Question 1

Explain how astronomers use the Doppler effect to detect the presence of extra-solar planets.

Accepted Answer

As a planet orbits a star,the gravitatio

Question 2

You record the spectrum of a star and find that the calcium absorption line,whose rest wavelength is 393.3 nm,has an observed wavelength of 394.0 nm.What is the radial velocity of this star?

Accepted Answer

A)  500 km/s 
B)  50 km/s 
C)  5 km/s 
D)  0.5 km/s 
A)  500 km/s 
B)  50 km/s 
C)  5 km/s 
D)  0.5 km/s

Question 3

Doppler shift can be used to determine the 3-dimensional velocity of a star.

Accepted Answer

A) True 
 B)False

Question 4

Explain the process of protostar formation shown in the figure below.

Accepted Answer

The molecular-cloud core collapses under

Question 5

Was it ever possible (or is it currently possible)for Jupiter to become a star?

Accepted Answer

A)  No,its composition is too different from stars for it to become one. 
B)  Yes,but it cooled off before it could become a star. 
C)  No,it would have to be at least 80 times more massive. 
D)  Yes,it is in the process of becoming a star in the near future. 
A)  No,its composition is too different from stars for it to become one. 
B)  Yes,but it cooled off before it could become a star. 
C)  No,it would have to be at least 80 times more massive. 
D)  Yes,it is in the process of becoming a star in the near future.

Question 6

The planet Mercury still shows evidence of impact craters from the early periods of solar system formation.

Accepted Answer

A) True 
 B)False

Question 7

Explain why astronomers believe that the formation of planets is a natural by-product of star formation.

Accepted Answer

To explain the structure of the Solar Sy

Question 8

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 9

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

Question 10

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 11

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 12

An observer outside our solar system,who monitors the velocity of our Sun over time,will find that its velocity varies by +/- 12 m/s over a period of 12 years,because of:

Accepted Answer

A)  Jupiter's gravitational pull 
B)  Earth's gravitational pull 
C)  convection on the Sun's surface 
D)  the sunspot cycle 
A)  Jupiter's gravitational pull 
B)  Earth's gravitational pull 
C)  convection on the Sun's surface 
D)  the sunspot cycle

Question 13

Astronomers have used radial velocity monitoring to discover:

Accepted Answer

A)  extra-solar planetary systems that are similar to our own solar system 
B)  Earth-sized planets around other stars 
C)  Earth-sized planets at distances of 10 AU from their parent stars 
D)  extra-solar planetary systems that contain more than one planet 
A)  extra-solar planetary systems that are similar to our own solar system 
B)  Earth-sized planets around other stars 
C)  Earth-sized planets at distances of 10 AU from their parent stars 
D)  extra-solar planetary systems that contain more than one planet

Question 14

When astronomers began searching for extra-solar planets,they were surprised to discover Jupiter-sized planets much closer than 1 AU from their parent stars.Why is this surprising?

Accepted Answer

A)  These planets must have formed at larger radius where temperatures were cooler and then migrated inward. 
B)  Jupiter-sized,rocky planets were thought to be uncommon in other solar systems. 
C)  These planets must be the remnants of failed stars. 
D)  Earth-like planets must be rarer than Jupiter-sized planets in other solar systems. 
A)  These planets must have formed at larger radius where temperatures were cooler and then migrated inward. 
B)  Jupiter-sized,rocky planets were thought to be uncommon in other solar systems. 
C)  These planets must be the remnants of failed stars. 
D)  Earth-like planets must be rarer than Jupiter-sized planets in other solar systems.

Question 15

If a collapsing interstellar cloud formed only a protostar without an accretion disk around it,what would happen?

Accepted Answer

A)  The forming protostar would be significantly less massive than it would have been otherwise. 
B)  The forming protostar would be rotating too fast to hold itself together. 
C)  Only Jovian planets would form around the protostar. 
D)  Only terrestrial planets would form around the protostar. 
A)  The forming protostar would be significantly less massive than it would have been otherwise. 
B)  The forming protostar would be rotating too fast to hold itself together. 
C)  Only Jovian planets would form around the protostar. 
D)  Only terrestrial planets would form around the protostar.

Question 16

Conservation of angular momentum 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 17

The Solar System was formed when a passing star tidally extruded mass from the forming Sun.

Accepted Answer

A) True 
 B)False

Question 18

In order to "see" into the dense molecular clouds of the Eagle Nebula (image below),what wavelength of light must be used?

