1. What does "critical density" mean? What is the ultimate fate of the Universe if its density is less than the critical density? What if it's greater than the critical density?
2. What elements were created by the Big Bang (hint: four)? Three of these (in some isotopic form) have often been created after the Big Bang as well, by fusion processes -- where can this happen? (Note: sometimes these elements are also "created" as by-products of radioactive decay, which is known as fission. This tends to happen after the elements in question are in relatively low-energy surroundings)
3. If the farther away a galaxy is from us, the faster it appears to be receding from us, why don't really distant galaxies show evidence of their near-lightspeed velocities, like streaming all of their gas behind them? Why would we see everything expaning away from us, if we're not the "center of the Universe?"
4. What is the "microwave background radiation" also known as the "three-degree-background"? Where does it come from? If it's a spectrum, what kind of spectrum (there are three types) is it?
5. How can the Hubble constant tell us how old the Universe is? It's good to know what the formula is, but do you also know why it works? Think about (Distance covered)=velocityXtime. If we want to know how long something's been traveling, we figure out how fast it's going and how far it's come...
6. What is the currently accepted range of values for the Hubble constant? Why does it have the funny units it has (hint: if I tell you a galaxy is 3 Mpc away, can you tell me its recession velocity?)
7. Our planet is here. What does that tell you about the history of the interstellar gas cloud that collapsed to form our Sun and its cr¸che-mates? (hint: where did the silicon come from?)
8. Why do so many things form into pancakes rather than spherical dynamical systems when they collapse? What property of the collapsing matter flattens out the mass into a pancake shape?
9. The orbits of the planets are aligned within the plane of the Sun's:
a. poles b. equator c. Sunspots d. magnetic field e. rising astrological house
10. Name the two main groups of planetary types and their members. What is the main reason for the compositional differences: a) within a group (outward from the Sun) and b) between the two groups?
11. The asteroids were discovered because their presence was suggested by the pattern shown in the _______________ rule. How was Uranus discovered? How was Neptune discovered?
12. What is the difference between a meteor and a meteorite? What is a meteoroid?
13. Why are there gaps at certain distances from the Sun in the asteroid belt?
14. What is condensation, and how is it different from accretion? How do small bodies accrete mass? How do really large bodies accrete mass?
15. Give two alternative explanations of how differentiated bodies get that way.
16. Describe the stages of clearing the nebula. The solar wind works on gas and some dust -- what works to get the boulders out?
17. Describe the four stages of terrestrial planetary development. How have these manifested themselves in Earth's history?
18. What evidence do we have for plate tectonics and continental drift?
19. Where would you expect to find the youngest surfaces on the Earth? Where would you expect to find the largest number of surviving impact craters? What do really big impact craters look like, now?
20. Where do the mountain ranges usually occur? What causes mid-ocean island chains, like Hawaii?
21. How do we know that Earth's core is partially molten (liquid)? (hint: think about earthquake detection)
22. What evidence do we have that the Earth's magnetic field, like the Sun's, occasionally changes polarity? While we're at it, what else is this evidence of?
23. What happened to all the carbon dioxide (CO2) in our atmosphere? What processes removed it? What significant difference between Earth and Venus existed that kept the same processes from removing the CO2Chapter 22: Moon and Mercury
24. What is the main compositional difference between the rocks of the lunar highlands and the mare basins?(hint: it's due to how they got there)
25. Does the moon have the same percentage of iron/nickel that Earth has? Which theories of lunar formation account for the moon's observed percentage of iron?
26. Which is older, the maria or the highlands? Describe two ways in which we can tell the relative ages of the different lunar surfaces.
27. What processes destroy the evidence of ancient craters on the Moon?
28. Are there moonquakes, and if so, where do they originate?
29. What surface feature does Mercury have that suggests that it has been shrinking as it cooled?
30. Why is Mercury the highest-density planet? Does it have any atmosphere? How about polar caps?
31. Does Mercury always keep the same face toward the Sun, or not? How long does it take to go around on its axis? How long to orbit the Sun?
