You should try to understand the questions by looking at your notes and the textbook.
Chapter 7: (Start of chapter)
1. Are all the planets similar to the Earth, or are they all very different? The
terrestrials are similar, the Jovians are very different.
2. Do other planets have Moons like the Earth’s Moon? Yes, some other planets
have Moon’s like ours, but not all planets have Moons.
3. How do astronomers know what the other planets are made of? They can look at
the average density (terrestrials are denser than the Jovians). They can also use
spectroscopy.
4. Are all the planets made of basically the same material? No, the terrestrials are
made of heavier elements like iron and silicon, while the Jovians have ore
hydrogen and helium.
5. What is the difference between an asteroid and a comet? An asteroid comes from
the asteroid belt between Mars and Jupiter—it is mostly rock. A comet comes
from beyond the orbit of Neptune (for example the Kuiper belt) and has rock and
ice in it.
6. Why are craters common on the Moon and rare on the Earth? The Moon’s surface
is much older—it hasn’t done any “renewal.” Earth is constantly “erasing” its
craters through weathering, erosion, and geologic activity.
7. If a planet has a magnetic field, what does that indicate? A magnetic field
indicates a planet or satellite has a liquid core and an active geology.
8. Do all planets have a common origin? In the nebular hypothesis, the planets
formed together in the nebular disk
9. Do all the planets orbit the Sun in the same direction? Yes. Are all orbits
circular? No.
10. Are all of the planets rotating (on their axis) in the same direction that they orbit
the Sun? No, Uranus is on its side
11. What are the characteristics of a terrestrial planet? Close to the Sun, hard surface,
smaller than Jovians, higher density than Jovians.
12. What are the characteristics of a Jovian planet? Large, farther from Sun than
terrestrials, no hard surface, lower density than terrestrials.
13. In what ways does Pluto not fit the usual classification of either terrestrial or
Jovian planets? Pluto is small with a hard surface like the terrestrials, but it is
beyond the orbit of Neptune. It has a density somewhere between the terrestrials
and the Jovians.
14. What is meant by the average density of a planet? What does the average density
tell us? The average density is the total mass of the planet divided by its total
volume. The average density is an indicator of the composition of the planet.
15. In what ways are the largest satellites (“moons”) in the solar system like the
terrestrial planets? They have hard surfaces and high densities. In what ways are
they different? They orbit planets rather than the Sun, they are actually a little
smaller and a little less dense than the terrestrials.
16. What are the differences in chemical composition between the terrestrial and the
Jovian planets? The terrestrials are primarily iron and magnesium and heavier
elements—the Jovians are primarily hydrogen and helium and light elements.
17. What is unique about Uranus motion? It is rotating on its side.
18. Why are hydrogen and helium abundant in Jovian atmospheres, but rare in
terrestrial atmospheres? The Jovians have large gravitational fields which can
trap these light gases, The terrestrials are warm and have smaller gravitational
fields, so the hydrogen and helium can escape.
19. What is an asteroid? What is a comet? In what ways are these members of the
solar system like or unlike planets? Asteroids come from the asteroid belt between
Jupiter and Mars. Comets typically come from the Kuiper belt outside the orbits
of Neptune and Pluto.
20. Where are the asteroid belt and the Kuiper belt, where are they located?
21. What is one piece of evidence that impact craters are actually caused by impacts?
The central peak in craters is the result of an impact.
22. What is the relationship between the extent to which a planet is cratered and the
amount of geologic activity on that planet. More cratering means less geologic
activity.
23. How do Robotic spacecraft work? They use computer controls, their own power
(often solar power), cameras and other sensing instruments.
24. What are the 4 major categories of robotic missions?
a. Flyby—just goes past the planet
b. Orbiter—goes into orbit around he planet
c. Lander—lands on the planet or enters its atmosphere
d. Sample return mission—gets a sample from the planet (or other object)
and returns the sample to Earth.
Keywords: asteroid belt, impact crater, spectroscopy