Phys 1404 Exam 3

Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?

Surface water only exists as frozen ice.

Go to the screen in the interactive figure called "Major Geological Features." Which of the following statements about the Tharsis Bulge, often simply called "Tharsis," are true?

-Tharsis has higher elevation than surrounding regions. -Tharsis has several large volcanoes. -One end of Valles Marineris is connected to Tharsis.

Based on Planet Z's size, orbital distance, and rotation rate, which of the following properties is it likely to have?

-active tectonics -active volcanoes -an atmosphere produced by outgassing Submit

Make a prediction: If the rise in carbon dioxide concentration continues at its current pace, the concentration in the year 2050 will be about _____ parts per million.

460

Using the data in the table Satellites of the Solar System in the textbook, identify the orbital resonance relationship between Titan and Hyperion. (Hint: If the orbital period of one were 1.5 times the other, we would say that they are in a 3:2 resonance.)

4:3

Using only pencil and paper calculations, Arrhenius concluded that a doubling of the carbon dioxide concentration would raise global temperatures by about _____.

5° C

What do we mean by a runaway greenhouse effect?

A greenhouse effect that keeps getting stronger until all of a planet's greenhouse gases are in its atmosphere.

This painting shows an artist's conception of what it would look like to be within Saturn's system of rings. Notice the many whitish "balls" visible in this painting. Based on what you have learned about rings, about how large are each of these "balls," on average?

About a size that you could hold in your arms.

Which of the four labeled arrows in this photo of the full moon is point to one of the lunar maria?

Arrow 1

The image below shows a rock formation nicknamed "the face on Mars" that was taken by the Viking 1 orbiter in 1976. Given the clear resemblance to a face, what is an appropriate scientific reaction to this image?

Assume it is most likely a coincidental result of light and shadow, and plan higher resolution follow-up observations.

Click the fourth tab (labeled "Computer Models"), then explore how the graph changes as you click among the three buttons to its left. What is the primary message of the full graph (with all three curves shown)?

Climate models successfully reproduce the major recent trend in temperature data only if both human and natural factors are included.

How do the jovian planets influence life on Earth?

Close gravitational encounters between icy planetesimals and the jovian planets flung the comets outward to huge distances where they formed the Oort cloud. Most of that comets never re-enter the inner solar system, so they can't collide with Earth.

How does it explain the differences between seafloor and continental crust?

Denser oceanic crust is constantly recycled, sinking in mantle at subduction zones and forming anew from mantle matter at spreading zones. Continental crust is less dense than the oceanic crust, so it does not sink at subduction zones and is older than oceanic crust.

Which medium-size moon is in a 2:1 resonance with Enceladus?

Dione

Which of the following best describes the geological histories of the Moon and Mercury?

Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all.

Which are thought to have formed farthest from the Sun?

Kuiper belt comets

Which of the following statements best explains why the densities of Uranus and Neptune are higher than that of Saturn, even though Saturn is much more massive?

They have a higher proportion of hydrogen compounds and rock.

Which of the following best describes the nature and origin of the atmospheres of the Moon and Mercury?

They have thin exospheres only, with gas coming from impacts of subatomic particles and photons.

What is the significance of the yellow lines on this map of Earth?

They represent boundaries between the plates that make up Earth's lithosphere.

This photo from the Curiosity rover shows what appears to be layered sedimentary rock on Mars. What does this photo seem to be telling us?

This region of Mars once held a body of water such as a lake.

Choose the correct summary of the role of the jovian planets in shaping the orbits of small bodies in the solar system.

Through the orbital resonances, Jupiter affects the asteroid belt and Neptune affects the Kuiper belt. Jovian planets' gravitational influence prevented the formation of terrestrial planet in asteroid belt.

How is Neptune's moon Triton important to our understanding of the Kuiper belt origin?

Triton has a backward orbit, which indicates that it was captured by Neptune from the Kuiper belt. The study of Triton helps to understand other Kuiper belt objects.

In which direction do hurricanes in the Southern Hemisphere rotate?

clockwise

Which of the following was a new discovery about Pluto by the New Horizons mission?

evidence of recent geological activity

Click the third tab (labeled "Global Warming"), then explore the graph and the expanded views you will find by clicking the "?" buttons. Which of the following statements are supported by the data shown?

-Atmospheric carbon dioxide levels have risen dramatically over the past century. -Earth's global average temperature has generally risen over the past century. -Rises in global average temperature tend to be closely associated with rises in atmospheric carbon dioxide concentration.

