ASTR 1101 Spring 2017 - Ch. 8

13. Which of the following statements is false? The surface of Venus has very few craters primarily because asteroids burn up in its thick atmosphere. Geological features and the chemical composition of some rocks on Mars suggest liquid water flowed on the surface in the past, but not at the present time. Darker regions of the Moon's surface have fewer craters and are approximately 1 billion years younger than the lighter regions. Volcanoes on Mars are larger, on average, than Earth's volcanoes because Mars does not have moving continental plates. Impact craters on Earth are erased over time because of erosion due to water and the recycling of its crust.

A

6. According to studies of impact cratering, which of these terrestrial objects has, on average, the oldest surface? Mercury Venus Earth Mars the Moon

A

Based on the number of impact craters observed per square meter on their surface, place these terrestrial planets in order from youngest to oldest surface. Earth, Venus, Mercury Venus, Earth, Mercury Mercury, Venus, Earth Earth, Mercury, Venus Venus, Mercury, Earth

A

Compared to the dark-colored regions of the surface of the Moon, the light-colored regions are approximately 1 billion years older. 1 billion years younger. 1 million years older. 1 million years younger. a few thousand years younger.

A

If you obtained a sample of rock from Venus and determined the abundances of uranium (238U) and lead (207Pb) in it, and found that for every one uranium atom there were three lead atoms, then what would be the age of this rock? Note that this form of uranium decays to this form of lead with a half-life of 700 million years. For simplicity, you can assume that there was no lead in the rock when it originally formed. 1.4 billion years 2.8 billion years 4.0 million years 10.5 billion years 3.6 billion years

A

Mars has a diameter that is approximately half that of Earth's. If the interiors of these planets are heated by radioactive decays, how does the heating rate of Mars' interior compare to that of Earth's? Mars's heating rate is 0.125 times that of Earth's. Mars's heating rate is 8 times that of Earth's. Mars's heating rate is 0.5 times that of Earth's. Mars's heating rate is 4 times that of Earth's. The heating rates are about the same.

A

Space rocks less than 100 m in diameter, when they hit the ground, are called meteorites. meteoroids. meteors. asteroids.

A

Studies of the amount of cratering at different locations on the Moon indicate that the rate of cratering in the Solar System has changed dramatically over time. the younger lunar surfaces are hundreds of billions of years younger than the oldest surfaces. the Moon has never been geologically active at any point in its history. most of the heavy cratering in the Solar System occurred before Earth formed. cratering is no longer occurring in the Solar System.

A

Suppose an earthquake occurs on an imaginary planet. Scientists on the other side of the planet detect primary waves but not secondary waves after the quake occurs. This suggests that part of the planet's interior is liquid. all of the planet's interior is solid. the planet has an iron core. the planet's interior consists entirely of rocky materials. The planet's mantle is liquid.

A

The Moon has a diameter that is approximately one-fourth that of Earth. If these objects' interiors are heated by radioactive decays and the total amount of energy in decays is proportional to the object's volume, how does the amount of internal heat the Moon has compare to that of Earth? The Moon's heating rate is 8 times that of Earth's. The Moon's heating rate is 0.5 times that of Earth's. The Moon's heating rate is 4 times that of Earth's. The heating rates are about the same.

A

The balance between pressure and weight is known as hydrostatic equilibrium. gravitational equilibrium. pressure balancing. mantel pressure. differentiation.

A

What is the age of our Solar System? 4.6 billion years 4.6 million years 13.7 trillion years 13.7 billion years 13.7 million years

A

What would you study in order to determine the timescale on which Earth's magnetic field reverses direction? a spreading center on the sea floor a volcano in the middle of a continental plate a fault at the border between two plates a subduction zone on the sea floor the rate of motion of tectonic plates

A

Which object would have the largest impact if it were to strike Earth? a 1-m diameter asteroid moving at 100 m/s a 1-m diameter comet moving at 100 m/s a 10-m diameter comet moving at 10 m/s a 10-m diameter asteroid moving at 10 m/s a 1-m diameter comet moving at 50 m/s

A

Which of the following will not be a consequence of Earth's consumption of the bulk of its radioactive "fuel" in the future? Earth will spin more slowly on its axis. The interior of the planet will solidify. Volcanic activity will cease. Continental drift will no longer occur. Earth's mass will decrease.

