1. Chapter 27 Planets of the Solar System
Standards: 1b Students know the evidence from Earth and Moon rocks indicates that the Solar System was formed from a Nebula cloud of dust and gas approximately 4.6 billion years ago (bya). 1c Students know the evidence from geological studies of Earth and other planets suggest that the early Earth was very different from Earth today.

2. Vocabulary
Solar System: The Sun and all of the planets and other bodies that travel around it.
Planet: any of the primary bodies that orbit the Sun; a similar body that orbits another star.
Solar Nebula: a rotating cloud of dust and gas from which the sun and planets formed; also any nebula from which stars and planets form.
Planetismal: a small body from which a planet originated in the early stages of development of the solar system.

3. Learning Goals SWBAT: Describe how the Solar System was formed.
Compare early models of solar system formation to recent models.
Use Kepler’s law to show to orbits move.
Compare contrast Early Earth to Present Earth.

4. How was the Solar System Formed?
The Solar System consists of the Sun and all the planets and other bodies that orbit around it. Planets are large bodies that orbit the sun.
: Planetismal Theory
1796: Pierre-Simon marquis de Laplace introduced Solar Nebula Theory
Youtube:Formation of Solar System (Ignite)

5. Solar Nebula Theory
Sun and Planets formed at about the same time out of a cloud of rotating gas and dust called a nebula.
Matter from the Universe gathers into cloud
5 bya: Cloud forms when a supernova explodes. Under intense gravity and pressure caused the center of the solar nebula to become hotter and denser. At 10 million degrees fusion begins and the Sun is formed. The sun is composed of 99% of the matter from the solar nebula.

6. Our Solar System Explosion of Super nova
2. Cloud of dust and gas condense and form hot dense center: Sun
3. Heavy materials left over orbit the sun, collide and form innerplanets.
4. Gases float farther away, frozen and collide to form outer Planets.
5. Planets orbit our sun making up our solar system.

7. How did Planets Form? While the Sun was forming in the center
of the solar nebula
Planets were forming
in the outer
Regions.
Planetismals:small
Bodies from which
A planet originated.
Some Planetismals
collide and through
gravity form
Protoplanets.

8. Formation of Inner Planets
Features of the newly formed planets depends on the distance from the sun!
The four closest planets: Mercury,Venus, Earth and Mars contain heavy elements such as Iron and Nickel. Also called Terrestrial Planets.
These planets lose their gases because gravity is not strong enough to hold gas.
Dense Materials sink to the center of the planets. The planets form layers.
Inner planets: Solid, Rocky , Dense, Hotter!

9. The Outer Planets Jupiter, Saturn, Uranus, and Neptune
Formed in colder region of solar nebula.
Far from the Sun and very cold!
Did not lose lighter elements such as Hydrogen and Helium, or ice, methane ice and ammonia ice.
Referred to as the gas planets, low density. Jupiter, only 24% of Earth’s density but 11 times the diameter

10. Solar System Review
Students always ask “How come Pluto isn’t a Planet anymore”

11. Formation of Solid Earth
Early Solid Earth: How did the Earth form? What does differentiation have to do with it?
How does the Present solid Earth contribute to the Atmosphere.

12. Formation of Earth’s Atmosphere
What happened to Hydrogen and Helium that were present in the early formation of the Earth?
What role does the Solar Wind and Gravity play in the atmosphere forming?
Describe the benefits of outgassing.
How does Ozone protect us?
How did early organisms increase the amount of oxygen in the air?

13. Formation of the Oceans
Where did the water from the oceans come from?
Describe the process of Fresh water to Salt water.
What are salt precipitates?
What are the effects of the atmosphere from the oceans?

14. Section 2 Models of the Solar System
Geo-Centric Model: 2,000 years ago Aristotle proposes Earth Centered model of solar system.
Ptolemy’s Model:

15. Helio-Centric Model
1543, Polish Astronomer, Nicholaus Copernicus proposes Helio-Centric Model.

16. Kepler’s Laws
Detailed observations of patterns of starst through improved telescopes, led to Kepler’s development of 3 laws.
1st Law: Law of Ellipses. States each planet orbits the sun in an elliptical pattern.
Ellipse: a closed curve whose shape is determined by 2 points,
foci.
Eccentricity: measure of the ellipse
Circular orbit e=0

17. 2nd Law Law of Equal Areas
Describes the speed of objects which travel at different points in their orbits.
Q: When do planets travel at their fastest speed?
A: When they are closest to the Sun
A line from the center of the sund to the center of the object sweeps through equal areas in equal periods of time.

18. 3rd Law Law of Periods
Third law describes the relationship between the average distance of a planet from the sun and the orbital period of the planet.
Orbital Period: the time it takes for a planet to complete one orbit.
Distance measured in Astronomical Units: AU

19. Animation: Kepler’s Laws