Name: __________________________  Date: _____________

1.	Why is it relatively difficult to observe details on the surface of Mercury from the Earth?	
A)	Because its surface is always completely covered in clouds	
B)	Because its surface appears very bright from reflected ultraviolet sunlight and emitted infrared radiation from its very hot surface	
C)	Because it is a small object that always appears close to the Sun in our sky	
D)	Because its orbit always keeps it on the opposite side of the Sun from the Earth	

2.	Which of the following statements about the similarities of Mercury and our Moon is NOT true?	
A)	They both have heavily cratered surfaces.	
B)	They both have very dark surfaces or low reflectivities or albedos.	
C)	They both have large, circular, and relatively flat basins or maria on parts of their surfaces.	
D)	They have no atmospheres.	

3.	Mercury, unlike the Moon, has extensive plains between the craters.  The reason for this is thought to be that	
A)	the plains on Mercury are older than the maria on the Moon.  Thus, more time has elapsed during which cratering has erased evidence of earlier maria on Mercury.	
B)	older craters have been worn down and obliterated by the solar wind.	
C)	because of its large iron core, Mercury has a thinner mantle and therefore experienced fewer volcanoes that produce craters.	
D)	Mercury is closer to the Sun and did not receive as many crater-forming impacts as the Moon.	

4.	How do we know the Caloris Basin on Mercury was formed late in the period of intense bombardment?	
A)	Radioactive dating of rock samples has fixed the date of formation.	
B)	The basin contains very few craters.	
C)	The surface of the basin is much darker than the rest of the planet, suggesting the surface had not yet been churned over by meteoric impacts.	
D)	Mountain ranges in the basin are very high because they have not had time to suffer significant erosion.	

5.	The impact that formed the Caloris Basin on Mercury also created intense seismic waves that disrupted the surface of Mercury on the opposite side of the planet. Which other solar system feature is known to have involved a major impact with a similar result?	
A)	Mare Orientalis on the Moon	
B)	Hellas Basin on Mars	
C)	The Great Rift Valley on the Earth	
D)	Cleopatra Caldera on Venus	

6.	Mercury is unique among the inner planets in having	
A)	one hemisphere with many craters and few volcanoes and the other hemisphere with few craters and many volcanoes.	
B)	extensive volcanic activity and crustal deformation over most of its history, but no evidence of plate tectonics.	
C)	no evidence of an iron core.	
D)	an iron core that occupies almost half its volume.	

7.	Both Mercury and the Earth have global magnetic fields. Compared to the Earth, which feature is Mercury known to lack that is thought necessary for generating such a field?	
A)	Mercury does not lack any such feature.	
B)	A large iron core	
C)	Rapid planetary rotation	
D)	A molten iron core	

8.	Why has Mercury become locked into a 3-to-2 spin orbit coupling, instead of a 1-to-1 coupling like the Moon around the Earth?	
A)	Mercury feels a stronger gravitational pull from the more massive Sun than the Moon does from the Earth, so its rotation became locked on the Sun before it had slowed enough for a 1-to-1 lock.	
B)	Mercury's orbit is very eccentric, so its orbital speed varies while its rotation rate remains constant, and this prevents a 1-to-1 lock.	
C)	Mercury's rotation rate is still slowing down, and the apparent 3-to-2 lock is actually just coincidence.	
D)	Mercury's orbit is highly inclined (tipped up at an angle to the orbits of the other planets), so the Sun sometimes pulls more on Mercury's north pole and sometimes more on its south pole.	

9.	Mercury's atmosphere is	
A)	almost non-existent.	
B)	relatively dense, composed mostly of nitrogen (80%) and oxygen (20%).	
C)	very thin, made up of sulfur dioxide and hydrogen sulfide from volcanoes.	
D)	relatively thin, composed of carbon dioxide with small quantities of nitrogen and argon.	

10.	The conditions on the surface of Venus are	
A)	no atmosphere, and hence very variable temperatures under direct sunlight.	
B)	a low pressure, low temperature, carbon dioxide atmosphere.	
C)	a high pressure, high temperature, carbon dioxide atmosphere.	
D)	a dense atmosphere of methane, ammonia, and water, at a low temperature.	

11.	The clouds in the atmosphere of Venus consist primarily of	
A)	dust particles.	
B)	droplets of carbon dioxide.	
C)	water.	
D)	droplets of sulfuric acid.	

12.	The main reason for the very high temperature (750 K) on the surface of the planet Venus is thought to be	
A)	chemical reactions between constituents of the atmosphere, particularly sulfuric acid.	
B)	the radiation from hot lava, produced by intense and continuous volcanic action.	
C)	the continuous bombardment of the surface by solar wind particles and meteoroids.	
D)	the absorption of visible radiation by the Venusian surface and the subsequent trapping of infrared radiation emitted by the surface by the atmosphere and clouds.	

13.	The overall geography of the Venus surface has been determined largely by	
A)	photography from orbiting spacecraft in long elliptical orbits in order to descend below the clouds during part of their orbits.	
B)	unmanned spacecraft that landed on the surface.	
C)	radar techniques from orbiting spacecraft.	
D)	visible light photography.	

