Question 1

Briefly summarize current knowledge about the term Np in the equation
Number of Civilizations =Np × flife × fcivilization × fnow.

Accepted Answer

We have evidence now for more than a doz

Question 2

If you were in charge of NASA and wanted to fund a mission to search for life elsewhere,what type of mission would you choose? Would you travel to someplace in the solar system (what place?),look for evidence remotely in distant solar systems,listen for alien contact,or something else entirely? Explain what you would do,defend why that is your favored approach,and tell what you would hope to find.

Accepted Answer

If I were in charge of NASA and wanted t

Question 3

How did oxygen (O₂)get into Earth's atmosphere?

Accepted Answer

A) It was captured from the solar nebula. 
B) It was outgassed from volcanoes. 
C) It came from chemical reactions with surface rocks. 
D) It was released by life through the process of photosynthesis. 
A) It was captured from the solar nebula. 
B) It was outgassed from volcanoes. 
C) It came from chemical reactions with surface rocks. 
D) It was released by life through the process of photosynthesis.

Question 4

Where have scientists begun a concerted search for life outside of Earth?

Accepted Answer

A) the Moon 
B) Venus 
C) Mars 
D) Jupiter 
E) Titan 
A) the Moon 
B) Venus 
C) Mars 
D) Jupiter 
E) Titan

Question 5

Suppose it turns out that one in 1 million stars has a planet that at some point in its history is home to an advanced civilization.Then the total number of civilizations that have arisen in our galaxy would be closest to

Accepted Answer

A) 4. 
B) 40. 
C) 400. 
D) 4,000. 
E) 40,000.
F)400,000. 
A) 4. 
B) 40. 
C) 400. 
D) 4,000. 
E) 40,000.
F)400,000.

Question 6

After Mars,the next most likely candidates for life in the solar system are

Accepted Answer

A) Oort-cloud comets. 
B) the jovian planets. 
C) the large moons of the jovian planets. 
D) asteroids. 
E) Kuiper-belt comets. 
A) Oort-cloud comets. 
B) the jovian planets. 
C) the large moons of the jovian planets. 
D) asteroids. 
E) Kuiper-belt comets.

Question 7

We are not yet capable of detecting life on planets around other stars.But as our technology develops,our first real chance of detecting such life will probably come from

Accepted Answer

A) sending spacecraft to study the planets up close. 
B) examining spectral lines from the atmospheres of distant planets. 
C) examining high-resolution images of the planets made by orbiting telescopes. 
D) determining the orbital properties of the planets. 
A) sending spacecraft to study the planets up close. 
B) examining spectral lines from the atmospheres of distant planets. 
C) examining high-resolution images of the planets made by orbiting telescopes. 
D) determining the orbital properties of the planets.

Question 8

Explain how it is possible that there are moons within habitable zones that have habitable surfaces in other solar systems given that no such thing exists in our own solar system.

Accepted Answer

They may form as a consequence

Question 9

We have sent several spacecraft on trajectories that will ultimately take them into interstellar space (Pioneer 10 and 11,Voyager 1 and 2,New Horizons).How long will it take these spacecraft to travel as far as the nearest stars?

Accepted Answer

A) a few decades 
B) a few hundred years 
C) about a thousand years 
D) tens of thousands of years 
A) a few decades 
B) a few hundred years 
C) about a thousand years 
D) tens of thousands of years

Question 10

Why do scientists say that evolution is a "theory"?

Accepted Answer

A) because it explains a great deal about life and is supported by an enormous body of evidence 
B) because they are not very confident that it really happened 
C) because it's really just a guess about how life developed on Earth 
D) because it is supported by only a small amount of evidence 
A) because it explains a great deal about life and is supported by an enormous body of evidence 
B) because they are not very confident that it really happened 
C) because it's really just a guess about how life developed on Earth 
D) because it is supported by only a small amount of evidence

Question 11

Which living organisms most resemble the common ancestor of all life according to genetic testing?

Accepted Answer

A) bacteria such as E.coli 
B) organisms living deep in the oceans around seafloor volcanic vents and in hot springs 
C) plankton that use sunlight as an energy source through photosynthesis 
D) viruses 
E) stromatolites 
A) bacteria such as E.coli 
B) organisms living deep in the oceans around seafloor volcanic vents and in hot springs 
C) plankton that use sunlight as an energy source through photosynthesis 
D) viruses 
E) stromatolites

Question 12

Which of the following best describes natural selection?

Accepted Answer

A) It is the idea that the strong survive and the weak die off. 
B) It is a guess made by scientists about how life develops,but it has no hard evidence to support it. 
C) It is the idea that organisms with genetic traits that improve their ability to reproduce are more likely to pass those traits on to future generations. 
D) It is the idea that organisms naturally increase in complexity and intelligence with time. 
A) It is the idea that the strong survive and the weak die off. 
B) It is a guess made by scientists about how life develops,but it has no hard evidence to support it. 
C) It is the idea that organisms with genetic traits that improve their ability to reproduce are more likely to pass those traits on to future generations. 
D) It is the idea that organisms naturally increase in complexity and intelligence with time.

