Question 1

What is the best method to detect Earth-sized exoplanets with the telescopes and instrumentation that exist today?

Accepted Answer

A)  Doppler shift is the best method. 
B)  Transit is the best method. 
C)  Microlensing is the best method. 
D)  Direct imaging is the best method. 
E)  All of the above methods can be used. 
A)  Doppler shift is the best method. 
B)  Transit is the best method. 
C)  Microlensing is the best method. 
D)  Direct imaging is the best method. 
E)  All of the above methods can be used. B

Question 2

Which method can be used to determine the radius of an extrasolar planet?

Accepted Answer

A)  Doppler shift can be used. 
B)  Transit can be used. 
C)  Microlensing can be used. 
D)  Direct imaging can be used. 
E)  None of these methods are able to do this. 
A)  Doppler shift can be used. 
B)  Transit can be used. 
C)  Microlensing can be used. 
D)  Direct imaging can be used. 
E)  None of these methods are able to do this. B

Question 3

Why do the terrestrial planets have a much higher fraction of their mass in heavy chemical elements (as opposed to lighter chemical elements) than the giant planets?

Accepted Answer

A)  Terrestrial planets are low in mass and high in temperature, thus their lighter chemical elements eventually escaped to the outer reaches of the Solar System. 
B)  The heavier elements in the forming solar nebula sank to the center of the Solar System, thus the inner terrestrial planets formed mostly from heavy chemical elements. 
C)  The giant planets were more massive than terrestrial planets, and the giant planets preferentially pulled the lighter elements from the inner to the outer Solar System. 
D)  Terrestrial planets formed much earlier than giant planets before the hydrogen and helium had a chance to cool and condense onto them. 
E)  Terrestrial planets are colder and thus more massive chemical elements condensed on then than the giant planets. 
A)  Terrestrial planets are low in mass and high in temperature, thus their lighter chemical elements eventually escaped to the outer reaches of the Solar System. 
B)  The heavier elements in the forming solar nebula sank to the center of the Solar System, thus the inner terrestrial planets formed mostly from heavy chemical elements. 
C)  The giant planets were more massive than terrestrial planets, and the giant planets preferentially pulled the lighter elements from the inner to the outer Solar System. 
D)  Terrestrial planets formed much earlier than giant planets before the hydrogen and helium had a chance to cool and condense onto them. 
E)  Terrestrial planets are colder and thus more massive chemical elements condensed on then than the giant planets. A

Question 4

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

Accepted Answer

A)  4 Jupiter masses 
B)  13 Jupiter masses 
C)  120 Jupiter masses 
D)  80 Jupiter masses 
E)  45 Jupiter masses 
A)  4 Jupiter masses 
B)  13 Jupiter masses 
C)  120 Jupiter masses 
D)  80 Jupiter masses 
E)  45 Jupiter masses

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

Have any Earth-sized, terrestrial, extrasolar planets been detected? If so, explain what method(s) is (are) used.

Accepted Answer

The Kepler mission has been finding Eart

Question 7

What is the ratio of the orbital angular momentum of the Earth compared to its spin angular momentum? Note that the Earth has a radius of 6* 106 m, and 1 AU is 1.5 * 1011 m.

Accepted Answer

A)  1 
B)  70 
C)  640 
D)  25,000 
E)  4.3 * 106 
A)  1 
B)  70 
C)  640 
D)  25,000 
E)  4.3 * 106

Question 8

What does conservation of angular momentum mean?

Accepted Answer

It means the angular momentum

Question 9

Approximately 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)  "25 percent" 
C)  "10 percent" 
D)  "5 percent" 
E)  "$\lt$ 1 percent" 
A)  "50 percent" 
B)  "25 percent" 
C)  "10 percent" 
D)  "5 percent" 
E)  "$\lt$ 1 percent"

Question 10

Which of the following is NOT a characteristic of the early Solar System, based on current observations?

Accepted Answer

A)  The early solar nebula must have been flattened. 
B)  The material from which the planets formed was swirling about the Sun in the same average rotational direction. 
C)  The first objects to form started out small and grew in size over time. 
D)  The initial composition of the solar nebula varied between its inner and outer regions. 
E)  Temperatures decreased with increasing distance from the Sun. 
A)  The early solar nebula must have been flattened. 
B)  The material from which the planets formed was swirling about the Sun in the same average rotational direction. 
C)  The first objects to form started out small and grew in size over time. 
D)  The initial composition of the solar nebula varied between its inner and outer regions. 
E)  Temperatures decreased with increasing distance from the Sun.

Question 11

If an astronomer on a planet orbiting a nearby star observed the Sun when Neptune was transiting in front of the Sun, how would the Sun's brightness change? Note that the radius of Neptune is 2.5 * 107 m.

Accepted Answer

A)  The Sun's brightness would decrease by 0.1 percent. 
B)  The Sun's brightness would increase by 0.1 percent. 
C)  The Sun's brightness would increase by 1 percent. 
D)  The Sun's brightness would decrease by 1 percent. 
E)  The Sun's brightness would not change at all. 
A)  The Sun's brightness would decrease by 0.1 percent. 
B)  The Sun's brightness would increase by 0.1 percent. 
C)  The Sun's brightness would increase by 1 percent. 
D)  The Sun's brightness would decrease by 1 percent. 
E)  The Sun's brightness would not change at all.

