Final Study Guide Astronomy

What are Phobos and Deimos? Two of the largest asteroids of the asteroid belt Moons of Uranus and Neptune, respectively Two of Jupiter's many small moons The two small moons of Mars

The two small moons of Mars

Drake Equation: represents the total number of planets on which intelligent beings have evolved and developed a communicating civilization at some time in the galaxy's history.

NHP×f life×f civ

Based on scientific study of the evidence, scientists conclude that the famous Roswell crash of 1947 most likely involved ________. an alien spacecraft a Russian spy plane an unknown vehicle made of materials unlike any that humans can produce an Air Force balloon experiment

an Air Force balloon experiment

The martian "blueberries" are ________. layered boulders that look like the sediment layers found in Earth's Grand Canyon bluish features seen in orbital photos pebble-sized spheres containing the mineral hematite small, rocky spheres thought likely to contain fossilized ancient microbes

pebble-sized spheres containing the mineral hematite

The first confirmed detections of extrasolar planets occurred in ____________. the 1990s 2009 the mid-20th century the mid-17th century

the 1990s (The first detection around a Sun-like star was a planet orbiting the star 51 Pegasi in 1995.)

Each of the following figures shows Earth with a different axis tilt. (Assume that Earth's rotation period is unchanged.) Each also shows a person located in Florida (not to scale). Rank the figures based on how much time the person spends in daylight during a 24-hour period, from most to least.

(Most daylight- least)

The following figures are the same as those from Part A. This time, imagine that each person places an identical glass of water outside. Consider only the effects of the season — meaning the amount of daylight and the height of the Sun's path through the sky — on the water temperature. Rank the figures based on the highest (warmest) temperature the glass of water would reach during a 24-hour period, from highest to lowest. To rank items as equivalent, overlap them.

(highest temperature) the 3 Earth's with people with two arrows (lowest temperature) the 3 Earth's with people with one arrow

1. The largest moon in the solar system is . 2. The jovian moon with the most geologically active surface is . 3. Strong evidence both from surface features and magnetic field data support the existence of a subsurface ocean on . 4. is responsible for the tremendous volcanic activity on Io. 5. is the most distant of Jupiter's four Galilean moons. 6. The fact that Europa orbits Jupiter twice for every one orbit of Ganymede is an example of a(n)

1. Ganymede 2. Io 3. Europa 4. Tidal heating 5. Callisto 6. Orbital Resonance

After a 9-year journey, the New Horizons spacecraft flew past Pluto in 2015. About how long will it take it to reach the distance of the nearest stars? 10 million years 1000 years 100,000 years 10 years

100,000 years

Which of the following might once have been orbited by an Earth-like planet? A neutron star A black hole A white dwarf A supernova

A white dwarf

Which of the following have we found on Titan? Abundant organic compounds Geysers spewing icy fountains into space Clear evidence of a subsurface ocean Conditions suggesting a high probability of life

Abundant organic compounds

Which statement about the martian seasons is not true? The carbon dioxide at the martian polar caps sublimates to gas in summer, leaving a residual polar cap of water ice. Seasons on Mars are affected by the orbit as well as by the axis tilt. All of Mars has summer at the same time, and half an orbit later all of Mars has winter. Seasons on Mars last almost twice as long as seasons on Earth.

All of Mars has summer at the same time, and half an orbit later all of Mars has winter.

Besides Titan, for what other moons of Saturn have we observed evidence of liquids either on their surface or subsurface? Enceladus Enceladus and Iapetus Enceladus, Mimas, and Iapetus Enceladus and Mimas

Enceladus

The diagrams below each show the motion of a distant star relative to Earth (not to scale). The red arrows indicate the speed and direction of the star's motion: Longer arrows mean faster speed. Rank the stars based on the Doppler shift that we would detect on Earth, from largest blueshift, through no shift, to largest redshift.

As your correct answer indicates, the star moving fastest toward Earth will have the greatest blueshift, the star moving across our line of sight will have no shift at all, and the star moving fastest away from us will have the greatest redshift.

The martian surface is usually divided into regions of three different age ranges (early, middle, and recent). How do we decide in which age range a region belongs? By counting the number of craters in the region From radiometric dating of martian rocks By estimating when different regions of the planet first solidified as Mars was forming By counting the number of volcanoes in the region

By counting the number of craters in the region

The spaceship that is currently orbiting Saturn is ________. New Horizons Rosetta Cassini MESSENGER

Cassini

Which of the following does not vary much among ordinary, hydrogen-fusing (main-sequence) stars? (That is, which does not change as you go along the spectral sequence OBAFGKM?) Mass Luminosity Chemical composition Surface temperature

Chemical composition

used for most of the first 200 extrasolar planet detections currently best-suited to find Jupiter-sized extrasolar planets orbiting close to their stars

Doppler Method

Discovering planets through the ------- requires obtaining and studying many spectra of the same star.

Doppler method

The ------ is designed as a way of estimating the number of intelligent civilizations in the Milky Way.

Drake equation

This moon of Jupiter has an icy surface with very few impact craters, suggesting that craters have been covered by upwelling water.

Europa

Which of the following did Nikola Tesla do? He invented the electric car. He invented the radio. He claimed to have detected an interplanetary communication from another civilization. He built a large telescope for studying civilization on Mars.

He claimed to have detected an interplanetary communication from another civilization.

What does the graph below tell us about humans compared to other animals? Based on averages determined from other animals, human brains are the size we'd expect for animals of our weight. Humans have the most massive brains of any animal. Humans are the only animal with an EQ of 1. Humans have a brain mass that is unusually large for an animal of our body mass.

Humans have a brain mass that is unusually large for an animal of our body mass.

What role has Jupiter played in Earth's habitability? Jupiter's extended magnetosphere has protected Earth from radiation from distant supernovae. Jupiter helps stabilize Earth's axis. Jupiter helps stabilize Earth's orbit. Jupiter's gravitational effects helped clear the inner solar system of objects that could cause impacts.

Jupiter's gravitational effects helped clear the inner solar system of objects that could cause impacts.

The ------ successfully discovered thousands of extrasolar planets with a spacecraft that searched for transits among some 100,000 stars.

Kepler mission

The following four graphs show the velocities, toward and away from Earth, of four identical stars (the same graphs shown in Parts A and B). Assume that all four identical stars have extrasolar planets orbiting them at the same distance. Rank the graphs from left to right based on the mass of the extrasolar planet that orbits the star, from smallest to largest.

Notice that the graphs are ranked in order of velocity, because a more massive planet exerts a larger force on its companion star and therefore causes it to orbit the center of mass with a greater velocity.

Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars? the polar caps the southern highlands Valles Marineris Olympus Mons

Olympus Mons

As shown in the video, Earth has two tidal bulges at all times. Approximately where are these bulges located? One faces the Moon and one faces the Sun. One faces the Moon and one faces opposite the Moon. Both are on lines perpendicular to the Earth-Moon line. One is over the Atlantic Ocean, and one is over the Pacific Ocean.

One faces the Moon and one faces opposite the Moon.

Suppose that our Sun was cool enough to include Mercury in its habitable zone. Which of the following would be true in that case? Only Mercury would be in the Sun's habitable zone. Mercury and Venus would be in the Sun's habitable zone, but Earth and Mars would not. Mercury, Venus, and Earth would be in the Sun's habitable zone, but Mars would not. All the terrestrial planets would be in the Sun's habitable zone.

Only Mercury would be in the Sun's habitable zone.

Which of the following is not a key piece of evidence in favor of past liquid water on Mars? Orbital photos reveal networks of channels that look like dried-up rivers and deltas. Robotic rovers have found rocks that appear to be composed of layered sediments. Robotic rovers have found hematite and other minerals thought to form in water. Orbital photos show a relatively small number of craters on volcanic slopes. Orbital images and spectra reveal the presence of hydrated minerals such as clays and opal.

Orbital photos show a relatively small number of craters on volcanic slopes.

Based on discoveries to date, which of the following conclusions is justified? Planetary systems are common and planets similar in size to Earth are also common. Although planetary systems are common, few resemble ours with terrestrial planets near the Sun and jovian planets far from the Sun. Most stars have one or more terrestrial planets orbiting within their habitable zones. Planets are common, but planets as small as Earth are extremely rare.

Planetary systems are common and planets similar in size to Earth are also common.

