Solar System Final Week 4

Why do jovian planets bulge around the equator, that is, have a "squashed" appearance? A. all of the above B. Their internal heat sources exert a pressure against the sides of the planets. C. Their large systems of moons and rings gravitationally attract the mass around the equator more. D. Their rapid rotation flings the mass near the equator outward. E. They are much more massive than the terrestrial planets.

D

Why do the jovian planet interiors differ? A. The more distant planets had longer to form than the closer planets, since the solar nebula lasted longer at greater distances from the Sun. B. The more distant planets formed in a cooler region of the solar nebula and therefore contain a greater proportion of ices than the closer jovian planets. C. They differ due to giant impacts at the late stages of planet formation. D. Accretion took longer further from the Sun, so the more distant planets formed their cores later and captured less gas from the solar nebula than the closer jovian planets. E. The solar heating is less for the more distant planets than the closer planets.

D

Why does the plasma tail of a comet always point away from the Sun? A. Radiation pressure from the Sun's light pushes the ions away. B. The conservation of the angular momentum of the tail keeps it always pointing away from the Sun. C. It is allergic to sunlight. D. The solar wind blows the ions directly away from the Sun. E. Gases from the comet, heated by the Sun, push the tail away from the Sun.

D

How do we think the "hot Jupiters" around other stars were formed? A. They formed as gas giants beyond the frost line and then migrated inwards. B. Many planets were formed around the star but coalesced into a single planet close in. C. They formed as dense, rocky planets close to the star in the same orbits that they are seen today. D. They formed as gas giants close to the star in the same orbits that they are seen today.

A

In order to have a comet named after you, you have to A. be one of the first three discoverers who report it to the International Astronomical Union (IAU). B. publish a picture of it in an astronomical journal. C. be and do all of the above D. calculate its orbit and predict when it will return. E. be a well-known astronomer.

A

Planetary rings are A. all of the above B. orbiting in the equatorial plane of their planet. C. nearer to their planet than any of the planet's large moons. D. known to exist for all of the jovian planets. E. composed of a large number of individual particles that orbit their planet in accord with Kepler's third law.

A

What do we call a small piece of solar system debris found on Earth? A. meteorite B. meteor C. solar system debris D. cometary fragment E. meteoroid

A

Which moon has the most substantial atmosphere? A. Titan B. Io C. Mimas D. Europa E. Ganymede

A

Which of the jovian planets have rings? A. all of the above B. Jupiter C. Uranus D. Saturn E. Neptune

A

Which planet search technique is currently best suited to finding Earth-like planets? A. transit B. gravitational lensing C. astrometric D. Doppler

A

Why aren't small asteroids spherical in shape? A. The strength of gravity on small asteroids is less than the strength of the rock. B. Large asteroids were once molten and therefore became spherical, but small asteroids were never molten. C. Small asteroids have odd shapes because they were all chipped off larger objects. D. Large asteroids became spherical because many small collisions chipped off pieces until only a sphere was left; this did not occur with small asteroids.

A

Why do asteroids and comets differ in composition? A. Asteroids formed inside the frost line, while comets formed outside. B. Asteroids and comets formed at different times. C. Comets formed from the jovian nebula, while asteroids did not. D. Comets are much larger than asteroids. E. Asteroids are much larger than comets.

A

A typical shooting star in a meteor shower is caused by a ________ entering the earth's atmosphere. A. microscopic particle of interstellar dust B. pea-size particle from a comet C. pea-size particle from an asteroid D. boulder-size particle from a comet E. boulder-size particle from an asteroid

B

All meteorites collected on Earth come from asteroids or comets. A. True B. False

B

How do the jovian planet interiors differ? A. The composition changes from mostly ammonia in Jupiter and Saturn to mostly methane in Uranus and Neptune. B. All have cores of about the same mass, but differ in the amount of surrounding hydrogen and helium. C. All have about the same amount of hydrogen and helium but the proportion of rocks is greater in those planets closer to the Sun. D. The composition changes from mostly hydrogen in Jupiter and Saturn to mostly helium in Uranus and Neptune. E. The core mass decreases with the mass of the planet.

