Deck 7: Formation of Planetary Systems

Question 1

Any model of solar system formation must explain why every planet is relatively isolated in space.

Answer 1

True

Question 2

Super-Earths are earthlike planets where life is possible.

Answer 2

False

Question 3

Different temperatures within the solar nebula ultimately determined the compositions of the planets and their moons.

Answer 3

True

Question 4

The asteroids are very young and appear to be made from the same material.

Question 5

While most large moons orbit counterclockwise above their planets' equators, the smaller moons often show eccentric or even retrograde orbits, suggesting capture.

Question 6

Stars with multiple planets orbiting them are expected to be rare.

Question 7

None of the other stars yet studied has more than one planet orbiting it.

Question 8

We now know of over 100 jovian exoplanets, but no terrestrial planets around other stars similar to the Sun.

Question 9

As the solar nebula contracts due to gravitation, the cloud

A) spins faster.
B) expands.
C) becomes more spherical in shape.
D) changes direction of motion.
E) begins to cool.

Question 10

Around other suns, we have found Jupiters where Mercury should be.

Question 11

Most hot Jupiters are thought to have formed in the orbits they have been discovered.

Question 12

All planets revolve around the Sun counterclockwise, and most also rotate on their axis counterclockwise.

Question 13

Jupiter and the other jovian planets may have formed significantly closer to the Sun than their current orbits.

Question 14

Concerning our solar nebula theory, the presence of so many "hot Jupiters" gives us problems with how they can form that close to their star.

Question 15

Most extrasolar planets are hot Jupiters, discovered in the infrared by the Spitzer Space telescope.

Question 16

Any model of solar system formation must explain why terrestrial planets and jovian planets formed differently.

Question 17

It is expected that most of the planet candidates found by the Kepler mission will eventually be confirmed.

Question 18

Any model of solar system formation must explain why the planets revolve in the same direction as the Sun rotates.

Question 19

Any model of solar system formation must explain why comets come from the Oort Cloud, with orbits very different from the planets, asteroids, and Kuiper Belt Objects.

Question 20

The Kuiper Belt is a collection of asteroid-sized icy bodies orbiting the Sun beyond the orbit of Neptune.

Question 21

What is the process of accretion?

A) The separation of materials in a protoplanet by density, with dense material in core
B) Growth of an object by the accumulation of matter
C) The breakup of large objects by violent collisions with other similar-sized objects
D) The period of time during which the Sun swept away all the excess material in the solar nebula
E) The process by which the solar nebula became heated during its collapse

Question 22

Which objects in the solar system have been least modified since the formation of the solar system?

A) Asteroids
B) Kuiper Belt objects
C) Meteoroids
D) Terrestrial planets
E) Jovian moons

Question 23

The Kuiper Belt is found where in the solar system?

A) Among the orbits of the terrestrial planets
B) Beyond the orbit of Neptune
C) Between the orbits of Mars and Jupiter
D) Between the orbits of Jupiter and Uranus
E) Sixty degrees ahead or behind Jupiter

Question 24

What happens when a solar nebula contracts?

A) It flattens out.
B) It spins faster.
C) It heats up.
D) All of the above
E) None of the above

Question 25

What might have made the original solar nebula begin to contract?

A) The Big Bang
B) The formation of our arm of the Milky Way
C) The shock wave from a nearby exploding star
D) Interstellar magnetism generated by pulsars
E) The large amount of angular momentum in the nebula

Question 26

Planetary orbits

A) are evenly spaced throughout the solar system.
B) are highly inclined to the ecliptic.
C) are almost circular, with low eccentricities.
D) have the Sun at their exact center.
E) are spaced more closely together as they get further from the Sun.

Question 27

Which of these is NOT a characteristic of the solar nebula theory?

A) The ecliptic is the equator for the Sun.
B) All the planets should follow the ecliptic plane.
C) All the planets should orbit the Sun counterclockwise.
D) Larger planets should form closer to their star, where there is more debris.
E) Planets should rotate counterclockwise as well.

Question 28

What factor caused different planets to form out of different types of material?

A) The angular momentum of the forming planet; faster rotating planets lost the lightest elements.
B) The quantity of dust particles in the solar nebula; more dust caused some planets to contain heavier elements.
C) The variation in temperature throughout the solar nebula; the higher the temperature, the lower the percentage of light elements in the forming planet.
D) The angular momentum of the solar nebula pushed the heavy elements towards the outer regions of the nebula.
E) The innate variation of chemical composition of the original nebula; the outer parts of the nebula contained a greater abundance of heavy elements.

Question 29

A successful theory of the formation of the solar system must explain

A) that all planets rotate in a prograde sense.
B) that all planets have elliptical orbits with high eccentricities.
C) the existence of the asteroid belt between Jupiter and Neptune.
D) that the inner planets have more hydrogen and helium in their atmospheres than do the outer planets.
E) all observed properties of the solar system.