32. What is responsible for the very high surface temperature of Venus -- much higher than the sunlight heating it ought to produce at that distance?
33. What sorts of compounds are found in Venus' atmosphere? What is the surface pressure, relative to Earth's?
34. I thought the presolar nebula was mostly H and He -- where did all this CO2 come from, anyway?
35. Venus has volcanoes and raised land masses such as Ishtar Terra. If that's not evidence of plate tectonics, then what causes the volcanoes and the raised land?
36. What is the weirdest aspect of Venus' rotation? Possible cause of this?
37. Mars has the highest mountain and the deepest valley in the Solar System (so far). What are they called?
38. What evidence do we see that Mars used to have a thicker CO2 atmosphere?
39. What is the future of Mars' closest moon, phobos?
40. Whay are Phobos and Deimos irregular, rather than spherical?
41. Describe the constituents of Jupiter's atmosphere as you descend into the planet. What causes the intense magnetic field?
42. What is the Great Red Spot? Where in the Solar System is there another spot of similar proportions?
43. Do any of the Jovian planets not have rings?
44. Why are Jupiter's four large inner moons called the Galilean Moons of Jupiter?
45. What size particles make up Jupiter's rings?
46. How fast does Jupiter rotate on its axis (what is the length of the "day")?
47. What is Jupiter's weather-circulation pattern called?
48. Why dopes Jupiter radiate more heat than it receives from the Sun?
49. How does the "braided" ring of Saturn stay braided?
50. Which is the moon with the greatest geologic activity in the solar system (that we know about)? Which is the moon with the thickest atmosphere? What is believed to be a source of internal heat for moons that should have cooled long ago?
51. Why is Amalthea radioactive? What does a planet have to have in order to have "radiation belts"?
52. Which planet would float in water?
53. There are at least three (or 4) places in the solar system (so far) that we've found where "space debris" or moonlets accumulate ahead of and behind bodies in their orbits. What are the points where this accumulation occurs called, and where are they along the orbit? Find all three cases in your review sheet?
54. Why is Saturn's coloration less vivid than Jupiter's?
55. Describe the layers of the atmosphere of Uranus, then of Neptune, as you descend through it. Why are there so few visible atmospheric features? Where are the clouds? What makes the blue color?
56. Which one has a weird axial tilt, and what is it?
57. What is odd about the magnetic fields of these two planets?
58. What's an ovoid, where are they found, and how might one have formed?
59. What's Pluto's structure? Compare its density with Charon's. Did Charon form as a "double planet" with Pluto, or was it captured? Why is the plane of Pluto's orbit so inclined to the ecliptic?
60. Where do periodic meteor showers come from? Where do sporadic meteors come from?
61. If you find a metallic meteorite, where did it probably come from? How can you tell it's "alien"?
62. If you find a carbonaceous chondrite, what do you know about its heating history before it entered Earth's atmosphere?
63. Which group of asteroids constitutes the greatest threat to Earth? Why are they also probably responsible for most of the asteroid collisions that create meteoroids?
64. Where does the gas come from in the gas tail of a comet?
65. Why does a comet not have a tail when it's out near the orbit of Neptune? At what radius (approximately) does the tail "turn on"?
66. Why is approaching a comet closely dangerous for spacecraft?
67. Name the three parts of a come in the inner solar system. What part remains when the comet is in the outer solar system? What other bodies might that part resemble after many passes through the inner solar system?
68. Name the three types of asteroids, and the three types of meteorites to which they most closely correspond.
69. Where do short-period comets originate (name it)? Where do long-period comets originate? Which kind has randomly-inclined orbits, and why?
70. Which planet is the biggest gravitational trouble-maker in the solar system? List some of the things it does to 1) other planets 2) planetesimals 3) comets and asteroids.
You can reach me by email at:hpreston@valdosta.peachnet.edu
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