B

Most of the planets discovered around other stars A. are less massive than Earth and orbit very far from the star. B. are more massive than Earth and orbit very close to the star. C. are less massive than Earth and orbit very close to the star. D. are found around neutron stars. E. are more massive than Earth and orbit very far from the star.

B

Primitive meteorites can be distinguished from other meteorites and terrestrial rocks because they A. resemble the composition of rocks from lava flows that occurred on asteroids very shortly after the formation of the solar system. B. contain a noticeable fraction of pure metallic flakes. C. resemble the composition of the earth's core. D. resemble the composition of the earth's mantle. E. contain a lot of iron and were used by humans to make iron tools.

B

The Doppler technique only provides a measure of the minimum mass of a planet because A. we do not have the technology to make a direct image of a planet yet. B. only the motion of star toward the observer is measured, not the full motion. C. without a transit observation, the size and therefore density of the planet is unknown. D. we do not know the exact composition of the planet. E. only a small part of the planet's motion is measured.

B

The large gaps in the asteroid belt (often called Kirkwood gaps) are caused by A. large asteroids that clear certain regions of the asteroid belt. B. orbital resonances with Jupiter. C. tidal forces from Jupiter. D. the competing gravitational tugs of Mars and Jupiter. E. tidal forces from the Sun.

B

When was Pluto discovered? A. about 2000 years ago B. about 70 years ago C. about 20 years ago D. about 200 years ago E. in ancient history

B

Which of the following is a consequence of the discovery of hot Jupiters for the nebular theory of solar system formation? A. Its status is unclear and awaits further observations that will determine whether hot Jupiters are dense Earth like planets or gas giants. B. It has been modified to allow for planets to migrate inwards or outwards due to gravitational interactions. C. It has been modified to allow for the formation of gas giants within the frost line. D. It has been discarded.

B

Which of the following statements about Titan is not true? A. Its atmosphere is mostly nitrogen. B. It is the coldest moon in the solar system. C. Its surface is hidden from view by its thick atmosphere. D. Its temperature is too cold for liquid water to exist. E. It may have an ocean of liquid ethane.

B

Why do astronomers believe Triton may have been a planet that was captured by Neptune? A. It is colder than any other moon or planet. B. It orbits Neptune in the opposite direction of Neptune's rotation. C. It is too large to have been formed in the jovian nebula that formed Neptune. D. It has an atmosphere and a measurable greenhouse effect. E. It undergoes seasonal changes.

B

Why is Neptune denser than Saturn? A. Its hydrogen is molecular, whereas Saturn's hydrogen is atomic. B. It has a different composition than Saturn, including a higher proportion of hydrogen compounds and rocks. C. It is not denser than Saturn. D. It has a greater proportion of hydrogen than Saturn. E. The extra mass of Neptune compresses its interior to a greater extent than that of Saturn.

B

Why won't Pluto collide with Neptune? A. Pluto's orbit never comes anywhere close to Neptune's orbit. B. The two planets have an orbital resonance that prevents them from colliding. C. It could! D. Pluto's orbit is completely inside Neptune's orbit. E. Pluto's orbit is completely outside Neptune's orbit.

B

tion of a planet can be determined by A. transit observations. B. spectra C. the Doppler technique. D. all of these E. astrometric measurements.

B

Most meteorites are A. carbon-rich and processed. B. iron-rich and processed. C. carbon-rich and primitive. D. rocky and processed. E. rocky and primitive.

E

How do astronomers think Jupiter generates its internal heat? A. radioactive decay B. nuclear fusion in the core C. by contracting, changing gravitational potential energy into thermal energy D. internal friction due to its high rotation rate E. chemical processes

C

How thick are Saturn's rings from top to bottom? A. few tens of thousands of kilometers B. few hundred kilometers C. few tens of meters D. few kilometers E. few million kilometers

C

Processed meteorites with high metal content probably are A. chunks of rock chipped off the planet Mars. B. pieces of comets rather than of asteroids. C. chunks of a larger asteroid that was shattered by a collision. D. chunks of rock chipped off the planet Mercury. E. leftover chunks of rock from the earliest period in the formation of the solar system.

