Deck 5: The Architecture and Birth of Planetary Systems

Question 1

The density of a terrestrial planet is an imperfect indicator of its location in the Solar System because:

A) it is affected by the planet's rotation.
B) the trend in mass with orbital radius is stronger.
C) it is affected by the planet's self-gravity.
D) it depends on composition.

Answer 1

it is affected by the planet's self-gravity.

Question 2

A comet is best described as a:

A) ball of gas.
B) ball of ice.
C) dirty snowball.
D) carbonaceous rock.

Answer 2

dirty snowball.

Question 3

Astronomers discover an icy body in our Solar System with a radius of 10,000 km traveling on a circular orbit.It is most likely to be a(n):

A) Kuiper Belt object.
B) meteor.
C) ice giant planet.
D) asteroid.

Answer 3

Kuiper Belt object.

Question 4

A body passing through Earth's atmosphere that creates a streak of light in the sky is a:

A) meteor.
B) meteorite.
C) meteoroid.
D) nova.

Question 5

Arrange the following types of planets in order of increasing distance from the Sun:

A) terrestrial planets, ice giants, gas giants.
B) gas giants, terrestrial planets, ice giants.
C) terrestrial planets, gas giants, ice giants.
D) ice giants, gas giants, terrestrial planets.

Question 6

Pluto is closest in mass to:

A) Ceres.
B) Mercury.
C) Earth's Moon.
D) Eris.

Question 7

The largest explosions in Earth's history were a result of:

A) radioactivity in Earth's core.
B) Earth-crossing asteroids.
C) nuclear weapons.
D) volcanoes.

Question 8

Among the terrestrial planets,which of the following properties decreases with distance from the Sun?

A) mass
B) uncompressed density
C) radius
D) rotation rate

Question 9

A Solar System body with a dozen moons,a mass of 15 Earth masses,and strong magnetic fields is most likely a(n):

A) dwarf planet.
B) terrestrial planet.
C) gas giant.
D) ice giant.

Question 10

A meteor shower occurs when:

A) an asteroid breaks up near Earth.
B) Earth passes through the asteroid belt.
C) Earth passes through a comet's orbit.
D) a comet breaks up near Earth.

Question 11

Most of the dwarf planets in our Solar System reside within the:

A) scattered disk.
B) Kuiper Belt.
C) asteroid belt.
D) moons of the giant planets.

Question 12

A bright,extended object appears in the sky one evening,visible to the naked eye.Over the next several weeks,it moves across the sky,becoming brighter as it approaches the Sun and then fainter again as it moves away.After six weeks,it fades away.This is most likely a(n):

A) supernova.
B) Earth-crossing asteroid.
C) Trojan asteroid.
D) comet.

Question 13

A comet with an orbit near the ecliptic plane and an orbital period of 75 years most likely comes from the:

A) asteroid belt.
B) Kuiper Belt.
C) Oort Cloud.
D) Trojan asteroids.

Question 14

The thinker who advocated the existence of worlds around other planets at the end of the sixteenth century was:

A) Tycho Brahe.
B) Johannes Kepler.
C) Nicolaus Copernicus.
D) Giordano Bruno.

Question 15

Arrange the following objects in order of increasing distance from the Sun:

A) Earth, asteroid belt, Jupiter, Kuiper Belt, scattered disk, Oort Cloud.
B) Earth, Jupiter, asteroid belt, scattered disk, Kuiper Belt, Oort Cloud.
C) asteroid belt, Earth, Oort Cloud, Jupiter, Kuiper Belt, scattered disk.
D) scattered disk, Earth, asteroid belt, Oort Cloud, Jupiter, Kuiper Belt.

Question 16

An icy,rocky body on a highly elliptical orbit through our Solar System is most likely a:

A) Kuiper Belt object.
B) asteroid.
C) comet.
D) dwarf planet.

Question 17

A Solar System body that has a composition similar to a comet,a strong magnetic field,and a radius about four times larger than Earth must have an average orbital radius closest to:

A) 1 AU.
B) 5 AU.
C) 30 AU.
D) 60 AU.

Question 18

The asteroid belt:

A) is the debris field of a destroyed planet.
B) consists of roughly spherical bodies made of silicon and iron.
C) was kept from forming a planet by the gravitational disturbance of Jupiter.
D) contains as much mass as Saturn.

Question 19

Meteoroids can come from:

A) comets.
B) the Moon
C) Mars.
D) all of the above.

Question 20

The first extrasolar planets were discovered in:

A) 1601.
B) 1951.
C) 1995.
D) 2011.

Question 21

The theory that describes the formation of planetary systems is the:

A) condensation theory.
B) core accretion model.
C) disk theory.
D) protoplanetary theory.

