Download The Solar System

Solar System Formation
Your Parents’ Solar System
st
21
Century Solar System
The 21st Century Solar System
Sun
Terrestrial
Planets
Asteroid Belt
Jovian
Planets
Kuiper Belt
Oort Cloud
The Solar System:
List of Ingredients
Ingredient
Sun
Jupiter
Other planets
Everything else
Percent of total mass
99.8%
0.1%
0.05%
0.05%
The Sun
• A middle-aged, average star:
– Mostly Hydrogen & Helium
– 99.8% of the Solar System
– ~4.6 billion years old
• Shines because it is hot:
– Surface Temp ~6000 C
– Mostly Visible, UV & IR light
• Kept hot by nuclear fusion in
its core:
– Builds Helium from Hydrogen
fusion.
– Will shine for ~12 billion years
The Sun dominates the Solar
System
Terrestrial Planets
• Mercury, Venus, Earth & Mars
– “Earth-Like” Rocky Planets
– Largest is Earth
– Only in the inner solar system (0.4 to 1.5 AU)
• Rocky Planets:
–
–
–
–
Solid Surfaces
Mostly Silicates and Iron
High Density: (rock & metal)
Earth, Venus, & Mars have atmospheres
The Terrestrial Planets
Mercury
Venus
(0.055 M) (0.82 M)
Earth
(1 M)
Mars
(0.11 M)
The Jovian Planets
• Jupiter, Saturn, Uranus & Neptune
–
–
–
–
Largest Planets: at least 15 times mass of Earth.
Only in the outer solar system (5 to 30 AU)
No solid surfaces (mostly atmosphere)
Low density
• Gas Giants: (Jupiter & Saturn)
– Thick H/He atmosphere, liquid hydrogen mantle, ice core
• Ice Giants: (Uranus & Neptune)
– Ice/rock core & mantle, thin H/He atmosphere
The Jovian Planets
Jupiter
(318 M)
Saturn
(95 M)
Uranus Neptune
(15 M) (17 M)
If the Moon were replaced with some of our planets
http://www.youtube.com/watch?v=usYC_Z36rHw (1.5 min)
Is Pluto a Planet?
What to consider?
• Size?
• Shape?
• Orbit?
• What is it made
of?
IAU Definition of a Planet
In 2006, the International Astronomical Union
(IAU) came up with the following definition of
a planet:
 orbits the Sun
 has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a hydrostatic
equilibrium shape (i.e., it is spherical),
 has cleared the neighborhood around its orbit,
 is not a satellite
IAU Definition of a Dwarf Planet
In 2006, the International Astronomical Union
(IAU) came up with the following definition of
a dwarf planet:
 orbits the Sun
 has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a hydrostatic
equilibrium shape (i.e., it is spherical),
 has not cleared the neighborhood around its orbit,
 is not a satellite
Life on other planets??
• Why Mars Died, and Earth Lived (9.4
min)
Or• http://www.youtube.com/watch?v=v3Kcw0
UrIFI (21 min)
Water on the moon
• http://solarsystem.nasa.gov/multimedia/vide
o-view.cfm?Vid_ID=3263
• Earth 100 Million Years From Now
http://www.youtube.com/watch?v=uGcDed4x
VD4