ASTRO 100 - HW 3

For studying purposes only

The largest asteroid, and probably the only one to be a spherical "world" is
Select one:
a. Vesta.
b. Eros.
c. Ida.
d. Gaspra.
e. Ceres.

E

How do asteroids differ from comets?
Select one:
a. Asteroids are made of icy material. Comets are made of rocky material.
b. Asteroids and comets are both made of rocky and icy material, but asteroids are smaller in size than comets.
c. Asteroids are made of rocky material. Comets are made of icy material.
d. Asteroids and comets are both made of rocky and icy material, but asteroids are larger in size than comets.

C

Which of the following signs of water is NOT seen on Mars?
Select one:
a. Melt-water pools at the edges of the polar caps
b. Evidence of permafrost under the Martian surface
c. Water ice (as opposed to carbon dioxide ice) in the polar caps
d. Occasional clouds around the large volcanoes

A

Where are most of the known asteroids found?
Select one:
a. In the Oort cloud
b. Between the orbits of the jovian planets
c. In the Kuiper belt
d. Between the orbits of Mars and Jupiter
e. Between the orbits of the terrestrial planets

D

Suppose you could float in space just a few meters above Saturn's rings. What would you see as you looked down on the rings?
Select one:
a. Countless icy particles, ranging in size from dust grains to large boulders
b. A solid, shiny surface, looking much like a piece of a DVD but a lot bigger
c. Dozens of large "moonlets" made of metal and rock, each a few kilometers across
d. Nothing up close; the rings would be so completely invisible that you'd have no way to know they are there. They can be seen only from a distance.

A

A rock found on Earth that crashed down from space is called ________.
Select one:
a. a meteor
b. an impact
c. a meteorite
d. an asteroid

C

Which two geological processes appear to have been most important in shaping the present surface of Venus?
Select one:
a. Impacts and volcanoes
b. Tectonics and erosion
c. Impacts and tectonics
d. Volcanoes and erosion
e. Volcanoes and tectonics

E

The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that
Select one:
a. the Caloris Basin was formed by a volcano.
b. Mercury's atmosphere prevented smaller objects from hitting the surface.
c. the Caloris Basin formed toward the end of the solar system's period of heavy bombardment.
d. erosion destroyed the smaller craters that formed on the basin.
e. only very large impactors hit Mercury's surface in the past.

C

What do we mean by the period of heavy bombardment in the context of the history of our solar system?
Select one:
a. The period about 65 million years ago when an impact is thought to have led to the extinction of the dinosaurs
b. The time during which heavy elements condensed into rock and metal in the solar nebula
c. The first few hundred million years after the planets formed, which is when most impact craters were formed
d. The time before planetesimals finished accreting into planets, during which many growing planetesimals must have shattered in collisions

C

According to modern scientific dating techniques, approximately how old is the solar system?
Select one:
a. 4.6 million years
b. 4.6 billion years
c. 10,000 years
d. 14 billion years

B

Why do asteroids and comets differ in composition?
Select one:
a. Asteroids are much larger than comets.
b. Asteroids formed inside the frost line, while comets formed outside.
c. Comets are much larger than asteroids.
d. Asteroids and comets formed at different times.
e. Comets formed from the jovian nebula, while asteroids did not.

B

What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?
Select one:
a. Mercury's unusually high density
b. The presence of many impact craters
c. The presence of many long, tall cliffs
d. The characteristics of the Caloris Basin

C

What do we mean when we say that the terrestrial worlds underwent differentiation?
Select one:
a. They lost interior heat to outer space.
b. Their surfaces show a variety of different geological features resulting from different geological processes.
c. When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces.
d. The five terrestrial worlds all started similarly but ended up looking quite different.

C

The planet in our solar system with the highest average surface temperature is ________.
Select one:
a. Neptune
b. Venus
c. Earth
d. Mercury

B

If Saturn takes about 30 years to orbit the Sun, and its rings were seen edge-on in 2009, when will they appear edge-on again?
Select one:
a. 2019
b. 2024
c. 2015
d. 2012
e. 2039

B

In what ways is Earth different from the other terrestrial planets?
Select one:
a. It has oxygen in its atmosphere.
b. Life can be found almost everywhere.
c. Most of its surface is covered with liquid water.
d. Its crust is broken into plates that move around.
e. All of the above are true.

