Homework 4

  1. Chapter 10, problems 4—7
    1. Nonsense. Earth's orbit is nearly circular, but it has very nice seasons!
    2. Not plausible. If the solar wind were stronger, there would be more bomdment creating more atmosphere, but it would still be silicates.
    3. Not plausible. Earth needs that extra 33 K of temperature to be warm enough for liquid water!
    4. No plausible. Venus is farther from the Sun than Mercury, but it is much hotter than Mercury is. The greenhouse effect can overwelm the distance factor.
  2. Chapter 10, problem 8
    1. Because of Venus's high albedo, most of the sunlight is reflected away from the planet, thus not being used to heat it.
    2. Venus would be hotter than the no-greenhouse temperature (since the albedo would drop), but it would not be as hot as it is with the greenhouse effect.
    3. Clouds on Venus are due to sulfuric acid. If the sufuric acid goes away, the clouds go away, too. The source of the acid is volcanic outgasing. So if the volanoes turn off, the sufuric acid goes away and the clouds disappear.
  3. Chapter 11, problems 1—5
    1. Not reasonable. No impactors would make it down that far. And there would be no basaltic lava, given that the core is mostly ices.
    2. Not reasonable. There is not "surface" on Neptune. Neptune is too cold for liquid water at normal pressures. And water isn't blue, it reflects the blue sky. So Neptune would still need a blue sky.
    3. Sounds reasonable. Mars-sized is a bit large, but not so very large that it would be totally overwelming. After all, there are giant-planet moons which are bigger than Mercury.
    4. According to the pillow effect, any planet the mass of Jupiter should be the same radius, roughly. (There will be a slight expansion if the planet is closer to its sun, but not by that much.)
    5. Not reasonable. Small moons at large distances shouldn't have enough heating (tidal, radioactive, accretion or differentiation) to drive volcanic activity.
  4. Chapter 11, problem 8
    Not reasonable. The rings are produced by removing material from moons. If the moons don't exist, then there should be no rings. (Especially since rings don't last very long.)