What is the distinguishing characteristic that radio SETI experiments are looking for when searching for signs of extraterrestrial intelligence? Radio emissions spread over a wide band of frequencies Radio emission containing the value of pi or other mathematical constants Radio emission that extends over only a narrow band of frequencies Radio emission that has all its spectral lines at the frequencies produced by hydrogen atoms

Radio emission that extends over only a narrow band of frequencies

Models indicate that over hundreds of thousands to millions of years, Mars undergoes large changes in axis tilt. What do we expect to happen when Mars has a larger axis tilt? Seasons become less extreme, causing more of the atmosphere to freeze out. The changes that lead to the large axis tilt also cause a tremendous increase in volcanic activity. The larger tilt releases vast quantities of liquid water, filling a northern ocean and allowing rivers to flow. Seasons become more extreme, which can enhance the atmosphere and greenhouse effect.

Seasons become more extreme, which can enhance the atmosphere and greenhouse effect.

Which of the following statements about the Drake equation is true? Astronomical research will soon give us firm values for all the terms. Some of the terms depend on sociological factors and therefore cannot be determined through astronomy alone. We know all the terms in the equation within a few percent, except for the last term, f now. We currently know all the terms of the equation to an accuracy within a factor of two.

Some of the terms depend on sociological factors and therefore cannot be determined through astronomy alone.

What one change would make it possible for liquid water to exist stably on Mars today? Substantially raising the atmospheric pressure Substantially increasing the surface temperature Increasing the amount of water ice present on the martian surface Slightly increasing both the surface temperature and pressure

Substantially raising the atmospheric pressure

Based on what you have learned from your rankings in Parts A and B, why is it generally hotter in summer than in winter? Check all that apply. Earth rotates more rapidly in summer. We are closer to the Sun in the summer. The Sun is higher in the sky in summer. We have more hours of daylight in summer.

The Sun is higher in the sky in summer. We have more hours of daylight in summer.

Which of the following is not an expected consequence of global warming? An increase in the number and intensity of hurricanes. The entire Earth will warm up by the same amount. An increase in the severity of winter blizzards. Melting of polar ice and glaciers.

The entire Earth will warm up by the same amount.

Scientists think it is very unlikely that complex and large forms of life could evolve on planets that orbit stars that are much more massive than the Sun. Why? The habitable zone of a massive star covers too wide a range of distances from the star to allow for the evolution of complex life The habitable zone of a massive star is too far from the star to allow for the evolution of complex life The expected lifetime of a massive star is too short to allow for the evolution of complex life

The expected lifetime of a massive star is too short to allow for the evolution of complex life

In the Drake equation (Number of Civilizations = NHP × flife fciv × fnow), what do we mean by fnow The fraction of planets that have had a civilization (capable of sending signals) on which the civilization exists at the present time. The fraction of civilizations capable of radio communication that currently are beaming messages in our direction The fraction of all species ever to exist that we currently are aware of The fraction of planets with life on which a civilization has at some point arisen

The fraction of planets that have had a civilization (capable of sending signals) on which the civilization exists at the present time.

What is Ceres? One of Jupiter's large moons. The largest asteroid, which is also classified as a dwarf planet. An object orbiting beyond Neptune that is larger in mass than Pluto. A comet that was visited by the Rosetta spacecraft

The largest asteroid, which is also classified as a dwarf planet.

Why is it so difficult to take pictures (direct images) of extrasolar planets? No telescope is powerful enough to detect the faint light from a distant planet. The light of the planets is overwhelmed by the light from their star. Telescopes are too busy with other projects. Extrasolar planets give off light at different wavelengths than planets in our solar system.

The light of the planets is overwhelmed by the light from their star.

According to the leading hypothesis, what role did a magnetic field play in Mars's global climate change? The magnetic field shielded the atmosphere from the solar wind while it existed, and the atmosphere was lost after the magnetic field weakened. The magnetic field kept the surface warmer while it existed, so the planet cooled after the magnetic field weakened. The magnetic field helped promote ocean circulation, and once this circulation stopped the oceans evaporated. The magnetic field trapped gas from volcanoes while it existed, and this gas escaped to space once the magnetic field weakened.

The magnetic field shielded the atmosphere from the solar wind while it existed, and the atmosphere was lost after the magnetic field weakened.

What is an animal's encephalization quotient (EQ)? The ratio of its brain mass to body mass The time since the animal split off from its last common ancestor The result of an IQ test given to the animal The ratio of the cortex size to the size of the rest of the brain

The ratio of its brain mass to body mass

One tidal bulge faces toward the Moon because that is where the gravitational attraction between Earth and the Moon is strongest. Which of the following best explains why there is also a second tidal bulge? The second tidal bulge is created by the Sun's gravity. The second tidal bulge arises because gravity weakens with distance, essentially stretching Earth along the Earth-Moon line. The second tidal bulge is a rebound effect, created when water on the side facing the Moon falls back down and thereby pushes up the water on the opposite side of Earth. The second tidal bulge is created by the centrifugal force caused by Earth's rapid rotation.

The second tidal bulge arises because gravity weakens with distance, essentially stretching Earth along the Earth-Moon line.

Why does the Doppler method generally give a planet's "minimum mass" rather than an exact mass? The size of the Doppler shift that we detect depends on knowing the star's mass, which can be uncertain. Doppler measurements are difficult, producing noisy data that often cause astronomers to underestimate a planet's mass. Extrasolar planets are always increasing in mass. The size of the Doppler shift that we detect depends on the tilt of a planet's orbit.

The size of the Doppler shift that we detect depends on the tilt of a planet's orbit. (We get a precise mass from the Doppler method only if the planet's orbit is edge-on to us; we'll know if it is edge on because in that case we will see transits by the planet.)

Which of the following is not relative in the special theory of relativity? Motion Distances Time The speed of light

The speed of light

The martian meteorite ALH84001 has structures that look like fossilized bacteria. Why do most scientists doubt that they are actually fossil life? The meteorite has been contaminated by terrestrial bacteria. The structures are too small. The structures do not contain organic matter. We see nearly identical structures in volcanic rock on Earth.

The structures are too small.

Venus probably once had as much water (or water vapor) as Earth. What do we think happened to all this water? It exists as water vapor in Venus's clouds. It became locked into rocks as hydrated minerals. It is hidden in subsurface reservoirs. The water molecules were destroyed, and the hydrogen atoms escaped to space

The water molecules were destroyed, and the hydrogen atoms escaped to space

What do the astrometric, Doppler, and transit methods share in common? They all require very high-resolution imaging. They all search for planets by measuring properties of a star rather than of the planets themselves. They all require high-resolution spectroscopy. They all allow us to measure a planet's size (radius). All of the above.

They all search for planets by measuring properties of a star rather than of the planets themselves.

What is the common property that distinguishes stars on the main sequence of the H-R diagram from other stars on the diagram? They all have a mass approximately the same as that of our Sun. They are all quite young. They are all made mostly of hydrogen. They are fusing hydrogen in their central cores.

They are fusing hydrogen in their central cores.

Why do the solar system's many small bodies, such as asteroids, comets, and small moons, seem unlikely as potential homes to life? Gravity is too weak on these small worlds. They are too far from the Sun. They are too cold inside to have liquid water. They lack atmospheres.

They are too cold inside to have liquid water.

Based on what we know about the terrestrial worlds, why is it surprising to find geological activity on jovian moons? They are too far from the Sun. They are too small. They rotate too slowly. They are moons rather than planets.

They are too small.

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 estimate it by averaging guesses made by many individual scientists. Ancient fossils allow them to infer Earth's temperature at a time before our atmosphere contained greenhouse gases. They assume that this temperature would be about the same as the temperature of Mars, which has much less of an atmosphere than Earth. They calculate this temperature from Earth's reflectivity and distance from the Sun.

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

The list of moons in our solar system on which life seems at least potentially possible includes Europa, Ganymede, Callisto, Titan, Enceladus, and ________. Phobos Triton Iapetus our Moon

Triton

This moon of Neptune orbits "backward" compared to Neptune's rotation.

Triton

What is the relevance of tidal heating to the possibility of life on jovian moons? Tidal heating can melt surface ices into liquid lakes and seas. Tidal heating can lead to subsurface zones of liquid water. Tidal heating is thought to be necessary for life on any world. Tidal heating causes surface oceans to slosh back and forth with the tides.

Tidal heating can lead to subsurface zones of liquid water.

