Question 1

Process of Science: The Fermi paradox shows that there can be no successful theory that predicts how common life is in the Universe.

Accepted Answer

A) True 
 B)False

Question 2

Why are fossils of early life on Earth more rare than fossils of plants and animals from the past few hundred million years?

Accepted Answer

A) Life was far less abundant prior to a few hundred million years ago. 
B) Early organisms lacked skeletons and other hard structures that are most likely to be fossilized. 
C) Fossils could not form before there was oxygen in the atmosphere. 
D) We find fossils in sedimentary layers,and no sediments were deposited until just a few hundred million years ago. 
A) Life was far less abundant prior to a few hundred million years ago. 
B) Early organisms lacked skeletons and other hard structures that are most likely to be fossilized. 
C) Fossils could not form before there was oxygen in the atmosphere. 
D) We find fossils in sedimentary layers,and no sediments were deposited until just a few hundred million years ago.

Question 3

It is possible that life exists on orphan planets,even though they do not orbit a star.

Accepted Answer

A) True 
 B)False

Question 4

We have already launched a spacecraft bound for Alpha Centauri.

Accepted Answer

A) True 
 B)False

Question 5

Why is the discovery of ice fountains on Enceladus so important?

Accepted Answer

Ice fountains suggest that eve

Question 6

Which of the following is not considered a potential solution to the question of why we lack any evidence of a galactic civilization?

Accepted Answer

A) There is no galactic civilization because we are the first species ever to achieve the ability to study the universe. 
B) The galactic civilization probably is undetectable because they operate under different laws of physics from the ones we know. 
C) The galactic civilization is deliberately avoiding contact with us. 
D) There is no galactic civilization because all civilizations destroy themselves before they achieve the ability to colonize the galaxy. 
A) There is no galactic civilization because we are the first species ever to achieve the ability to study the universe. 
B) The galactic civilization probably is undetectable because they operate under different laws of physics from the ones we know. 
C) The galactic civilization is deliberately avoiding contact with us. 
D) There is no galactic civilization because all civilizations destroy themselves before they achieve the ability to colonize the galaxy.

Question 7

At present,what is the primary way that the search for extraterrestrial intelligence (SETI)is carried out?

Accepted Answer

A) by using radio telescopes to search for signals from extraterrestrial civilizations 
B) by analyzing high-resolution images of nearby stars in search of evidence for structures that could not have developed naturally 
C) by searching for planets around distant stars 
D) by using X-ray telescopes to search for exhaust from interstellar spacecraft 
E) by seeking access to the secret records and alien corpses kept at the military's Area 51 in Nevada 
A) by using radio telescopes to search for signals from extraterrestrial civilizations 
B) by analyzing high-resolution images of nearby stars in search of evidence for structures that could not have developed naturally 
C) by searching for planets around distant stars 
D) by using X-ray telescopes to search for exhaust from interstellar spacecraft 
E) by seeking access to the secret records and alien corpses kept at the military's Area 51 in Nevada

Question 8

Which of the following describes a major danger of interstellar travel at near light speed?

Accepted Answer

A) Any interstellar journey will take much longer than the lives of the crew members. 
B) Time dilation will slow the heartbeats of the crew to a dangerously low rate. 
C) Atoms and ions in interstellar space will hit a fast-moving spacecraft like a flood of dangerous cosmic rays. 
D) Asteroid fields floating in interstellar space will present a navigational challenge. 
E) Supernova explosions will destroy spaceships passing nearby. 
A) Any interstellar journey will take much longer than the lives of the crew members. 
B) Time dilation will slow the heartbeats of the crew to a dangerously low rate. 
C) Atoms and ions in interstellar space will hit a fast-moving spacecraft like a flood of dangerous cosmic rays. 
D) Asteroid fields floating in interstellar space will present a navigational challenge. 
E) Supernova explosions will destroy spaceships passing nearby.

Question 9

Why don't we expect to find life on planets orbiting high-mass stars?

Accepted Answer

A) The stars are too hot to allow for life. 
B) Planets cannot have stable orbits around high-mass stars. 
C) The high-mass stars emit too much ultraviolet radiation. 
D) The lifetime of a high-mass star is too short. 
A) The stars are too hot to allow for life. 
B) Planets cannot have stable orbits around high-mass stars. 
C) The high-mass stars emit too much ultraviolet radiation. 
D) The lifetime of a high-mass star is too short.

Question 10

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

Accepted Answer

We know that at least one plan

Question 11

If they existed,and if they were watching,a civilization at the center of the Milky Way could have detected our first TV signals by now.

Accepted Answer

A) True 
 B)False

Question 12

Despite being only a medium-size moon,Enceladus may have subsurface habitable zones.

Accepted Answer

A) True 
 B)False

Question 13

Why is Titan considered a good candidate for life?

Accepted Answer

A) It has lakes and rivers of liquid methane and ethane that could support life as water does on Earth. 
B) Cassini measurements suggest it has an ocean of liquid water beneath its surface. 
C) There is evidence for several volcanic cones that likely erupt liquid water that is below Titan's frozen crust. 
D) All of the above 
A) It has lakes and rivers of liquid methane and ethane that could support life as water does on Earth. 
B) Cassini measurements suggest it has an ocean of liquid water beneath its surface. 
C) There is evidence for several volcanic cones that likely erupt liquid water that is below Titan's frozen crust. 
D) All of the above

Question 14

Process of Science: Are those who advocate creationism or "intelligent design" following the scientific method? Defend your answer.

