Question 1

The asteroid Vesta is believed to have suffered a major collision a few billion years ago. Where is the debris created from this collision?

Accepted Answer

A) The gravity of the asteroid pulled virtually all of it back to Vesta, where it created a "rubble pile" resting in the crater. 
B) It now exists as a small satellite orbiting Vesta. 
C) The Dawn spacecraft imaged the crater on Vesta in infrared. The chemical composition was found to match that of many of the meteorites that have landed on Earth. 
D) It was pulverized into a fine white dust that blankets much of Vesta. 
A) The gravity of the asteroid pulled virtually all of it back to Vesta, where it created a "rubble pile" resting in the crater. 
B) It now exists as a small satellite orbiting Vesta. 
C) The Dawn spacecraft imaged the crater on Vesta in infrared. The chemical composition was found to match that of many of the meteorites that have landed on Earth. 
D) It was pulverized into a fine white dust that blankets much of Vesta.

Question 2

The first asteroid to be photographed in detail by a spacecraft was:

Accepted Answer

A) Ceres. 
B) Icarus. 
C) Gaspra. 
D) Vesta. 
A) Ceres. 
B) Icarus. 
C) Gaspra. 
D) Vesta.

Question 3

Widmanstätten patterns uniquely identify samples as iron meteorites. Why is this?

Accepted Answer

A) These patterns require iridium, which is common in iron meteorites but is rare on Earth. 
B) Widmanstätten patterns are radioactive. 
C) These patterns involve crystals, which only form after millions of years of slow cooling. 
D) These patterns are actually cracks in the structure of the meteorite that form only when an iron meteorite becomes heated during its passage through Earth's atmosphere. 
A) These patterns require iridium, which is common in iron meteorites but is rare on Earth. 
B) Widmanstätten patterns are radioactive. 
C) These patterns involve crystals, which only form after millions of years of slow cooling. 
D) These patterns are actually cracks in the structure of the meteorite that form only when an iron meteorite becomes heated during its passage through Earth's atmosphere.

Question 4

The general shape of most asteroids is thought to be:

Accepted Answer

A) double lobed, as though two asteroids had stuck together. 
B) perfectly spherical. 
C) oblong but smooth. 
D) irregular. 
A) double lobed, as though two asteroids had stuck together. 
B) perfectly spherical. 
C) oblong but smooth. 
D) irregular.

Question 5

Which one of the following parts of a comet is not visible to the naked eye?

Accepted Answer

A) dust tail 
B) ion tail 
C) coma 
D) hydrogen envelope 
A) dust tail 
B) ion tail 
C) coma 
D) hydrogen envelope

Question 6

What is the orbital sidereal period of a Trojan asteroid?

Accepted Answer

A) The period is 1.88 years. 
B) It is difficult to be specific because they all have different orbital periods, depending on their masses. 
C) The period is 5.9 years, the same as most asteroids in the asteroid belt. 
D) The period is 11.86 years. 
A) The period is 1.88 years. 
B) It is difficult to be specific because they all have different orbital periods, depending on their masses. 
C) The period is 5.9 years, the same as most asteroids in the asteroid belt. 
D) The period is 11.86 years.

Question 7

A comet's gas and ion tail:

Accepted Answer

A) always lies in the ecliptic plane, because a comet is a part of the solar system. 
B) lies between the comet and the Sun, because of gravitational attraction. 
C) always trails along the orbital path, because of the comet's motion. 
D) is always blown away from the comet in the anti-Sun direction by the solar wind. 
A) always lies in the ecliptic plane, because a comet is a part of the solar system. 
B) lies between the comet and the Sun, because of gravitational attraction. 
C) always trails along the orbital path, because of the comet's motion. 
D) is always blown away from the comet in the anti-Sun direction by the solar wind.

Question 8

Some meteorites have been identified as coming from other bodies in our solar system. Which of the following is NOT one of those sources?

Accepted Answer

A) Ceres 
B) Moon 
C) Vesta 
D) Mars 
A) Ceres 
B) Moon 
C) Vesta 
D) Mars

Question 9

Stony meteorites:

Accepted Answer

A) are composed of rocks similar to terrestrial rocks. 
B) contain large quantities of carbon and H2O, and even hydrocarbons and amino acids. 
C) have solid iron cores and rocky silicate shells. 
D) are made of solid iron and nickel. 
A) are composed of rocks similar to terrestrial rocks. 
B) contain large quantities of carbon and H2O, and even hydrocarbons and amino acids. 
C) have solid iron cores and rocky silicate shells. 
D) are made of solid iron and nickel.