Question 13

Which of the following statements best reflects our current knowledge about the term ( f )life in the equation Number of Civilizations == Np × flife × fcivilization × fnow?

Accepted Answer

A) The value of ( f )life must be either 0 percent or 100 percent. 
B) The value of ( f )life is between 0 percent and 100 percent. 
C) The value of ( f )life is between 0 percent and 1 percent. 
D) The value of ( f )life is roughly 50 percent. 
E) The value of ( f )life is presently unknown but should be well known within just a few years. 
A) The value of ( f )life must be either 0 percent or 100 percent. 
B) The value of ( f )life is between 0 percent and 100 percent. 
C) The value of ( f )life is between 0 percent and 1 percent. 
D) The value of ( f )life is roughly 50 percent. 
E) The value of ( f )life is presently unknown but should be well known within just a few years.

Question 14

Why is ozone so crucial to the continued well-being of life on Earth?

Accepted Answer

Ozone (O₃)absorbs ultraviolet

Question 15

Why might the presence of a giant planet be both good and bad news for life on a terrestrial planet in another solar system?

Accepted Answer

A giant planet can "kick" comets out of

Question 16

Briefly explain the purpose of the equation
Number of Civilizations =Np × flife × fcivilization × fnow.

Accepted Answer

This equation is used to estim

Question 17

Which of the following best describes how the Drake equation is useful?

Accepted Answer

A) It has allowed us to determine the number of civilizations in the Milky Way Galaxy. 
B) It allows us to calculate the masses of planets orbiting other stars. 
C) It tells us what wavelengths of light will be most useful to examine in the search for extraterrestrial intelligence. 
D) It helps us understand what we need to know in order to determine the likelihood of finding other civilizations. 
A) It has allowed us to determine the number of civilizations in the Milky Way Galaxy. 
B) It allows us to calculate the masses of planets orbiting other stars. 
C) It tells us what wavelengths of light will be most useful to examine in the search for extraterrestrial intelligence. 
D) It helps us understand what we need to know in order to determine the likelihood of finding other civilizations.

Question 18

How is it possible that orphan planets are potentially habitable,even though they do not orbit a star?

Accepted Answer

Even on Earth,there is plenty of life th

Question 19

Process of Science: Since the Drake equation does not give us a clear answer on how many aliens we expect to find,why it is useful scientifically?

Accepted Answer

The Drake equation helps us organize our

Question 20

Which of the following best describes what we mean by a habitable world?

Accepted Answer

A) a planet or moon that could support life,if any life happened to be on it 
B) a planet or moon with life 
C) a planet or moon that lies within its star's habitable zone 
D) a planet or moon on which humans could survive if we happened to go there 
A) a planet or moon that could support life,if any life happened to be on it 
B) a planet or moon with life 
C) a planet or moon that lies within its star's habitable zone 
D) a planet or moon on which humans could survive if we happened to go there

Exam 24: Life in the Universe

Briefly summarize current knowledge about the term Np in the equation Number of Civilizations =Np × flife × fcivilization × fnow.

How did oxygen (O₂)get into Earth's atmosphere?

Where have scientists begun a concerted search for life outside of Earth?

Suppose it turns out that one in 1 million stars has a planet that at some point in its history is home to an advanced civilization.Then the total number of civilizations that have arisen in our galaxy would be closest to

After Mars,the next most likely candidates for life in the solar system are

We are not yet capable of detecting life on planets around other stars.But as our technology develops,our first real chance of detecting such life will probably come from

Explain how it is possible that there are moons within habitable zones that have habitable surfaces in other solar systems given that no such thing exists in our own solar system.

We have sent several spacecraft on trajectories that will ultimately take them into interstellar space (Pioneer 10 and 11,Voyager 1 and 2,New Horizons).How long will it take these spacecraft to travel as far as the nearest stars?

Why do scientists say that evolution is a "theory"?

Which living organisms most resemble the common ancestor of all life according to genetic testing?

Which of the following best describes natural selection?

Which of the following statements best reflects our current knowledge about the term ( f )life in the equation Number of Civilizations == Np × flife × fcivilization × fnow?

Why is ozone so crucial to the continued well-being of life on Earth?

Why might the presence of a giant planet be both good and bad news for life on a terrestrial planet in another solar system?

Briefly explain the purpose of the equation Number of Civilizations =Np × flife × fcivilization × fnow.

Which of the following best describes how the Drake equation is useful?

How is it possible that orphan planets are potentially habitable,even though they do not orbit a star?

Process of Science: Since the Drake equation does not give us a clear answer on how many aliens we expect to find,why it is useful scientifically?

Which of the following best describes what we mean by a habitable world?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Telescopes: Portals of Discovery

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters