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 System The 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 Outside the frost line metals, silicates, and hydrogen compounds condense It’s hot inside the frost line, so only metals and rock condense Hydrogen and helium don’t condense anywhere in the solar nebula

Which materials condense depends on temperature Outside the frost line, planets could form from metals, rocks, AND hydrogen compounds – 2.0 % of the nebular material Inside the frost line, the planets built up from rock and metal – only 0.6% of the nebular material Hydrogen and helium could only be held by the most massive planets

Which explains the two types of planets! Small, rocky planets: “Terrestrial” Large, gaseous planets: “Jovian”

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

Asteroids formed inside the frost line, so are rock & metal. 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?

All planets rotate in the same direction as they orbit the Sun. 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