AST 111T-Th 9:15 - 10:30

STUDY GUIDE FOR EXAM 3

MAKE SURE THAT YOUR NAME IS ON THE ANSWER SHEET AND YOU HAVE PUT IN YOUR FULL UNIVERSITY ID NUMBER-LEFT JUSTIFIED. 

DO NOT USE YOUR AFFILIATE ID NUMBER

I will subtract points if this is not done. 

BRING A PICTURE ID. I WILL ASK YOU TO PLACE IT ON THE TABLE IN FRONT OF YOU AND WILL GO AROUND THE CLASS DURING THE EXAM CHECKING EACH ID.

Chapter 20. Formation of the Solar System:

1. The earliest theories for the formation of the solar system assumed that the sun was already present and the planets formed later.2. LaPlace was the first to propose the nebular hypothesis in which the solar system formed from a contracting nebula. LaPlace understood gravity a lot better since he had the work of Newton on which to build.

3. What was the Angular Momentum problem?

4. Know that the atoms in your body (except for hydrogen and helium) were formed by nuclear processes in stars.

5. The Solar Nebula Hypothesis assumes that the sun and planets were formed at the same time out of the same material but the sun formed slightly faster than the planets.This is slightly different from what is said in the textbook but more correct.

6. What is the evidence that the Solar nebula hypothesis is probably correct?

7. What is an extra-solar planet? What physical principal (discussed in an earlier chapter) is used to find these planets?Which planets in our solar system do they resemble? 

8. Remember the difference between rotation and revolution. A planet rotates on its axis and revolves around the Sun.

9. What are the facts that must be explained in order to understand the formation of our own solar system? Discussed in class. See also Table 20-1.

10.What are the major similarities and differences between the inner Terrestrial planets and the outer Jovian planets?

11. What is the importance of impact craters in determining the evolution of the solar system?

12. What is liquid metallic hydrogen? Where is it found?

13. Why are the 4 largest satellites of Jupiter called the Galilean Satellites?

14. Where are the asteroids found? Comets? What is the Oort cloud? The Kuiper belt?

15. How is the age of the solar system determined? What is the half-life of a radioactive element?

16. What is meant by the condensation sequence of the gas in the solar nebula?

17. The planets formed in the spinning disk around the sun. Small particles condensed to form larger particles which collided to form planetesimals which collected into the proto planets. The planets closest to the sun lost most of their gas, those farthest did not.

18.Gas from young stars is blown out into space in a AStellar Wind@ that is just like the Solar Wind only more intense.This gas eventually accumulates with other gas to form new stars.

19. What is meant by differentiation of a planetary interior?

20. What is meant by outgassing?How is this related to the present atmosphere of our earth? The first atmosphere?

21. Radiation pressure describes the fact that light exerts a force on gas and small particles.

22. What are the four effects for clearing the gas from the inner part of the solar nebula?

23.Note that the nebular theory has been confirmed by studying other solar systems and regions of space where stars are forming.

24. The inner planets have higher densities - they are rocks and iron rich material. The outer planets are mostly thick atmosphere.

25. The magnetic field of the sun was tied to the spinning nebula and caused the sun to slow down. 

26. Asteroids and comets are the Aleft-overs@ from the formation of the solar system. (The turkey on Friday the 23th).

27. There were enough asteroids and comets around in the young Solar System to fall onto the surfaces of all the planets and cause craters and reheating in some cases.We cannot see the surfaces of the outer planets but their moons (except Io) also show impacts.

28. We are searching, even as you read this, for possible large bodies that might impact the earth. 

29. Deimos and Phobos are captured asteroids.

30. Our own Moon was probably caused by an impact of a large, Mars size, object with the earth after differentiation had occurred. That is why its composition resembles the mantle and crust of the earth.

31. Radioactive dating is used to determine the age of the solar system.The half-life is the time it takes for half of a radioactive element to decay into its decay element. We measure the proportion of original element to the product element to see how much time has passed.

32. Radioactive elements are produced in nova and supernova explosions. Possibly one went off nearby and caused the gas cloud to start collapsing into our sun and planets.

Chapter 21: Planet Earth

1. What are the 4 stages of planetary evolution: differentiation, cratering, flooding, slow surface evolution? What is comparative planetology?

2. What are the four processes that effect the geology of the earth and the other inner planets: impact craters, volcanism, tectonics, and erosion.

3. What is seismology? How are pressure or p-waves and shear or s-waves used to determine the internal structure of the Earth?

4. What are the various parts of the interior of the earth and where are they located?The four layers of the Earth are the inner solid core, the liquid core, the mantle, and the crust. Why is the core thought to be iron?

5.What is the heat source in the Earth's interior? How do we know the ages of the rocks?

6. The Earth has a magnetic field that protects us from particles emitted from the Sun. What are the major parts of the Earth=s magnetic field?What is the evidence that the direction of the magnetic field changes with time:

7. What is the relationship between the Aurora and the Earth=s magnetic field and radiation belts?

8. What is Plate Tectonics? Where is the Lithosphere?How is the midocean rise and midocean rift connected?

9. What is a subduction zone (see Fig 21-9)?What is basalt rock formed out of?

10. What kind of mountain range is formed from the collisions of plates?

11. A rift valley is formed when a crustal plate splits.Where is the crust of the earth thinnest? Thickest?

12. What will the continents look like in about 250 million years (figure shown in class)?Plates can slip along each other.

