Download Chapter 9 Practice Questions

Name: __________________________ Date: _____________
1. The asteroid belt exists between the orbits of the planets
A) Earth and Mars.
B) Jupiter and Saturn.
C) Venus and Earth.
D) Mars and Jupiter.
2. If all the material in the asteroid belt were to be combined to produce a
planet, how big would it be?
A) About 1500 km in diameter, significantly smaller than the Moon
B) Only a few kilometers in diameter, similar to an average mountain on
the Earth
C) About the size of the Earth, with a diameter of about 13,000 km.
D) About the size of Mercury, with a diameter of about 5000 km.
3. The number of asteroids with diameters greater than 100 km is
A) just over 1000.
B) 3.
C) about 30.
D) about 230.
4. The total number of asteroids orbiting the Sun among the planets is
estimated to be
A) several thousand.
B) hundreds of billions.
C) more than a million.
D) a few hundred.
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5. How would a typical asteroid appear on a time exposure photograph of the
sky as it orbited the Sun if the camera were tracking the background stars.
A) It would look like any other star, a small extra dot not shown on star
charts of this area of the sky.
B) It would look like a small, diffuse patch against the sharp images of
stars because of the dust and gas surrounding it.
C) It would produce a flash of light as it crossed the field of view of the
camera.
D) It would produce a short trail as it moved slowly against the
background stars.
6. Where do the Trojan asteroids orbit the Sun?
A) In circular orbits at the same orbital distance as Jupiter
B) In circular orbits at the same orbital distance as the Earth
C) Within the asteroid belt, so-named because they are large
D) In elliptical orbits that cross the orbit of the Earth
7. What is the difference between an Apollo asteroid and an Amor asteroid?
A) Apollo asteroids cross the orbit of the Earth, whereas Amor asteroids
cross the orbit of Mars but not the Earth's orbit.
B) Apollo asteroids orbit entirely inside the Earth's orbit and therefore do
not cross it, whereas Amor asteroids cross the Earth's orbit and
therefore might hit the Earth.
C) Apollo asteroids pass near terrestrial planets, whereas Amor asteroids
remain in the same orbit as Jupiter.
D) Apollo asteroids approach the orbit of Mercury, whereas Amor
asteroids pass only within the orbit of the Earth.
8. The Kuiper belt is
A) another name for the asteroid belt.
B) a flat or donut-shaped distribution of distant comets around the Sun,
extending out about 500 AU.
C) a spherical distribution of distant comets around the Sun, extending out
about 50,000 AU.
D) a random distribution of short-period comets extending from inside the
orbit of Jupiter to approximately the orbit of Neptune.
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9. Most comet nuclei are believed to be
A) carbonaceous chondrite meteorites, carbon material, ignited by sunlight
and trailing long smoke trails.
B) pieces of dusty ice left over from the formation of the solar system.
C) pieces of dirty ice ejected from the surface of the icy satellites of the
outer planets by asteroid impacts.
D) pieces of rock or iron chipped from asteroids by impacts.
10. Comet tails are the result of
A) melting and evaporation of ices from the comet core.
B) sunlight glinting on the central icy comet core.
C) interplanetary dust collected by the comet as it moves in its orbit.
D) interplanetary material streaming into the comet because of its gravity.
11. A comet's tail
A) always points toward the nearest planet, being attracted by its gravity
field as the comet passes by it.
B) always trails behind the comet in its orbit, and so points away from the
Sun only while the comet is approaching the Sun.
C) always points away from the Sun, regardless of the motion of the
comet.
D) points toward the Sun because it is caused by jets of gases evaporated
from the comet's nucleus on the side heated by the Sun.
12. The orbits of comets are
A) primarily in the plane of the ecliptic and can extend far out beyond the
orbit of Pluto.
B) randomly oriented in the solar system and confined to distances closer
to the Sun than approximately the orbit of Pluto.
C) primarily in the plane of the ecliptic and confined to distances closer to
the Sun than approximately the orbit of Pluto.
D) randomly oriented in the solar system and can extend far beyond the
orbit of Pluto.
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13. A meteoroid is the name used to describe a solid particle that
A) is drifting around in space.
B) has fallen to the Earth from space.
C) burns up as it falls through the Earth's atmosphere.
D) originated on the Moon but was knocked onto the Earth by a massive
impact.
14. A meteor shower results from
A) material ejected by a massive impact on the Moon; the Earth's gravity
attracts it toward the Earth.
B) material re-entering the Earth's atmosphere after being ejected into
space by violent volcanic eruptions on the Earth.
C) the Earth passing through debris of an old comet.
D) a small piece of rock fragmenting as it passes through the Earth's
atmosphere.
15. Which are the most common types of meteoroids in space?
A) Stony-irons
B) Stones
C) Irons
D) Carbonaceous chondrites
16. The most common meteorites to hit the Earth are
A) the carbonaceous chondrites.
B) the iron meteorites.
C) the stony-iron meteorites.
D) the stony meteorites.
17. What fraction of the material arriving on the Earth from outer space is in
the form of iron meteorites?
A) 50%
B) A few %
C) 95%
D) 10 to 20%
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18. What fraction of the material arriving on the Earth from outer space is in
the form of stony meteorites?
A) A few %
B) 10 to 20%
C) 50%
D) 95%
19. Stony-iron meteorites are believed to
A) have been ejected by volcanoes on Mars.
B) originate from differentiated asteroids (in which iron sank to the
center).
C) be pieces of primordial solar system material, unaltered since the solar
system formed.
D) originate from undifferentiated asteroids (same composition
throughout).
20. Why are carbonaceous chondrites thought to be original material that
formed in the early solar nebula?
A) They show a Widmanstätten pattern, which indicates slow condensation
from gaseous material.
B) Their minerals contain up to 20% water, which would have evaporated
away if the chondrite had been strongly heated.
C) They consist mostly of carbon, which was the dominant substance
condensing in the outer solar nebula.
D) They consist almost entirely of ice, which would have sublimed away
by now if this were not the first time the chondrite was passing close to
the Sun.
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21. What is the likely connection between the metal iridium and the demise of
the Earth's dinosaur population?
A) Iridium, which is found in abundance on Earth's surface, is poisonous to
reptiles.
B) Iridium is found beneath the Earth's crust. Meteor impacts during the
dinosaur age probably exposed and uncovered enough of it to poison
the dinosaurs.
C) Iridium is found in meteorites but is rare on the Earth. The existence of
a world-wide layer of it suggests a large meteor impact during the
dinosaur age. This probably raised enough dust to block out sunlight
and kill the dinosaurs.
D) Iridium is highly radioactive. Its presence in a geologic layer dating to
the dinosaur age suggests that natural radioactivity reached dangerous
levels at that time, and the dinosaurs died from overexposure.
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Answer Key
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