0.721569	0.312784	0.1333	The Huygens probe to the satellite Titan found: a. an almost pure oxygen atmosphere b. liquid water c. a hot atmosphere like Venus d. sand-like particles and rocks composed of water ice e. that the “haze layer” did not exist	d
0.865258	0.96183	0.249535	Comet tails are oriented so that: a. they point toward the Sun b. they point ahead of the comet in its orbit c. they point behind the comet in its orbit d. they point away from the Sun e. none of the above	d
0.624349	0.915175	0.794069	A famous example of a terrestrial feature produced by meteoroid impact is: a. the Grand Canyon b. Olympus Mons c. the Arizona (Barringer) Meteor Crater d. the Great Barrier Reef e. Monument Valley	c
0.862574	0.885645	0.789765	The basic physical process in comets is __________ of ices caused by solar heating. a. accretion b. dissipation c. gravitational pull d. sublimation e. condensation	d
0.982123	0.726337	0.013205	The rotation axis of _________lies close to the plane of the planet’s orbit. a. Venus b. Uranus c. Mars d. Neptune e. Ceres	b
0.242189	0.459538	0.008131	Most Kuiper Belt Objects (KBOs), including Pluto, are found: a. between 5 and 10 AU b. between 39 and 50 AU c. beyond 100 AU d. inside the orbit of Mercury e. near the asteroid belt	b
0.621262	0.824288	0.908388	A planet’s orbital period is: a. the time it takes to rotate and have the same face towards us again b. the time it takes to return to the same location in its orbit, relative to the Sun c. the time it takes for a satellite to orbit it d. the time it takes to retrograde back to the same position as we pass it e. the time its magnetic field takes to spin once	b
0.173094	0.66393	0.732609	Masses of the planets are easiest to determine if: a. they are terrestrial and the extra size of the planet’s disk can be measured b. they are Jovian and their oblateness can be found c. they have natural satellites whose motions can be precisely measured d. they are dense and easily deflect the path of passing spacecraft e. they move rapidly and their periods are easily measured	c
0.131956	0.785611	0.794297	The plane in which almost all planets orbit the Sun is called the: a. equator of the solar system b. ecliptic c. equant d. node e. galactic plane	b
0.188608	0.832312	0.299405	Which of these gases was NOT a product of outgassing in the formation of our secondary atmosphere ? a. water vapor b. sulfur dioxide c. carbon dioxide d. oxygen e. methane	d
0.542368	0.121799	0.661094	What is the best description of the Earth’s rotation over its entire history ? a. It has periodically reversed direction, as the magnetic polarity reversals show b. It has been constant over the entire history of the solar system c. It undergoes abrupt changes, as the magnetic variations show d. It has slowed down very gradually e. It has sped up at a fairly rapid rate	d
0.878823	0.070771	0.023372	At what lunar phase would the tidal variation be greatest ? a. new moon b. waxing crescent moon c. full moon d. third quarter moon e. Both new and full moon produce spring tides	e
0.040583	0.37325	0.244968	Mercury is very hard to observe from Earth because: a. it always appears as only half lit from Earth b. it never gets more than 28 degrees from the Sun’s glare c. its elliptical orbit causes it to change speed unpredictably d. its barren surface reflects too little sunlight; it is almost invisible always e. its very rugged surface does not allow radar to bounce back to Earth	b
0.062161	0.064194	0.542762	Which of the following, along with temperature, determines whether a body will retain an atmosphere of a given composition ? a. size b. density c. rotation rate d. escape velocity e. distance from the Sun	d
0.544757	0.24936	0.738033	Mercury’s surface most resembles that of which other body ? a. Earth b. Moon c. Venus d. Mars e. Io	b
0.346225	0.427079	0.429025	What effect does the Greenhouse effect have on the surface environment of Venus ? a. It has little or no effect b. Its effect is about the same as on Earth c. It has reduced the surface temperature by about 30 K d. It has raised the surface temperature by hundreds of K e. It causes the surface temperature of Venus to become much hotter than the Sun	d
0.055402	0.706942	0.114154	What is the main constituent of the atmosphere of Venus ? a. oxygen b. nitrogen c. hydrogen d. carbon dioxide e. sulfuric acid	d
0.603421	0.777174	0.698021	The most striking valley in the solar system is: a. the Grand Canyon in Arizona b. Gwenivere on Venus c. The Discovery Scarp of Mercury d. Valles Marineris on Mars e. Valhalla on Callisto	d
0.48855	0.869735	0.416708	Compare the atmospheres of Mars and Venus. a. Both are made of hydrogen and helium, like the Jovian planets b. Like Earth, nitrogen is the chief atmospheric gas c. Both are chiefly carbon dioxide, but at Mars it can freeze as dry ice d. Mars is rich in oxygen, like ours, accounting for its red surface e. Both are too hot for water to now exist as a liquid at the surface	c