E

In which of the following physical characteristics are the Earth and Mars most similar to each other?
Select one:
a. Number of moons
b. Planetary diameter
c. Length of solar day
d. Total mass

C

Which of the following statements best characterizes the surface of the planet Mars?
Select one:
a. All of the big volcanoes are in the northern hemisphere, and most of the craters are in the southern hemisphere.
b. Eighty percent of the surface is rolling plains, with a number of major volcanoes and only two continent-sized uplands.
c. The surface is continuously resurfaced by ongoing volcanic activity; consequently, there are almost no visible impact craters.
d. There are several moving crustal plates rimmed by long mountain chains, deep subduction trenches, and several large rift valleys.

A

Which of the following statements is not true?
Select one:
a. Objects in the Kuiper belt are made mostly of rock and metal.
b. Objects in the asteroid and Kuiper belts orbit the Sun in nearly the same plane as the planets, but objects in the Oort cloud do not.
c. Objects in the asteroid belt are made mostly of rock and metal.
d. Objects in the Oort cloud contain large proportions of ice.

A

According to current evidence, Pluto is best explained as ________.
Select one:
a. an escaped moon of Jupiter or Saturn
b. a terrestrial planet that is surprisingly far from the Sun
c. a large member of the Kuiper belt
d. a very small jovian planet

C

Which of the following is not a general characteristic of the four jovian planets in our solar system?
Select one:
a. They lack solid surfaces.
b. They are composed mainly of hydrogen, helium, and hydrogen compounds.
c. They are much more massive than any of the terrestrial planets.
d. They are higher in average density than are the terrestrial planets.

D

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true?
Select one:
a. The inner planets orbit the Sun counterclockwise while the outer planets orbit the Sun clockwise.
b. All the planets orbit counterclockwise around the Sun.
c. All the planets except Uranus orbit the Sun counterclockwise; Uranus orbits in the opposite direction.
d. The inner planets orbit the Sun clockwise while the outer planets orbit the Sun counterclockwise.

B

The two most important processes in heating the interiors of the terrestrial worlds are:
Select one:
a. (1) heat deposited by the process of formation; (2) heat released by radioactive decay.
b. (1) heat deposited by the process of formation; (2) heat that came from the gravitational potential energy of incoming planetesimals.
c. (1) heat from convection; (2) heat from thermal radiation.
d. (1) volcanism; (2) tectonics.

A

What is Eris?
Select one:
a. A moon of Pluto
b. An icy object that orbits in the Kuiper belt about the same size as Pluto
c. An extrasolar planet ejected by another solar system and captured by ours
d. The largest known asteroid

B

Which of the following is not a characteristic of the inner planets?
Select one:
a. They all have solid, rocky surfaces.
b. They all have substantial atmospheres.
c. They have very few, if any, satellites.
d. They are relatively smaller than the outer planets.
e. Their orbits are relatively closely spaced.

B

What atmospheric constituent is responsible for the blue color of Uranus and Neptune?
Select one:
a. Water
b. Ammonia
c. Hydrogen
d. Methane

D

According to our theory of solar system formation, what are asteroids and comets?
Select one:
a. Leftover planetesimals that never accreted into planets
b. Chunks of rock or ice that were expelled from planets by volcanoes
c. Chunks of rock or ice that condensed after the planets and moons finished forming
d. The shattered remains of collisions between planets

A

Which of the following best describes the lunar maria?
Select one:
a. Frozen oceans of liquid water on the Moon
b. Mountainous regions on the Moon
c. Densely cratered regions on the Moon
d. Relatively smooth, flat plains on the Moon

D

When we see a region of a planet that is not as heavily cratered as other regions, we conclude that
Select one:
a. the surface in the region is younger than the surface in more heavily cratered regions.
b. there is little volcanic activity to create craters.
c. the planet is rotating very slowly and only one side was hit by impactors.
d. the surface in the region is older than the surface in more heavily cratered regions.
e. the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals.

A

Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years have passed?
Select one:
a. You'll have 0.25 kilogram of the radioactive substance remaining.
b. You'll have 0.5 kilogram of the radioactive substance remaining.
c. All the material will have completely decayed.
d. You'll have 0.75 kilogram of the radioactive substance remaining.

A

Olympus Mons is ________.
Select one:
a. a huge shield volcano on Mars
b. a huge stratovolcano on Venus
c. a large lava plain on the Moon
d. a great canyon on Mars

A

The planet closest in size to Earth is
Select one:
a. the Moon.
b. Mercury.
c. Pluto.
d. Venus.
e. Mars.