The only moon in the solar system with a thick atmosphere, it also has lakes of liquid methane and ethane.

Titan

The following images show the four terrestrial planets in our solar system (not to scale). Rank these planets from left to right based on the total amount of gas in their atmospheres, from most to least.

Venus, Earth, Mars, Mercury

Which of the following is not an advantage of water over methane, ethane, and ammonia as a potential liquid medium for life? Water is the only one that melts from solid to liquid form as the temperature increases. Water is the only one for which the solid form floats in the liquid form. Water is the one that is a liquid at the highest temperatures. Water is the only one with charge separation in its molecules.

Water is the only one that melts from solid to liquid form as the temperature increases.

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true? Global warming poses a grave threat to our future. Humans are causing global warming. We should expect an increase in the greenhouse gas concentration to lead to global warming. We do not yet understand the greenhouse effect well enough to make predictions about how it affects our planet.

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

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? We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. 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. Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts. Isotope ratios in atmospheric carbon dioxide show that much of the carbon dioxide in Earth's atmosphere today comes from the burning of fossil fuels.

We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. 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. Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts

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 greater distance from its star a smaller size a larger axis tilt a faster rotation rate

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 larger axis tilt a smaller size a larger size a greater distance from its star

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 a greater distance from its star a faster rotation rate a smaller size

a larger axis tilt

In general, which type of planet would you expect to cause the largest Doppler shift in the spectrum of its star? a massive planet that is far from its star a low-mass planet that is far from its star a low-mass planet that is close to its star a massive planet that is close to its star

a massive planet that is close to its star

A giant or supergiant star is ________. an unusually massive star a young star that is still forming a star that is near the end of its life a star that has exhausted all possible forms of fuel for fusion

a star that is near the end of its life

On the graphs shown, you can identify an ice age by looking for __________. a place on the temperature graph where the temperature curve falls steeply a peak on the temperature graph a trough (bottom of a dip) on the carbon dioxide graph a trough (bottom of a dip) on the temperature graph

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

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 form clouds that emit thermal radiation absorb visible light coming from the Sun reflect visible light coming from the Sun

absorb infrared light emitted by the surface

The following four graphs show the velocities, toward and away from Earth, of four identical stars (the same graphs shown in Part A). Assume that all four stars have extrasolar planets orbiting them at the same distance. Rank the graphs from left to right based on the amount of time that it takes the extrasolar planet orbiting each star to complete one orbit, from shortest to longest. If you think that two (or more) of the graphs should be ranked as equal, drag one on top of the other(s) to show this equality.

all same (see image)

Saturn's moon Mimas takes exactly twice as long to orbit Saturn as the moon Tethys. This is an example of what we call ________. tidal heating a synchronous orbit an orbital resonance retrograde orbits

an orbital resonance

When we say that liquid water is unstable on Mars today, we mean that ________. any liquid water on the surface would quickly freeze or evaporate it is impossible for liquid water to exist on the surface even for a very short time any liquid water on the surface would quickly undergo chemical reactions converting the water molecules to other molecules a cup of water would shake uncontrollably

any liquid water on the surface would quickly freeze or evaporate

The larger of the jovian moons ________. have a diameter about 10% that of Jupiter are larger than Earth are smaller than any of the planets are larger than Mercury but smaller than Mars

are larger than Mercury but smaller than Mars

The ------- was used to find a Jupiter-sized planet through careful measurements of the changing position of a star in the sky.

astrometric method

measures precise changes in a star's position in the sky,in fractions of arcseconds

astrometric method

Based on current data, about what fraction of stars have one or more planets? at least about 70% approximately 1% approximately 20% no more than 30%.

at least about 70%

The result of a calculation with the Drake equation is intended to be an estimate of the number of worlds in the galaxy on which ________. life has arisen at some time civilizations capable of radio communication currently exist civilizations of any type have existed at any time, past or present intelligent life has arisen at some time

civilizations capable of radio communication currently exist

The fact that marine predators such as dolphins and sharks have similar streamlined shapes despite different ancestry is an example of what we call ________. narrow bandwidth convergent evolution natural selection adaptive behavior

convergent evolution (In other words, organisms of different evolutionary backgrounds will still end up with similar characteristics that help them thrive in a particular ecological niche)

Compared to a high-luminosity main-sequence star, stars in the upper right of the H-R diagram are __________. hotter and larger in radius cooler and larger in radius cooler and smaller in radius hotter and smaller in radius

cooler and larger in radius

Drake Equation: essentially represents the probability that on a planet with life, some organisms will eventually evolve to the point where they can build radio telescopes.

f civ

Drake Equation: essentially represents the probability that life eventually arises on a habitable planet.

f life

Suppose that we discover life on Mars with an origin independent of life on Earth. Which term in the Drake equation would we then think likely to be higher than we would consider it if there were no life on Mars? f now f life NHP f civ

f life (Finding a second example of an origin of life here in our own solar system would certainly make it seem like the fraction of habitable planets with life must be fairly high.)

Drake Equation: is a factor that depends on how long civilizations that reach our level of technology are able to survive.

f now

The different time periods of the -----are defined by changes in fossils found from those time periods.

geological time scale

atmosphere: Mars

global dust storms extremely low density atmosphere

High-mass main-sequence stars have a more distant and wider ---------- than low-mass stars.

habitable zone

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 slow rotation rate. lacks axis tilt. closely orbits its star. has a large size for a terrestrial planet.

has a large size for a terrestrial planet.

Based on all current evidence, if Venus had been born at Earth's distance from the Sun, then Venus today would probably ________. have seas of liquid carbon dioxide still have suffered a runaway greenhouse effect because it has so much carbon dioxide have oceans and an atmosphere much like Earth be similar in temperature to Earth but would lack plate tectonics and a carbon dioxide cycle

have oceans and an atmosphere much like Earth

Compared to a low-luminosity main-sequence star, stars in the lower left of the H-R diagram are __________. hotter and larger in radius cooler and larger in radius cooler and smaller in radius hotter and smaller in radius

hotter and smaller in radius

Recall that stars are classified with types from the spectra sequence OBAFGKM. In general, an ordinary (hydrogen-fusing, or main-sequence) star of spectral type A is ________ than a star of spectral type K. cooler, less luminous, and less massive hotter, more luminous, and less massive hotter, more luminous, and more massive cooler, more luminous, and more massive

hotter, more luminous, and more massive (As shown in the table in your textbook, surface temperature, luminosity, and mass all tend to decrease for ordinary (hydrogen-fusing) stars along the spectral sequence from O to M.)

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? Select all the factors that contribute. orbiting far from the Sun ice-rich composition orbiting far from their planet having a core of metal and rock tidal heating

ice-rich composition tidal heating

Earth has been gradually warming over the past few decades. Based on a great deal of evidence, scientists conclude that this warming is caused by _____. human activities that are increasing the concentration of greenhouse gases in Earth's atmosphere the human release of chemicals called CFCs into the stratosphere a small increase in the amount of energy coming from the Sun the fact that our politicians spout a lot of hot air the increase in forest fires during recent years

human activities that are increasing the concentration of greenhouse gases in Earth's atmosphere

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? volcanism and erosion impact cratering and erosion impact cratering and volcanism tectonics and erosion volcanism and tectonics

impact cratering and erosion

As the mass of the central star increases, the distance to the habitable zone __________ and the size (width) of the habitable zone __________. increases / increases decreases / increases increases / decreases decreases / decrease

increases / increases (The habitable zone is both farther from the star and larger in size for a higher-mass star than for a lower-mass star.)