Although the data show only a correlation between the carbon dioxide concentration and the global average temperature, scientists have other reasons to think that a rise in the carbon dioxide concentration actually causes a rise in the global average temperature. All of the following statements are true. Which statements lend support to the idea that carbon dioxide is a cause of planetary warming?

-Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts. -Models of Earth's climate that include recent increases in the carbon dioxide concentration match observed temperature increases better than those that do not include it. -We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. Submit

Start on the home screen of the interactive figure, with "Elevation is off." Then turn elevation on, and compare what you see. You may wish to switch back and forth between elevation on and off a few times. Then select the statements below that are true. Note: Features such as impact craters that are actually round in shape are distorted into oval shapes at mid- to high-latitudes by map projection effects. Select all that apply.

-Several large volcanoes are found near or somewhat north of Mars's equator. -Most of the northern hemisphere has much lower elevation than the southern hemisphere. -There is a long, deep canyon that strectches along a region close to Mars's equator. -There is a large, roundish region of low-elevation in the southern hemisphere.

Go to the screen "Key Evidence of Water," and and select the feature called "Recurring Slope Lineae." Study this feature at each of the four zoom levels offered, and be sure to view the animation called "recurring slope linaea (gif)" that you will see at the third zoom level. Which of the following statements are true?

-The recurring slope lineae are found among impact craters. -The recurring slope lineae appear to grow in spring and summer. -The recurring slope lineae look like narrow dark streaks.

According to this graph, the minimum size of an object that could cause a mass extinction is a little less than _____.

10 km

A few hundred tons of comet dust gets added to Earth daily from the millions of meteors that enter our atmosphere. Estimate the time it would take for Earth to get 0.1% heavier at this rate.

10^14 years

Choose the correct description of size and shape of asteroids.

Asteroids are much smaller than the planets. The largest asteroids are fairly round, and the smallest can be very irregular.

Why do we think that ring particles must be replenished over time? Where we think ring particles come from? Choose the correct statement.

Because collisions are constantly occurring within the ring systems, ring particles are continually being ground down to dust. Dust cannot survive long in ring systems because sunlight pressure makes the particles slowly fall onto the planet. So we think that ring systems cannot survive very long and thus that ring particles must be replenished, probably by impacts on small embedded moons and ring particles by micrometeorites and the occasional larger impacts.

Based on this graph, which statement below most accurately describes the impacts we should expect on Earth during the coming year?

Earth will be hit by at least one object a few meters in diameter, along with many smaller objects.

Compare your result in the previous part to the Earth's actual reflectivity, 29%, and choose the correct conclusion.

Earth would be frozen, if there were no greenhouse effect in the atmosphere.

Choose the correct description of the conveyor-like action of plate tectonics on Earth.

Earth's lithosphere is broken up into plates that float on the underlying mantle. The tops of the mantle's convection cells drag the bottoms of the plates, making them move relatively to each other.

Arrhenius was not particularly alarmed by his discovery at the time. What changed that made later scientists become much more concerned about the climate effects of carbon dioxide?

Emissions of carbon dioxide rose much faster than Arrhenius had anticipated.

How did the discovery of Eris force astronomers to reconsider the definition of planet?

Eris is similar to Pluto that was considered as the ninth planet. After the discovery of Eris, astronomers created a new category called dwarf planets and excluded Pluto from the category of planets.

In what direction do the tails point?

Gas tail points directly away from the Sun. Dust tail is curve extending out from the Sun and backwards at comet's orbit.

What motivated Arrhenius to calculate how changes in carbon dioxide might affect the climate?

He was seeking to understand the causes of ice ages.

Why is Io more volcanically active than our moon?

Io has a different internal heat source. Submit

What happens to the energy that the ground absorbs in the form of visible sunlight?

It is returned upward in the form of infrared light.

What is unusual about Triton?

It orbits its planet backward.

On a cloudless day, what happens to most of the visible light headed toward Earth?

It reaches Earth's surface, where some is reflected and some is absorbed. Submit

Which describes our understanding of flowing water on Mars?

It was important once, but no longer.

What would happen if a 1-kilometer object struck Earth?

It would cause widespread devastation and climate change.

This photo shows Comet Hale-Bopp in the night sky. Suppose you had taken another photograph from the same spot 10 minutes after this photo was taken. How would the scene have appeared at that time?

It would have looked virtually the same.

Why is Jupiter denser than Saturn?

Its higher mass and gravity compress its interior.