14.	The most common surface features on Venus are	
A)	impact craters.	
B)	ancient river valleys and huge flood plains.	
C)	evidence of plate tectonic motion, including long mountain ranges and subduction troughs.	
D)	volcanoes and lava flows.	

15.	Venus rotates	
A)	“locked-in”  to the Sun, maintaining one side toward it at all times in synchronous rotation.	
B)	in the same direction as the Earth, but very rapidly (in a few hours).	
C)	in the same direction as the Earth, but very slowly.	
D)	in the opposite direction as the Earth, but very slowly.	

16.	Mars has a period and direction of rotation that are	
A)	a little longer than 24 hours and in the same direction as the Earth.	
B)	687 days (1 Martian year) because Mars always turns the same face toward the Sun.	
C)	just less than 10 hours and in the same direction as Earth.	
D)	about 240 days and in the opposite direction as the Earth (retrograde rotation).	

17.	What is the principal reason we have no volcanoes on the Earth anywhere near the size of Olympus Mons?	
A)	Mars's smaller gravity allows the formation of taller structures without crumbling.	
B)	Mars, being smaller, retained its interior heat longer and allowed volcanic activity for a longer time.	
C)	Because of tectonic activity on the Earth, a volcano does not sit over the same spot for long periods and continue to grow.	
D)	Because of colder temperatures on Mars, lava solidified more quickly before it had time to move far from the volcanic cone.	

18.	Hot-spot volcanism is a process that	
A)	produces gigantic volcanoes on Venus and Mars but chains of smaller volcanoes on the Earth (e.g., the Hawaiian Islands).	
B)	produces dome-shaped rises on Venus and Mars and mid-ocean ridges on the Earth (e.g., the Mid-Atlantic Ridge).	
C)	produces large rift valleys on Mars, Venus, and the Earth (e.g., the Great Rift Valley of Africa).	
D)	does not operate on Venus or Mars but produces folded mountain chains and subduction zones on the Earth (e.g., along the west coast of North and South America).	

19.	What are the Valles Marineris?	
A)	A large rift valley system associated with the great volcanoes on Mars	
B)	A long scarp-and-trough system in the lava plains of Mercury	
C)	A system of deep trenches bordering Aphrodite Terra on Venus	
D)	A system of tectonic faults on the Jovian satellite Ganymede	

20.	The reddish color of Mars is probably due to	
A)	the glow from the very high temperature surface on the sunlit parts of Mars.	
B)	iron oxides such as rust.	
C)	vegetation turning red in the Martian autumn.	
D)	sulfur compounds thrown out by active volcanoes.	

21.	Mars experiences similar seasonal changes to those on the Earth because	
A)	its has about the same shape of elliptical orbit as the Earth, and this produces similar changes in solar radiation intensity as the planet orbits the Sun.	
B)	its spin axis is tilted at about the same angle to its orbital plane as is the Earth's axis.	
C)	the length of its day is very close to an Earth day.	
D)	the length of its year is very close to that of the Earth.	

22.	Atmospheric pressure at the surface of Mars, compared to the atmospheric pressure at the Earth's surface, is	
A)	about 90 times greater.	
B)	less than 1/100.	
C)	extremely small (less than 1 millionth).	
D)	about the same.	

23.	The polar caps on Mars are most likely made up of	
A)	volcanic outflows of light-colored lava and dust similar to that produced by Earth-based volcanoes (such as Mt. St. Helens).	
B)	sulfur dioxide and sulfur compounds.	
C)	light-colored dust, blown there by the Martian dust storms.	
D)	water and carbon dioxide ices.	

24.	Tomorrow's (and most day's) weather forecast for Mars is likely to be	
A)	sunny and clear; Mars has no atmosphere in which clouds can form.	
B)	sunny, possible thin, high clouds, windy.	
C)	continuous rain, possible flooding in low-lying areas.	
D)	heavy overcast, possible light acid rain and mist.	

25.	The moons of Mars are	
A)	ice-covered, approximately spherical, but flattened by rapid rotation.	
B)	spherical and have active volcanoes on their surfaces.	
C)	spherical and smooth-surfaced (no visible craters or volcanoes).	
D)	irregularly shaped, cratered, and grooved.	

26.	The pressures of the atmospheres at the surfaces of Mercury, Venus, and Mars, in terms of the pressure at the surface of the Earth (known as 1 atmosphere), are	
A)	0; about 10 atmospheres; 1/10 atmosphere.	
B)	1/100 atmosphere; almost 100 atmospheres; 1/10 atmosphere.	
C)	1/10 atmosphere; almost 100 atmospheres; 1/10 atmosphere.	
D)	0; almost 100 atmospheres; 1/100 atmosphere.	

27.	Which of the following are the youngest?	
A)	The oldest craters on Mercury	
B)	The oldest craters on Venus	
C)	The oldest craters on the Moon	
D)	The oldest craters on Mars	

Answer Key

1.	C	
2.	C	
3.	A	
4.	B	
5.	A	
6.	D	
7.	D	
8.	B	
9.	A	
10.	C	
11.	D	
12.	D	
13.	C	
14.	D	
15.	D	
16.	A	
17.	C	
18.	A	
19.	A	
20.	B	
21.	B	
22.	B	
23.	D	
24.	B	
25.	D	
26.	D	
27.	B