C

The combined mass of all the asteroids in the asteroid belt is A. about the same as that of the earth. B. more than that of all the planets combined. C. less than that of any terrestrial planet. D. about twice that of the earth. E. about the same as that of Jupiter.

C

The depth of the dip in a star's brightness due to the transit of a planet depends most directly on A. the eccentricity of the planet's orbit. B. the size of the planet's orbit. C. the planet's diameter. D. the planet's density. E. the planet's mass.

C

The first planets around other Sun-like stars were discovered A. around 1900. B. around 1800. C. within the last decade or two. D. by Huygens, following his realization that other stars are Suns. E. by Galileo following the invention of the telescope.

C

We know that there are large gaps in the average distances of asteroids from the Sun (within the asteroid belt) because we A. see the gaps via stellar occultation. B. know they are there theoretically, although we haven't detected them. C. have plotted distributions of the orbital radii of the asteroids. D. see the gaps through telescopes. E. actually don't know whether there really are gaps or not.

C

What are the two main differences between most extrasolar planetary systems discovered to date and our Solar System? A. extrasolar planets tend to be more massive and dense than Jupiter B. extrasolar planets tend to be bigger and denser than Jupiter C. extrasolar planet orbits tend to be closer and more eccentric than in our Solar System D. extrasolar planet orbits tend to be more eccentric and inclined than in our Solar System E. extrasolar planet orbits tend to be closer and more circular than in our Solar System

C

What characteristic distinguishes a meteorite from a terrestrial rock? A. A meteorite is usually covered with a dark crust from burning in the earth's atmosphere. B. Meteorites have different isotope ratios of particular elements when compared to terrestrial rocks. C. All of the above are true. D. A meteorite usually has a high metal content. E. Meteorites contain rare elements, such as iridium, that terrestrial rocks do not.

C

What is the most important reason why an icy moon is more likely to be geologically active than a rocky moon of the same size? A. Ice is affected by tidal forces to a greater extent than rock. B. Ice is less dense than rock. C. Ice has a lower melting point than rock. D. Ice is rigid rock aren't. E. Ice contains more radioactive elements than rock.

C

What is the size of the largest asteroid? A. 100 km B. 10 km C. 1,000 km D. 10,000 km E. 1 km

C

Which of the following does not yield information on jovian planet interiors? A. laboratory studies and theoretical models B. spacecraft measurements of magnetic and gravitational fields C. spectroscopy of the cloud layers D. detailed observations of planetary shapes E. Earth-based observations of the mass and size of the planets

C

Which of the following statements about the rings of the four jovian planets is not true? A. All the particle orbits are fairly circular, near their planet's equatorial plane. B. All are made of individual particles of rock or ice that orbit in accord with Kepler's laws: inner ring particles orbiting faster, and outer ring particles orbiting slower. C. All probably look much like they did when the solar system first formed. D. All have gaps and ringlets, probably due to gap moons, shepherd moons, and orbital resonances. E. All rings lie within their planet's Roche zone.

C

Why are Saturn's rings so thin? A. Saturn's gravity prevents particles from migrating upwards out of the rings. B. The "gap" moons shepherd the particles and maintain its thin profile. C. Any particle in the ring with an orbital tilt would collide with other ring particles, flattening its orbit. D. The current thinness is a short-lived phenomenon that is special to this time. E. Solar radiation pressure keeps particles pressed into the rings.

C

Why do Uranus and Neptune have blue methane clouds but Jupiter and Saturn do not? A. Methane did not exist in the solar nebula at the radii of Jupiter and Saturn when the planets formed. B. Methane reacts with the abundant ammonia clouds in Jupiter and Saturn. C. Methane does not condense into ice in the warmer atmospheric temperatures of Jupiter and Saturn. D. The greater gravitational force of Jupiter and Saturn prevents the methane from rising to the upper edges of the atmosphere. E. The relatively slow rotation of Uranus and Neptune allows methane to migrate to higher levels in the atmosphere and condense into clouds.

