Question 1

If astronomers focused only on studying planets in the habitable zones of single stars, what potentially life-harboring objects would be overlooked?

Accepted Answer

Based on what we know from our own Solar System,there are moons orbiting Jupiter (e.g.,Europa)and Saturn (e.g.,Titan,Enceladus)whose environments could harbor primitive life-forms.There are also planets that orbit binary stellar systems in a complex "choreography" and the corresponding habitable zone would be much more difficult to define.

Question 2

You find a planet orbiting an F-type star (surface temperature 6500 K).Where is this planet with respect to the habitable zone, if this planet has a circular orbit with a radius of 2.6 AU? The figure below may be helpful.

Accepted Answer

A)  not in the habitable zone (too hot) 
B)  on the hot edge of the habitable zone 
C)  right in the middle of the habitable zone 
D)  on the cold edge of the habitable zone 
E)  not in the habitable zone (too cold) 
A)  not in the habitable zone (too hot) 
B)  on the hot edge of the habitable zone 
C)  right in the middle of the habitable zone 
D)  on the cold edge of the habitable zone 
E)  not in the habitable zone (too cold) D

Question 3

The "waste" product in the process of photosynthesis is

Accepted Answer

A)  sugar. 
B)  carbon dioxide. 
C)  oxygen. 
D)  amino acids. 
E)  carbohydrates. 
A)  sugar. 
B)  carbon dioxide. 
C)  oxygen. 
D)  amino acids. 
E)  carbohydrates. C

Question 4

If the most pessimistic assumptions in the Drake equation were true, we would

Accepted Answer

A)  have to wait millions of years to get a message back from the nearest intelligent life. 
B)  have to wait approximately 40 years to get a message back from the nearest intelligent life. 
C)  certainly be the only intelligent life in the universe. 
D)  need to concentrate on the Andromeda Galaxy when searching for intelligent life. 
E)  need to concentrate on the most distant galaxies to find signs of intelligent life. 
A)  have to wait millions of years to get a message back from the nearest intelligent life. 
B)  have to wait approximately 40 years to get a message back from the nearest intelligent life. 
C)  certainly be the only intelligent life in the universe. 
D)  need to concentrate on the Andromeda Galaxy when searching for intelligent life. 
E)  need to concentrate on the most distant galaxies to find signs of intelligent life.

Question 5

The habitable zone for a 2MSUN star is ________ and covers a ________ distance range compared with the habitable zone for a 1MSUN star.

Accepted Answer

A)  closer inward; narrower 
B)  further outward; narrower 
C)  further outward; wider 
D)  closer inward; the same 
E)  further outward; the same 
A)  closer inward; narrower 
B)  further outward; narrower 
C)  further outward; wider 
D)  closer inward; the same 
E)  further outward; the same

Question 6

Why was the comet or asteroid impact 65 million years ago an event that benefited the evolution of humans?

Accepted Answer

A)  It deposited a significant amount of nitrogen into Earth's atmosphere. 
B)  It led to an increase in global UV radiation, which killed off most of the forests and jungles. 
C)  Conditions became more favorable for mammalian life. 
D)  Plant life began to decline. 
E)  It brought human DNA to Earth. 
A)  It deposited a significant amount of nitrogen into Earth's atmosphere. 
B)  It led to an increase in global UV radiation, which killed off most of the forests and jungles. 
C)  Conditions became more favorable for mammalian life. 
D)  Plant life began to decline. 
E)  It brought human DNA to Earth.

Question 7

What is the origin of the atmospheric oxygen on Earth?

Accepted Answer

The atmospheric oxygen on Earth is a pro

Question 8

The current oxygen level in the Earth's atmosphere was reached about

Accepted Answer

A)  4.6 billion years ago. 
B)  2 billion years ago. 
C)  20 million years ago. 
D)  250 million years ago. 
E)  540 million years ago. 
A)  4.6 billion years ago. 
B)  2 billion years ago. 
C)  20 million years ago. 
D)  250 million years ago. 
E)  540 million years ago.

Question 9

One general property of living organisms is that they

Accepted Answer

A)  modify their environment. 
B)  require direct sunlight to exist. 
C)  do not necessarily require food or sustenance. 
D)  can be found at any possible temperature. 
E)  only require the chemical elements created during the Big Bang. 
A)  modify their environment. 
B)  require direct sunlight to exist. 
C)  do not necessarily require food or sustenance. 
D)  can be found at any possible temperature. 
E)  only require the chemical elements created during the Big Bang.

Question 10

What is the main impediment for interstellar travel?

Accepted Answer

A)  the high cost of technology enabling travel at the speed of light 
B)  the fear of encountering hostile life-forms 
C)  a lack of international cooperation 
D)  that only unstable wormholes can be created with current technology 
E)  Current technology cannot produce the energy necessary to travel at high enough speeds to make interstellar travel worthwhile. 
A)  the high cost of technology enabling travel at the speed of light 
B)  the fear of encountering hostile life-forms 
C)  a lack of international cooperation 
D)  that only unstable wormholes can be created with current technology 
E)  Current technology cannot produce the energy necessary to travel at high enough speeds to make interstellar travel worthwhile.

Question 11

What makes molecules organic?