Question 22

The physical principle most directly responsible for the shape of planetary systems is:

A) Newton's second law of motion.
B) the universal law of gravity.
C) conservation of angular momentum.
D) conservation of energy.

Question 23

The orbits of the planets in our Solar System:

A) imply that the planets formed elsewhere and were captured by the Sun's gravity.
B) all proceed in the same direction.
C) have a wide range of inclinations.
D) have semimajor axes that follow a regular, repeating pattern.

Question 24

Suppose Jupiter's gravity disturbs an asteroid and sends it on an elliptical orbit with a high eccentricity.If the semimajor axis of the resulting orbit is 2 AU,the object would be classified as a(n):

A) Kuiper Belt object.
B) C-type asteroid.
C) Trojan asteroid.
D) Earth-crossing asteroid.

Question 25

How do comets from the Oort Cloud differ from comets from the Kuiper Belt?

A) Oort Cloud comets have shorter periods.
B) Oort Cloud comets have smaller masses.
C) Oort Cloud comets have different compositions.
D) Oort Cloud comets have larger inclinations, on average.

Question 26

Compared to our Solar System,the majority of exoplanets have orbits with:

A) higher eccentricity.
B) higher inclinations.
C) smaller semimajor axes.
D) all of the above.

Question 27

Hot Jupiters provide evidence for:

A) the greenhouse effect.
B) super-Earths.
C) the condensation theory.
D) planetary migration.

Question 28

Venus is unusual within the Solar System because it:

A) rotates in the opposite sense from its orbit around the Sun.
B) is so massive.
C) has no evidence for active plate tectonics.
D) has a highly inclined orbit.

Question 29

The most successful method to date in detecting Earth-sized exoplanets is:

A) the radial velocity method.
B) the transit method.
C) direct imaging.
D) gravitational lensing.

Question 30

A planet orbiting a star with a mass one-quarter that of the Sun has an orbital radius of 1/25 AU.If Earth's orbital velocity is 30 km/s,what is the orbital velocity of this planet?

A) 15 km/s
B) 30 km/s
C) 60 km/s
D) 75 km/s

Question 31

Arrange the following solar system bodies in order of increasing average orbital inclination:

A) long-period comets, short-period comets, planets, and the asteroid belt.
B) planets, the asteroid belt, short-period comets, and long-period comets.
C) the asteroid belt, planets, long-period comets, and short-period comets.
D) long-period comets, short-period comets, the asteroid belt, and planets.

Question 32

The figure below shows two stars.Star A has a mass twice that of our Sun,while Star B has a mass four times that of our Sun.Which labeled point identifies the center of mass of the system?

A) A
B) B
C) C
D) D

Question 33

The ion tail of a comet points:

A) in the direction of the solar wind.
B) in a trailing orbit near the comet.
C) in the direction of gas jets flowing out of the comet's nucleus.
D) directly behind the comet's position along its orbit.

Question 34

The radial velocity method is best at detecting exoplanets with ________ orbital radii and ________ masses.

A) small; small
B) small; large
C) large; large
D) large; small

Question 35

Astronomers detect a gas giant exoplanet orbiting its host star on an eccentric orbit with a semimajor axis of 100 AU.This provides evidence for:

A) hot Jupiters.
B) eccentric disks.
C) scattering.
D) the snow line.

Question 36

The majority of meteoroids are most similar to:

A) the Moon.
B) comets.
C) S-type asteroids.
D) C-type asteroids.

Question 37

C-type asteroids differ from S-type asteroids in that C-type asteroids:

A) never underwent differentiation.
B) never have Earth-crossing orbits.
C) are more reflective.
D) are more numerous.

Question 38

The most successful method to date in determining an exoplanet's radius is:

A) the transit method.
B) the radial velocity method.
C) direct imaging.
D) gravitational lensing.

Question 39

A planet with a mass of 7-ME is a(n):

A) terrestrial planet.
B) super-Earth.
C) ice giant.
D) gas giant.

Question 40

The coma of a comet glows because:

A) of heating produced by radioactive decay in the interior of the comet.
B) atoms become neutral within the coma.
C) of heating and sublimation of the comet's nucleus by sunlight.
D) of refraction by dust grains.

Question 41

Most of the asteroids in the asteroid belt are S-type.What does this tell us about their history?

Question 42

According to the condensation theory,extrasolar gas giants with orbital radii of about 100 AU formed:

A) about 10 AU from their stars.
B) about 40 AU from their stars.
C) near their present positions.
D) around other stars, and then were captured.