C

Why is Jupiter denser than Saturn? A. It is made of a different composition than Saturn, including a higher proportion of hydrogen compounds and rocks. B. Its core is much larger than Saturn's. C. The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn. D. It has a greater proportion of helium to hydrogen compared to Saturn. E. It is unknown why this is so.

C

Why is Saturn almost as big as Jupiter, despite its smaller mass? A. Saturn's rings make the planet look bigger. B. Saturn is further from the Sun, thus cooler, and therefore less compact. C. Jupiter's greater mass compresses it more, thus increasing its density. D. Saturn has a larger proportion of hydrogen and helium than Jupiter, and is therefore less dense. E. Jupiter's strong magnetic field constrains its size.

C

Why was the Shoemaker-Levy 9 impact so important to astronomers? A. It wiped out the dinosaurs. B. It was the first event in modern history that was brighter than the full moon in the sky. C. It dredged up material that gave us our first direct look at Jupiter's interior composition. D. It was the first direct proof that impacts really occur. E. It confirmed our theory of solar system formation.

C

Halley's comet is named after the English scientist Edmund Halley because he A. was the first to see it in 1682. B. was the first to publish pictures of it and report it to the International Astronomical Union (IAU). C. was the most famous astronomer in England during its appearance. D. calculated its orbit and predicted that it would return in 1758. E. discovered it.

D

In the asteroid impact theory of the extinction of the dinosaurs some 65 million years ago, the dinosaurs (and over half of all the other species on the earth at that time) died off largely because A. radiation from iridium in the asteroid caused the dinosaurs to die of cancer. B. dust settled on the leaves of plants, making them inedible, so the animals died of starvation. C. of injuries suffered from direct hits of pieces of the asteroid or comet. D. dust injected into the stratosphere from the impact absorbed visible light from the Sun, causing global temperatures to plummet. E. the impact caused massive earthquakes and volcanic activity worldwide.

D

On average, how often do impactors about 10 km in size, large enough to produce mass extinction, hit the earth? A. once in Earth's history B. once every century C. once every million years D. once every hundred million years E. once every thousand years

D

What are the spokes in Saturn's rings? A. gaps between the particles in the rings B. large, elongated rocks in the rings C. dark particles in the rings D. particles of dust suspended above the rings by magnetic forces E. shadows caused by larger rocks in the rings

D

What is a meteorite? A. a streak of light caused by a small particle from space burning up in the earth's atmosphere B. a small moon that orbits one of the giant planets C. a comet that burns up in the earth's atmosphere D. a fragment of an asteroid from the solar system that has fallen to the earth's surface E. a streak of light caused by a star moving across the sky

D

What is the Cassini division of Saturn's rings? A. the widest ring of Saturn, located between two large ring gaps B. the most opaque ring of Saturn, made of highly reflective ice particles C. the imaginary circle marking the halfway point of Saturn's rings D. a large gap, visible from Earth, produced by an orbital resonance with the moon Mimas E. a dark ring, visible from Earth, composed of dark, dusty particles

D

Where are the Trojan asteroids located? A. on orbits that cross Mars's orbit B. in the center of the asteroid belt C. surrounding Jupiter D. along Jupiter's orbit, 60° ahead of and behind Jupiter E. on orbits that cross Earth's orbit

D

Which of the following statements about comets and asteroids is true? A. There are about 1 million known asteroids in the solar system. B. Most of the trillions of comets in our solar system have tails. C. All asteroids lie in the asteroid belt between Mars and Jupiter. D. Comets are balls of ice and dust. E. Only asteroids collide with the earth.

D

A rocky leftover planetesimal orbiting the Sun is A. a meteor. B. a meteorite. C. possibly any of the above D. a comet. E. an asteroid.

E

Comets with extremely elliptical orbits, like comets Hyakutake and Hale-Bopp, A. come from the asteroid belt. B. come from the Kuiper belt. C. are captured by Jupiter. D. are Trojan comets. E. come from the Oort cloud.

E

How does the largest asteroid, Ceres, compare in size to other solar system worlds? A. It is smaller than any jovian moon. B. It is larger than Pluto and Mercury. C. It is about the size of Pluto. D. It is about the size of a large jovian moon. E. It is about half the size of Pluto.

