Question 1

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

Accepted Answer

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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

The answer of If you were in charge of NASA...

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.

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

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.

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.

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.

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.

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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

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

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

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.

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.

Question 14

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

Accepted Answer

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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?

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Question 16

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

Accepted Answer

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Number...

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.

Question 18

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

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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

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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

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?