What is the leading hypothesis for Venus's lack of water?

Its water molecules were broken apart, and hydrogen was lost to space.

Based on the leading scientific theory of solar system formation, which of the following statements best explains why Uranus and Neptune have a significantly different composition than Jupiter and Saturn?

Jupiter and Saturn captured more gas from the solar nebula than Uranus and Neptune.

Which of the following best explains why Jupiter's density is higher than Saturn's?

Jupiter is more massive than Saturn.

What are all the blue lines connecting to Jupiter supposed to represent in this picture?

Jupiter's magnetic field

After the New Horizons flyby, scientists concluded that Pluto has probably been geologically active within the past 100 million years or less. Why?

Large regions of the surface have very few impact craters.

The asteroid belt lies between the orbits of

Mars and Jupiter.

This photo was taken from orbit around some planet. What planet is it, and how do you know?

Mars because we see dried up riverbeds

Why does Neptune appear blue and Jupiter red?

Methane in Neptune's atmosphere absorbs red light.

Did a large terrestrial planet ever form in the region of the asteroid belt?

No, because Jupiter prevented one from accreting.

The impact of a 100-meter object will not cause "widespread" devastation, but it could still kill millions of people if it struck a major city. In Part C, you found that the probability of such an impact in any single year is only 1 in 1000. Suppose we learn that it has already been 1200 years since the last such impact. What would that tell us?

Nothing; we would still presume that the chance of such an impact during the next year is 1 in 1000.

This photo, taken from orbit of Mars, shows a feature known as _____________________.

Olympus Mons

Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?

Olympus Mons

What do we conclude if a planet has few impact craters of any size?

Other geological processes have wiped out craters.

Which of the following statements correctly describes the motion of the particles in Saturn's rings?

Particles in the inner rings orbit Saturn at a faster speed than particles in the outer rings.

This diagram shows the temperature structure of Earth's atmosphere, and dashed lines separate different atmospheric regions. Which region is the troposphere?

Region 1

How do current models explain the origin of the Kuiper belt? What role does planetary migration play?

The Kuiper belt is composed of ice-rich planetesimals that formed outside the orbit of Neptune. During the planetary migration processes, the Kuiper belt lost the majority of its original mass and orbital resonances with jovian planets gave the belt the form it has today.

The evidence for recent geological activity on Pluto came as a surprise to most scientists, because they did not expect Pluto to retain enough heat to drive such activity. Which of the following best explains why Pluto is so geologically active despite its small size?

The activity involves nitrogen ice, so Pluto does not need much heat to cause this ice to undergo change.

Based on the evidence that atmospheric carbon dioxide is a cause of planetary warming, what aspect of the graphs should most concern us?

The carbon dioxide concentration today is significantly higher than at any time in the past 800,000 years and is rapidly rising. Submit

Choose the correct description of density and composition of asteroids.

The densities of asteroids are between 1.5 and 3.5 g/cm3. Asteroids are made mostly of metal and rock.

This figure summarizes the geological histories of the terrestrial worlds. Based on this figure, what can you conclude?

The most important factor in a planet's geological history is its size.

What clues do other Kuiper belt comets offer about the origin of the belt?

The similar characteristics of Kuiper belt objects such as travel direction, orbit inclination, stable orbital resonance with Neptune, and composition suggest that these objects have the common origin and were formed in the outer region of the solar system.

How does the total mass of all asteroids compare to the mass of a terrestrial world?

The total mass of all asteroids is less than that of our Moon.

Which of the following best summarizes current understanding of other extinctions in Earth's past history?

There have been a few other fairly sudden mass extinctions, but none are as clearly tied to impacts as the dinosaur extinction

Look at the average densities of the jovian planets given in the figure. Can you identify a trend in jovian planet densities with mass or distance from the Sun?

There is no clear trend in the densities with mass or distance.

How do typical wind speeds in Jupiter's atmosphere compare to typical wind speeds on Earth?

They are much faster than hurricane winds on Earth.

Choose the correct explanation, whether the discovery below should be considered reasonable or surprising: A planet orbiting another star is made primarily of hydrogen and helium and has approximately the same mass as Jupiter but is the same size as Neptune.

This would be surprising and possibly implausible. The mass and composition defines the size and density, so Jupiter-mass hydrogen planet should have sizes similar to Jupiter too.

What is the relevance of tidal heating to the possibility of life on jovian moons?

Tidal heating can lead to subsurface zones of liquid water.