Question 43

Two planets,A and B,have identical compositions.Planet A has an orbital radius of 0.5 AU and a mass equal to 0.5 Earth masses.Planet B has an orbital radius of 1 AU and a mass equal to 1 Earth mass.Which planet is denser? Why?

Question 44

Dust grains form within a protoplanetary disk because:

A) binary accretion begins.
B) the interstellar cloud collapses and heats up.
C) gas accretes onto large protoplanets, clearing out the medium.
D) the disk cools through radiation.

Question 45

Giant planets attain their atmospheres through:

A) collisions of gaseous protoplanets.
B) migration.
C) binary accretion.
D) processes that are not yet well understood.

Question 46

An interstellar cloud of gas and dust with a radius of 10⁵ AU rotates slowly,with its outer edge traveling at 10⁻³ km/s.How fast is the outer edge of the cloud rotating after it contracts to 100 AU?

A) 10^-1 km/s
B) 1 km/s
C) 100 km/s
D) 10³ km/s

Question 47

The figure below shows the orbits (or portions of orbits)of planets in our Solar System with solid lines.The dashed line is between the orbits of Saturn and Uranus.At what lettered location is the snow line?

A) A
B) B
C) C
D) D

Question 48

Explain the differences between meteoroids,meteorites,and meteors.

Question 49

The figure below shows the orbits of planets within our Solar System (not to scale),with three of the orbits labeled by letters A,B,and C.Which type of planet is most likely to follow each of these orbits?

Question 50

Compare the following properties between Mars and Jupiter: mass,orbital radius,rotation rate,and density.

Question 51

Two comets approach the Sun with the same perihelion distance.Comet A's orbit has a higher eccentricity and is more inclined relative to the ecliptic than comet B's orbit.Which comet is more likely to come from the Oort Cloud?

Question 52

An asteroid follows a highly elliptical orbit that carries it into the inner Solar System.What could eventually happen to it?

Question 53

Suppose that a protoplanetary disk around a Sun-like star is heated past about 5 AU by an unknown process.How might the resulting planetary system differ from our own?

A) The outer planets would orbit faster.
B) The outer planets would be rockier.
C) The outer planets would be more massive.
D) This would not affect any of the planets.

Question 54

The figure below shows the orbits of the planets within the Solar System as well as the orbits of three other objects labeled A,B,and C.Based on their orbits,of what parts of the Solar System are objects A,B,and C part?

Question 55

The figure below shows the orbit of a comet around the Sun.Sketch the locations of the comet's ion and dust tails at points A,B,and C.

Question 56

Which of the following would most directly favor the core accretion model over the hydrodynamic instability model for the formation of giant planets?

A) an accurate census of the "hot Jupiters"
B) observations of comet-gas giant collisions in our Solar System
C) a detection of a massive, rocky core in the outer part of a very young protoplanetary disk
D) precise calculations of the formation sites of Jupiter and Saturn

Question 57

What property of the protoplanetary disk was most responsible for differentiation between the planets?

A) temperature
B) composition
C) density
D) illumination

Question 58

Binary accretion describes the:

A) buildup of planetesimals through collisions.
B) gravitational capture of gas by a black hole.
C) rapid growth of giant planets through gas instabilities.
D) merger of two stars in a close mutual orbit.

Question 59

What is a dwarf planet?

Question 60

The orbits of gas giants can move after their formation because of:

A) cooling of the planet.
B) transfer of angular momentum from the planet's rotation to its orbit.
C) evolution of the central protostar.
D) collisions with comets.

Question 61

Why do the compositions of planets in our Solar System depend on distance from the Sun?

Question 62

Suppose Jupiter's orbit suddenly became highly eccentric.How would this affect the Solar System?

Question 63

How did the first exoplanets to be discovered differ from those in our Solar System?

Question 64

What is the key difference between the core accretion and hydrodynamic instability models for gas giant formation?

Question 65

Why are planetary systems disks with rapid rotation if they begin their lives as spherical,slowly rotating gas clouds?

Question 66

How would the outer parts of our Solar System be different if the gaseous portion of the protoplanetary disk remained for longer?

Question 67

The figure below shows the orbits of three gas giants around the star Upsilon Andromedae (labeled B,C,and D in the diagram,following their astronomical names).How do the orbits of these planets differ from gas giants in our Solar System?

Question 68

How do terrestrial planets form?

Question 69

A star-exoplanet system is oriented on the sky as shown in the figure below,which shows several snapshots of the planet's orbit.How could astronomers measure the density of this planet?

Question 70

Astronomers discover a star with several planets orbiting it.The planets have orbits with a wide range of inclinations,and (as viewed from Earth)half orbit clockwise,while half orbit counterclockwise.How must the formation of this system have differed from the formation of our own Solar System?