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Pathways to Astronomy

Stephen E. Schneider

Chapter 42

Comparative Planetology - all with Video Answers

Educators

Chapter Questions

02:20

Problem 1

What differences between the planets support the solar nebula theory for the formation of the Solar System?

Rodger Claar
Rodger Claar
Numerade Educator
04:34

Problem 2

Compare the lengths of the sidereal and solar days for each of the terrestrial planets as given in Table 42.1 . Are the reasons for the differences in the lengths of these days the same for each planet? Explain.

Farhanul Hasan
Farhanul Hasan
Numerade Educator
01:58

Problem 3

Table 42.2 lists the sidereal and solar days for the four giant planets. Why are these values the same for each of these planets?

Brandon Fox
Brandon Fox
Numerade Educator
01:37

Problem 4

The mass of Uranus is about 14.5 times that of the Earth, yet the escape velocity for Uranus is a little less than twice that of Earth's. Explain the seeming discrepancy.

Narayan Hari
Narayan Hari
Numerade Educator
01:10

Problem 5

Scientists classify objects based upon various characteristics. If we rank the terrestrial planets according to their densities (mass divided by volume), we will get one relationship. If we then rank the terrestrial planets according to their uncompressed densities, we will get a slightly different relationship. Compare the rankings. What do the differences in the rankings tell us about the planets themselves?

Jheremiah Simon
Jheremiah Simon
Numerade Educator
02:18

Problem 6

Examine the data in Tables 42.1 and $42.2,$ and consider that the average speed of a molecule in a gas with temperature $T$ is approximately
\[
V_{m o l}=0.15 \mathrm{km} / \mathrm{sec} \times \sqrt{T / m}
\]
where $T$ is the temperature in Kelvin and $m$ is the mass of the molecule in atomic mass units; so $m\left(\mathrm{H}_{2}\right)=2,$ and $m\left(\mathrm{CO}_{2}\right)=$
44. About how many times smaller than the escape velocity does $V_{m d}$ have to be for a planet to retain a gas?

Sri Datta Vikas Buchemmavari
Sri Datta Vikas Buchemmavari
Numerade Educator
05:30

Problem 7

Heating by the Sun decreases with distance. For an object absorbing all sunlight, we can predict that the temperature will be $227 \mathrm{K} \times(1 / \sqrt{a}),$ where a is the distance from the Sun in AU. Find the expected temperatures at the distances of Venus, Mars, and Jupiter. What factors might cause the temperatures to differ from what this formula yields?

Eduard Sanchez
Eduard Sanchez
Numerade Educator