Question 1

Why is it highly likely that life, should it exist elsewhere in the universe than just on Earth, would be based on carbon chemistry?

Accepted Answer

A)  Carbon can form a resilient bond with many more atomic species in a wider variety of complex forms than other equivalent elements, such as silicon. 
B)  Carbon combines more readily than other atoms with nitrogen, the major component of atmospheres such as that of Earth, to produce complex molecules. 
C)  Carbon is expected to be far more abundant than silicon or other like elements that can combine to produce complex molecules. 
D)  Carbon releases more energy than do most other atoms when it combines with oxygen, providing the energy for life processes in living organisms. 
A)  Carbon can form a resilient bond with many more atomic species in a wider variety of complex forms than other equivalent elements, such as silicon. 
B)  Carbon combines more readily than other atoms with nitrogen, the major component of atmospheres such as that of Earth, to produce complex molecules. 
C)  Carbon is expected to be far more abundant than silicon or other like elements that can combine to produce complex molecules. 
D)  Carbon releases more energy than do most other atoms when it combines with oxygen, providing the energy for life processes in living organisms.

Question 2

The earliest searches for radio signals from extraterrestrial civilizations were made about

Accepted Answer

A)  1973. 
B)  1960. 
C)  1995. 
D)  1948. 
A)  1973. 
B)  1960. 
C)  1995. 
D)  1948.

Question 3

Which of these events of the past 150 years announced human presence on Earth MOST effectively to extraterrestrial watchers?

Accepted Answer

A)  appearance of artificial satellites orbiting Earth after 1957 
B)  nuclear weapon explosions producing extremely intense but brief flashes of light and electromagnetic radiation 
C)  slow changes in vegetation patterns and the appearance of humanmade structures such as road systems and cities on Earth 
D)  slow buildup of radio transmissions after the invention of radio, with modulated signals carrying sound and visual television images 
A)  appearance of artificial satellites orbiting Earth after 1957 
B)  nuclear weapon explosions producing extremely intense but brief flashes of light and electromagnetic radiation 
C)  slow changes in vegetation patterns and the appearance of humanmade structures such as road systems and cities on Earth 
D)  slow buildup of radio transmissions after the invention of radio, with modulated signals carrying sound and visual television images

Question 4

Why is liquid water believed to be essential to the development of life on a planet or other body?

Accepted Answer

A)  Liquid water provides an electricity-conducting medium in which lightning currents can create complex organic molecules. 
B)  Liquid water allows many other chemical elements to interact and form complex molecules. 
C)  Without water, there would be no shoreline onto which primitive fish could crawl to begin life on land. 
D)  Liquid water combines chemically with other compounds to form the building blocks of life. 
A)  Liquid water provides an electricity-conducting medium in which lightning currents can create complex organic molecules. 
B)  Liquid water allows many other chemical elements to interact and form complex molecules. 
C)  Without water, there would be no shoreline onto which primitive fish could crawl to begin life on land. 
D)  Liquid water combines chemically with other compounds to form the building blocks of life.

Question 5

Earth has been sending out radio messages for about 120 years, so detection equipment on a hypothetical planet 120 light-years away might just now begin receiving them. What is the parallax angle subtended by a system at this distance? Can astronomers detect such a parallax angle with existing technology?

Accepted Answer

A)  0.0026 arcseconds; no 
B)  0.0084 arcseconds; yes 
C)  0.027 arcseconds; yes 
D)  120 arcseconds; yes 
A)  0.0026 arcseconds; no 
B)  0.0084 arcseconds; yes 
C)  0.027 arcseconds; yes 
D)  120 arcseconds; yes

Question 6

Does a planet's location within the Milky Way Galaxy affect the likelihood of evolving life on the planet?

