1. Bellwork 10/2
What kind of “stuff” is in our Solar System? List as many items as you can.

2. Coming Up: Today 10/2: Formation of the Solar System
This material will NOT be on your Unit 1 Test
Thursday 10/4: Unit 1 Test
Monday 10/8: Planet Classification & Minor Members

3. Coming Up: Today 10/1: Formation of the Solar System
This material will NOT be on your Unit 1 Test
Wednesday 10/3: Unit 1 Test
Friday 10/5: Planet Classification & Minor Members

4. Touring Our Solar System
Covered in this unit:
Planets, Dwarf Planets, Exoplanets
Earth’s moon & star
Kepler’s Laws
Asteroid Belt & Kuiper Belt
Oort cloud
Comets, Meteoroids, Meteorites, Asteroids
Astrobiology

5. Nebular Hypothesis Activity Purpose: Identify physical features of our Solar System and describe why it is arranged the way it is
Obtain the materials listed on your sheet
Answer the questions as a group
Be prepared to go over this!

6. Let’s review the trends…

7. Overview of the solar system
Solar system includes
Eight planets and their satellites
Sun
Asteroids
Comets
Meteoroids

8. Structure of the Solar System
A planet's orbit lies in an orbital plane
The orbital planes of the planets are inclined
Planes of seven planets lie within 3 degrees of the Sun's equator
Mercury's is inclined 7 degrees

9. How did the Solar System form?
Solar Nebular hypothesis
Planets formed about 4.6 billion years ago
Planets formed from a rotating disk of dust and gases that surrounded the sun

10. What happened…? A large cloud of gas/dust formed
This cloud contracts in on itself due to gravity and the “core” becomes hotter & more dense

11. 3. The cloud collapses into an accretion disk that starts spinning with a protostar forming in the middle
4. The protostar’s temperature increases enough to begin nuclear fusion
--How long did this take?
From nebula to nuclear fusion took about 50 million years…

12. What about the planets…?
Light gases were pushed to the outer regions of the system
Rocky materials & metallics with high melting points were left near the Sun
Through mutual gravity, particles stuck together to form rocks…and eventually planets
Accretion

13. This created two types of planets:
Terrestrial
Jovian
Mercury, Venus, Earth, Mars
Rocky & dense
Metal cores
Small
Jupiter, Saturn, Uranus, Neptune
Gaseous & less dense
Icy cores
Large
Thick atmospheres
H, He, Methane, Ammonia
Temperature
LOTS of gas and dust pushed far away from the sun…HUGE planets

15. What kind of “stuff” was in the nebula?
Gases
Hydrogen
Helium
Rocks
Silicate minerals
Metallic iron
Ices
Ammonia (NH3)
Methane (CH4)
Carbon dioxide (CO2)
Water (H2O)
This is the “stuff” that makes up our planets.

17. Bellwork 10/8
Why do we have two types of planets in our solar system? Describe how the process of solar system formation lead to these two types…

18. Meteor Shower! Draconid Meteor Shower
New Moon, so the sky should be nice and dark, making for excellent viewing conditions 
“The best evening to watch is likely October 8; try the evenings of October 7 and 9 also. Notice the word evening. This is one shower you don’t have to stay up late to see. Start watching first thing at nightfall.”

19. Quick chat about the article…

20. Pretend you’re back in biology class…What would you use to classify these organisms? Why is this necessary?

21. We sort or classify in all of the sciences.
Phylogenetic trees in Biology
Periodic table in Chemistry
Contact vs. Action at a Distance forces in Physics
What does classifying allow us to do?

22. We classify space objects as well..
Planets
Asteroids
Dwarf planet
Satellites
Comets
Trans Neptunian Objects
Let’s take a look at some of these objects and try to classify them based on physical characteristics.

23. Space Object Classification Activity
Let’s talk through what you found

24. We classify space objects as well..
Planet: an object that is in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects.
Asteroids: small rocky irregular shaped (hence no hydro-static equilibrium) objects, most of them located in the asteroid belt, roughly between the orbits of Mars and Jupiter. 

25. We classify space objects as well..
Dwarf planet: planet-like object that is generally smaller than the planet Mercury. Dwarf planets tend to orbit in zones of similar objects that can cross their path around the sun.
Satellites: a celestial body that orbits a planet

26. We classify space objects as well..
Comets: A celestial body, observed only when it is relatively close to the sun. It is made up of icy material and creates a long “tail” of vapor as it orbits the sun
Trans Neptunian Objects: any object in the solar system with all or most of its orbit beyond that of Neptune.

27. …Elephant in the room…
What about Pluto???

28. Why did Pluto get “demoted”?
August 2006: Pluto is named a “Dwarf Planet”
“The International Astronomical Union defines a planet as being in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects.
This last criterion is the point at which planets and dwarf planets differ. A planet's gravity either attracts or pushes away the smaller bodies that would otherwise intersect its orbit; the gravity of a dwarf planet is not sufficient to make this happen.”

29. Dwarf Planets in the Solar System
Probably over 200
5 “Named & Confirmed” Dwarf Planets…as of now

30. Pluto might still have a chance…
There are still lots of conversations happening about whether Pluto (and others) should be considered planets
The problem: If we let Pluto in…we have to let others in as well.
The definition of “Planet” is not clear

31. Ted Talk: Pluto’s Day of Reckoning

32. Now, given the definitions & criteria, let’s classify for real.