Our Solar System and How It Formed
Dec 14, 2015
Our Solar System and How It Formed
There are patterns in our solar system that give clues to its formation…
1. The motions of the major bodies in our solar system are orderly.
2. The planets fall into two major categories:
Terrestrial and Jovian
• high density (~5 gm/cc)• solid surface • low density (~1 gm/cc)
• no solid surface
In a science fiction movie the characters land their spacecraft on an alien planet. What kind of planet is it?
A) Terrestrial
B) Jovian
C) Can’t tell without more information
3. Swarms of asteroids and comets populate the solar system.
4. There are important exceptions to the patterns…
Venus’s rotation
You should know these four clues…
1. The motions of the major bodies in our solar system are orderly.
2. The planets fall into two major categories.
3. Swarms of asteroids and comets populate the solar system.
4. There are important exceptions to the patterns.
Which planets have rings?
A) Mars, Jupiter, Saturn, Venus
B) Jupiter, Saturn, Mercury, Neptune
C) Saturn, Venus, Mars, Neptune
D) Saturn, Neptune, Jupiter, Uranus
E) Uranus, Neptune, Saturn, Mars
Which group below lists only planets with moons?
A) Earth, Mercury, Jupiter, Neptune
B) Saturn, Earth, Uranus, Mars
C) Mercury, Uranus, Earth, Mars
D) Mars, Jupiter, Saturn, Venus
E) Mars, Earth, Mercury, Neptune
Chapter 8 – The Formation of Our Solar SystemThe Nebular Theory
Star system formation is part of a cyclic process
Stars start as clouds of gas and dust in space
The densest parts of the cloud collapse due to gravity
Conservation of angular
momentum makes it spin
Conservation of energy
causes it to heat up
Collisions cause it to flatten out
This explains the orderly motion of the major solar system bodies
Conservation of angular
momentum makes it spin
Conservation of energy
causes it to heat up
Collisions cause it to flatten out
Materials in the solar nebula
Which materials condense depends on temperature
It’s hot inside the frost line, so only metals and rock condense
Outside the frost line metals, silicates, and hydrogen compounds
condense
Hydrogen and helium don’t condense anywhere in the solar nebula
Outside the frost line, planets could form from
metals, rocks, AND hydrogen compounds –
2.0 % of the nebular material
Hydrogen and helium could only be held by the most massive planets
Inside the frost line, the planets built up from rock and metal – only 0.6% of the
nebular material
Which materials condense depends on temperature
Which explains the two types of planets!
Large, gaseous planets:“Jovian”
Small, rocky planets:“Terrestrial”
Jovian planets formed almost like mini-solar systems
What is the primary physical law responsible for the heating of the solar nebula as it collapsed?
A) Conservation of energy
B) Conservation of linear momentum
C) Conservation of angular momentum
D) Kepler’s third law
In the early history of the solar system, planets and moons grew by collecting
leftover planetesimals
Many of those leftover bits remain today. They’re called
asteroids and comets.
Asteroids formed inside the frost line, so are rock & metal.
Comets formed outside the frost line, and so are made
mostly of hydrogen compound ices
The exceptions to the rules
Captured moons
Many captured moons have retrograde,highly inclined,
or highly eccentric orbits
The exceptions to the rules
Our relatively large moon – collisions
Astro-Cash Cab!
Taylor Trujillo
Casey Veneman
Francisco Andrade
Lena Joycox
Demi Mizokami
1) Which terrestrial planets have moons?
2) True or False?
All planets rotate in the same direction as they orbit the Sun.
3) Which materials that were present in the solar nebula condensed closest to the Sun?
Hydrogen and Helium
Hydrogen compounds
Rocks
Metals
4) Select the features that describe all Jovian planets (may be more than one!)
solid surface
many moons
rings
mostly rock and metal
low density