Ch 21

(a) What is occurring in the figure? (b) How does the above figure suggest that heat is flowing out of Earth's interior?

a volcanic eruption Both of the above are true.

What evidence can you cite that the climate on Mars has changed?

all of the above

What makes Earth peculiar among the terrestrial planets?

all of the above

(a) Which is something that Venus and Earth have in common? (b) Which is something about Venus and Earth that is different?

all of the above all of the above

How is the planet Mercury different than Earth's moon?

all of the below

What adverse affect is human activity having on today's atmosphere?

all of the below

What evidence do we have that Mars had much more liquid water at its surface in the past than it has today?

all of the below

Which of the following is due to the moon's small size?

all of the below

(a) Which is not considered a terrestrial planet? (b) What is the reason for the answer to the above question?

All of the above are considered terrestrial planets. Earth's moon has many features in common with the terrestrial planets.

(a) Which is not true about ozone? (b) Which is not true about the decreasing density of the stratospheric ozone layer?

All of the above are true. All of the above are true.

(a) What must be true about Earth's core to generate Earth's magnetic field? (b) Which is not a conducting material in Earth's core? (c) What must be true for a large portion of Earth's core in order for convection to occur?

All of the above must be true. copper It must be liquid.

What evidence is there that the Atlantic Ocean is growing wider?

Astronomers timing pulsars with radio telescopes in Europe and the Americas.

How do we know Earth differentiated?

Both of the above are true.

How can astronomers estimate the ages of the streambeds on Mars?

By examining nearby cratered surfaces.

(a) Which location experiences earthquakes caused by shifts along a tectonic plate? (b) Which location experiences earthquakes caused by volcanism?

California Hawaii

What creates Earth's strong dipole magnetic field?

Convection in Earth's outer liquid iron-nickel core combined with Earth's rotation.

(a) Why is the figure a typical view of the surface of Earth? (b) What about the above figure makes Earth unique among terrestrial planets?

Earth's surface is mostly covered by water. Earth is the only terrestrial planet with oceans.

How do we know that Copernicus is a young impact crater?

It has bright rays that extend onto the surrounding maria.

(a) Which is not true about the greenhouse effect? (b) What is not true about global warming?

It is bad for the environment. It is just another name for the greenhouse effect.

Which of the following is true about Earth's ozone layer?

It is located at an altitude of about 25 km and a hole develops every October over Antarctica.

(a) What is the relative age of the crater Copernicus? (b) How do astronomers know the answer to the above question?

It is relatively new. bright ejecta blankets and rays

(a) Which of the following is true for Earth's core? (b) What evidence can be cited for the answer to the previous question? (c) Why doesn't the material in Earth's core vaporize?

It is solid on the inside, and liquid on the outside. Shear waves cannot travel through Earth's center. The tremendous pressure from the weight of Earth's outer layers keeps the outer core liquid and the inner core solid.

(a) Has tectonics occurred on the moon? (b) What evidence can be cited for the answer to the previous question?

It never occurred. large ancient craters that would have been broken up by tectonics have not been

The layered rock and spherical concretions seen here are evidence that water once flowed on the surface of which of the following?

Mars

(a) How was the Hawaiian-Emperor island chain formed? (b) How does the formation of the Hawaiian-Emperor island chain help in the understanding of tectonics?

Motion of the Pacific plate allowed volcanic hot-spots to punch through the crust. It is an example of tectonics and volcanism working together to form mountains.

What evidence do we have that Earth's outer core is a metallic liquid?

S waves are blocked resulting in an S-wave shadow zone and Earth has a strong magnetic field.

(a) What is the name of the volcano shown in the figure below? (b) On what planet is the volcano in the figure located? (c) What kind of volcano is shown in the figure? (d) Why does the volcano shown in the figure appear orange in color? (e) What color would the volcano in the figure appear to be if you could see it with your own eyes?

Sif Mons Venus a shield volcano, produced by hot-spot volcanism False color was added to the radar map, to mimic the orange light that filters through Venus' atmosphere. It is dark grey or brown, like rocks on Earth.

(a) What do the vesicular basalts tell us about the evolution of the lunar surface? (b) What feature of vesicular basalts tells us what they do about the evolution of the lunar surface?

That it was once molten. They filled with holes. (c) How does this feature of vesicular basalts tell us what it does about the evolution of the lunar surface?

How did the moon achieve its synchronous rotation?

The Earth raises tidal bulges on the moon. As the moon rotated through these bulges, internal friction slowed the moon's rotation until it achieved tidal coupling.

What evidence do we have that Earth differentiated?

The curved paths of seismic waves indicate that the interior density of Earth is greater than can be explained by compression alone.

The lunar breccia shown here is formed by rock fragments bonded together by heat and pressure. How did this very common type of lunar rock form?

The explosive impact of meteoritic bodies formed the lunar breccias.

When Earth formed, it melted and differentiated. What was the source of heat that melted Earth?

The infall of matter that formed Earth and the decay of radioactive elements.

What distinguishes Earth's inner core from its outer core?

The inner core is solid, and the outer core is liquid.

(a) How does the large-impact hypothesis explain the moon's lack of iron? (b) How does the large-impact hypothesis explain the moon's lack of volatile elements?

The iron core of the impacting object could have fallen into the larger body. Most of the volatile elements would have vaporized in the collision and/or been lost into space.

