Question 1

Detecting a planet around another star using the transit method is difficult because

Accepted Answer

A)  the planet must pass directly in front of the star. 
B)  the planet must have a rocky composition. 
C)  the star must be very dim. 
D)  the star must be moving with respect to us. 
A)  the planet must pass directly in front of the star. 
B)  the planet must have a rocky composition. 
C)  the star must be very dim. 
D)  the star must be moving with respect to us. A

Question 2

What happens to the kinetic energy of gas as it falls toward and eventually hits the accretion disk surrounding a protostar?

Accepted Answer

A)  It is converted into thermal energy,heating the disk. 
B)  It is converted into light energy,giving off a flash of light upon impact. 
C)  It is converted into potential energy as the gas plows through the disk and comes out the other side. 
D)  It simply dissipates. 
A)  It is converted into thermal energy,heating the disk. 
B)  It is converted into light energy,giving off a flash of light upon impact. 
C)  It is converted into potential energy as the gas plows through the disk and comes out the other side. 
D)  It simply dissipates. A

Question 3

Explain the two primary reasons why the inner solar nebula was hotter than the outer solar nebula.

Accepted Answer

The inner solar nebular was hotter than the outer solar nebula because the inner regions converted more of their potential energy into kinetic energy and heat when the original cloud collapsed to form the solar system.In addition,when the Sun began to shine,it heated the inner solar system more than the outer solar system.

Question 4

Astronomers believe that the "hot Jupiters" found orbiting other stars must have migrated inward over time by

Accepted Answer

A)  losing orbital angular momentum. 
B)  colliding with another planet. 
C)  slowly accreting large amounts of gas and increasing their gravitational pull. 
D)  losing their gas due to evaporation. 
A)  losing orbital angular momentum. 
B)  colliding with another planet. 
C)  slowly accreting large amounts of gas and increasing their gravitational pull. 
D)  losing their gas due to evaporation.

Question 5

What evidence do we have that the accretion disk that formed the Solar System was initially very centrally condensed?

Accepted Answer

The Sun contains 99

Question 6

Conservation of angular moment slows a cloud's collapse

Accepted Answer

A)  equally in all directions. 
B)  only when the cloud is not rotating initially. 
C)  mostly along directions perpendicular to the cloud's axis of rotation. 
D)  mostly at the poles that lie along the cloud's axis of rotation. 
A)  equally in all directions. 
B)  only when the cloud is not rotating initially. 
C)  mostly along directions perpendicular to the cloud's axis of rotation. 
D)  mostly at the poles that lie along the cloud's axis of rotation.

Question 7

The Moon probably formed

Accepted Answer

A)  out of a collision between the Earth and a Mars-sized object. 
B)  when the Earth's gravity captured a planetesimal. 
C)  when the accretion disk around the Earth fragmented. 
D)  when planetesimals collided to form a more massive object. 
A)  out of a collision between the Earth and a Mars-sized object. 
B)  when the Earth's gravity captured a planetesimal. 
C)  when the accretion disk around the Earth fragmented. 
D)  when planetesimals collided to form a more massive object.

Question 8

The plane of an accretion disk is always perpendicular to the axis of rotation of the interstellar cloud out of which it forms.

Accepted Answer

A) True 
 B)False

Question 9

The primary atmospheres of the planets are made mostly of

Accepted Answer

A)  carbon and oxygen. 
B)  hydrogen and helium. 
C)  iron and nickel. 
D)  nitrogen and argon. 
A)  carbon and oxygen. 
B)  hydrogen and helium. 
C)  iron and nickel. 
D)  nitrogen and argon.

Question 10

Astronomers believe that Venus was created with the thick atmosphere it currently has.

Accepted Answer

A) True 
 B)False

Question 11

Have astronomers detected any Earth-sized planets around normal stars yet?

Accepted Answer

A)  Yes,although the ones detected lie much closer to their stars than we do to ours. 
B)  Yes,although the ones detected lie much farther from their stars than we do from ours. 
C)  No,we do not have the technology to detect such low-mass planets yet. 
D)  No.Although we have the technology to detect low-mass planets,we haven't found any others yet. 
A)  Yes,although the ones detected lie much closer to their stars than we do to ours. 
B)  Yes,although the ones detected lie much farther from their stars than we do from ours. 
C)  No,we do not have the technology to detect such low-mass planets yet. 
D)  No.Although we have the technology to detect low-mass planets,we haven't found any others yet.