Question 10

Recent calculations show that the Tunguska explosion in Siberia in 1908, which had an explosive power of several hundred kilotons of TNT, was probably caused by:

Accepted Answer

A) a small comet nucleus about 150 m across suddenly vaporizing in the atmosphere. 
B) the impact and annihilation of a very small amount of antimatter from somewhere else in the universe. 
C) a small natural nuclear explosion in uranium deposits. 
D) a small stony asteroid about 80 m across disintegrating explosively in the atmosphere before hitting the ground. 
A) a small comet nucleus about 150 m across suddenly vaporizing in the atmosphere. 
B) the impact and annihilation of a very small amount of antimatter from somewhere else in the universe. 
C) a small natural nuclear explosion in uranium deposits. 
D) a small stony asteroid about 80 m across disintegrating explosively in the atmosphere before hitting the ground.

Question 11

The Widmanstätten pattern uncovered by acid etching of the surfaces of many iron meteorites consists of:

Accepted Answer

A) fracture lines, created by the impact that knocked the meteoroid off the parent asteroid. 
B) large crystals, formed as the iron cooled slowly over many millions of years. 
C) small holes and bubbles, created by partial melting of the meteorite as it entered Earth's atmosphere. 
D) minute crystals, formed when the iron cooled quickly in the vacuum of space. 
A) fracture lines, created by the impact that knocked the meteoroid off the parent asteroid. 
B) large crystals, formed as the iron cooled slowly over many millions of years. 
C) small holes and bubbles, created by partial melting of the meteorite as it entered Earth's atmosphere. 
D) minute crystals, formed when the iron cooled quickly in the vacuum of space.

Question 12

Which of the following governs the direction in which a comet's ion tail is aligned in space?

Accepted Answer

A) its direction of motion, because the tail simply trails behind it in its orbit 
B) the gravitational attraction of the Sun for the tail material 
C) the gravitational attraction of Earth for the tail material 
D) the flow of solar wind past the comet's nucleus 
A) its direction of motion, because the tail simply trails behind it in its orbit 
B) the gravitational attraction of the Sun for the tail material 
C) the gravitational attraction of Earth for the tail material 
D) the flow of solar wind past the comet's nucleus

Question 13

A stony meteorite might show evidence of each of the following EXCEPT ONE. Which is the EXCEPTION?

Accepted Answer

A) carbonaceous chondrites 
B) fusion crust 
C) high abundance of 26Mg 
D) Widmanstätten pattern 
A) carbonaceous chondrites 
B) fusion crust 
C) high abundance of 26Mg 
D) Widmanstätten pattern

Question 14

What influence did Jupiter have on the formation of the asteroid belt, and how do we know?

Accepted Answer

A) We have watched other solar systems in their early stages of formation. They show Jupiter-size planets clearing out much of their asteroid belts. 
B) Computer simulations have shown that in the absence of a Jupiter-size planet, an Earth-size planet would have formed in the asteroid belt. 
C) Computer simulations have shown that a Jupiter-size planet has no influence on the formation of the asteroid belt. 
D) We have watched other solar systems in their early stages of formation. They show that Jupiter-size planets have no influence on the formation of an asteroid belt. 
A) We have watched other solar systems in their early stages of formation. They show Jupiter-size planets clearing out much of their asteroid belts. 
B) Computer simulations have shown that in the absence of a Jupiter-size planet, an Earth-size planet would have formed in the asteroid belt. 
C) Computer simulations have shown that a Jupiter-size planet has no influence on the formation of the asteroid belt. 
D) We have watched other solar systems in their early stages of formation. They show that Jupiter-size planets have no influence on the formation of an asteroid belt.

Question 15

Although there is no official dividing line, a chunk of rock orbiting the Sun is generally considered an asteroid rather than a meteoroid if it:

Accepted Answer

A) is larger than 1 cm across. 
B) is larger than 1 m across. 
C) is larger than 2 km across. 
D) has a mass larger than 1% the mass of Earth. 
A) is larger than 1 cm across. 
B) is larger than 1 m across. 
C) is larger than 2 km across. 
D) has a mass larger than 1% the mass of Earth.

Question 16

Astronomers have been searching for additional planets, especially since the discovery of Uranus in 1781. But why were efforts concentrated around 2 to 3 au from the Sun in the early nineteenth century?

Accepted Answer

A) Kepler's third law predicts a planet within this distance. 
B) The Titus-Bode law predicts a planet within this distance. 
C) The discrepancies in Uranus's orbit suggested a planet around this radius. 
D) The telescope, newly invented in 1781, was not powerful enough to detect anything beyond this range. 
A) Kepler's third law predicts a planet within this distance. 
B) The Titus-Bode law predicts a planet within this distance. 
C) The discrepancies in Uranus's orbit suggested a planet around this radius. 
D) The telescope, newly invented in 1781, was not powerful enough to detect anything beyond this range.

Question 17

As of 2013, we had done all of the following comet investigations EXCEPT ONE. Which is the EXCEPTION?