Why do you suppose that the smallest impact craters on the moon are microscopic, the smallest on Earth are tens of meters in diameter, and the smallest on Venus are more than one kilometer in diameter?

The moon has no atmosphere and Venus has an atmosphere much denser than Earth's and atmospheric gases easily slow the speed of smaller incoming meteoroids.

(a) What is the effect of the tidal coupling between Earth and the moon? (b) What is the effect of the tidal coupling between Mercury and the sun?

The moon rotates once every revolution around Earth. Mercury rotates 3 times for every 2 revolutions around the sun.

(a) Why doesn't Mars have large mountain ranges like those on Earth? (b) Why doesn't Earth have large volcanoes like those on Mars?

The tectonic processes that formed mountains on Earth did not occur on Mars. Tectonics carries mountains away from volcanic hot spots before they can grow too big.

Why are Phobos and Deimos not spherical?

Their gravity fields are too weak to pull their material into a spherical shape.

What do the multiple calderas and immense size of the volcano in the above picture indicate about the geology of Mars?

There is no tectonics on Mars to move mountains away from volcanic hot spots.

(a) Which is not true about the intercrater plains on Mercury? (b) Which is not true about the smooth plains on Mercury?

They are old surfaces. They appear to have formed just before the Caloris impact.

(a) Why are Mars' moons, Phobos and Deimos, nonspherical? (b) Why is Earth's moon much more spherical than Phobos and Deimos?

They do not have enough mass to gravitationally pull themselves into a spherical shape. Earth's moon is massive enough to gravitationally pull itself into a spherical shape.

(a) A large fraction of lunar samples collected are________. (b) How are the rocks in the previous question formed?

breccias cementing together of fragments of earlier rocks by heat and pressure

Which gas is most abundant in the atmospheres of Venus and Mars?

carbon dioxide (CO2)

Earth's interior can be divided up into four zones: the inner core, the outer core, the mantle, and the crust. Which of these zones has the lowest density?

crust

(a) Which hypothesis of lunar formation would require Earth to have spun much faster in the past than it does now? (b) Which hypothesis of lunar formation is ruled out by Earth and moon having different chemical compositions and density? (c) Which hypothesis of lunar formation requires the occurrence of highly unlikely events?

fission condensation capture (d) Which hypothesis of lunar formation currently fits the data best?

(a) Which type of atmosphere is Earth now believed never to have had? (b) What is the reason for the answer to the previous question?

hydrogen and helium Earth formed rapidly and was heated by in-falling material, and this caused continuous outgassing from the cooling of molten material.

(a) Where did the first Apollo missions land? (b) What was the reason for the choice of landing site? (c) What sites on the lunar surface were considered of the most scientific interest? (d) What is the reason for the answer to the previous question?

in the maria It had the smoothest landing surface. the highlands they held more important geological features

(a) Rocks from the lunar crust are____________ (b) What is suggested by rocks collected from the lunar crust?

low-density and igneous That the moon formed in a molten state in which differentiation occurred.

(a) Which is an older surface? (b) How do astronomers know the answer to the above question?

lunar highlands The presence of many more craters means that there has been more time for impacts in the highlands, so they are older surfaces.

(a) What is the composition of Venus' atmosphere? (b) What is the composition of Mars' atmosphere? (c) What is the composition of Earth's atmosphere? (d) How was Earth's atmosphere able to evolve to its current state? (e) What is the main reason that Venus' atmosphere ended up the way it did? (f) What is the main reason Mars' atmosphere ended up the way it did? (g) Which planet's atmosphere has evolved the most?

mostly carbon dioxide mostly carbon dioxide nitrogen and oxygen both of the above lack of liquid water it was too thin Earth

(a) What evidence is there that Venus had more water in the past? (b) Where did Venus' water come from? (c) Where did Venus' water go? (d) What evidence is there that Mars had more water in the past? (e) Where did Mars' water come from? (f) Where did Mars' water go?

none of these feature exist on Venus Volcanic degassing is known to release water vapor. It was broken up by ultraviolet radiation from the sun. all of the above Volcanic degassing is known to release water vapor. Some of it is still there but frozen.

(a) What were the "canals" on Mars? (b) How do the canals differ from the dry streambeds on Mars?

optical illusions The streambeds really exist, while the canals do not.

(a) Mercury's core is probably which of the following? (b) What evidence do astronomers have for the answer to the previous question? (c) Mercury's core is probably which of the following? (d) What evidence do astronomers have for the answer to the previous question?

partially molten a weak magnetic field metallic Mercury is small and of high density.

What produced the oxygen in Earth's atmosphere?

plants

The figure is from Apollo 12, the second mission to the moon. (a) Which is the best description of the surface in the above figure? (b) What kind of lunar terrain is shown in the above figure? (c) Why was the lunar terrain shown in the above figure chosen for the early Apollo missions?

smoother plains maria It was easier to land on.

(a) Which is not a stage of planetary development? (b) Which is the first stage of planetary development? (c) How can planets with no liquid water have a flooding stage?

subduction differentiation The flooding is also by lava.

(a) What evidence would you look for to see if plate tectonics is occurring on Venus? (b) Do the features cited in the previous question exist on Venus?

you would look for a worldwide network including all of the above Some of the features have been found, but not enough of a planet wide network to suggest that tectonics is an important process on Venus.