Accepted Answer

A)  They can reproduce. 
B)  They are very complex. 
C)  They are unique to Earth. 
D)  They need oxygen to form. 
E)  They contain carbon. 
A)  They can reproduce. 
B)  They are very complex. 
C)  They are unique to Earth. 
D)  They need oxygen to form. 
E)  They contain carbon.

Question 12

Which of the following sequences correctly ranks the number of atoms in the human body from highest to lowest?

Accepted Answer

A)  carbon, oxygen, nitrogen, silicon 
B)  carbon, oxygen, nitrogen, phosphorous 
C)  hydrogen, oxygen, carbon, nitrogen 
D)  hydrogen, oxygen, carbon, phosphorous 
E)  carbon, hydrogen, oxygen, nitrogen 
A)  carbon, oxygen, nitrogen, silicon 
B)  carbon, oxygen, nitrogen, phosphorous 
C)  hydrogen, oxygen, carbon, nitrogen 
D)  hydrogen, oxygen, carbon, phosphorous 
E)  carbon, hydrogen, oxygen, nitrogen

Question 13

Heredity essentially implies the ability to

Accepted Answer

A)  pass on a genetic code to the next generation. 
B)  avoid interaction with the environment. 
C)  divide exponentially. 
D)  adapt to environmental changes. 
E)  avoid genetic mutations. 
A)  pass on a genetic code to the next generation. 
B)  avoid interaction with the environment. 
C)  divide exponentially. 
D)  adapt to environmental changes. 
E)  avoid genetic mutations.

Question 14

The field of astrobiology uses our knowledge of ________ to study life in the universe.

Accepted Answer

A)  biology 
B)  chemistry 
C)  physics 
D)  astronomy 
E)  all of these 
A)  biology 
B)  chemistry 
C)  physics 
D)  astronomy 
E)  all of these

Question 15

Out of the chemical elements, the second-best candidate for enabling biological life-forms is

Accepted Answer

A)  oxygen. 
B)  helium. 
C)  hydrogen. 
D)  silicon. 
E)  phosphorus. 
A)  oxygen. 
B)  helium. 
C)  hydrogen. 
D)  silicon. 
E)  phosphorus.

Question 16

Which of the following properties would be a unique marker of life, as compared to other natural processes?

Accepted Answer

A)  patterned structure 
B)  self-replication 
C)  utilizing energy from an environment 
D)  growing in size with time 
E)  evolutionary adaptation 
A)  patterned structure 
B)  self-replication 
C)  utilizing energy from an environment 
D)  growing in size with time 
E)  evolutionary adaptation

Question 17

As seen in the figure below, evolution allows

Accepted Answer

A)  life to diversify into different species. 
B)  a species to revert to an earlier species, if beneficial. 
C)  organisms to become more complicated, but not more diverse. 
D)  different species to merge into one as time goes on. 
E)  organisms to become more diverse, but not more complex. 
A)  life to diversify into different species. 
B)  a species to revert to an earlier species, if beneficial. 
C)  organisms to become more complicated, but not more diverse. 
D)  different species to merge into one as time goes on. 
E)  organisms to become more diverse, but not more complex.

Question 18

What stars, in terms of mass, are preferred by scientists in the search for highly evolved
life-forms and why?

Accepted Answer

Based on our understanding of life on Ea

Question 19

At approximately what fraction of the Earth's current age were the dinosaurs wiped out by a large asteroid or comet?

Accepted Answer

A)  > 99% 
B)  98% 
C)  90% 
D)  20% 
E)  5% 
A)  > 99% 
B)  98% 
C)  90% 
D)  20% 
E)  5%

Question 20

What is a biosignature, and why is the presence of oxygen considered to be a weak one?

Accepted Answer

A biosignature is a chemical by-product

Exam 24: Life

If astronomers focused only on studying planets in the habitable zones of single stars, what potentially life-harboring objects would be overlooked?

You find a planet orbiting an F-type star (surface temperature 6500 K).Where is this planet with respect to the habitable zone, if this planet has a circular orbit with a radius of 2.6 AU? The figure below may be helpful.

The "waste" product in the process of photosynthesis is

If the most pessimistic assumptions in the Drake equation were true, we would

The habitable zone for a 2MSUN star is ________ and covers a ________ distance range compared with the habitable zone for a 1MSUN star.

Why was the comet or asteroid impact 65 million years ago an event that benefited the evolution of humans?

What is the origin of the atmospheric oxygen on Earth?

The current oxygen level in the Earth's atmosphere was reached about

One general property of living organisms is that they

What is the main impediment for interstellar travel?

What makes molecules organic?

Which of the following sequences correctly ranks the number of atoms in the human body from highest to lowest?

Heredity essentially implies the ability to

The field of astrobiology uses our knowledge of ________ to study life in the universe.

Out of the chemical elements, the second-best candidate for enabling biological life-forms is

Which of the following properties would be a unique marker of life, as compared to other natural processes?

As seen in the figure below, evolution allows

What stars, in terms of mass, are preferred by scientists in the search for highly evolved life-forms and why?

At approximately what fraction of the Earth's current age were the dinosaurs wiped out by a large asteroid or comet?

What is a biosignature, and why is the presence of oxygen considered to be a weak one?

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Filters

The habitable zone for a 2M_SUN star is and covers a distance range compared with the habitable zone for a 1M_SUN star.