Comets
Satellites
Asteroids
I. Medium
99.85%
0.135%
0.01%
0.00005
0.0000002%
0.0000001%
B. Other members of the SS include:
a. The Sun
i. The sun is 71%Hydrogen (H) and 27% Helium, but contains
almost all other elements.
b. Planets:
i. Terrestrial—mostly silicate minerals and metals
1. Major—the big eight
2. Dwarf—objects that are large enough to have a spherical
shape (have enough mass/ gravity to pull themselves into
ball shape) and orbit the sun, but have not swept their orbital
areas clear of other objects. (In 2005, Eris was discovered,
68 AU from sun.
ii. Jovian—the gas giants
c. Planetary satellites
i. Only Mercury and Venus are moonless. In general, more
mass/gravity means more moons.
d. Asteroids
i. Rocky or metallic, few m to 100okm in diameter
ii. Most found in Asteroid Belt, between Mars and Jupiter.
e. Comets
i. Icy, 10km or less in diameter
ii. Found in Oort cloud (40AU to 100AU from Earth) or Kuiper belt
(Neptune out to about 50A.U.)
f. Interplanetary medium—gas molecules and solid particles