In a runaway greenhouse effect, more water begins to evaporate from the oceans, which in turn ________. causes more carbon dioxide to be outgassed from volcanoes, increasing the greenhouse effect increases the strength of the greenhouse effect, causing even more warming means less water available to cause rainfall, causing a planet to become more desert-like exposes deeper waters to the atmosphere, so that they can evaporate too

increases the strength of the greenhouse effect, causing even more warming

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

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

Compared to a main-sequence star with a short lifetime, a main-sequence star with a long lifetime is __________. more luminous, hotter, larger, and more massive more luminous, hotter, smaller, and less massive less luminous, cooler, larger, and more massive less luminous, cooler, smaller, and less massive

less luminous, cooler, smaller, and less massive

A carbon dioxide concentration of 400 parts per million (ppm) means that carbon dioxide represents ________ of Earth's atmosphere. about 0.4% less than 0.1% about 40% about 4%

less than 0.1%

In essence, the Kepler mission searched for extrasolar planets by ____________. monitoring stars for slight dimming that might occur as unseen planets pass in front of them obtaining high-resolution photographs of other star systems observing Doppler shifts in a star's spectrum caused by an unseen planet looking for slight back and forth shifts in a star's position in our sky

monitoring stars for slight dimming that might occur as unseen planets pass in front of them

n nuclear fusion of hydrogen into helium, about 0.7% of the starting mass is converted to energy. How much more efficient is matter-antimatter annihilation than fusion? about 5 times as efficient about 10 times as efficient about twice as efficient more than 100 times as efficient

more than 100 times as efficient

The amount of energy that would be needed to accelerate a large spaceship (large enough to contain a modest number of human passengers) to a speed close to the speed of light is ________. about 100 times as much energy as is needed to launch a space shuttle more than the amount of energy that the Sun emits in a year more than the total amount of energy currently used by everyone on Earth in a year about as much energy as the Large Hadron Collider in Switzerland uses to accelerate subatomic particles to very close to the speed of light

more than the total amount of energy currently used by everyone on Earth in a year

Incoming ultraviolet light from the Sun can cause a ----- in a living organism's DNA that can affect its ability to survive and reproduce.

mutation

The notion that living organisms with advantages that give them greater reproductive success (in some local environment) will survive while others perish is an example of what Darwin called -----.

natural selection

Life is probably not possible in Jupiter's atmosphere because ________. it is too cold at Jupiter's great distance from the Sun the winds blow horizontally at high speeds of strong, vertical winds there is no liquid water anywhere

of strong, vertical winds

Jupiter is about five times as far from the Sun as Earth. Therefore, the strength of sunlight at Jupiter is about ________ as strong as it is at Earth. one-fifth one-twenty-fifth twenty-five times five times

one-twenty-fifth

The astrometric method looks for planets with careful measurements of a star's _________. position in the sky Brightness velocity toward or away from us all of the above

position in the sky (The word astrometric means measurement of the stars.)

In the Drake equation, a value of f life that is close to one and a value of f civ that is close to zero would imply ________. most habitable planets never actually get life on them primitive life is very rare, but those planets that have life almost inevitably get a civilization primitive life is common but intelligent life is rare most civilizations destroy themselves within just a few hundred years of arising

primitive life is common but intelligent life is rare

Stars of spectral type A and F are considered ________. unlikely to have planets of any kind reasonably likely to have habitable planets but much less likely to have planets with complex plant- or animal-like life unlikely to have habitable planets reasonably likely to have Earth-like planets with complex plant- and animal-like life

reasonably likely to have habitable planets but much less likely to have planets with complex plant- or animal-like life (These stars live only 1 to 2 billion years, which is plenty long enough for habitable planets to form and life to take hold, but based on the example of Earth, they are much less likely to be long enough for complex plant and animal life to evolve.)

Sky surveys looking for radio signals generated by technology are part of the -------.

search for extraterrestrial intelligence

The figure shows a standard Hertzsprung-Russell (H-R) diagram. Label the horizontal and vertical axes using the two blanks nearest the center of each axis, and label the extremes on the two axes using the blanks on the ends of the axes.

see image

The following four graphs show the velocities, toward and away from Earth, of four identical stars. Assume that all four stars have extrasolar planets orbiting them at the same distance, and that the velocities are inferred by measuring Doppler shifts in the spectra of the stars. Rank the graphs from left to right based on the amount of orbital Doppler shift observed in each star's spectrum, from smallest to largest.

see image

Use the labels to identify what kinds of stars inhabit each region of the the H-R diagram.

see image

The position of a star along the main sequence tells you both its mass and its hydrogen-burning lifetime. Label the indicated blanks on the main sequence with the approximate lifetimes of stars at those positions.

see image (green line)

The diagonal lines on the H-R diagram represent lines along which all stars would have the same radius. Label the three white lines with the correct values for the radii of stars that fall on them.

see image (indigo line)

More massive stars live ________. longer lives only near the center of the galaxy shorter lives only near the outskirts of the galaxy

shorter lives

The current concentration of carbon dioxide in Earth's atmosphere is ________. rising, but still about average for the past few hundred thousand years higher than it has been during the past century, but lower than at many other times during past millennia significantly higher than it has been for at least several hundred thousand years higher than it has ever been in Earth's history

significantly higher than it has been for at least several hundred thousand years

The Viking experiments found ________. some evidence of past life on Mars, but no evidence of present-day life no evidence of life on Mars some results consistent with life but insufficient evidence to conclude that life exists conclusive evidence of life on Mars

some results consistent with life but insufficient evidence to conclude that life exists

If you flew a spaceship straight into Jupiter, aiming toward Jupiter's center, the spaceship would ________. plunge downward until it came to rest on Jupiter's solid core fly right through this gaseous planet soon be destroyed by the increasing temperature and pressure be spun at a rapid rate by Jupiter's storms

soon be destroyed by the increasing temperature and pressure

Based on current evidence, if Mars had been born at Earth's distance from the Sun, then Mars today would probably ________. have much more volcanic activity and outgassing have suffered a runaway greenhouse effect have oceans and an atmosphere much like Earth still have a dry surface

still have a dry surface

atmosphere: Venus

sulfuric acid clouds runaway greenhouse effect almost no surface winds

March (northern spring) equinox 149.0 million km June (northern summer) solstice 152.0 million km September (northern fall) equinox 150.2 million km December (northern winter) solstice 147.2 million km Refer to the data in the introduction. Rank the seasons for the Southern Hemisphere based on Earth's distance from the Sun when each season begins, from closest to farthest.

summer, fall, spring, winter

An extrasolar planet that is rocky and larger than Earth is often called a ------.

super-Earth

The reason that some scientists think that Venus might have had oceans early in its history is that _________. the Sun was probably dimmer at that time Venus probably was born farther from the Sun and migrated to its current orbit Venus's surface shows evidence of continents and ocean basins old regions of Venus's surface show impact craters that appear eroded by rainfall

the Sun was probably dimmer at that time

Io's main distinction is being ________. the most volcanically active world in the solar system one of several moons thought to have a subsurface ocean the nearest moon to Jupiter the largest moon in the solar system

the most volcanically active world in the solar system

Consider a star orbiting the center of mass of its star system. We can tell when the star is on the side of its orbit in which it is coming toward us, because during that time ________. the star's spectral lines are shifted to slightly shorter wavelengths than their average wavelengths for the entire orbit the star's spectral lines will be shifted to slightly longer wavelengths than their average wavelengths for the entire orbit the star is slightly dimmer than its average for the entire orbit the star is slightly brighter than its average for the entire orbit

the star's spectral lines are shifted to slightly shorter wavelengths than their average wavelengths for the entire orbit (This is an example of the Doppler shift; objects coming toward us have blue shifts (shorter wavelengths), whereas objects moving away from us have red shifts (longer wavelengths) )

One of the key premises for the ----- is that living organisms are able to produce far more offspring than their environment can support.

theory of evolution

Stars of spectral type O and B are unlikely to have planets with life because ________. they don't live long enough for planets to form they do not have enough rocky and metal material to make terrestrial planets their high luminosities would prevent the formation of terrestrial planets their intense ultraviolet radiation would sterilize planets

they don't live long enough for planets to form

Based on current evidence, the elements needed for life are found ________. only on planets the size of Earth or smaller throughout the universe only on planets around a small fraction of all stars among stars of the same mass as the Sun but not around other stars

throughout the universe

The geological activity of Io and Europa is caused primarily by ________. heat from radioactive decay rapid rotation tidal forces from Jupiter that heat the interiors synchronous rotation

tidal forces from Jupiter that heat the interiors

The geological activity of Io and Europa is caused primarily by ________. rapid rotation heat from radioactive decay synchronous rotation tidal forces from Jupiter that heat the interiors

tidal forces from Jupiter that heat the interiors

-planet-detection strategy of NASA's Kepler Mission -looks for very slight, periodic dimming of a star -this method was first to identify Earth-sized extrasolar planets -can potentially detect planets in only a few percent of all planetary systems -allows for the extrasolar planet's radius to be determined

transit method

In terms of the gases outgassed by volcanoes, Venus's atmosphere today seems to have ________. too little carbon dioxide too little water vapor too much carbon dioxide too much carbon dioxide and too little water vapor

too little water vapor

The------ is used to find extrasolar planets by carefully monitoring changes in a star's brightness with time.

