ISP205  Spring 2001 Exam #2 Study Guide:

This guide is intended to highlight the important material you should know for the second exam. It is intended that everything on the exam is covered in this review sheet.

  1. Chpt. 6 – Solar System
    1. What are the properties of our solar system?
      1. Planets lie in the same plane
      2. Orbits around the Sun are counterclockwise
      3. Most spins are counterclockwise (Venus is clockwise, Uranus is sideways)
      4. Inner planets are more dense, 5 g/cm2 (rock and iron) than the outer planets 1 g/cm2.
      5. The Sun has only 2% of the angular momentum of the solar system.
      6. Be able to recognize orbits of the planets, comets, etc. (The CAPA problem)
      7. Know the names and order of the planets.
      8. The solar system is about 4.5 billion years old.
    2. Dating Methods for things in our solar system
      1. Counting Craters

a)       The number of craters per unit area can be used to date a surface.

b)       Early in the history of the solar system, meteor bombardment was very intese

c)       About 4 billion years ago the intense bombardment stopped

d)       A very heavily cratered surface means it is older than around 4 billion years.

      1. Radioactive Rocks

a)       Half-life is the time for half of the atoms in a sample to decay.

b)       Example: Atom B decays to atom C with a certain half-life. If we start with a ratio of A:B as 10:1 what is the ratio after 2 half-lives? Answer 40:1 .

c)       The ratio of one type of atom to another can be used to date objects.

d)       Example: Comets form without argon. However they do contain potassium-40. Potassium-40 decays to argon with a half-life of 1.3 billion years. How old is the comet is the ratio of potassium-40 to Argon is 1 to 7 (1:7)? Answer: 3 half-lives or 3.9 billion years