Accepted Answer

The scientific method involves making ob

Question 15

Process of Science: Explain the phrase used by Carl Sagan,"Extraordinary claims require extraordinary evidence."

Accepted Answer

Whenever someone claims to have found or

Question 16

When did oxygen begin to accumulate in the atmosphere?

Accepted Answer

A) as soon as Earth was formed 
B) about 2 billion years ago 
C) about 200 million years ago 
D) as soon as the early bombardment ended 
E) as soon as life appeared 
A) as soon as Earth was formed 
B) about 2 billion years ago 
C) about 200 million years ago 
D) as soon as the early bombardment ended 
E) as soon as life appeared

Question 17

Why do some scientists think that Jupiter's existence may have been critical for life to evolve on Earth?

Accepted Answer

A) It prevented Earth from migrating outward and thus ensured a stable climate. 
B) It prevented Earth from migrating inward and thus ensured a stable climate. 
C) It kicked out many comets from the inner solar system through gravitational encounters,thus limiting the number of objects that could potentially hit the inner planets. 
D) Meteorites from Jupiter may contain bacteria that started life on Earth. 
E) It stabilized Earth's axis tilt and thus ensured a stable climate. 
A) It prevented Earth from migrating outward and thus ensured a stable climate. 
B) It prevented Earth from migrating inward and thus ensured a stable climate. 
C) It kicked out many comets from the inner solar system through gravitational encounters,thus limiting the number of objects that could potentially hit the inner planets. 
D) Meteorites from Jupiter may contain bacteria that started life on Earth. 
E) It stabilized Earth's axis tilt and thus ensured a stable climate.

Question 18

Which of the following describes a major danger of interstellar travel at near-light speed?

Accepted Answer

A) Atoms and ions in interstellar space will hit a fast-moving spacecraft like a flood of dangerous cosmic rays. 
B) Any interstellar journey will take much longer than the lives of the crew members. 
C) Time dilation will slow the heart beats of the crew to a dangerously low rate. 
D) Asteroid fields floating in interstellar space will present a navigational challenge. 
A) Atoms and ions in interstellar space will hit a fast-moving spacecraft like a flood of dangerous cosmic rays. 
B) Any interstellar journey will take much longer than the lives of the crew members. 
C) Time dilation will slow the heart beats of the crew to a dangerously low rate. 
D) Asteroid fields floating in interstellar space will present a navigational challenge.

Question 19

Which of the following is the most important for maintaining a stable climate on Earth over the time it took for large organisms to evolve?

Accepted Answer

A) sustained volcanic activity 
B) the cessation of the heavy bombardment phase 
C) plate tectonics 
D) the Moon 
E) underground sea vents 
A) sustained volcanic activity 
B) the cessation of the heavy bombardment phase 
C) plate tectonics 
D) the Moon 
E) underground sea vents

Question 20

What defines the habitable zone around a star?

Accepted Answer

A) the region around a star where rocky planets form 
B) the region around a star where humans can survive 
C) the region around a star where liquid water can potentially exist on planetary surfaces 
D) the region around a star where the ultraviolet radiation does not destroy organisms on a planetary surface 
E) the region around a star where life exists 
A) the region around a star where rocky planets form 
B) the region around a star where humans can survive 
C) the region around a star where liquid water can potentially exist on planetary surfaces 
D) the region around a star where the ultraviolet radiation does not destroy organisms on a planetary surface 
E) the region around a star where life exists

Exam 24: Life in the Universe

Process of Science: The Fermi paradox shows that there can be no successful theory that predicts how common life is in the Universe.

Why are fossils of early life on Earth more rare than fossils of plants and animals from the past few hundred million years?

It is possible that life exists on orphan planets,even though they do not orbit a star.

We have already launched a spacecraft bound for Alpha Centauri.

Why is the discovery of ice fountains on Enceladus so important?

Which of the following is not considered a potential solution to the question of why we lack any evidence of a galactic civilization?

At present,what is the primary way that the search for extraterrestrial intelligence (SETI)is carried out?

Which of the following describes a major danger of interstellar travel at near light speed?

Why don't we expect to find life on planets orbiting high-mass stars?

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

If they existed,and if they were watching,a civilization at the center of the Milky Way could have detected our first TV signals by now.

Despite being only a medium-size moon,Enceladus may have subsurface habitable zones.

Why is Titan considered a good candidate for life?

Process of Science: Are those who advocate creationism or "intelligent design" following the scientific method? Defend your answer.

Process of Science: Explain the phrase used by Carl Sagan,"Extraordinary claims require extraordinary evidence."

When did oxygen begin to accumulate in the atmosphere?

Why do some scientists think that Jupiter's existence may have been critical for life to evolve on Earth?

Which of the following describes a major danger of interstellar travel at near-light speed?

Which of the following is the most important for maintaining a stable climate on Earth over the time it took for large organisms to evolve?

What defines the habitable zone around a star?

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