Astronomy Chapter Seven

1. What kind of surface features may result from tectonics?

Mountains

Valleys

Volcanos

Cliffs

All of the above

2. In what ways is Earth different from the other terrestrial planets?

Its lithosphere is broken into plates that move around.

It has oxygen in its atmosphere.

Most of its surface is covered with liquid water.

Life can be found almost everywhere.

All of the above are true.

3. The core, mantle, and crust of a planet are defined by differences in their

Geological activity.

Temperature.

Strength.

Density.

4. Which of the terrestrial worlds has the strongest magnetic field?

Mars

Earth

The Moon

Venus

Mercury

5. The lithosphere of a planet is the layer that consists of

Material above the crust.

Material between the crust and the mantle.

The rigid rocky material of the crust and uppermost portion of the mantle.

The softer rocky material of the mantle.

The lava that comes out of volcanoes.

6. Which of the following best describes convection?

It is the process by which rocks sink in water.

It is the process in which warm material expands and rises while cool material contracts and falls.

It is the process in which warm material gets even warmer and cool material gets even cooler.

It is the process in which bubbles of gas move upward through a liquid.

7. The terrestrial planet cores contain mostly metal because

The entire planets are made mostly of metal.

Metals condensed first in the solar nebula and the rocks then accreted around them.

Metals sank to the center during a time when the interiors were molten throughout.

Radioactivity created metals in the core from the decay of uranium.

Convection carried the metals to the core.

8. Which of the following describes impact cratering?

The excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface

The eruption of molten rock from a planet's interior to its surface

The disruption of a planet's surface by internal stresses

The wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

9. What are the conditions necessary for a terrestrial planet to have a strong magnetic field?

A molten metallic core only

Fast rotation only

A rocky mantle only

Both a molten metallic core and reasonably fast rotation

Both a metal core and a rocky mantle

10. Which of the following describes tectonics?

The excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface

The eruption of molten rock from a planet's interior to its surface

The disruption of a planet's surface by internal stresses

The wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

11. Suppose Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be

-16°C, which is well below freezing.

0°C, or about the freezing point for water.

10°C or about 5°C cooler than it is now.

15°C, or about the same as it is now.

20°C, or about 5°C warmer than it is now.

12. There are no auroras on Venus because it

Lacks atmospheric oxygen.

Is too hot.

Lacks a strong magnetic field.

Lacks strong winds.

13. How is the atmosphere of a planet affected by the rotation rate?

The rotation rate determines how much atmosphere a planet has.

The rotation rate determines how long the planet is able to retain its atmosphere.

Faster rotation rates raise surface temperatures and thus determine how much material is gaseous versus icy or liquid.

Faster rotation rates raise the atmospheric temperature.

Faster rotation rates produce stronger winds.

14. Why do we think Mercury has so many tremendous cliffs?

They were probably carved in Mercury's early history by running water.

They were probably formed by tectonic stresses when the entire planet shrank as its core cooled.

They probably formed when a series of large impacts hit Mercury one after the other.

They are almost certainly volcanic in origin, carved by flowing lava.

15. Under what circumstances can differentiation occur in a planet?

The planet must have a rocky surface.

The planet must be made of both metal and rock.

The planet must have an atmosphere.

The planet must be geologically active, that is, have volcanoes, planetquakes, and erosion from weather.

The planet must have a molten interior.

16. The three principal sources of the internal heat of terrestrial planets are

Conduction, differentiation, and accretion.

Accretion, differentiation, and radioactivity.

Accretion, differentiation, and eruption.

Convection, differentiation, and eruption.

Conduction, convection, and eruption.

17. Which of the following worlds have the thinnest lithospheres?

Earth and the Moon

Venus and the Moon

Mercury and Venus

Earth and Mars

Earth and Venus

18. What is the most important factor that determines the thickness, and therefore strength, of the lithosphere?

Pressure

Composition

Internal temperature

Distance of planet from Sun

19. How did the lunar maria form?

Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins.

The early bombardment created heat that melted the lunar surface in the regions of the maria.

Volatiles escaping from the Moon's interior heated and eroded the surface in the regions of the maria.

The giant impact that created the Moon left smooth areas that we call the maria.

The maria are the result of gradual erosion by micrometeorites striking the Moon.

20. 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

Erosion destroyed the smaller craters that formed on the basin.

Mercury's atmosphere prevented smaller objects from hitting the surface.

Only very large impactors hit Mercury's surface in the past.

The Caloris Basin formed toward the end of the solar system's period of heavy bombardment.

The Caloris Basin was formed by a volcano.

21. What drives the motion of the continental plates on Earth?

Convection cells in the mantle

Rotation of the liquid core

Lava flows in trenches along the sea floor

Earth's magnetic field

Tidal forces

22. What type of stresses broke Earth's lithosphere into plates?

Impacts of asteroids and planetesimals

Internal temperature changes that caused the crust to expand and stretch

The circulation of convection cells in the mantle, which dragged against the lithosphere

Cooling and contracting of the planet's interior, which caused the mantle and lithosphere to be compressed

Volcanism, which produced heavy volcanoes that bent and cracked the lithosphere

23. Which two geological processes appear to have been most important in shaping the present surface of Venus?

Impacts and volcanoes

Impacts and tectonics

Tectonics and erosion

Volcanoes and tectonics

Volcanoes and erosion

24. Why is continental crust lower in density than seafloor crust?

Continental crust is made from remelted seafloor crust and therefore only the lower-density material rises to form it.

Continental crust is made of rock, while seafloor crust has more metals.

Continental crust is actually denser than seafloor crust.

25. Of the four gases CO2, H2O, N2, and O2, which are greenhouse gases?

Only CO2

CO2 and H2O

CO2 and N2

All except O2

All four

26. Sunsets are red because

The Sun emits more red light when it's setting.

Sunlight must pass through more atmosphere, and this scatters even more light at bluer wavelengths, transmitting mostly red light.

Sunlight must pass through more atmosphere, and this scatters more light at red wavelengths than bluer wavelengths.

The cooler atmosphere in the evening absorbs more blue light.

None of the above

27. Earth's atmosphere contains only small amounts of carbon dioxide because

The earth's volcanoes did not outgas as much carbon dioxide as those on Venus and Mars.

Most of the carbon dioxide was lost during the age of bombardment.

Carbon dioxide dissolves in water, and most of it is now contained in the oceans and carbonate rocks.

Earth doesn't have as strong a greenhouse effect as is present on Venus.

28. What are fossil fuels?

Any fuel that releases CO2 into the atmosphere upon burning

Any fuel that is extracted from the interior of the earth

Mineral-rich deposits from ancient seabeds

The carbon-rich remains of plants that died millions of years ago

Carbonate-rich deposits from ancient seabeds

29. Valles Marineris is a(n)

Large valley on the Moon.

Extensive plain on Mars.

Huge series of cliffs on Mercury.

Large canyon on Mars.

Large canyon on Venus.

30. If the earth were to warm up a bit, what would happen?

The ice caps would melt and cool the earth back to its normal temperature.

31. Ridges in the middle of the ocean are places where

One plate slides under another, returning older crust to the mantle.

Hot mantle material rises upward, creating volcanic islands.

Hot mantle material rises upward and spreads sideways, pushing the plates apart.

Plates push together, creating ocean mountain chains.

Plates slip sideways relative to one another.