Accepted Answer

A)  Infrared 
B)  Visible 
C)  Ultraviolet 
D)  X-ray 
A)  Infrared 
B)  Visible 
C)  Ultraviolet 
D)  X-ray

Question 19

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 20

Why do outer planets like Jupiter have huge gaseous atmospheres of hydrogen and helium while the inner planets do not?

Accepted Answer

A)  These gases were more abundant in the outer regions of the accretion disk where the outer planets formed. 
B)  The outer planets grew massive quickly enough to gravitationally hold on to these gases before the solar wind dispersed the accretion disk. 
C)  The inner planets were too close to the Sun,and solar winds blew away their original gaseous atmospheres. 
D)  Frequent early collisions by comets with the inner planets caused most of their original atmospheres to dissipate. 
A)  These gases were more abundant in the outer regions of the accretion disk where the outer planets formed. 
B)  The outer planets grew massive quickly enough to gravitationally hold on to these gases before the solar wind dispersed the accretion disk. 
C)  The inner planets were too close to the Sun,and solar winds blew away their original gaseous atmospheres. 
D)  Frequent early collisions by comets with the inner planets caused most of their original atmospheres to dissipate.

Explain how astronomers use the Doppler effect to detect the presence of extra-solar planets.

You record the spectrum of a star and find that the calcium absorption line,whose rest wavelength is 393.3 nm,has an observed wavelength of 394.0 nm.What is the radial velocity of this star?

Doppler shift can be used to determine the 3-dimensional velocity of a star.

Explain the process of protostar formation shown in the figure below.

Was it ever possible (or is it currently possible)for Jupiter to become a star?

The planet Mercury still shows evidence of impact craters from the early periods of solar system formation.

Explain why astronomers believe that the formation of planets is a natural by-product of star formation.

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

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

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

The Moon probably formed:

An observer outside our solar system,who monitors the velocity of our Sun over time,will find that its velocity varies by +/- 12 m/s over a period of 12 years,because of:

Astronomers have used radial velocity monitoring to discover:

When astronomers began searching for extra-solar planets,they were surprised to discover Jupiter-sized planets much closer than 1 AU from their parent stars.Why is this surprising?

If a collapsing interstellar cloud formed only a protostar without an accretion disk around it,what would happen?

Conservation of angular momentum slows a cloud's collapse:

The Solar System was formed when a passing star tidally extruded mass from the forming Sun.

In order to "see" into the dense molecular clouds of the Eagle Nebula (image below),what wavelength of light must be used?

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

Why do outer planets like Jupiter have huge gaseous atmospheres of hydrogen and helium while the inner planets do not?

Our Place in the Universe

Patterns in the Skymotions of Earth

Laws of Motion

Light and Telescopes

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, Earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: The Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expansion of Space

The Realm of the Galaxies

Our Galaxy: The Milky Way

Modern Cosmology and the Origin of Structure

Life in the Universe

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Exam 5: The Formation of Stars and Planets

Explain how astronomers use the Doppler effect to detect the presence of extra-solar planets.

You record the spectrum of a star and find that the calcium absorption line,whose rest wavelength is 393.3 nm,has an observed wavelength of 394.0 nm.What is the radial velocity of this star?

Doppler shift can be used to determine the 3-dimensional velocity of a star.

Explain the process of protostar formation shown in the figure below.

Was it ever possible (or is it currently possible)for Jupiter to become a star?

The planet Mercury still shows evidence of impact craters from the early periods of solar system formation.

Explain why astronomers believe that the formation of planets is a natural by-product of star formation.

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

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

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

The Moon probably formed:

An observer outside our solar system,who monitors the velocity of our Sun over time,will find that its velocity varies by +/- 12 m/s over a period of 12 years,because of:

Astronomers have used radial velocity monitoring to discover:

When astronomers began searching for extra-solar planets,they were surprised to discover Jupiter-sized planets much closer than 1 AU from their parent stars.Why is this surprising?

If a collapsing interstellar cloud formed only a protostar without an accretion disk around it,what would happen?

Conservation of angular momentum slows a cloud's collapse:

The Solar System was formed when a passing star tidally extruded mass from the forming Sun.

In order to "see" into the dense molecular clouds of the Eagle Nebula (image below),what wavelength of light must be used?

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

Why do outer planets like Jupiter have huge gaseous atmospheres of hydrogen and helium while the inner planets do not?

Our Place in the Universe

Patterns in the Skymotions of Earth

Laws of Motion

Light and Telescopes

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, Earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: The Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expansion of Space

The Realm of the Galaxies

Our Galaxy: The Milky Way

Modern Cosmology and the Origin of Structure

Life in the Universe

Filters