Question 1

Scientists are now targeting Europa,one of Jupiter's moons,as a likely site for searching for elementary life-forms because:

Accepted Answer

A)  radio signals that follow a recognizable pattern have been detected from this moon. 
B)  there appears to be large amounts of dark organic material spread on its surface. 
C)  changes seen in the dark lines crossing the icy surface have a spectral signature of vegetation. 
D)  there is strong evidence for liquid water beneath the thick ice layer on its surface. 
A)  radio signals that follow a recognizable pattern have been detected from this moon. 
B)  there appears to be large amounts of dark organic material spread on its surface. 
C)  changes seen in the dark lines crossing the icy surface have a spectral signature of vegetation. 
D)  there is strong evidence for liquid water beneath the thick ice layer on its surface. D

Question 2

The habitable zone around the Sun includes:

Accepted Answer

A)  only Earth. 
B)  Earth and Mars. 
C)  Earth and Venus. 
D)  Earth, Mars, and Venus. 
A)  only Earth. 
B)  Earth and Mars. 
C)  Earth and Venus. 
D)  Earth, Mars, and Venus. A

Question 3

Probably the MOST difficult factor to estimate in the Drake equation is:

Accepted Answer

A)  R*, the rate at which solar-type stars form in the Galaxy. 
B)  fp, the fraction of stars that have planets. 
C)  nₑ, the number of planets per solar system that are Earthlike (suitable for life). 
D)  L, the lifetime of a technologically advanced civilization. 
A)  R*, the rate at which solar-type stars form in the Galaxy. 
B)  fp, the fraction of stars that have planets. 
C)  nₑ, the number of planets per solar system that are Earthlike (suitable for life). 
D)  L, the lifetime of a technologically advanced civilization. D

Question 4

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 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 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 5

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 6

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

Question 7

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

Accepted Answer

A)  Earth's atmosphere 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 IR 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)  Earth's atmosphere 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 IR 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 8

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 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 us. 
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 since water is essential for life as we know it. 
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 us. 
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 since water is essential for life as we know it. 
D)  water vapor absorption in Earth's atmosphere reaches a sharp minimum at this wavelength.

Question 10

Pioneer 10 and 11 carried plaques intended to show any alien civilization that found them the location of the solar system in the Galaxy.The location was marked relative to various pulsars (see Figure 15-10,Comins,Discovering the Essential Universe,6th ed.).Which statement is a good reason to choose pulsars for this purpose?

Accepted Answer

A)  Pulsars can be detected a long way across the Galaxy and thus presumably would be known to the aliens. 
B)  Pulsars can be identified uniquely by the frequencies of the radiation they emit. 
C)  Pulsar pulse rates are constant, never changing. 
D)  Pulsars form a more-or-less uniform ring around the galactic center (like the globular cluster halo) and thus provide a good coordinate system. 
A)  Pulsars can be detected a long way across the Galaxy and thus presumably would be known to the aliens. 
B)  Pulsars can be identified uniquely by the frequencies of the radiation they emit. 
C)  Pulsar pulse rates are constant, never changing. 
D)  Pulsars form a more-or-less uniform ring around the galactic center (like the globular cluster halo) and thus provide a good coordinate system.

Question 11

What is the current state of the search for extraterrestrial radio communications?

Accepted Answer

A)  Several extraterrestrial civilizations have been found, but they are not intelligent enough for us to bother with and the search is continuing. 
B)  Occasional single-frequency searches have been made for extraterrestrial signals, but funds are still being sought for the first major continuous monitoring effort. 
C)  A number of frequencies in the "water hole" are being monitored, but there has been no major effort as yet to send out continuous signals from Earth at these frequencies. 
D)  Continuous transmissions are being sent out from Earth at several frequencies in the "water hole," and tens of millions of other frequencies are being monitored. 
A)  Several extraterrestrial civilizations have been found, but they are not intelligent enough for us to bother with and the search is continuing. 
B)  Occasional single-frequency searches have been made for extraterrestrial signals, but funds are still being sought for the first major continuous monitoring effort. 
C)  A number of frequencies in the "water hole" are being monitored, but there has been no major effort as yet to send out continuous signals from Earth at these frequencies. 
D)  Continuous transmissions are being sent out from Earth at several frequencies in the "water hole," and tens of millions of other frequencies are being monitored.

Question 12

There are now over 1700 known extrasolar planets.When we consider them as possible homes for life,it is important to remember that most of them are:

Accepted Answer

A)  Earthlike planets with water on their surfaces. 
B)  hydrogen-rich planets like Jupiter. 
C)  in extremely elliptical orbits, like comets. 
D)  still in the process of forming and thus not old enough to have evolved life. 
A)  Earthlike planets with water on their surfaces. 
B)  hydrogen-rich planets like Jupiter. 
C)  in extremely elliptical orbits, like comets. 
D)  still in the process of forming and thus not old enough to have evolved life.

Question 13

Frank Drake began his SETI investigations by listening for signals from two particular stars: Ʈ Ceti and ɛ Eridani.Why these two?Ʈ

Accepted Answer

A)  These are among the half dozen closest stars to Earth. 
B)  These stars are similar to the Sun. 
C)  It was thought that previous signals had been detected from these sources. 
D)  These stars are both very old and thus would have had time to evolve an advanced civilization. 
A)  These are among the half dozen closest stars to Earth. 
B)  These stars are similar to the Sun. 
C)  It was thought that previous signals had been detected from these sources. 
D)  These stars are both very old and thus would have had time to evolve an advanced civilization.