transit method

atmosphere: Earth

ultraviolet-absorbing stratosphere atmosphere composed primarily of nitrogen

Likely to be habitable

underground on Mars subsurface ocean on Europa moon w/ atm. orbiting Jovian planet 1 AU from 1 Msun star

Assuming we receive a signal from a civilization on the other side of our galaxy, a two-way conversation with them is ________. unlikely because one civilization may be much more advanced than the other likely because once communication is established, it would be natural to want to converse unlikely because of the great distance involved unlikely because they won't speak our language

unlikely because of the great distance involved

Mars's seasonal winds are driven primarily by ________. vaporization of carbon dioxide ice at the summer pole the fact that Mars has a more elliptical orbit than Earth vaporization of water ice at the summer pole dust storms

vaporization of carbon dioxide ice at the summer pole

The average temperature over the past 1000 years has been about 15∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________. never been as high as it is today varied between about −10∘C and +4∘C stayed remarkable steady, never varying by more than about 2∘C varied between about 7∘C and 19∘C

varied between about 7∘C and 19∘C

Unlikely to be habitable

volcanoes on Io Surface on Mars surface of terrestrial planet 10 AU from 0.5 Msun Star

Media reports sometimes mention the discovery of "water on the Moon." What has really been found is ________. evidence of a subsurface liquid water ocean water ice in polar craters subsurface water near the Moon's volcanoes small amounts of liquid water mixed into the surface rock

water ice in polar craters

March (northern spring) equinox 149.0 million km June (northern summer) solstice 152.0 million km September (northern fall) equinox 150.2 million km December (northern winter) solstice 147.2 million km Rank the seasons for the Northern Hemisphere based on Earth's distance from the Sun when each season begins, from closest to farthest.

winter, spring, fall, summer

How do the possibilities for life on Ganymede and Callisto compare to those on Europa? Life seems less likely because these moons have less energy available for life. Life is possible for Ganymede but not for Callisto, because Callisto does not participate in the orbital resonance of Io, Europa, and Ganymede. Life seems just as likely as on Europa, because both may have subsurface oceans. Life seems less likely because neither of these moons shows evidence of a subsurface ocean.

Life seems less likely because these moons have less energy available for life.

Is Europa in the Sun's habitable zone? It is if it really has a subsurface ocean, but otherwise is not. Yes No

No

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? Abundant surface water is found in large, brownish pools inside craters. There are numerous small streams flowing with water. Surface water only exists as frozen ice. No surface water currently exists in any form.

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 several large volcanoes. Tharsis has higher elevation than surrounding regions. Tharsis was probably the site of an ancient ocean. Tharsis is the most heavily cratered region of Mars. Tharsis is located close to Mars's north pole. One end of Valles Marineris is connected to Tharsis.

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

What is the significance of the discovery of hydrated minerals such as clay and opal on Mars? These minerals require active volcanism and therefore tell us that Mars has had abundant geological activity. They suggest that Mars once had surface liquid water. They suggest that Mars still has liquid water on its surface. They indicate that Mars once had a planet-wide ocean.

They suggest that Mars once had surface liquid water.

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? Mercury is much hotter than the Moon. Venus has a higher average temperature than Mercury. Earth has a higher average temperature than Mars. Earth is the only planet with an ozone layer in its atmosphere.

Venus has a higher average temperature than Mercury.

Venus's atmosphere has much more carbon dioxide than Earth's because ________. Venus was born in a region of the solar system that had more carbon dioxide Venus lacks oceans Venus was born in a region of the solar system where carbon dioxide could condense volcanoes on Venus must have outgassed much more carbon dioxide than those on Earth

Venus lacks oceans

Which of the following explains why Venus is so much hotter than Earth? Venus has much higher atmospheric pressure than Earth. Venus has much more volcanic activity than Earth. Venus's atmosphere contains far more carbon dioxide than Earth's. Venus is closer to the Sun and therefore receives far more intense sunlight.

Venus's atmosphere contains far more carbon dioxide than Earth's.

Key evidence that Venus once had much more water than it does today comes from ________. Venus's relatively high ratio of deuterium to ordinary hydrogen atoms measurements of the amount of sulfuric acid in Venus's clouds studies of the composition of outgassing by volcanoes on Venus surface features that appear to be former ocean basins

Venus's relatively high ratio of deuterium to ordinary hydrogen atoms

The following images show the four terrestrial planets in our solar system (not to scale). Rank these planets from left to right based on the atmospheric pressure at the surface, from highest to lowest.

Venus, Earth, Mars, Mercury

Which statement explains the observations that make it seem possible that Mars could have life underground? We have detected water ice on Mars, and Mars still has some volcanic heat. Mars is located within the Sun's habitable zone. We have detected subsurface wells of liquid water in equatorial regions of Mars. We have found surface liquid water on Mars, so it should also have water underground.

We have detected water ice on Mars, and Mars still has some volcanic heat.

If all the ice now known on Mars were to melt, it would represent enough water to fill ________. a few small lakes in craters but no more a planet-wide ocean about 1 meter deep a planet-wide ocean about 1.5 kilometers deep a planet-wide ocean about 10 meters deep

a planet-wide ocean about 10 meters deep

Suppose a planet is discovered by the Doppler method and is then discovered to have transits. In that case, we can determine all the following about the planet except ______________. its physical size (radius) its orbital period its precise mass its rotation period its density

its rotation period (We do not get any direct information about rotation period. (However, if the planet is close to its star, we can sometimes conclude that it has synchronous rotation, in which case the rotation period and orbital period are the same.) )

The largest moon in the solar system, this moon has some regions that are heavily cratered other regions that have very few craters.

Ganymede

If Europa really has an ocean, life that gets energy through photosynthesis is unlikely in this ocean because ________. the icy crust is too thick sunlight at Europa's distance from the Sun is too weak there is no soil on which plants could grow life could exist only at the bottom of the ocean, where it is dark

the icy crust is too thick

Olympus Mons is ________ on Mars. a continent-sized plateau the largest volcano a huge canyon network the largest impact crater

the largest volcano (in the solar system)

If we are searching for life that is at least somewhat Earth-like, the most important criterion in identifying a potentially habitable world is ________. the size of the world the distance of the world from its star the presence of an atmosphere the presence of surface or subsurface liquid water

the presence of surface or subsurface liquid water

In Part A, you found that Earth emits only infrared light. This infrared light can be absorbed by greenhouse gases, such as carbon dioxide and water vapor, in the atmosphere. In fact, all the terrestrial planets emit infrared light from their surfaces. The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of infrared-absorbing greenhouse gases in their atmospheres, from greatest to least.

(greatest Greenhouse gas) Venus, Earth, Mars, Mercury

The following images represent four types (wavelength bands) of light. Rank these from left to right based on the amount of each that is emitted (as thermal radiation) by Earth's surface, from greatest to least. If you think that two (or more) types should be ranked as equal, drag one on top of the other(s) to show this equality.

(greatest amount) infrared (least amount) x-ray, visible light, ultraviolet light

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the amount by which the greenhouse effect increases their surface temperatures, compared to what their temperatures would be without the greenhouse effect, from largest to smallest increase.

(largest increase) Venus, Earth, Mars, Mercury (smallest increase)

Each of the following figures shows a person (not to scale) located on Earth at either 40°N or 40°S latitude. Rank the figures based on how much time the person spends in daylight during each 24-hour period, from most to least. To rank items as equivalent, overlap them.

(most daylight) the 3 Earth's with people with two arrows (least daylight) the 3 Earth's with people with one arrow

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the strength of the greenhouse effect occurring at their surfaces, from strongest to weakest.

(strongest) Venus, Earth, Mars. Mercury (weakest)

Moons of Jupiter: characteristics 1. Io 2. Europa 3. Ganymede 4. Callisto

1. source of ionized gas in the donut-shaped charged particle belt around Jupiter, volcanoes currently erupting, hot, glowing lava, visible in some photos 2. ice covered surface with few impact craters, double-ridged surface features strongly suggest a subsurface ocean below 3. largest moon in the solar system, heavily cratered terrain adjacent to fairly smooth terrain 4. entire surface appears heavily cratered and ancient, most distant from Jupiter of these four moons

Suppose that a spaceship is launched in the year 2120 on a round-trip journey to a star that is 100 light-years away, and it makes the entire trip at a speed of 99.99% of the speed of light. Approximately what year would it be on Earth when the ship returns to Earth? 2520 2170 2320 2121

2320 (Because the ship is traveling at nearly the speed of light, the 100 light-year journey each way will take about 200 years.)