Question 30

An alternative to the core-accretion theory that explains the formation of the jovian planets is the

A) differentiation theory.
B) collision theory.
C) gravitational instability theory.
D) Big Bang theory.
E) nebular contraction theory.

Question 31

In the conventional scenario, during phase of planet formation caused the jovian planets to form?

A) Core-accretion
B) Fragmentation
C) Differentiation
D) Collision
E) Condensation

Question 32

As a result of the ejection of planetesimals into the Oort Cloud, simulations indicate that Uranus and Neptune moved

A) closer to the Sun.
B) further from the Sun.
C) along their orbits at a different rate.
D) from the inner solar system to the outer solar system.
E) from the outer solar system to the inner solar system.

Question 33

What is the role of irregularities in the solar system in terms of theories of its origin?

A) They are too minor to play a role; astronomers ignore them.
B) They introduce a need for flexibility in theories of the solar system's origin.
C) Theories of the solar system are entirely based on the many irregularities found among the planets and moons.
D) The solar system has no irregularities; it is perfectly regular and orderly.
E) The solar system is chaotic, with irregularities the rule.

Question 34

As the solar nebula contracts it

A) flattens out into the ecliptic plane around the Sun's poles.
B) spins faster due to conservation of angular momentum.
C) cools due to condensation.
D) loses angular momentum.
E) reverses it direction of rotation.

Question 35

The jovian planets

A) all lie less than 5 AU from the Sun.
B) all have rings around their equators.
C) all spin slower than the Earth.
D) have satellite systems with less than 4 moons.
E) are all much more dense than any of the terrestrials planets.

Question 36

The moons of the jovian planets formed by which two processes?

A) Accretion and collisions
B) Capture and collisions
C) Collisions and differentiation
D) Accretion and capture
E) Differentiation and capture

Question 37

In light of modern solar system theory, why do the orbits of the planets all lie in the same plane?

A) The Sun's gravity forced them into these orbits.
B) The angular momentum of the solar system was kept to a minimum this way.
C) The early solar nebula flattened into a disk.
D) Comets would have wiped out any not in this protected plane.
E) This happened purely by chance.

Question 38

Dust is an important part of the nebular theory of solar system formation because dust is needed to explain

A) how the inner planets came to be rocky bodies.
B) how the outer planets came to be gaseous bodies.
C) how the initial cloud cooled enough to collapse.
D) how the initial cloud heated as it contracted.
E) why the icy bodies are located so far from the Sun.

Question 39

Conservation of angular momentum means that a spinning body tends to

A) fly apart.
B) slow down.
C) wobble into an eccentric orbit.
D) gravitationally collapse.
E) keep spinning.

Question 40

As a rotating gas cloud contracts, it spins

A) faster due to an increase in angular momentum.
B) slower due to a decrease in angular momentum.
C) at a constant rate.
D) faster due to conservation of angular momentum.
E) slower due to conservation of angular momentum.

Question 41

The Kuiper Belt is located beyond the orbit of ________.

Question 42

The ________ theory describes the origin of the planets as having been formed by accretion of small particles into progressively larger and larger bodies.

Question 43

The Doppler radial velocity technique works best for

A) planets whose orbits are along are line of sight.
B) planets whose orbits are perpendicular to our line of sight.
C) planets whose orbits are nearly circular.
D) planets whose orbits are very eccentric.

Question 44

When we are lucky enough to see an extra-solar planet transit its star

A) It will cause the star to vanish for several hours.
B) We can by the drop in light find the planet's size, mass, and density.
C) We can determine what elements are in its atmosphere.
D) We can determine its shape.
E) We can be certain it is a terrestrial, not a jovian.

Question 45

Most extrasolar Neptunes and Jupiters found to date have

A) orbits very close to their parent stars, making them hot Neptunes and hot Jupiters.
B) orbits that are more eccentric than those of planets in our solar system, with eccentricities greater than 0.1
C) orbits that are less eccentric than those of planets in our solar system, with eccentricities less than 0.01.
D) much larger orbits than the jovian planets in our solar system.

Question 46

The Kepler mission uses which technique to detect planet candidates?

A) Radial velocity measurements
B) Direct imaging
C) Measurements of transverse motion
D) Planetary transits

Question 47

While all planet orbits are ellipses, the orbits of the eight large planets are relatively ________.

Question 48

The Oort Cloud is believed to have been formed by

A) planetesimals that were flung far from the Sun in gravitational encounters with the jovian planets.
B) icy bodies formed between stars that have been captured by our solar system's gravity.
C) moons that escaped from the jovian planets.
D) debris from an icy planet that broke apart early in the solar system's history.
E) debris from impacts of planetesimals, asteroids and comets with the jovian planets.