Question 12

Approximately how massive are nearly all the extra-solar planets that have been discovered thus far,and how is this related to the way in which we detect them?

Accepted Answer

They are all about Neptune-siz

Question 13

Briefly explain the four different observational methods we use to detect extra-solar planets.Which has detected the largest number of extra-solar planets to date?

Accepted Answer

The four different observational methods

Question 14

How much mass was there in the protoplanetary disk out of which the planets formed,compared to the mass of the Sun?

Accepted Answer

A)  50 percent 
B)  10 percent 
C)  5 percent 
D)  < 1 percent 
A)  50 percent 
B)  10 percent 
C)  5 percent 
D)  < 1 percent

Question 15

The maximum mass of a planet is approximately 0.08 times the mass of the Sun.

Accepted Answer

A) True 
 B)False

Question 16

What is the ratio of the orbital angular momentum of Jupiter to its spin angular momentum? Jupiter's orbit has a semimajor axis of 5 AU and period of 12 years,and Jupiter has a rotation period of 0.4 day and a radius of 70,000 km.

Accepted Answer

A)  10 
B)  26 thousand 
C)  36 million 
D)  50 billion 
A)  10 
B)  26 thousand 
C)  36 million 
D)  50 billion

Question 17

What does conservation of angular momentum mean?

Accepted Answer

It means the angular momentum

Question 18

The borderline between the most massive planet and the least massive brown dwarf occurs at

Accepted Answer

A)  1 Jupiter mass. 
B)  13 Jupiter masses. 
C)  42 Jupiter masses. 
D)  80 Jupiter masses. 
A)  1 Jupiter mass. 
B)  13 Jupiter masses. 
C)  42 Jupiter masses. 
D)  80 Jupiter masses.

Question 19

What sets the temperature of the pocket of gas in a protoplanetary disk?

Accepted Answer

A)  Its distance from the forming star 
B)  How much kinetic energy was converted to heat 
C)  How much radiation from the forming star shines on the gas 
D)  All of the above 
A)  Its distance from the forming star 
B)  How much kinetic energy was converted to heat 
C)  How much radiation from the forming star shines on the gas 
D)  All of the above

Question 20

In the smaller nebula,as smaller particles collide and stick together,forming larger particles,their self-gravity prevents them from breaking apart,regardless of the strength of the collision.

Accepted Answer

A) True 
 B)False

Exam 6: The Birth and Evolution of Planetary Systems

Detecting a planet around another star using the transit method is difficult because

What happens to the kinetic energy of gas as it falls toward and eventually hits the accretion disk surrounding a protostar?

Explain the two primary reasons why the inner solar nebula was hotter than the outer solar nebula.

Astronomers believe that the "hot Jupiters" found orbiting other stars must have migrated inward over time by

What evidence do we have that the accretion disk that formed the Solar System was initially very centrally condensed?

Conservation of angular moment slows a cloud's collapse

The Moon probably formed

The plane of an accretion disk is always perpendicular to the axis of rotation of the interstellar cloud out of which it forms.

The primary atmospheres of the planets are made mostly of

Astronomers believe that Venus was created with the thick atmosphere it currently has.

Have astronomers detected any Earth-sized planets around normal stars yet?

Approximately how massive are nearly all the extra-solar planets that have been discovered thus far,and how is this related to the way in which we detect them?

Briefly explain the four different observational methods we use to detect extra-solar planets.Which has detected the largest number of extra-solar planets to date?

How much mass was there in the protoplanetary disk out of which the planets formed,compared to the mass of the Sun?

The maximum mass of a planet is approximately 0.08 times the mass of the Sun.

What is the ratio of the orbital angular momentum of Jupiter to its spin angular momentum? Jupiter's orbit has a semimajor axis of 5 AU and period of 12 years,and Jupiter has a rotation period of 0.4 day and a radius of 70,000 km.

What does conservation of angular momentum mean?

The borderline between the most massive planet and the least massive brown dwarf occurs at

What sets the temperature of the pocket of gas in a protoplanetary disk?

In the smaller nebula,as smaller particles collide and stick together,forming larger particles,their self-gravity prevents them from breaking apart,regardless of the strength of the collision.

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

Light

The Tools of the Astronomer

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

Life

Filters