Question 12

Explain why an accretion disk forms around a protostar when an interstellar cloud collapses.

Accepted Answer

As the cloud collapses, the ra

Question 13

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

Accepted Answer

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

Question 14

Figure 2
-Figure 2 shows data from the transit study of a star in which three different planets repeatedly transit in front of the star (A, B, and C). Which dips are caused by the transit of the planet with the smallest radius?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  A, B, and C 
E)  impossible to tell from this data 
A)  A 
B)  B 
C)  C 
D)  A, B, and C 
E)  impossible to tell from this data

Question 15

Astronomers have used radial velocity monitoring to discover:

Accepted Answer

A)  extrasolar 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)  extrasolar planetary systems that contain more than one planet 
E)  all of the above 
A)  extrasolar 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)  extrasolar planetary systems that contain more than one planet 
E)  all of the above

Question 16

Figure 1
-From the data shown in Figure 1, which property of an extrasolar planet CANNOT be determined?

Accepted Answer

A)  orbital period 
B)  orbital distance 
C)  radius 
D)  mass 
E)  All of the properties above can be determined. 
A)  orbital period 
B)  orbital distance 
C)  radius 
D)  mass 
E)  All of the properties above can be determined.

Question 17

Figure 1
-Using the Doppler effect data for a particular star shown in Figure 1, and assuming the star is about the same mass as our Sun, determine the approximate orbital distance of its exoplanet.

Accepted Answer

A)  1.1 AU 
B)  6.4 AU 
C)  18 AU 
D)  36 AU 
E)  3.3 AU 
A)  1.1 AU 
B)  6.4 AU 
C)  18 AU 
D)  36 AU 
E)  3.3 AU

Question 18

Which of the following is FALSE?

Accepted Answer

A)  Hundreds of extrasolar planets have been discovered to date from radial velocity surveys. 
B)  The most common types of extrasolar planets found to date have masses 10 times the mass of Jupiter and lie within 5 AU from their parent star. 
C)  Some planetary systems have been found that contain multiple planets. 
D)  A star can brighten significantly due to gravitational lensing when a planet that orbits it passes directly in front of the star. 
E)  The Kepler mission has begun to find terrestrial planets similar in size to Earth. 
A)  Hundreds of extrasolar planets have been discovered to date from radial velocity surveys. 
B)  The most common types of extrasolar planets found to date have masses 10 times the mass of Jupiter and lie within 5 AU from their parent star. 
C)  Some planetary systems have been found that contain multiple planets. 
D)  A star can brighten significantly due to gravitational lensing when a planet that orbits it passes directly in front of the star. 
E)  The Kepler mission has begun to find terrestrial planets similar in size to Earth.

Question 19

Explain why there is a significant amount of methane and ammonia in the atmospheres of Uranus and Neptune but not nearly as much in the atmospheres of Jupiter and Saturn.

Accepted Answer

Ammonia and methane are volatile materia

Question 20

Why did the planetesimals in the asteroid belt never coalesce into a planet?

Accepted Answer

The gravity of Jupit

Exam 7: The Birth and Evolution of Planetary Systems

What is the best method to detect Earth-sized exoplanets with the telescopes and instrumentation that exist today?

Which method can be used to determine the radius of an extrasolar planet?

Why do the terrestrial planets have a much higher fraction of their mass in heavy chemical elements (as opposed to lighter chemical elements) than the giant planets?

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

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

Have any Earth-sized, terrestrial, extrasolar planets been detected? If so, explain what method(s) is (are) used.

What is the ratio of the orbital angular momentum of the Earth compared to its spin angular momentum? Note that the Earth has a radius of 6* 106 m, and 1 AU is 1.5 * 1011 m.

What does conservation of angular momentum mean?

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

Which of the following is NOT a characteristic of the early Solar System, based on current observations?

If an astronomer on a planet orbiting a nearby star observed the Sun when Neptune was transiting in front of the Sun, how would the Sun's brightness change? Note that the radius of Neptune is 2.5 * 107 m.

Explain why an accretion disk forms around a protostar when an interstellar cloud collapses.

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

Figure 2 -Figure 2 shows data from the transit study of a star in which three different planets repeatedly transit in front of the star (A, B, and C). Which dips are caused by the transit of the planet with the smallest radius?

Astronomers have used radial velocity monitoring to discover:

Figure 1 -From the data shown in Figure 1, which property of an extrasolar planet CANNOT be determined?

Figure 1 -Using the Doppler effect data for a particular star shown in Figure 1, and assuming the star is about the same mass as our Sun, determine the approximate orbital distance of its exoplanet.

Which of the following is FALSE?

Explain why there is a significant amount of methane and ammonia in the atmospheres of Uranus and Neptune but not nearly as much in the atmospheres of Jupiter and Saturn.

Why did the planetesimals in the asteroid belt never coalesce into a planet?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

What is the ratio of the orbital angular momentum of the Earth compared to its spin angular momentum? Note that the Earth has a radius of 6* 10⁶ m, and 1 AU is 1.5 * 10¹¹ m.

If an astronomer on a planet orbiting a nearby star observed the Sun when Neptune was transiting in front of the Sun, how would the Sun's brightness change? Note that the radius of Neptune is 2.5 * 10⁷ m.