Question 49

According to the planetary migration model, the jovian planets are thought to have formed

A) in the orbit where they are now.
B) further from the Sun than they are now.
C) in another solar system.
D) closer to the Sun than they are now.
E) none of the above.

Question 50

The Kuiper Belt is

A) another name for the Asteroid Belt.
B) a band of icy planetesimals found beyond Neptune's orbit.
C) where all comets come from.
D) the name given to icy bodies found between Jupiter and Saturn.
E) the name given to icy bodies found between Mars and Jupiter.

Question 51

Most of first extrasolar planets found were detected by

A) noting the drop in the star's light as the planet transits its disk.
B) imaging them with the HST in the infrared, where they are easier to stop.
C) noting the Doppler shifts of the star as the planet orbits it from side to side.
D) receiving radio transmissions from them, much like Jupiter emits.
E) detecting the oxygen in their atmospheres spectroscopically.

Question 52

In general, the surfaces of the planets will be ________ than the age of the solar system.

Question 53

When looking for the "Doppler Wobble" (radial velocity changes detected due to Doppler shifts), which mass combination is most likely to be detected?

A) High mass star, high mass planet
B) High mass star, low mass planet
C) Low mass star, high mass planet
D) Low mass star, low mass planet
E) A high mass planet; the mass of the star is irrelevant.

Question 54

Super-earths are

A) planets that are most earthlike, likely to harbor life.
B) planets that are a few times the mass of the Earth.
C) planets that have earthlike masses, but orbit much closer to their star than the Earth does to the Sun.
D) any rocky (or terrestrial) planet.
E) Earth-mass planets that are much lower in density than the Earth, giving them larger radii.

Question 55

Which molecule has not yet been detected in the atmospheres of exoplanets?

A) Methane
B) Carbon dioxide
C) Oxygen
D) Water

Question 56

In the process of planetary formation, when would the inward migration of Jupiters have been most likely?

A) Shortly after all of the planets had finished forming
B) Just after the system was cleared of the remaining gas
C) Before these planets had grown to full size
D) After these planets had reached full size, but before terrestrial planets had finished forming
E) At least hundreds of millions of years after planetary formation ended

Question 57

When was the first confirmed exoplanet discovered?

A) Shortly after the invention of the telescope, in the early 1600s
B) In prehistoric times
C) Around 350 BC, by the Ancient Greeks
D) Early in the 21st century
E) Near the end of the 20th century

Question 58

Which statement about extrasolar planets found to date is TRUE?

A) All are terrestrials, comparable in size to Earth.
B) Few are found by Doppler shifts of their stars, due to their gravity.
C) All lie more than 2 AU from their star.
D) Most have orbital periods of more than a year.
E) Some are so close to their stars that their periods are just a few days.

Question 59

Planets found in the habitable zone of other stars

A) are all rocky planets, like the terrestrial planets in our solar system.
B) are all jovian planets.
C) include some Earths and super-Earths.
D) include hot Jupiters.
E) have been demonstrated to be barren of all life.

Question 60

In the currently accepted theory for the formation of the solar system, the planets and other minor bodies and the ________ formed at about the same time.

Question 61

What is the most important consideration in the "habitable zone" of a planetary system?

Question 62

What are the chemical and physical properties of the solar system that any theory of its origin must explain?

Question 63

What is the role of dust in the condensation theory?

Question 64

Explain how the Doppler Effect has been used to detect invisible planets orbiting other Sun-like stars.

Question 65

Describe how the observable properties of the solar system are related to its process of formation.

Question 66

The Kepler mission uses the ________ technique to detect exoplanets.

Question 67

Explain the stage in which the solar system formed pretty much in a plane.

Question 68

Extrasolar planets are placed in groups by their approximate masses. What are four of these classes?

Question 69

The radial velocity method is less likely to detect low mass planets than high mass planets because low mass planets cause smaller ________ fluctuations.

Question 70

What support for the solar nebula theory has come from observations of nearby young stars?

Question 71

The chemical composition differences between the planets are basically the result of the fact that different elements condense out of gas at different ________.

Question 72

Why are infrared observations useful when observing extrasolar planets?

Question 73

Explain the effect angular momentum has on a gas cloud as it contracts.

Question 74

Why do the present methods of finding extrasolar planets (Doppler measurement and planetary transits) not favor finding solar systems like ours?

Question 75

What are the properties of the Sun that any theory of the origin of the solar system must explain?

Question 76

Hot jupiters have ________ period orbits.

Question 77

Name three properties of the solar nebula still seen in planet orbits.

Question 78

Comets that we can see originate in the ________ and ________.

Question 79

The ________ around a star is the region where liquid water could exist on a planet.

Question 80

Why do instruments that are looking for transiting planets need to look for very small brightness changes?