A

Which of these three lunar surfaces shown in the figure below is the oldest? A B C A and C are probably about the same age and are older than B. It is impossible to tell without radioactive dating.

A

Which terrestrial object shows the least evidence of recent volcanic activity? Mercury Venus Earth Mars the Moon

A

17. Of the following methods, the age of the Solar System can be determined most accurately by measuring the number of craters per square meter on Mercury. radioactive dating of rocks retrieved from the Moon. carbon dating of rocks from mountains on Earth. measurement of the magnetic field variations in rocks under Earth's oceans. measuring the rate of energy production in the Sun.

B

A wave whose amplitude is perpendicular to its direction of motion is longitudinal. transverse. sound. primary. seismic.

B

Based on the age of the light- and dark-colored regions of the Moon and the number of craters observed in these regions, we know that impacts in the inner Solar System rapidly decreased approximately 1 billion years ago. rapidly decreased approximately 3 billion years ago. were very rare in the last 4.6 billion years. occurred at approximately a constant rate throughout most of the age of the Solar System. never occur anymore.

B

Continental drift occurs at a typical rate of a few mm/yr. cm/yr. m/yr. km/yr. nm/yr.

B

Flows of material surrounding Martian craters suggest volcanism in its interior. the presence of water in surface rocks. active plate tectonics at the time of impact. a very thin crust. the presence of ice.

B

If you obtained a sample of a meteorite and determined the abundances of uranium (238U) and lead (207Pb) in it, and found that for every one uranium atom there were 15 lead atoms, what would be the age of this rock? Note that this form of uranium decays to this form of lead with a half-life of 700 million years. For simplicity, you can assume that there was no lead in the rock when it originally formed. 1.4 billion years 2.8 billion years 4.0 billion years 10.5 billion years 3.6 billion years

B

If you start off with 16 atoms of a parent radioisotope, after how many half-lives will only one atom of the parent remain? 2 4 8 15 16

B

Plate tectonics is not responsible for mountain ranges. canyons. volcanoes. ocean trenches. continental drift.

B

Rocks less than 100 meters (m) in diameter, when they are in space, are called meteorites. meteoroids. meteors. asteroids.

B

Secondary craters are craters formed by water impact. craters formed by ejecta during another impact. a crater that forms later, inside a larger crater. craters formed on a new surface. craters formed on planets other than Earth.

B

The feature on Mars shown in the image below is _________ named _________. an impact crater; Meteor Crater a volcano; Olympus Mons a canyon; Valles Marineris a canyon; Caloris Basin a mountain; Mount Neil Armstrong

B

The rovers named Spirit and Opportunity that recently explored the surface of Mars discovered tiny streams of flowing water too small to be detected by orbiting satellites. minerals that must have formed in an environment rich in liquid water. dust storms that rapidly erode the surfaces of most geological formations. the northern polar ice cap is made primarily of frozen water ice. the presence of methane that arises from biological life.

B

Which is not a reason for the large size of volcanoes on Mars as compared to Earth's smaller volcanoes? absence of plate tectonics lack of atmosphere, therefore no erosion less gravity than other terrestrial planets many repeated eruptions

B

Which layer in the figure below represents Earth's liquid mantle? A B C D

B

Which of the following is not a requirement for a planetary magnetic dynamo? rapid rotation solid iron core convective motions charged particles in the interior liquid interior

B

Which of the three lunar surfaces shown in the figure below is the youngest? A B C A and C are probably about the same age and are younger than B. It is impossible to tell without radioactive dating.

B

Based on the assumption that a liquid conducting core and rapid rotation both are required for a magnetic dynamo to operate, which terrestrial planets would you expect to have magnetic fields? only Earth only Earth, Venus, and Mars only Earth and Mars only Earth and Mercury Earth, Venus, Mars, and Mercury

C

Consider an external solar system in which there are three terrestrial planets. All are located far from other objects, so tidal forces aren't significant. If planet A has a radius of 1 Earth radius, planet B has a radius of 2 Earth radii, and planet C has a radius of 3 Earth radii, which planet has the highest chance of having at least a partially liquid core and a detectable magnetic field? Planet A Planet B Planet C They all have the same likelihood of having a liquid core. None of these planets should have a liquid core because they all should have completely solidified.