Evidence indicates that Mars's era of being significantly warmer and wetter ended at least about ________. 500 million years ago 3 billion years ago 4.3 billion years ago 1 million years ago

3 billion years ago

Combined, all stars more massive than the Sun (meaning spectral types O, B, A, and F) represent about ________ of all stars. 20% 3% 97% 50%

3% (Therefore, even though the short lifetimes of these stars make them less likely candidates for life (and especially for complex life), they hardly affect the overall prospects of finding life among the stars.)

Suppose that a spaceship is launched in the year 2120 on a round-trip journey to a star that is 50 light-years away, and it makes the entire trip at a speed of 99.99% of the speed of light. If one of the crew members is 30 years old when the trip begins, about how old would she be (biologically) when she returns? 80 31 130 29

31 (At 99.99% of the speed of light, time dilation means that time will pass slowly for the spaceship compared to time back on Earth, so only about a year will pass on the spaceship. (See Table 13.1 in your textbook.) )

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. 400 430 460 510

460

To make sure you understand how to use the equation, suppose that there are 1000 habitable planets in our galaxy, that 1 in 10 habitable planets has life, that 1 in 4 planets with life has at some point had an intelligent civilization, and that 1 in 5 civilizations that have ever existed is in existence now. How many civilizations would exist at present? 1 5 10 50 100 500

5

Which statement about the possibility of life on Mars accurately reflects the situation from the first decade of the 20th century? A few scientists claimed to see evidence of a great Martian civilization. Some scientists suspected there was microscopic life on Mars, but none thought there might be a Martian civilization. Nearly all scientists were convinced that there was a Martian civilization. No scientist thought there was any chance of finding life on Mars.

A few scientists claimed to see evidence of a great Martian civilization.

What do we mean by a "hot Jupiter"? A planet similar to Jupiter that orbits an unusually massive star A planet so large that it actually puts out heat from fusion in its core A brown dwarf A massive planet that orbits very close to its star

A massive planet that orbits very close to its star

What do we mean by a "super Earth"? A planet with an Earth-like orbit that has more abundant life than Earth. A planet made of metal and rock that is larger in mass than Earth. A planet that is more massive than Earth and also has surface oceans. A planet similar in size to Earth but orbiting close to its star.

A planet made of metal and rock that is larger in mass than Earth.

In the context of astrobiology, what is an "orphan planet"? A planet that has microbial life but no larger organisms. A planet with no moons, such as Mercury or Venus. A planet orbiting a star that is not a member of a galaxy. A planet-size object that does not orbit a star.

A planet-size object that does not orbit a star. (It may either have been ejected from its star system or, perhaps, formed independently from the collapse of a gas cloud in interstellar space.)

Each diagram below shows a pair of spectra with a set of spectral lines. The top spectrum always shows the lines as they appear in a spectrum created in a laboratory on Earth ("Lab") and the bottom spectrum shows the same set of lines from a distant star. The left (blue/violet) end of each spectrum corresponds to shorter wavelengths and the right (red) end to longer wavelengths. Rank the five stars based on the Doppler shifts of their spectra, from largest blueshift, through no shift, to largest redshift.

As your answer correctly indicates, lines that are shifted to the left (toward the blue/violet) compared to the laboratory spectrum represent blue shifts, and lines shifted to the right (toward the red) represent redshifts.

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? Conclude that the resemblance to a human face is so clear that it cannot have been made by nature and that this geological feature must have been built by an advanced civilization. Assume that the image is probably evidence of an advanced civilization, and develop plans to attempt radio communication with the civilization. Assume that NASA's spacecraft must have been hacked by someone perpetrating a hoax, and therefore ignore the image. Assume it is most likely a coincidental result of light and shadow, and plan higher resolution follow-up observations.

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

Which of the following would tend to make the term fnow small (close to 0)? Civilizations that reach our level of technology tend to destroy themselves. Civilizations that reach our level of technology tend to continue to advance and to colonize other star systems. Most of the civilizations that have ever existed first arose billions of years ago. Most of the civilizations that have ever existed don't arise until after their planets have been around at least 4 billion years.

Civilizations that reach our level of technology tend to destroy themselves.

Suppose you are using the Doppler method to look for planets around another star. What must you do? Carefully examine a single spectrum of an orbiting planet. Compare the brightness of the star over a period of many months or years. Compare many spectra of the star taken over a period of many months or years. Compare many spectra of an orbiting planet taken over a period of many months or years.Carefully examine a single spectrum of the star.

Compare many spectra of the star taken over a period of many months or years. (We look for Doppler shifts in the star's spectrum that, over time, shift back and forth to indicate the influence of an orbiting planet.)

Which of the following will allow you to learn something about a transiting planet's atmospheric composition? Compare spectra obtained before and during an eclipse. Use the Doppler method to study the planet throughout a cycle from one transit to the next. Calculate the planet's size, and then use size to infer what its atmospheric composition must be. Look for slight variations in the time between transits.

Compare spectra obtained before and during an eclipse.

Orbits Saturn and has been observed to be spraying fountains of ice crystals into space.

Enceladus

All of the following are important pieces of evidence for a subsurface ocean on Europa except ________. Europa's average density calculations of Europa's internal tidal heating surface features that look like jumbled icebergs variations in Europa's magnetic field

Europa's average density

Which of the following would lead an animal to a higher encephalization quotient (EQ) as it evolved? Growth in brain mass but not in body mass Growth in technological capabilities Growth in body mass but not in brain mass Growth in both brain mass and body mass

Growth in brain mass but not in body mass

As you watch the video, notice that the size of the tidal bulges varies with the Moon's phase, which depends on its orbital position relative to the Sun. Which of the following statement(s) accurately describe(s) this variation? Low tides are highest at full moon and lowest at new moon. Low tides are highest at both full moon and new moon. High tides are highest at both full moon and new moon. High tides are highest at first- and third-quarter moon. High tides are highest at full moon and lowest at new moon. Low tides are lowest at both full moon and new moon.

High tides are highest at both full moon and new moon. Low tides are lowest at both full moon and new moon.

Life arose relatively early in Earth's history, but intelligence evolved only recently. If we assume Earth is "typical," what would we conclude? SETI efforts should focus on globular clusters, which contain the oldest stars in the galaxy. Intelligence is likely only around stars at least about as old as the Sun. On an Earth-like planet, intelligence will inevitably evolve from more primitive life. Intelligence inevitably evolves once you have life.

Intelligence is likely only around stars at least about as old as the Sun.

The most volcanically active world in the solar system.

Io

Tidal heating is stronger for Io than for Europa because ________. Io is larger than Europa Io is closer to Jupiter Io had more volcanoes than Europa Io is rocky whereas Europa contains more ice

Io is closer to Jupiter

What do we mean when we say that a moon is in synchronous rotation? It orbits in its planet's equatorial plane. It has no axis tilt. It always keeps the same face toward its planet. It rotates in the same amount of time as its planet.

It always keeps the same face toward its planet.

From the viewpoint of an alien astronomer, how does Jupiter affect observations of our Sun? It causes the Sun to move in a small ellipse with an orbital period of about 12 years. It causes the Sun to move in a small ellipse in the sky, with the same ellipse repeated every night. It makes the Sun periodically get somewhat brighter. It makes the Sun appear dimmer when viewed with infrared light.

It causes the Sun to move in a small ellipse with an orbital period of about 12 years. (Jupiter exerts a gravitational tug on the Sun, causing the Sun to move around their mutual center of mass with the same orbital period as Jupiter.)

Which statement about synchronous rotation is true? It can develop only on moons born with very slow rotation. It is rare because it requires a highly unlikely process. It can develop only on moons made of solid rock. It is a natural consequence of tidal forces acting on a moon.

It is a natural consequence of tidal forces acting on a moon.

Which of the following best describes current understanding of Pluto? It is a rocky, cratered world in the asteroid belt. It is an ice-rich world with strong evidence of active geology on its surface. It is almost as large as Earth and has a thick atmosphere. It is made of comet-like material and is covered with impact craters.

It is an ice-rich world with strong evidence of active geology on its surface.