Accepted Answer

A)  No. As long as a star is nearby the chances for the evolution of life would not seem to depend on the rest of the Galaxy. 
B)  Yes. The closer to the center of the Galaxy a planet is, the greater will be the density of stars. Being bathed in large amounts of light should increase the possibilities of the evolution of life. 
C)  Yes. A planet on the outer edge of the Galaxy would be susceptible to radiation from outside the Galaxy because it would not be protected by the galactic magnetosphere. Chances for life would not be good. 
D)  Yes. Stellar systems too far from the galactic center are deficient in metals. Such elements are necessary to build Earthlike planets and life as known. 
A)  No. As long as a star is nearby the chances for the evolution of life would not seem to depend on the rest of the Galaxy. 
B)  Yes. The closer to the center of the Galaxy a planet is, the greater will be the density of stars. Being bathed in large amounts of light should increase the possibilities of the evolution of life. 
C)  Yes. A planet on the outer edge of the Galaxy would be susceptible to radiation from outside the Galaxy because it would not be protected by the galactic magnetosphere. Chances for life would not be good. 
D)  Yes. Stellar systems too far from the galactic center are deficient in metals. Such elements are necessary to build Earthlike planets and life as known.

Question 7

In what way does the Drake equation combine the various factors (e.g., fraction of stars with planets, fraction of planets that can support life) in an attempt to determine the number of technically advanced civilizations existing elsewhere in the Milky Way Galaxy?

Accepted Answer

A)  The product of all the probabilities is calculated. 
B)  The sum of each of the factors is determined. 
C)  The sum of three factors is divided by the sum of the other four factors. 
D)  The sum of the last six factors is subtracted from the initial factor, the rate of solar-type star formation. 
A)  The product of all the probabilities is calculated. 
B)  The sum of each of the factors is determined. 
C)  The sum of three factors is divided by the sum of the other four factors. 
D)  The sum of the last six factors is subtracted from the initial factor, the rate of solar-type star formation.

Question 8

The classical laboratory experiments performed by Urey and Miller to explore the necessary conditions for the production of organic molecules (the building blocks of living things) in the solar system involved the passing of electrical discharges through what mixture of gases?

Accepted Answer

A)  ammonia, methane, water vapor, and hydrogen 
B)  carbon dioxide, water vapor, and dust 
C)  hydrogen and helium 
D)  nitrogen, oxygen, water vapor, and carbon dioxide 
A)  ammonia, methane, water vapor, and hydrogen 
B)  carbon dioxide, water vapor, and dust 
C)  hydrogen and helium 
D)  nitrogen, oxygen, water vapor, and carbon dioxide

Question 9

The so-called water hole, a region of the radio spectrum chosen for searches for signals from intelligent life because galactic and Earth-based noise and atmospheric absorption are at a minimum, is so named because

Accepted Answer

A)  water vapor (H2O) has an intense laserlike emission line at this wavelength that extraterrestrials might use to communicate with Earth. 
B)  two astronomically important wavelengths, the 21-cm line of H and a line from the hydroxyl radical OH, are in this region, the letters H and OH signifying water. 
C)  water vapor emissions from planets at this wavelength will be a good indicator of life on other planets because water is essential for life as known. 
D)  water vapor absorption in Earth's atmosphere reaches a sharp minimum at this wavelength. 
A)  water vapor (H2O) has an intense laserlike emission line at this wavelength that extraterrestrials might use to communicate with Earth. 
B)  two astronomically important wavelengths, the 21-cm line of H and a line from the hydroxyl radical OH, are in this region, the letters H and OH signifying water. 
C)  water vapor emissions from planets at this wavelength will be a good indicator of life on other planets because water is essential for life as known. 
D)  water vapor absorption in Earth's atmosphere reaches a sharp minimum at this wavelength.

Question 10

Modern laboratory experiments that repeated those of Urey and Miller in exploring the possibility of producing organic molecules (the building blocks of life) from mixtures of gases expected to exist in the early planetary system passed electrical discharges through which mixture of gases?