Can an asteroid be pure metal?

Yes, it must have been the core of a shattered asteroid. Submit

In Part A, you found that Planet Z should not have strong winds and violent storms. What single change to Planet Z's characteristics would cause it to have strong winds and violent storms?

a faster rotation rate

In Part A, you found that Planet Z should not have polar ice caps or liquid water. What single change to Planet Z's characteristics would allow it to have these things?

a greater distance from its star

In Part A, you found that Planet Z should not have seasons. What single change to Planet Z's characteristics would cause it to have seasons?

a larger axis tilt

On the graphs shown, you can identify an ice age by looking for __________.

a trough (bottom of a dip) on the temperature graph

What is the probability that an object 100 meters in diameter will hit Earth during the coming year?

about 1 in 1000

According to the graph, an object 10 kilometers across hits Earth __________.

about once every 100 million years

The change in fossils at the K-T sediment layer suggests that in addition to the dinosaurs, _________ also went extinct.

about three-quarters of all species living at the time

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases __________.

absorb infrared light emitted by the surface

In light of what we know about geological activity on the terrestrial worlds, why might it seem surprising to find geological activity on jovian moons?

because they are relatively small in size

How many of the terrestrial worlds have lava plains or shield volcanoes?

five

A comet entering the inner solar system from afar will __________.

form a coma and some time later form a tail

You have found that Planet Z should have active tectonics and volcanism and an atmosphere produced by volcanic outgassing. What single factor explains why the planet should have these characteristics?

has a large size for a terrestrial planet.

The main ingredients of most satellites of the jovian planets are

hydrogen compound ices.

Go to the screen in the interactive figure called "Key Evidence of Water," then zoom in on the "Southern Highlands." Which geologic processes are most clearly evident in the southern highlands?

impact cratering and erosion

The greenhouse effect raises Earth's surface temperature (from what it would be otherwise) because the infrared light radiated by Earth's surface __________.

is absorbed by greenhouse gases, slowing the escape of this energy to space Submit

Which of the following is the underlying reason why Venus has so little wind erosion?

its slow rotation

What's the fundamental reason that Mars has so little geological activity compared to Earth?

its small size compared to Earth

Saturn's rings look bright because __________.

light from the Sun reflects off the material in the rings

What kind of gas is most affected by thermal escape?

light gases

Where is most of the CO2 that has outgassed from Earth's volcanoes?

locked up in rocks

Saturn's rings are composed of __________.

lots of individual particles of ice and rock

Is this mass accumulation significant for Earth as a planet?

no

A comet's plasma tail always points directly away from the Sun because __________.

of pressure exerted by the fast-moving charged particles in the solar wind

How many of the five terrestrial worlds have surfaces being constantly reshaped by plate tectonics?

one

Jupiter nudges the asteroids through the influence of

orbital resonances.

Saturn's many moons affect its rings through

orbital resonances.

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity?

size

The major way in which we learn about Earth's interior is through

studying seismic waves.

During the time that a comet passes through the inner solar system, the comet can appear quite bright because __________.

sunlight reflects off the comet's tail and coma

What is the name of the feature indicated by the arrow in this photo?

the Great Red Spot

What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?

the presence of many long, tall cliffs

If Earth had as much carbon dioxide in its atmosphere as Venus, our planet would not have oceans.

true

On how many of the five terrestrial worlds has erosion been an important process? (Be sure that you explain why erosion is important on this many worlds and not more.)

two

What kind of light warms the stratosphere?

ultraviolet

The average temperature over the past 1000 years has been about 15∘C∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________.

varied between about 7∘C and 19∘C

The energy that warms Earth's surface comes primarily in the form of __________.

visible light from the Sun

Percival Lowell's claims of a Martian civilization generated great public interest, but other scientists of his time were highly skeptical of these claims. Which two of the following statements (which are all true) explain why other scientists of the late 19th and early 20th centuries rejected Lowell's claims?

-Lowell's canals followed perfectly straight lines for thousands of kilometers. -Lowell's canals did not appear in photographs of Mars taken through telescopes. Submit

Based on what you learn about jovian moons by watching the videos or reading your textbook, what types of evidence for recent or ongoing geological activity have been observed on one or more jovian moons?

-river valleys feeding into surface lakes of very cold liquids -active volcanoes -surfaces with very few impact craters -ice crystals being sprayed out into space

Click on the first tab at the top of the interactive figure (labeled "The Greenhouse Effect"), then explore what happens as you click among the buttons (labeled "none," "low," "medium," and "high") that adjust the greenhouse gas concentration. Which of the following occur as the greenhouse gas concentration increase?