  1. Chpt 7 - Earth
    1. How do we use seismic studies to learn about the interior of the Earth?
    2. What is escape velocity?
      1. Depends on mass and radius of a planet; more mass higher EV; larger radius, smaller EV.
      2. The temperature of a gas is related to the average kinetic energy of gas molecules. Planets with low temperature are better able to keep their atmosphere.
    3. What are tides? How often do they occur? What causes them? Have they affected the rotation of the Moon?
    4. Atmosphere of the Earth is mostly nitrogen and oxygen from the process of life and death.
    5. Know what the greenhouse effect is. What gasses cause the greenhouse effect? (CO2 – carbon dioxide, water vapor, methane)
    6. Earth has a modest greenhouse effect that raises the average temperature by more than 20 centigrade.
    7. How are the Earth's magnetic fields are generated. Know what is needed for a dynamo effect (liquid core and rapid rotation).
    8. Know the theories for the formation of the Moon and the arguments for and against each theory.
    9. Density = mass/volume (1.0 g/cm3 Water) (3.3 g/cm3 rock) (5.5 g/cm3 rocky planet with iron core). How do we determine the density of a planet? Orbital period of a moon gives the mass and diameter gives the volume.
    10. The Earth has a young surface (200 million years old) due to plate tectonics and volcanic activity.
  2. Cpht 8 - Moon and Mercury
    1. Moon
      1. due to tides it always keeps the same face toward the Earth
      2. has highlands (older heavily cratered) and maria (younger, smoother, less heavily cratered)
      3. water has been found in craters near the poles
      4. overall density around 3.3 g/cm3 implies it is mostly rock.
    2. We think the Moon was formed in a giant collision between the Earth and another Planet early in the history of the solar system. This is called the giant impact or collision theory.
    3. Mercury
      1. surface similar to the highlands on the Moon
      2. most heavily cratered planet
      3. wide variation in surface temperature due to the lack of an atmosphere
    4. Why are craters circular? Impact causes the meteor to explode, making a circular impression.
  3. Chpt 9 – Venus and Mars
    1. Venus, very hot, volcanic activity, massive greenhouse effect from a thick carbon dioxide atmosphere, sulfuric acid clouds; Earth, life, ozone layer, a moderate greenhouse effect
    2. Mars, ancient volcanoes (volcanic activity stopped about 3 billion years ago); CO2 atmosphere, very low pressure; Olympus Mons + Valley of the Mariners; has a polar ice cap; shows lots of evidence for large amounts of water on its surface at one time; evidence from meteorites hints at early life on Mars.
    3. Nature of atmospheres:
      1. Mercury - low gravity + near the Sun means no atmosphere
      2. Venus - no liquid water means high CO2 levels (greenhouse effect)
      3. Earth - liquid water mean CO2 absorbed; life leads to nitrogen and oxygen; just the right greenhouse effect
      4. Mars – major volcanic activity stopped early due to Mars’s small size; low CO2 means no greenhouse effect and water remains frozen
  4. Chpt. 10 – Gas Giant Planets
    1. Know roughly the characteristics of the Jovian planets
      1. Jupiter - great red spot (a big hurricane), mostly hydrogen and helium
      2. Saturn - density less than water (it would float if we had a big bathtub, mostly hydrogen and helium, the upper atmosphere is depleted in helium
      3. Uranus - tipped on its side (most extreme seasons)
      4. Neptune – had the Great dark spot ( a big storm like the great red spot on Jupiter)
    2. Know the structures shown in figure 10.7
    3. Know what excess energy is and which planets have it. Where does the excess energy come from? Jupiter – left over, Saturn – falling helium, Neptune – probably falling heavier gasses
    4. Know which planets have magnetic fields.
  5. Chpt. 11 – Rings, Moons and Pluto
    1. Know the features of Jupiter’s Galilean satellites and the explanation for these features.
      1. Io – giant spherical pizza
      2. Europa – ice crust, water ocean underneath, chance of life
      3. Ganymede – largest moon (bigger than Mercury and almost the size of Mars), differentiated
      4. Callisto – very heavily cratered
    2. Know about Saturn’s moon Titan – atmosphere 60% greater than Earth’s, hydrocarbons in atmosphere and on the surface
    3. Know about Triton, a moon of Neptune – has nitrogen geysers
    4. Pluto
      1. Is like Triton, the frozen moon of Neptune
      2. It is possible Pluto and Triton were both moons of Neptune and an interaction through Pluto out and Triton ended up orbiting backwards.
      3. Pluto has a moon Charon
    5. Rings
      1. Jupiter - close to the cloud tops, made from volcanic activity and debris chipped of the inner moons.
      2. Saturn -many (complicated) rings made up of chunks of ice, spokes, braided rings
      3. Uranus - many thin widely spaced rings
      4. Neptune - material of varying composition. Has bright sections that look like arcs.
  6. Chpt. 12 – Comets and Asteroids
    1. Know the parts of a comet
    2. Know what the Oort and Kuiper comet clouds are.
    3. Comet details
      1. Very elliptical orbits
      2. Appear to come from all directions on the celestial sphere.
      3. Short-period comets (100 years) come from the Kuiper belt. Halleys (76 year period) comet is an example.
      4. Long-period comets come from the Oort Cloud
    4. Asteroids (Minor Planets)
      1. Characteristics (3 main types, made of carbon, metals, rock)
      2. Know orbits (most are found in the asteroid belt and have nearly circular orbits)
      3. Know where the Trojan asteroids are located.
  7. Chpt. 13 – Meteors and the Origin of the Solar system
    1. Know some of the details of the nebular hypothesis for the formation of the solar system
      1. Large cloud collapses, angular momentum keeps all the material from falling into the center
      2. Potential energy is converted to kinetic energy and the inner part of the solar system is hotter.
      3. The Sun has only 2% of the angular momentum of the solar system. This is a problem for the nebular hypothesis.
      4. The inner planets formed in a hotter environment and thus are made of metals. Outer planets have gas because they were cooler.
    2. Meteors, meteor shows and meteorites
      1. What causes a meteor shower?
      2. Meteor is a comet that enters the Earth’s atmosphere. Meteorite is the object found on the Earth.
      3. A meteorite from Mars shows evidence for ancient life.
  8. Chpt. 14 – Our Sun
    1. Know the basics of the structure of our Sun and what goes on in the various parts (see figure 14.1)
      1. photosphere - bright visible surface where absorption lines form; shows granulation
      2. chromosphere - cooler pinkish region beyond the photosphere (can be seen during an eclipse)
      3. corona – hot, thin outermost region of the Sun
      4. solar wind – stream of fast particles leaving the Sun
      5. know about prominences and flares (flares are tremendous explosions with the power of a million hydrogen bombs)
    2. Sunspots
      1. what is the Sun spot cycle in years? 11 years between maximums, 22 years total
      2. What causes the Sunspots? Twisting of the Sun's magnetic fields
      3. Low sunspot activity around 1300 appears correlated with a mini ice age.
    3. The Sun appears to be variable in its output.