13.What is the evidence for plate tectonics and continental drift?What is a Convection Cell and how does it transfer heat from the interior to the surface?What is Magma?

14. The Hawaiian Islands are caused by a hot spot in a plate which brings magma to the surface and the overlying plate moves with respect to the hot spot.

15. What is the composition of the Earth=s atmosphere? How is it similar to and different from other planetary atmospheres?

16. What happened to Earth=s first atmosphere? What is the source of our current atmosphere?

17. Where is the Ozone layer located? What human effects have changed the ozone layer?

18. What is the source of the oxygen in the atmosphere?

19. What is the Greenhouse effect? What are the Greenhouse gases?Where else is the Greenhouse effect important in the solar system?

20.Our water probably came from out gassing via volcanoes and maybe cometary impact. Since it did not freeze it could absorb carbon dioxide and reduce the impact of the Greenhouse Effect. Venus was so hot that the water vapor did escape and allowed carbon dioxide to increase and produce a Runaway Greenhouse effect. 

21. What is meant by the Albedo of a planet? 

22. What is global warming and how is it related to the amount of carbon dioxide in the atmosphere? 

23.How does the depletion of Ozone affect life on the earth? What causes ozone depletion? 

Chapter 22: The Moon and Mercury: Airless Worlds.

MOON:

1. The key similarity between the Moon and Mercury is their heavily cratered surfaces.Their surfaces provide a history of the early formation of the solar system.

2. The Moon keeps the same face toward the Earth because of Tidal Coupling. How fast did it rotate in the past? How will the rotation of the Earth change over the eons?

3. What is the terminator? What is a Mare (plural is Maria)? (And I don=t mean a female horse)

4. Why are the highlands on the Moon thought to be very old? And older than the Maria?

5. Read about impact craters - I went into this in some detail in class. What do the rays from some craters tell us?

6. Is their any evidence that impacts on the Moon blasted off rocks that fell onto the Earth?

7. Know about the various missions to the Moon in the 1960's and 1970's.

8. All the rocks brought back to the earth are igneous - formed by the solidification of molten rock. 

9. What is meant by anorthosites, breccias, regolith?

10. How did we learn about the internal structure of the moon?

11. How did the maria form? About how long ago? How do we know that they are younger than the highlands?

12. The only currently viable hypothesis for the formation of the Moon is the Large-Impact hypothesis originated by Al Cameron and collaborators.

MERCURY:

1. What does the surface of Mercury look like?What kind of craters are found on Mercury?

2. Remember that Mercury is tidally locked to the sun but does not keep the same face to the Sun.

3. What is the Caloris Basin?How did its formation produce the jumbled terrain?

4. What caused the dark lava Plains? The Scarps?

5. What do we know about the internal structure of Mercury? It's origin and evolution?

6. We know less about the interior of Mercury because it does not have a moon and because we have never sent an orbiting satellite to Mercury.

Chapter 26. Solar System Leftovers: Meteorites, Asteroids, and Comets

METEORITES:

1. What are meteoroids, meteors, meteorites? Where do the particles in meteor showers come from? What is a radiant?

2. What is the history of meteorites? What is a Fall and a Find?

3. Where is the Barringer Meteorite Crater?How old is it?

4. What are the different kinds of meteorites? What is the importance of carbonaceous chondrites?

5. What is meant by pre-solar grains in meteorites? 

6. What do the existence of iron, stony-iron, and stony meteorites tell us about the asteroid belt?

7. Do some meteorites come from Asteroids? From the Moon? From Mars?

8. What is the importance of the isotope of aluminum called aluminum-26.

ASTEROIDS:

1. Who was the first to discover an asteroid? When was this and which asteroid was it? How many are known now- roughly?

2. Where are most of the asteroids located? What do they look like? What are their sizes?

3. What are the Kirkwood gaps? What are the Trojan asteroids?Where are they located?What is the importance of earth crossing asteroids to us?

4.What is the evidence for asteroid collisions? 

5. NEAR orbited and took pictures of which asteroid? Shown in class.

6. What is so interesting about Mathilde?

7. What are the major classes of asteroids? What does the designations M and S mean?

8. Where are S type asteroids found? C types?

9. What is the evidence that some meteorites come from Vesta?

COMETS

1. What are the various parts of a comet? How big are they? What is the composition of the Coma?

2. What is a type I tail? A type II tail? What causes them to face away from the sun? What are the names of some famous comets?
3. What happens to the debris from a comet after a passage near the sun?
4. How long does a comet last? How does its appearance change as it orbits the sun?
5. What was Shoemaker-Levy 9?What does its existence and behavior tell us about hits on the earth?
6. What is the Oort cloud? The Kuiper belt?
7. How often do collisions of asteroids and comets with the earth occur?
8. What is the evidence for these collisions?Is there a nearby crater?
9. What is now thought to have caused the extinction of the dinosaurs?Where is the crater probably located?
10. What was the Tunguska Event? When did it happen? What do people think was the cause?
11. Where are comets located?How do they change as they pass near the sun?