0.72652	0.362779	0.448306	The most striking “cloudmark” in Jupiter’s atmosphere is the: a. Polar Dark Spot b. Cassini Division c. Great Red Spot d. Black Hole e. Brown Dwarf	c
0.338485	0.075113	0.673466	What material is thought to lie at the core of Jupiter? a. a hot liquid sea of hydrogen b. a massive core of rocky material c. gaseous hydrogen and helium, as is found throughout the entire planet d. a hydrosphere of liquid water larger than Earth e. hydrogen fusing into helium	b
0.952531	0.498847	0.624093	The atmosphere of Saturn is composed mostly of: a. methane and ammonia b. carbon dioxide and ethane c. hydrogen and helium d. hydrogen sulfide and ammonia e. nitrogen and oxygen	c
0.129937	0.514216	0.04609	Why does Saturn radiate even more excess energy than Jupiter ? a. Saturn is still radiating heat left over from its formation b. Saturn’s thick cloud layer contributes to a larger Greenhouse effect c. Helium Rain produced heat as it differentiates toward Saturn’s center d. Saturn’s atmosphere contains much methane, creating a large Greenhouse effect e. Saturn can fuse hydrogen into helium in its core, like the Sun	c
0.451308	0.468672	0.850955	Adams and Leverrier both predicted the position of Neptune, based on its effects on: a. the Sun b. Jupiter c. Saturn d. Pluto e. Uranus	e
0.976041	0.238359	0.080261	The outer Jovian planets have a bluish tint because: a. At their distances, the Sun appears blue, the red absorbed by dust in the ecliptic b. They are far away and distance makes objects appear bluish c. Their atmospheres contain methane, which absorbs red light d. Their atmospheres contain hydrogen and helium e. Ammonia ice reflects blue light better than any other color	c
0.645385	0.694592	0.566138	What is thought to be the cause of Io’s volcanoes ? a. Jupiter’s magnetosphere and its charged particles b. Saturn’s gravity and the heat it creates c. Tidal stresses from Jupiter d. Solar radiation focused by Jupiter’s gravity e. Radioactive decay in Io’s interior	c
0.599465	0.703585	0.402638	The atmosphere of Titan is composed mostly of: a. oxygen b. methane c. carbon dioxide d. hydrogen e. nitrogen	e
0.5152	0.836806	0.602868	What are Saturn’s rings ? a. a great disk of liquid helium b. large rocky boulders moving in orbit around Saturn c. a glowing, flat magnetospheric auroral display d. a solid thin disk of material encircling Saturn e. small icy particles moving in orbit around Saturn	e
0.828656	0.948364	0.067771	The rings of Saturn exist because: a. The ring material lies within the Roche limit of Saturn b. The gravitational influence of Titan confines them to those orbits c. The eruptions of Mimas’ volcanoes are keeping them supplied with ice d. There has not been sufficient time for the ring particles to form a moon e. Saturn’s rapid rotation is spinning material away from its equator, out into space	a
0.485462	0.806754	0.305367	How is the Roche limit defined ? a. the critical distance from a planet, inside of which a moon can be tidally destroyed b. the maximum density that a body can have depending on its composition c. the maximum distance from a planet that a moon can experience synchronous rotation d. the maximum mass a moon can have and still be classified as a moon e. the maximum size an impacting asteroid can be and not break up a moon	a
0.576502	0.194995	0.489631	Sheperd satellites are defined as: a. satellites in the coma of a comet b. moons that confine a narrow ring c. a type of moon that orbits another moon d. moons that follow the exact orbit of another, larger, moon e. moons that orbit inside the system of rings	b
0.180643	0.509174	0.790056	What is the prediction for the future of Triton ? a. It will provide the raw material for a future Neptunian ring via disruption b. It will develop active volcanoes as Neptune’s tidal stresses increase c. It will crash into Nereid when the smaller moon comes too close d. Its orbit, while retrograde, is very stable and will not change e. Its retrograde orbit will throw it back out into the Kuiper Belt again, with Pluto	a
0.846864	0.138214	0.852547	The Oort Cloud is thought to be: a. the cloud of gas and dust from which our solar system formed b. a cloud of debris that occasionally encounters the Earth, causing a meteor shower c. the spherical cloud of comets surrounding the outer solar system d. a cloud of asteroids moving between the orbits of Mars and Jupiter e. the material in the ecliptic plane that creates the zodiacal light	c
0.60583	0.894025	0.311881	The orbits of most asteroids: a. lie beyond Neptune b. lie beyond the orbit of Mars c. cross the orbit of Mars d.