C

If the Himalaya mountain range is presently 8,000 m in height and is rising at a rate of 0.5 m per century because of the convergence of two continental plates, how long did it take to create this mountain range? 1,600 years 160,000 years 1.6 million years 160 million years 1.6 billion years

C

In Earth's crust, lower-density igneous rock such as _________ make up the continents, and higher-density volcanic rock such as _________ make up the ocean floor. limestone; granite granite; iron-rich silicates granite; basalt limestone; sandstone marble; basalt

C

MSC: Remembering Magma on Earth is liquid rock from the core. outer core. upper mantle. lower mantle. center.

C

Present-day erosion on the surface of the Moon is primarily caused by flowing water. wind. solar radiation. dust storms. tectonic shifts.

C

Space rocks less than 100 m in diameter, when they burn up in the atmosphere, are called meteorites. meteoroids. meteors. asteroids.

C

The North American Plate and the Pacific Plate are sliding past one another at a rate of approximately 3 cm/yr. San Francisco, which is located on the edge of the North American Plate, is sliding southward toward Los Angeles, which is located on the Pacific Plate. If they are currently separated by a distance of 600 km, how many years will it take for the two cities to meet? 3 million years 300,000 years 20 million years 20,000 years 600 years

C

The dynamo theory says that a planet will have a strong magnetic field if it has fast rotation and a solid core. slow rotation and a liquid core. fast rotation and a liquid core. slow rotation and a solid core. fast rotation and a gaseous core.

C

The fact that Earth's interior is differentiated suggests that it formed first from denser material and then afterward accreted lighter material. it has both a liquid and solid core. it was entirely liquid at some point in the past. only the crust is solid; the rest of Earth's interior is liquid. it formed first from lighter material, then afterward accreted heavier material.

C

The large feature spanning the surface of Mars in shown the figure below is _________ and probably was created by _________. an impact crater; an asteroid or comet a dry riverbed; flowing water a canyon; a rapid cooling of the crust a canyon; flowing water a highway; an extinct civilization

C

To survive passage through Earth's atmosphere without burning or breaking up before it hits the ground, an asteroid must be at least 1 m in size. at least 10 m in size. at least 100 m in size. at least 1 kilometer (km) in size. at least 1,000 km in size.

C

We have direct evidence for the current existence of water on the surface of which terrestrial object? Mercury Venus Mars Ganymede Callisto

C

What is the main reason that Earth's interior is liquid today? tidal force of the Moon on Earth seismic waves that travel through Earth's interior decay of radioactive elements convective motions in the mantle pressure on the core from Earth's outer layers.

C

Which layer in the figure below represents Earth's liquid core? A B C D

C

Which of the following is not a factor that helps explain Earth's lack of craters compared to the Moon? wind erosion larger atmosphere higher density interior liquid water on surface active tectonics and volcanism

C

Which of the following statements is false? Approximately 65 million years ago, a 10-km-wide asteroid struck Earth and wiped out more than 50 percent of all living species. The Moon probably was formed by a collision between a Mars-sized body and Earth. During summer in the northern hemisphere of Mars, the polar ice cap melts and liquid water flows outward from it in rivers. The surface of Venus is relatively young, with an estimated age of less than 1 billion years. Mercury has many fractures and faults on its surface that probably arose when it cooled very rapidly and shrank.

C

Which terrestrial planet has the strongest magnetic field? Mercury Venus Earth Mars The Moon

C

. Magnetosphere refers to the metallic core of Earth. the liquid mantel of Earth. the magnetic dynamo effect. a region of magnetic field around Earth. Earth's ionosphere.

D

A rising convection cell in the mantle gives rise to a subduction zone. a sliding plate. converging plates. separating plates.