Accepted Answer

A)  nitrogen, hydrogen, water vapor, and carbon dioxide 
B)  ammonia, methane, water vapor, and hydrogen 
C)  hydrogen and helium 
D)  carbon dioxide, water vapor, and dust 
A)  nitrogen, hydrogen, water vapor, and carbon dioxide 
B)  ammonia, methane, water vapor, and hydrogen 
C)  hydrogen and helium 
D)  carbon dioxide, water vapor, and dust

Question 11

MOST searches of space for evidence of intelligent life concentrate on radio wavelengths because

Accepted Answer

A)  the atmosphere of Earth is most transparent at these wavelengths, and radio signals will be more easily detected from Earth. 
B)  radio energy is least affected by dust and gas in the interstellar medium. 
C)  it is likely that extraterrestrial beings will have developed radio transmitters before developing more complex lasers or infrared light transmitters. 
D)  radio signals can carry the greatest amount of information per unit of time, so information transfer will be most efficient at these wavelengths. 
A)  the atmosphere of Earth is most transparent at these wavelengths, and radio signals will be more easily detected from Earth. 
B)  radio energy is least affected by dust and gas in the interstellar medium. 
C)  it is likely that extraterrestrial beings will have developed radio transmitters before developing more complex lasers or infrared light transmitters. 
D)  radio signals can carry the greatest amount of information per unit of time, so information transfer will be most efficient at these wavelengths.

Question 12

Which type of meteorite was found to contain large organic molecules that make up the building blocks of life and provide strong evidence for their extraterrestrial production?

Accepted Answer

A)  iron meteorites 
B)  stony iron meteorites 
C)  carbonaceous chondrites 
D)  stony meteorites 
A)  iron meteorites 
B)  stony iron meteorites 
C)  carbonaceous chondrites 
D)  stony meteorites

Question 13

One of the first people to look for radio signals from extraterrestrial civilizations was

Accepted Answer

A)  Arno Penzias. 
B)  Frank Drake. 
C)  Jocelyn Bell. 
D)  Martin Schwarzschild. 
A)  Arno Penzias. 
B)  Frank Drake. 
C)  Jocelyn Bell. 
D)  Martin Schwarzschild.

Question 14

In the Drake equation for estimating the possible number of technologically advanced civilizations in the Milky Way Galaxy, why does the factor for the rate at which solar-type stars form in a galaxy exclude massive stars with masses greater than about 1.5 times that of the Sun?

Accepted Answer

A)  Such stars have much shorter lifetimes than it took for intelligent life to develop on Earth and hence should probably not be considered. 
B)  Such stars never develop a nuclear furnace in their interiors and hence can never heat any planet sufficiently to sustain life. 
C)  Such stars would never develop nuclear processes that could produce heavy elements (e.g., iron) needed for planetary formation. 
D)  Such stars are prone to repeated and violent supernova explosions throughout their lives, which would destroy any developing life-forms. 
A)  Such stars have much shorter lifetimes than it took for intelligent life to develop on Earth and hence should probably not be considered. 
B)  Such stars never develop a nuclear furnace in their interiors and hence can never heat any planet sufficiently to sustain life. 
C)  Such stars would never develop nuclear processes that could produce heavy elements (e.g., iron) needed for planetary formation. 
D)  Such stars are prone to repeated and violent supernova explosions throughout their lives, which would destroy any developing life-forms.

Question 15

In 1974 a radio signal was sent from the Arecibo radio telescope toward the globular cluster M13, which is about 6.8 kpc distant. How long will it take this signal to reach M13?

Accepted Answer

A)  6800 years 
B)  13,600 years 
C)  22,200 years 
D)  44,400 years 
A)  6800 years 
B)  13,600 years 
C)  22,200 years 
D)  44,400 years

Question 16

If astronomers are going to "listen" for electromagnetic radiation at 21 cm from extraterrestrial sources, then Earth had better not generate too many waves at this wavelength from terrestrial sources. The standard FM broadcast band (as observed on a radio dial) spans frequencies from 88 MHz (million cycles per second) to 108 MHz. How does the frequency of the 21-cm signal compare with the FM band? The frequency of the 21-cm line is

Accepted Answer

A)  below the low frequency end of the FM band by a factor of about 9. 
B)  right in the middle of the FM band. 
C)  right at the upper end of the FM band. 
D)  higher than the top end of the FM band by a factor of about 13. 
A)  below the low frequency end of the FM band by a factor of about 9. 
B)  right in the middle of the FM band. 
C)  right at the upper end of the FM band. 
D)  higher than the top end of the FM band by a factor of about 13.