D

A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.
Select one:
a. pea-size particle from an asteroid
b. microscopic particle of interstellar dust
c. boulder-size particle from a comet
d. pea-size particle from a comet
e. boulder-size particle from an asteroid

D

What are the main constituents of the jovian planets?
Select one:
a. Nitrogen and methane
b. Ammonia and water
c. Hydrogen and helium
d. Rocky minerals and water, as on Earth
e. Ammonia and methane

C

Which moon is considered likely to have a deep, subsurface ocean of liquid water?
Select one:
a. Triton
b. Io
c. Miranda
d. Europa

D

Based on our current theory of Earth's formation, the water we drink comes from
Select one:
a. ice that condensed in the solar nebula in the region where Earth formed.
b. chemical reactions that occurred in Earth's core after Earth formed.
c. comets that impacted Earth.
d. material left behind during the giant impact that formed the Moon.
e. chemical reactions that occurred in Earth's crust after Earth formed.

C

Which planet, other than Earth, has visible water ice on it?
Select one:
a. Mercury
b. the Moon
c. Mars
d. Venus
e. Jupiter

C

What is the main reason Venus is so much hotter than the Earth?
Select one:
a. Because it is closer to the Sun
b. Because it rotates backwards compared to its orbital rotation
c. Because it has much more carbon dioxide in its atmosphere
d. Because its clouds have a very high reflectivity

C

From center to surface, which of the following correctly lists the interior layers of a terrestrial world?
Select one:
a. Core, crust, mantle
b. Core, mantle, crust
c. Mantle, crust, core
d. Mantle, core, crust

B

What do we mean by accretion in the context of planet formation?
Select one:
a. The formation of moons around planets
b. The growth of the Sun as the density of gas increased in the center of the solar nebula
c. The growth of planetesimals from smaller solid particles that collided and stuck together
d. The solidification of ices, rocks, and metal from the gas of the solar nebula

C

Of the four gases CO2, H2O, N2, and O2, which are greenhouse gases?
Select one:
a. All four
b. CO2 and N2
c. All except O2
d. Only CO2
e. CO2 and H2O

E

Why does increasing the amount a greenhouse gas increase the temperature of a planet?
Select one:
a. Greenhouse gases emit infrared light.
b. Greenhouse gases absorb visible light.
c. Greenhouse gases absorb infrared light.
d. Greenhouse gases emit visible light.

C

Why are there no impact craters on the surface of Io?
Select one:
a. It is too small to have been bombarded by planetesimals in the early solar system.
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. Any craters that existed have been eroded through the strong winds on Io's surface.
e. Io did have impact craters but they have all been buried in lava flows.

E

The processes responsible for virtually all surface geology are ________.
Select one:
a. impact cratering, volcanisms, tectonics, and erosion
b. convection, conduction, and radiation
c. eruptions, lava flows, and outgassing
d. accretion, differentiation, and radioactive decay

A

What do we mean by the frost line when we discuss the formation of planets in the solar nebula?
Select one:
a. It is the altitude in a planet's atmosphere at which snow can form.
b. It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds.
c. It is another way of stating the temperature at which water freezes into ice.
d. It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense.

D

The average age of the surface of Venus has been determined primarily from
Select one:
a. soil analysis by Russian landers.
b. the number of impact craters per unit area of surface.
c. the amount of weathering of lava flows imaged by the Magellan radar mapper.
d. radio-isotope analysis of rocks brought back from Venus by space probes.

B

What is the Great Red Spot?
Select one:
a. A region on Jupiter where the temperature is so high that the gas glows with red visible light
b. A long-lived, high-pressure storm on Jupiter
c. A hurricane that comes and goes on Jupiter
d. A place where reddish particles from Io impact Jupiter's surface

B

Which planet has a ring system?
Select one:
a. Uranus
b. Neptune
c. Jupiter
d. Saturn
e. All of the above

E

The tail of a comet always points
Select one:
a. toward Earth and never varies.
b. toward the Sun and disappears at perihelion.
c. away from the Sun and becomes longest and brightest at perihelion.
d. away from the Sun and disappears at perihelion.
e. in the direction of the comet's motion.

C

The Huygens probe took numerous pictures as it descended to Titan's surface in 2005. What did the pictures show?
Select one:
a. Lava flows of molten basalt
b. Features or erosion, including what appeared to be dry river valleys and lakebeds
c. Primitive life forms
d. A densely cratered surface

B