-the average surface temperature rises -more infrared light is absorbed in the lower atmosphere Submit

Which of the following can contribute to explaining why jovian moons are sometimes much more geologically active than terrestrial worlds of similar (or smaller) size?

-tidal heating -ice-rich composition

Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what form(s) does Earth return most of this energy to space?

-visible light reflected by the surface -infrared light emitted by the surface and atmosphere -visible light reflected by clouds

Now go to the screen "Major Geological Features," and explore the main screen with labels on and off and elevation on and off. Then complete the sentences below.

Tharsis Bulge is a high-elevation region dotted by tall volcanoes. The tallest mountain on Mars is called Olympus Mons. The large, roundish, low-elevation region in the southern hemisphere is called Hellas Basin. The long, deep canyon running along the equator is called Valles Marineris.

Deuterium is much more abundant on Venus than Earth. What do scientists think this fact tells us about Venus?

That Venus has lost a tremendous amount of water as a result of molecules being split by ultraviolet light and the hydrogen escaping to space.

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true?

We should expect an increase in the greenhouse gas concentration to lead to global warming.

Since the time Arrhenius made his prediction, the carbon dioxide concentration has risen by about 30% and the global average temperature has risen by about 1°C. Which statement below best describes how scientists should evaluate Arrhenius's prediction?

Although Arrhenius's prediction was not exact, the actual change is similar enough to the predicted change to validate the general idea that a rising carbon dioxide concentration would lead to global warming.

Choose a descriptions of the effects of gap moons and orbital resonances on ring systems.

Small moons orbit in the ring gaps and keep gaps clear, also creating ripples on the ring edges. Distant massive moon can clear the larger gaps by orbital resonances and lunch waves in the rings.

All the following statements about Mars are true. Which one might have led to a significant loss of atmospheric gas to space?

Mars lost any global magnetic field that it may once have had.

On this graph, the black curve represents actual temperature measurements, the red curve represents models of the climate that include human emissions of greenhouse gases, and the blue curve represents models of the climate that include only natural factors but do not include human emissions of greenhouse gases. What is the key message that can be read from this graph?

Models support the conclusion that human emissions are driving global warming.

How do the interiors of the other jovian planets compare to that of Jupiter?

Saturn has structure similiar to Jupiter, but with a smaller layer of metallic hydrogen. Uranus and Neptune have no metallic and liquid hydrogen layers and have differentiated layers of hydrogen compound around the core.

Notice that the peaks and troughs on the temperature graph occur at the about the same times as peaks and troughs on the carbon dioxide graph. What can we infer from this fact alone?

There is a correlation between the carbon dioxide concentration and the global average temperature.

Now click the second tab (labeled "Terrestrial Planet Temperatures"), then explore what happens as you click the button that allows you to add or remove greenhouse gases. Which terrestrial planet would have its surface temperature the most dramatically changed if its greenhouse gases were removed from its atmosphere?

Venus

Which terrestrial world has the most atmosphere?

Venus

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise?

Venus has a higher average temperature than Mercury.

Choose the correct description of the interior structure of Jupiter and why it is layered in this way.

The great mass, generating enormous pressures inside the planet, and composition of mostly hydrogen determine the interior structure of Jupiter. From the outside to the center, layers are as follows: Gaseous atmosphere of hydrogen with clouds on top. Relatively thin layer of liqud hydrogen. The metal hydrogen layer, extending about three fourths of planet's radius. The relatively small core of metals, rocks, and hydrogen compounds.

Go to the screen "Mars Mission Landing Sites," and and select Opportunity landing site (2004). Explore all five zoom levels offered, making sure to read the captions at the tops of the screens. Based on the information provided, why was the landing site,called Meridiani Planum, chosen for the Opportunity mission?

The region was already known to have minerals likely to have formed in liquid water.

How does this affect Mars's seasons?

The southern hemisphere of Mars has short and hot summers as well as long and cold winters compared to the northern hemisphere.

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth's temperature would be without greenhouse gases?

They calculate this temperature from Earth's reflectivity and distance from the Sun. Submit

Which moon shows evidence of rainfall and erosion by some liquid substance?

Titan

Which of the following statements best describes the general pattern of composition among the four jovian planets?

Uranus and Neptune contain relatively more rock and hydrogen compounds than Jupiter and Saturn.