Accepted Answer

A) flying past a comet with a spacecraft 
B) collecting dust near the nucleus of a comet 
C) smashing a projectile onto a comet's surface 
D) landing on the surface of a comet 
A) flying past a comet with a spacecraft 
B) collecting dust near the nucleus of a comet 
C) smashing a projectile onto a comet's surface 
D) landing on the surface of a comet

Question 18

The surfaces of the asteroids Ida and Mathilde, photographed by the Galileo and NEAR Shoemaker spacecraft show:

Accepted Answer

A) icy surfaces crisscrossed with cracks and systems of parallel grooves. 
B) young, sharp, jagged surfaces, due to fragmentation by collision with other asteroids, and few craters. 
C) irregular, somewhat rounded and moderately cratered surfaces. 
D) ancient surfaces densely covered with large and small overlapping craters, like the surface of the highland areas of the Moon. 
A) icy surfaces crisscrossed with cracks and systems of parallel grooves. 
B) young, sharp, jagged surfaces, due to fragmentation by collision with other asteroids, and few craters. 
C) irregular, somewhat rounded and moderately cratered surfaces. 
D) ancient surfaces densely covered with large and small overlapping craters, like the surface of the highland areas of the Moon.

Question 19

It is believed there were originally far more objects in the asteroid belt than there are now. What happened to the rest of them?

Accepted Answer

A) The gravitational influence of Jupiter deflected most of them out of the solar system. 
B) Mars-sized objects moving through the asteroid belt disrupted the orbits and deflected most of them out of the solar system. 
C) The majority of the original asteroids coalesced to form a series of Mars-sized objects, one of which struck Earth and caused the formation of the Moon. 
D) A passing star pulled most of the original asteroids out of the solar system. 
A) The gravitational influence of Jupiter deflected most of them out of the solar system. 
B) Mars-sized objects moving through the asteroid belt disrupted the orbits and deflected most of them out of the solar system. 
C) The majority of the original asteroids coalesced to form a series of Mars-sized objects, one of which struck Earth and caused the formation of the Moon. 
D) A passing star pulled most of the original asteroids out of the solar system.

Question 20

When the solar system first formed, there were numerous icy planetesimals in the vicinity of the newly formed jovian planets. What happened to most of these planetesimals?

Accepted Answer

A) They formed the Kuiper belt. 
B) They formed the inner, doughnut-shaped part of the Oort cloud. 
C) They formed the outer, spherical part of the Oort cloud. 
D) They were expelled from the solar system by interaction with Jupiter's gravity. 
A) They formed the Kuiper belt. 
B) They formed the inner, doughnut-shaped part of the Oort cloud. 
C) They formed the outer, spherical part of the Oort cloud. 
D) They were expelled from the solar system by interaction with Jupiter's gravity.

Exam 15: Asteroids, Comets, and Impacts

The asteroid Vesta is believed to have suffered a major collision a few billion years ago. Where is the debris created from this collision?

The first asteroid to be photographed in detail by a spacecraft was:

Widmanstätten patterns uniquely identify samples as iron meteorites. Why is this?

The general shape of most asteroids is thought to be:

Which one of the following parts of a comet is not visible to the naked eye?

What is the orbital sidereal period of a Trojan asteroid?

A comet's gas and ion tail:

Some meteorites have been identified as coming from other bodies in our solar system. Which of the following is NOT one of those sources?

Stony meteorites:

Recent calculations show that the Tunguska explosion in Siberia in 1908, which had an explosive power of several hundred kilotons of TNT, was probably caused by:

The Widmanstätten pattern uncovered by acid etching of the surfaces of many iron meteorites consists of:

Which of the following governs the direction in which a comet's ion tail is aligned in space?

A stony meteorite might show evidence of each of the following EXCEPT ONE. Which is the EXCEPTION?

What influence did Jupiter have on the formation of the asteroid belt, and how do we know?

Although there is no official dividing line, a chunk of rock orbiting the Sun is generally considered an asteroid rather than a meteoroid if it:

Astronomers have been searching for additional planets, especially since the discovery of Uranus in 1781. But why were efforts concentrated around 2 to 3 au from the Sun in the early nineteenth century?

As of 2013, we had done all of the following comet investigations EXCEPT ONE. Which is the EXCEPTION?

The surfaces of the asteroids Ida and Mathilde, photographed by the Galileo and NEAR Shoemaker spacecraft show:

It is believed there were originally far more objects in the asteroid belt than there are now. What happened to the rest of them?

When the solar system first formed, there were numerous icy planetesimals in the vicinity of the newly formed jovian planets. What happened to most of these planetesimals?

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

Gravitation and the Waltz of the Planets

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Our Star, the Sun

The Nature of the Stars

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Evolution: The Death of Stars

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

Filters