What is the significance of the apparent detection of methane in Mars's atmosphere? It demonstrates volcanic activity. It demonstrates biological activity. It suggests either some type of volcanic activity or life. It tells us that Mars once had liquid water.

It suggests either some type of volcanic activity or life.

Which of the following is a reasonable hypothesis for how Valles Marineris formed on Mars? It was created by tectonic cracking. It is a lava flow from an ancient martian volcano. It was created by multiple impacts. It was carved by an ancient river.

It was created by tectonic cracking.

According to the leading hypothesis, what happened to most of Mars's ancient atmospheric gas? It was stripped away by the solar wind. It is now frozen in the polar caps. Mars's small size and weak gravity allowed gas to escape. It became bonded into surface rock.

It was stripped away by the solar wind.

Why do the moons of Saturn have large amounts of methane and ammonia ice, but the moons of Jupiter do not? Saturn is closer to the Oort Cloud comets, which bring in these ices. Jupiter's strong magnetic field prevented these ices from condensing. It was too warm for these ices to condense at Jupiter's distance in the solar nebula. Methane and ammonia are lightweight and therefore escaped to greater distances from the Sun than heavier gases.

It was too warm for these ices to condense at Jupiter's distance in the solar nebula.

What will happen to the Sun's habitable zone in the future? It will move inward. It will become much narrower. It will move outward. It will become much wider.

It will move outward.

Which of the following fundamental properties of Mars could explain why it once had a global magnetic field but then lost it? Its distance from the Sun Its small moons Its size Its rotation rate

Its size

Which of the following planets has essentially no seasons at all? Jupiter (axis tilt = 3.1°) Uranus (axis tilt = 97.9°) Mars (axis tilt = 25.2°) Neptune (axis tilt = 29.6°)

Jupiter (axis tilt = 3.1°)

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? Select exactly two of the following choices. Lowell's canals followed perfectly straight lines for thousands of kilometers. Mars has an axis tilt very similar to Earth's axis tilt. Lowell's canals did not appear in photographs of Mars taken through telescopes. Like Earth, Mars has polar ice caps.Mars rotates with a period only a little longer than Earth's rotation period.

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

Based on what you have learned from your rankings in Parts A and B, which of the following planets would you expect to have seasons most like Earth's? Jupiter (axis tilt = 3.1°) Mars (axis tilt = 25.2°) Uranus (axis tilt = 97.9°)

Mars (axis tilt = 25.2°) with Earth's being 23.5

Assuming that Mars really was warmer and wetter in the past, it is probably because ________ at the time. Mars was larger and more massive Mars was closer to the Sun the Sun was significantly brighter Mars had a much thicker atmosphere with a much stronger greenhouse effect

Mars had a much thicker atmosphere with a much stronger greenhouse effect

Why does Mars's axis swing much more wildly over time than Earth's? There is no known reason. Mars is farther from the Sun. Mars is closer to Jupiter than Earth is. Mars lacks a large moon.

Mars lacks a large moon.

What must be true if Mars was warmer and wetter in the past? The martian atmosphere must once have contained a significantly higher percentage of carbon dioxide than it does today. Mars once had a much thicker atmosphere than it does today. Mars must once have had a greater axis tilt than it does today. Mars was once closer to the Sun than it is today.

Mars once had a much thicker atmosphere than it does today.

Which statement most accurately captures what current evidence tell us about the habitability of Mars? Mars was almost certainly habitable at some times in the past and may have subsurface habitable regions today. Mars has never been habitable. Mars is a habitable world today. Mars was almost certainly habitable at some times in the past but cannot have any habitable regions today.

Mars was almost certainly habitable at some times in the past and may have subsurface habitable regions today.

Based on current science which of the following is the most reasonable range for possible values of the number of habitable planets, NHP, in our galaxy? Less than 10 Between about 10 and 100 Between about 1000 and 1 million Between about 1000 and 1 million Between 1 million and 1 billion More than 1 billion

More than 1 billion

Drake Equation: represents the number of planets in the galaxy that are in principle capable of having surface liquid water and life.

NHP

Drake equation: represents the number of life-bearing planets in the galaxy.

NHP×f life

Drake Equation: represents the number of civilizations in our galaxy that we could in principle communicate with today.

NHP×f life×f civ×f now

We have observed lakes of liquid methane or ethane on Titan, but we have not observed any lakes of liquid water. Is it possible that liquid water lakes also exist? Why or why not? No, because it is too cold. No, because like Mars, the atmospheric pressure is too low for water to be stable. Yes, but they exist only during Titan's summer season. Yes, but they are too small for our cameras to have detected so far.

No, because it is too cold.

Suppose that a civilization around a nearby star had television like we do. Could current SETI efforts detect their television transmissions? Why or why not? Yes, as long as the star is no more than about 100 light-years away. No, the frequencies used for television cannot travel far through space. Yes, as long as we look at the right frequencies. No, the signals are too weak.

No, the signals are too weak. (At the distance of even the nearest stars, the signal strength would be far below what our current radio telescopes can detect)

An important line of hydrogen occurs at a rest wavelength (as measured in a laboratory) of 656 nm (a nanometer (nm) is a billionth of a meter). Each diagram below has this line labeled with its wavelength in the spectrum of a distant star. Rank the motion of the stars along our line of sight (radial motion) based on their speed and direction, from moving fastest toward Earth, through zero (not moving toward or away from Earth), to moving fastest away from Earth.

Notice that your correct answer ranks the stars in wavelength order. The first two stars are moving toward us, because their lines have wavelength shorter than the rest wavelength of 656 nm. The last two stars are moving away from us, because their lines have wavelength longer than the rest wavelength of 656 nm.

Overall, what do current data suggest about planetary types in other planetary systems? Jovian planets are common, whereas terrestrial planets are rare. All planets fall into the same terrestrial and jovian categories as the planets in our solar system. Planets come in a wider range of types than the planets in our solar system. Planets that fall into either the terrestrial or jovian categories are extremely rare outside of our own solar system.

Planets come in a wider range of types than the planets in our solar system.

Scientifically speaking, which of the following ideas relevant to global warming is subject to the greatest uncertainty? Predictions of future consequences of global warming The idea that Earth has been warming over the past century The idea that more atmospheric carbon dioxide should cause Earth to get warmer The idea that human activity is increasing the atmospheric carbon dioxide concentration

Predictions of future consequences of global warming

In regard to Percival Lowell's claims of a vast canal system on Mars, Alfred Russel Wallace wrote "[a network of canals,] as Mr. Lowell describes, would be the work of a body of madmen rather than of intelligent beings." Why? Though he saw lots of canals, Lowell did not see any cities. Only a race of giants could have built such huge canals. The canals claimed by Lowell ran in straight lines for great distances. The canals all connected to the polar caps.

The canals claimed by Lowell ran in straight lines for great distances.

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. Earth's past temperature rises and falls naturally. Earth's past carbon dioxide concentration rises and falls naturally.

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

What is time dilation? The speeding up of time that you notice, such as everything in your spacecraft moving in fast motion, when you travel at a speed close to the speed of light The speeding up of time for an object moving past you at a speed close to the speed of light The slowing down of time for an object moving past you at a speed close to the speed of light The slowing of time that you notice, such as everything in your spacecraft moving in slow motion, when you travel at a speed close to the speed of light

The slowing down of time for an object moving past you at a speed close to the speed of light

The New Horizons mission flew past Pluto in 2015. Why would it have been much more expensive to make the mission a Pluto orbiter rather than a flyby? It would have had to go much slower. The fact that it would have been in orbit means more scientists would have needed to work longer on the mission. The spacecraft would have needed to carry far more fuel with it. It would have required more expensive scientific instruments.

The spacecraft would have needed to carry far more fuel with it.

You've now seen that Earth's varying distance cannot be the cause of our seasons. So what is the cause of the seasons? The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. The seasons are caused by variation in the amount of rainfall (or snowfall) in different places at different times of year. Earth's speed varies in its orbit around the Sun, giving us summer when Earth is moving fastest and winter when Earth is moving slowest. The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and vice versa in winter.

The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.

Based on what you have learned from your rankings in Parts A and B, which statement best describes how variation in the Earth-Sun distance affects the seasons? The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons. Summer occurs when Earth is closer to the Sun and winter occurs when Earth is farther from the Sun. No matter where you live or what the seasons, it is generally hotter when Earth is closer to the Sun and colder when Earth is farther from the Sun.

The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons.