Question 14

Life has been found on Earth in a lake deep under the Antarctic ice pack.This resembles what other environment in the solar system that has been considered a possible location for life?

Accepted Answer

A)  the surface of ancient Mars 
B)  Venus 
C)  Europa 
D)  Miranda 
A)  the surface of ancient Mars 
B)  Venus 
C)  Europa 
D)  Miranda

Question 15

If we are going to "listen" for electromagnetic radiation at 21 cm from extraterrestrial sources,then we had better not generate too many waves at this wavelength from terrestrial sources.The standard FM broadcast band (as you can see by looking at your 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 16

In searching for transmissions from intelligent civilizations,SETI is concentrating its efforts on a survey of:

Accepted Answer

A)  about a dozen or so of the closest stars. 
B)  just stars around which we believe we have detected planets. 
C)  thousands of stars within a 100 pc or so of the solar system. 
D)  stars in giant elliptical galaxies since these stars, being oldest, are most likely to have advanced civilizations. 
A)  about a dozen or so of the closest stars. 
B)  just stars around which we believe we have detected planets. 
C)  thousands of stars within a 100 pc or so of the solar system. 
D)  stars in giant elliptical galaxies since these stars, being oldest, are most likely to have advanced civilizations.

Question 17

Which phenomenon was probably NOT a source of large organic molecules,the building blocks of life,on the early Earth?

Accepted Answer

A)  comets 
B)  meteorites 
C)  lightning flashes in the early terrestrial atmosphere 
D)  volcanic eruptions 
A)  comets 
B)  meteorites 
C)  lightning flashes in the early terrestrial atmosphere 
D)  volcanic eruptions

Question 18

An important advance in the search for life elsewhere in the solar system was the:

Accepted Answer

A)  discovery of primitive life-forms on Mars. 
B)  replication in laboratories of silicon-based substitutes for the most important carbon-based life molecules. 
C)  discovery of liquid water on Europa, Ganymede, and various other places in the solar system. 
D)  discovery in meteorites of the remains of microbes. 
A)  discovery of primitive life-forms on Mars. 
B)  replication in laboratories of silicon-based substitutes for the most important carbon-based life molecules. 
C)  discovery of liquid water on Europa, Ganymede, and various other places in the solar system. 
D)  discovery in meteorites of the remains of microbes.

Question 19

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 is a fluid and therefore provides a physical medium in which the building blocks of life can move around and get together. 
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 is a fluid and therefore provides a physical medium in which the building blocks of life can move around and get together. 
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 20

In which type of meteorite has evidence been found for organic molecules,some of which,in contrast to most life molecules on Earth,have both right- and left-hand spiral structure?

Accepted Answer

A)  iron 
B)  stony iron 
C)  stony 
D)  carbonaceous chondrite 
A)  iron 
B)  stony iron 
C)  stony 
D)  carbonaceous chondrite

Scientists are now targeting Europa,one of Jupiter's moons,as a likely site for searching for elementary life-forms because:

The habitable zone around the Sun includes:

Probably the MOST difficult factor to estimate in the Drake equation is:

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 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?

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

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

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

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:

What is the current state of the search for extraterrestrial radio communications?

There are now over 1700 known extrasolar planets.When we consider them as possible homes for life,it is important to remember that most of them are:

Frank Drake began his SETI investigations by listening for signals from two particular stars: Ʈ Ceti and ɛ Eridani.Why these two?Ʈ

Life has been found on Earth in a lake deep under the Antarctic ice pack.This resembles what other environment in the solar system that has been considered a possible location for life?

In searching for transmissions from intelligent civilizations,SETI is concentrating its efforts on a survey of:

Which phenomenon was probably NOT a source of large organic molecules,the building blocks of life,on the early Earth?

An important advance in the search for life elsewhere in the solar system was the:

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

In which type of meteorite has evidence been found for organic molecules,some of which,in contrast to most life molecules on Earth,have both right- and left-hand spiral structure?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Filters

Exam 15: Astrobiology

Scientists are now targeting Europa,one of Jupiter's moons,as a likely site for searching for elementary life-forms because:

The habitable zone around the Sun includes:

Probably the MOST difficult factor to estimate in the Drake equation is:

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 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?

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

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

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

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:

What is the current state of the search for extraterrestrial radio communications?

There are now over 1700 known extrasolar planets.When we consider them as possible homes for life,it is important to remember that most of them are:

Frank Drake began his SETI investigations by listening for signals from two particular stars: Ʈ Ceti and ɛ Eridani.Why these two?Ʈ

Life has been found on Earth in a lake deep under the Antarctic ice pack.This resembles what other environment in the solar system that has been considered a possible location for life?

In searching for transmissions from intelligent civilizations,SETI is concentrating its efforts on a survey of:

Which phenomenon was probably NOT a source of large organic molecules,the building blocks of life,on the early Earth?

An important advance in the search for life elsewhere in the solar system was the:

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

In which type of meteorite has evidence been found for organic molecules,some of which,in contrast to most life molecules on Earth,have both right- and left-hand spiral structure?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Filters