E

The astrometric technique of planet detection works best for A. large planets around nearby stars. B. massive planets around distant stars. C. large planets around distant stars. D. planets in edge-on orbits. E. massive planets around nearby stars.

E

The four Galilean moons around Jupiter are A. all made of rock. B. a mixture of rock and ice, with the rock fraction increasing with distance from Jupiter. C. hydrogen and helium gas. D. all made of ice. E. a mixture of rock and ice, with the ice fraction increasing with distance from Jupiter.

E

The reason that most extrasolar planets are found close to their parent stars is A. planets that are close to a star are heated up and therefore larger. B. more of the starlight is blocked by the planet when it transits the star. C. the closer to a star, the hotter and therefore brighter the planet is. D. the planets reflect more light the closer they are to the star. E. the amount and frequency of the star's motion are both higher.

E

The transit method of planet detection works best for A. small planets in face-on orbits around big stars. B. big planets in face-on orbits around small stars. C. small planets in edge-on orbits around big stars. D. Earth-like planets in any orbit. E. big planets in edge-on orbits around around small stars.

E

What do asteroids and comets have in common? A. They have a similar range of orbital inclinations. B. They have nothing in common with each other. C. They have similar densities. D. They have similar orbital radii. E. Most are unchanged since their formation in the solar nebula.

E

What is Jupiter's Great Red Spot? A. a large mountain peak poking up above the clouds B. the place where reddish particles from Io impact Jupiter's surface C. the place where Jupiter's aurora is most visible D. a hurricane that comes and goes on Jupiter E. a long-lived, high-pressure storm

E

What mechanism is most responsible for generating the internal heat of Io that drives the volcanic activity? A. bombardment B. accretion C. radioactive decay D. differentiation E. tidal heating

E

What part of a comet points most directly away from the Sun? A. the coma B. the jets of gas C. the nucleus D. the dust tail E. the plasma tail

E

Which of the following does not lend support to the idea that Pluto is a Kuiper-belt object? A. Pluto has a more eccentric orbit than other planets. B. Some known Kuiper-belt objects are hundreds of kilometers across. C. Pluto has a cometlike composition and density. D. Some asteroids have their own moons. E. Pluto is smaller than many known comets, such as Halley's comet.

E

Which of the following is not due to tidal forces? A. the grooved terrain of Enceladus (a moon of Saturn) B. the synchronous rotation of the Moon around the earth C. the volcanos on Io (a moon of Jupiter) D. the rings of Saturn E. the retrograde orbit of Triton (a moon of Neptune)

E

Why are there no impact craters on the surface of Io? A. Any craters that existed have been eroded through the strong winds on Io's surface. B. Jupiter's strong gravity attracted the planetesimals more strongly than Io and thus none landed on its surface. C. Io's thick atmosphere obscures the view of the craters. D. It is too small to have been bombarded by planetesimals in the early solar system. Correct! E. Io did have impact craters but they have all been buried in lava flows.

E

Why does Titan have such a nitrogen-rich atmosphere? A. It was formed that way in the solar nebula. B. The nitrogen was formed from the chemical reaction of sulphuric acid with surface rocks. C. Through the impact of nitrogen rich comets during the early solar system. D. The nitrogen was created through a chain of fusion reactions in Titan's core. E. The nitrogen comes from the breakup of ammonia (NH3) by solar radiation and subsequent thermal escape of the hydrogen.

E

Why isn't there a planet where the asteroid belt is located? A. There was too much rocky material to form a terrestrial planet, but not enough gaseous material to form a jovian planet. B. There was not enough material in this part of the solar nebula to form a planet. C. A planet once formed here, but it was broken apart by a catastrophic collision. D. The temperature in this portion of the solar nebula was just right to prevent rock from sticking together. E. Gravitational tugs from Jupiter prevented material from collecting together to form a planet.

E

Which of the following planets cannot be seen with the naked eye? A. Mars B. Venus C. Jupiter D. Neptune E. Saturn

d