A piece of space debris that you pick up from the ground is called a(n):

Space debris that is a roughly equal mix of rock and ice is called a(n):

Which is the rarest type of meteorite found on Earth?

Which part of a comet is solid?

Suppose you were standing on Pluto. Describe the motions of Charon relative to the horizon. Under what circumstances would you never see Charon?

Describe the circumstantial evidence that supports the idea that Pluto is one of a thousand similar icy worlds that once occupied the outer regions of the solar system.

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What role did Charon play in enabling astronomers to determine Pluto’s mass?

Why are asteroids, meteoroids, and comets of special interest to astronomers who want to understand the early history of the solar system?

Describe the objects in the asteroid belt, including their sizes, orbits, and separation.

To test your understanding of the asteroid belt, do Interactive Exercise 8.1 on the assigned Web site. You can print out your results, if required.

Why are there many small asteroids but only a few very large ones?

Describe the different chemistries of the two tails of a comet.

In what directions do comet tails point, and why?

What are the Kirkwood gaps, and what causes them?

What are the Trojan asteroids, and where are they located?

Describe the three main classifications of meteorites. How do astronomers believe that these different types of meteorites originated?

Why do astronomers believe that the debris that creates many isolated meteors comes from asteroids, whereas the debris that creates meteor showers is related to comets?

To test your understanding of comets, do Interactive Exercise 8.2 on the assigned Web site. You can print out your results, if required.

Why is the phrase “dirty snowball” an appropriate characterization of a comet’s nucleus?

What and where is the Kuiper belt, and how is it related to debris left over from the formation of the solar system?

Why do scientists think the Tunguska event was caused by a large meteoroid and not a comet?

What evidence in Figure 8-35 supports the labeling of the ion (gas) and dust tails?

Would you expect the surfaces of Pluto and Charon to be heavily cratered? Explain.

How did the regolith on asteroid Eros form?

Why are comets generally brighter after passing perihelion (closest approach to the Sun) than before reaching perihelion?

Can you think of another place in the solar system where a phenomenon similar to the Kirkwood gaps in the asteroid belt is likely to exist? Explain your answer.

Where on Earth might you find large numbers of stony meteorites that have not been significantly changed by weathering?

Assuming a constant rate of meteor infall, how much mass has Earth gained in the past 4.6 billion years?

Suppose it was discovered that the asteroid Hermes had been perturbed in such a way as to put it on a collision course with Earth. Describe what you would do to counter such a catastrophe using present technology.

From the abundance of craters on the Moon and Mercury, we know that numerous asteroids and meteoroids struck the inner planets during the very early history of the solar system. Is it reasonable to suppose that numerous comets also pelted the planets 4 to 4½ billion years ago? What effects would such a cometary bombardment have had, especially with regard to the evolution of the primordial atmospheres of the terrestrial planets and oceans on Earth?

What are the differences between meteors, meteorites, and meteoroids?

Where are asteroids found in the solar system?

Why is Pluto no longer considered a planet?

Are planets the only solar system bodies with moons? If not, what other types of solar system bodies have them?

What is the typical separation between asteroids in the asteroid belt?

Of the following objects, which are the largest?