D

Differentiation refers to materials that are separate based on their weight. mass. volume. density. heat capacity.

D

Earth's innermost core is solid, not liquid, because the core temperature is too low to melt iron. differentiation caused all of the heavy, solid material to sink to the bottom while Earth was forming. all the liquid has moved up into the mantle via convection. the pressure is too high for the material to be in a liquid state. iron does not melt.

D

If a radioactive element has a half-life of 10,000 years, what fraction of it is left in a rock after 40,000 years? 1/2 1/4 1/8 1/16 1/32

D

Mars, Venus, and Earth are much less heavily cratered than Mercury and the Moon. This is explained by the fact that the rate of cratering in the early Solar System was strongly dependent on location. Mars, Venus, and Earth have thicker atmospheres. Earth and Venus were shielded from impacts by the Moon, and Mars was protected by the asteroid belt. Mars, Venus, and Earth were geologically active for a longer period of time than Mercury and the Moon. Mars, Venus, and Earth are much larger in size than Mercury and the Moon.

D

The feature shown in the image below is a(n) _________, the largest one of its kind in the Solar System, and is located on the planet _________. impact crater; Mercury mountain; Venus mountain; Earth volcano; Mars impact crater; the Moon

D

The figure below shows the continental plates of Earth and the locations of volcanoes and earthquakes. Which statement is false? Earth's crust is broken up into 13 separate continental plates. Volcanoes occur more often where two plates are coming together rather than spreading apart. Earthquakes happen where two plates come together and when they spread apart. The Atlantic Ocean is getting smaller with time. Southern California in the United States and Baja in Mexico are sliding northeastward relative to the rest of the North American Plate.

D

The large feature spanning the planet _________ shown in the figure below is called _________. Mars; Olympus Mons Venus; Valles Marineris Venus; Olympus Mons Mars; Valles Marineris Mercury; Caloris Basin

D

The largest volcanic mountains in the Solar System are found on Mercury. Venus. Earth. Mars. the Moon.

D

The lithosphere of a planet is the molten layer under the crust. the layer of the atmosphere in which clouds form. the upper layer of its atmosphere. its solid surface. its frozen surface.

D

The smallest number of craters per square meter are found on the surface of Mercury. Mars. Venus. Earth.

D

Which is not a reason that we suspect Mars once had liquid water on its surface? Mapping satellites have detected dry riverbeds. Rovers have detected minerals that must have formed in the presence of liquid water. Mapping satellites have detected outflow channels coming from impact craters. The observed presence of water ice in Mars's polar icecaps.

D

Which list below gives the correct order of the age of the three lunar surfaces shown in the the figure below going from youngest to oldest? A, B, C A, C, B B, A, C B, C, A C, B, A

D

8. Which is not a reason that we suspect that the extinction of the dinosaurs was caused by an explosive impact by a large object? Many dinosaur fossils are found below the K-T boundary, but none above it. The material in the K-T boundary is rich in iridium. Soot is found in the material in the K-T boundary, which probably came from fires caused by the impact. An impact crater has been found near Mexico's Yucatan Peninsula. The remaining meteorite has been identified on the bottom of the Gulf of Mexico.

E

Maria refer to a geological feature located on Mercury. Venus. Mars. Earth. The Moon.

E

The observation that the Moon's average density is similar to the density of Earth's _________ supports the collision theory of the Moon's origin. oceans average density core atmosphere mantle

E

What will eventually happen to Earth when radioactive decays in its interior cease? Earth's core will solidify. Continental drift will cease. Earthquakes will cease. The strength of Earth's magnetic field will decrease. all of the above

E

Which object would have the least effect on our planet if it were to strike Earth? a 1-kg asteroid traveling at 30 km/s a 5-kg asteroid traveling at 10 km/s a 100-kg comet traveling at 10 km/s a 1,000-kg Mini Cooper car traveling at 100 miles/h, which is 0.05 km/s a 3,000-kg truck traveling at 35 miles/h, which is 0.02 km/s

E

Which of the following are not sites of frequent volcanic and earthquake activity on Earth? local hotspots spreading centers subduction zones transform faults inactive faults

E