Question 17

In a few decades, a new generation of powerful telescopes especially designed to find extrasolar planets may be operational and producing data. What might these results mean for the Drake equation?

Accepted Answer

A)  With these results in hand, the Drake equation will become irrelevant. 
B)  The structure of the Drake equation itself will undoubtedly have to be drastically revised. 
C)  Astronomers will have much better values for the factors fp (the fraction of stars that have planets) and ne (the number of planets per solar system that are Earthlike). 
D)  Astronomers will have much better values for the factors fl (the fraction of Earthlike planets on which life actually arises), fi (the fraction of life-forms that evolve into intelligent species), and fc (the fraction of intelligent species that develop adequate technology and then choose to send messages out into space). 
A)  With these results in hand, the Drake equation will become irrelevant. 
B)  The structure of the Drake equation itself will undoubtedly have to be drastically revised. 
C)  Astronomers will have much better values for the factors fp (the fraction of stars that have planets) and ne (the number of planets per solar system that are Earthlike). 
D)  Astronomers will have much better values for the factors fl (the fraction of Earthlike planets on which life actually arises), fi (the fraction of life-forms that evolve into intelligent species), and fc (the fraction of intelligent species that develop adequate technology and then choose to send messages out into space).

Question 18

Other than Earth, which object in the solar system seems to be the only one capable of fostering an advanced civilization?

Accepted Answer

A)  Titan, a moon of Saturn 
B)  Europa, a moon of Jupiter 
C)  Callisto, a moon of Jupiter 
D)  No solar system body, other than Earth, seems likely to foster an advanced civilization. 
A)  Titan, a moon of Saturn 
B)  Europa, a moon of Jupiter 
C)  Callisto, a moon of Jupiter 
D)  No solar system body, other than Earth, seems likely to foster an advanced civilization.

Question 19

Which of these characteristics in extrasolar planets is one that astronomers look for as a likely characteristic of a life-bearing planet?

Accepted Answer

A)  large size (Jupiter-sized) 
B)  distance from a Sunlike star of about 1 au 
C)  orbits a star much more massive than the Sun 
D)  high-eccentricity planetary orbit 
A)  large size (Jupiter-sized) 
B)  distance from a Sunlike star of about 1 au 
C)  orbits a star much more massive than the Sun 
D)  high-eccentricity planetary orbit

Question 20

What source of energy was used to trigger the manufacture of complex organic compounds in laboratory simulations of conditions in primordial planetary atmospheres?

Accepted Answer

A)  thermal heating, to simulate volcanic heating 
B)  electric discharges, to simulate lightning 
C)  heat from chemical reactions in early reactive planetary atmospheres 
D)  UV and visible radiation, to simulate the intensity of sunlight at earlier times in planetary life 
A)  thermal heating, to simulate volcanic heating 
B)  electric discharges, to simulate lightning 
C)  heat from chemical reactions in early reactive planetary atmospheres 
D)  UV and visible radiation, to simulate the intensity of sunlight at earlier times in planetary life

Why is it highly likely that life, should it exist elsewhere in the universe than just on Earth, would be based on carbon chemistry?

The earliest searches for radio signals from extraterrestrial civilizations were made about

Which of these events of the past 150 years announced human presence on Earth MOST effectively to extraterrestrial watchers?

Why is liquid water believed to be essential to the development of life on a planet or other body?

Does a planet's location within the Milky Way Galaxy affect the likelihood of evolving life on the planet?

In what way does the Drake equation combine the various factors (e.g., fraction of stars with planets, fraction of planets that can support life) in an attempt to determine the number of technically advanced civilizations existing elsewhere in the Milky Way Galaxy?

The classical laboratory experiments performed by Urey and Miller to explore the necessary conditions for the production of organic molecules (the building blocks of living things) in the solar system involved the passing of electrical discharges through what mixture of gases?

The so-called water hole, a region of the radio spectrum chosen for searches for signals from intelligent life because galactic and Earth-based noise and atmospheric absorption are at a minimum, is so named because

Modern laboratory experiments that repeated those of Urey and Miller in exploring the possibility of producing organic molecules (the building blocks of life) from mixtures of gases expected to exist in the early planetary system passed electrical discharges through which mixture of gases?

MOST searches of space for evidence of intelligent life concentrate on radio wavelengths because

Which type of meteorite was found to contain large organic molecules that make up the building blocks of life and provide strong evidence for their extraterrestrial production?

One of the first people to look for radio signals from extraterrestrial civilizations was

In the Drake equation for estimating the possible number of technologically advanced civilizations in the Milky Way Galaxy, why does the factor for the rate at which solar-type stars form in a galaxy exclude massive stars with masses greater than about 1.5 times that of the Sun?

In 1974 a radio signal was sent from the Arecibo radio telescope toward the globular cluster M13, which is about 6.8 kpc distant. How long will it take this signal to reach M13?

In a few decades, a new generation of powerful telescopes especially designed to find extrasolar planets may be operational and producing data. What might these results mean for the Drake equation?

Other than Earth, which object in the solar system seems to be the only one capable of fostering an advanced civilization?

Which of these characteristics in extrasolar planets is one that astronomers look for as a likely characteristic of a life-bearing planet?

What source of energy was used to trigger the manufacture of complex organic compounds in laboratory simulations of conditions in primordial planetary atmospheres?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Filters

Exam 20: Astrobiology

Why is it highly likely that life, should it exist elsewhere in the universe than just on Earth, would be based on carbon chemistry?

The earliest searches for radio signals from extraterrestrial civilizations were made about

Which of these events of the past 150 years announced human presence on Earth MOST effectively to extraterrestrial watchers?

Why is liquid water believed to be essential to the development of life on a planet or other body?

Does a planet's location within the Milky Way Galaxy affect the likelihood of evolving life on the planet?

In what way does the Drake equation combine the various factors (e.g., fraction of stars with planets, fraction of planets that can support life) in an attempt to determine the number of technically advanced civilizations existing elsewhere in the Milky Way Galaxy?

The classical laboratory experiments performed by Urey and Miller to explore the necessary conditions for the production of organic molecules (the building blocks of living things) in the solar system involved the passing of electrical discharges through what mixture of gases?

The so-called water hole, a region of the radio spectrum chosen for searches for signals from intelligent life because galactic and Earth-based noise and atmospheric absorption are at a minimum, is so named because

Modern laboratory experiments that repeated those of Urey and Miller in exploring the possibility of producing organic molecules (the building blocks of life) from mixtures of gases expected to exist in the early planetary system passed electrical discharges through which mixture of gases?

MOST searches of space for evidence of intelligent life concentrate on radio wavelengths because

Which type of meteorite was found to contain large organic molecules that make up the building blocks of life and provide strong evidence for their extraterrestrial production?

One of the first people to look for radio signals from extraterrestrial civilizations was

In the Drake equation for estimating the possible number of technologically advanced civilizations in the Milky Way Galaxy, why does the factor for the rate at which solar-type stars form in a galaxy exclude massive stars with masses greater than about 1.5 times that of the Sun?

In 1974 a radio signal was sent from the Arecibo radio telescope toward the globular cluster M13, which is about 6.8 kpc distant. How long will it take this signal to reach M13?

In a few decades, a new generation of powerful telescopes especially designed to find extrasolar planets may be operational and producing data. What might these results mean for the Drake equation?

Other than Earth, which object in the solar system seems to be the only one capable of fostering an advanced civilization?

Which of these characteristics in extrasolar planets is one that astronomers look for as a likely characteristic of a life-bearing planet?

What source of energy was used to trigger the manufacture of complex organic compounds in laboratory simulations of conditions in primordial planetary atmospheres?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Filters