Scientists acknowledge that even in careful studies, they have been unable to explain about 10% of UFO sightings. Given that fact, why don't scientists generally accept that UFOs are alien spacecraft? Only an actual recovery of alien bodies would prove that the sightings are alien spacecraft. Scientists claim that these 10% are sightings by people who are delusional. Scientists are generally close-minded and won't consider a hypothesis until it has been definitively established. There are many possible explanations for the unexplained sightings besides alien spacecraft.

There are many possible explanations for the unexplained sightings besides alien spacecraft.

Why would it be surprising to find large fish-like organisms with rapid metabolism on Europa? There has not been enough time for such complex organisms to evolve on Europa. There does not seem to be enough energy available to support this type of metabolism. The likelihood of life evolving past the microbe stage is too small for it to have happened in two places in our solar system. If such large organisms existed, we would already know about them.

There does not seem to be enough energy available to support this type of metabolism.

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? Higher global average temperatures cause higher carbon dioxide concentrations. Higher carbon dioxide concentrations cause higher global average temperatures. The carbon dioxide concentration is inversely related to the global average temperature. There is a correlation between the carbon dioxide concentration and the global average temperature.

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

Which of the following planets should have the most extreme seasons? Uranus (axis tilt = 97.9°) Mars (axis tilt = 25.2°) Jupiter (axis tilt = 3.1°) Neptune (axis tilt = 29.6°)

Uranus (axis tilt = 97.9°)

Which of the following questions best represents what we call "Fermi's paradox"? Why do chemical rockets require so much mass to travel at even moderately high speeds? How can antimatter be stored for matter-antimatter engines? Why haven't we yet found evidence of alien civilizations? Why can't we travel faster than the speed of light?

Why haven't we yet found evidence of alien civilizations?

In Part A you found that the terrestrial planet 10 AU from a 0.5MSun star is unlikely to be habitable. Could this planet be habitable if it were in a different orbit around its star? Yes, if it had an eccentric orbit that sometimes brought it within 0.01 AU of its star. Yes, if it were 1 AU from its star. No, because its star is too small to have a habitable planet. Yes, but it would have to be less than 0.5 AU from its star.

Yes, but it would have to be less than 0.5 AU from its star.

Is there any place where we might find liquid water on Uranus or Neptune? No, these planets are too cold to have liquid water either on their exteriors or inside them. Yes, just under their icy surfaces. Yes, in the clouds of their upper atmospheres. Yes, but only very deep in their interiors.

Yes, but only very deep in their interiors.

Does Venus have any place where we may find liquid water today? Yes, in high-altitude clouds Yes, near active volcanoes that can provide heat No Yes, underground where the temperatures are cool enough for liquid water

Yes, in high-altitude clouds

Most people are familiar with the rise and fall of ocean tides. Do tides also affect land? No, tides only affect the oceans. Yes, though land rises and falls by a much smaller amount than the oceans. No, tides can only affect liquids and gases, not solids. Yes, land rises and falls with tides equally as high (and low) as the oceans.

Yes, though land rises and falls by a much smaller amount than the oceans.

Based on Planet Z's size, orbital distance, and rotation rate, which of the following properties is it likely to have? an atmosphere produced by outgassing seasons erosion due to liquid water polar ice caps strong winds and violent storms a surface crowded with impact craters active volcanoes active tectonics

an atmosphere produced by outgassing active volcanoes active tectonics

Global warming refers to ________. an increase in Earth's average surface temperature any warming caused by human activity the idea that every place on Earth is getting warmer the warming that will occur on Earth as the Sun brightens in the future

an increase in Earth's average surface temperature

You have found that tides on Earth are determined primarily by the position of the Moon, with the Sun playing only a secondary role. Why does the Moon play a greater role in causing tides than the Sun? because the Moon orbits Earth faster than Earth orbits the Sun because the gravitational attraction between Earth and the Moon varies more across Earth than does the gravitational attraction between Earth and the Sun because the gravitational force between Earth and the Moon is stronger than the gravitational force between Earth and the Sun

because the gravitational attraction between Earth and the Moon varies more across Earth than does the gravitational attraction between Earth and the Sun

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 some of them have orbital resonances with other moons because they are far from the Sun because they are relatively small in size because they are moons, not planets because they rotate slowly

because they are relatively small in size

The inner boundary of the Sun's habitable zone today is ________. slightly inside the orbit of Venus slightly beyond the orbit of Earth at 98% of Earth's distance from the Sun between the orbit of Venus and the orbit of Earth

between the orbit of Venus and the orbit of Earth

Overall, the requirements for a planet to have a habitable surface seem to be ________. both an orbit within the habitable zone and a size large enough to retain substantial internal heat only a size large enough to retain substantial internal heat only an orbit within the habitable zone

both an orbit within the habitable zone and a size large enough to retain substantial internal heat

The rocket engines of our current spacecraft are powered by ________. solar energy nuclear energy matter-antimatter annihilation chemical energy

chemical energy

The Hertzsprung-Russell (H-R) diagram is a way of ________. classifying stars according to their surface temperatures and luminosities classifying stars according to their masses and ages classifying planets according to their orbital periods and the distances at which they orbit their stars. classifying planets according to their sizes and the distances at which they orbit their stars

classifying stars according to their surface temperatures and luminosities (The horizontal axis is surface temperature and the vertical axis is luminosity.)

Consider a star that is less massive than the Sun. For a planet to receive the same intensity of light from this star as Earth receives from the Sun, the planet would have to orbit ________. farther from the star than Earth is to the Sun closer to the star than Earth is to the Sun slower than Earth orbits the Sun faster than Earth orbits the Sun

closer to the star than Earth is to the Sun

The key reason why scientists suspect that humans are the creators of crop circles is that ________. .the appearance of crop circles has not been correlated with UFO sightings crop circles are always beautiful crop circles can easily be made by humans crop circles most commonly appear in England, which is a small country

crop circles can easily be made by humans

We are not yet capable of detecting life on planets around other stars. But as our technology develops, our first real chance of detecting such life will probably come from _________. examining high-resolution images of the planets made by orbiting telescopes examining spectral lines from the atmospheres of distant planets sending spacecraft to study the planets up close determining the orbital properties of the planets

examining spectral lines from the atmospheres of distant planets

Suppose that life is very common on habitable worlds, meaning that life tends to get started on almost any world that has conditions that allow for life (such as surface liquid water). Which would then be true about the terms in the Drake equation? f life is very close to 1. f life is very close to 0. f life is approximately 0.5. f civ is very close to 1. f civ is very close to 0. f civ is approximately 0.5.

f life is very close to 1.

Earth's frozen lakes and seas often have liquid water beneath their ice surfaces primarily because ________. a. ice floats and provides insulation to the water below b. temperature tends to decline with altitude, so it is cold enough for the water to freeze only at the higher altitudes c. Earth's internal heat keeps the deep water warmer d. sunlight can penetrate through ice and warm the water below

ice floats and provides insulation to the water below

Observations indicating that other planetary systems often have jovian planets orbiting close to their stars are best explained by what we call -----.

migration

According to current scientific understanding, the idea that the Milky Way might be home to a civilization millions of years more advanced than ours is ________. one possible solution to Fermi's paradox an idea with a 1 in 3 chance of being correct not possible an absolute certainty

one possible solution to Fermi's paradox

The transit method allows us in principle to find planets around __________. only stars located within about 100 light-years of Earth only stars of about the same mass and size as our Sun all stars that have planets of any kind only a small fraction of stars that have planets

only a small fraction of stars that have planets

In the movie Star Wars, the planet Tatooine is shown with two suns that rise and set together in its sky. According to present understanding, this is ________. not possible possible, if the planet orbits around the two stars of a close binary possible, if the planet orbits halfway between two stars with nearly equal masses. possible, if the planet orbits in a binary system in which one star is many times more massive than the Sun and the other is much less massive than the Sun

possible, if the planet orbits around the two stars of a close binary

If Earth were moved to Venus's orbit, it would probably ________. become about 30°C warmer, making our planet more tropical suffer a runaway greenhouse effect and become hotter than Venus warm up enough to evaporate the oceans, but it would not approach the temperature of Venus stay about the same temperature, thanks to the relatively small amount of carbon dioxide in our atmosphere

suffer a runaway greenhouse effect and become hotter than Venus

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? Select all that apply. river valleys feeding into surface lakes of liquid water surfaces with very few impact craters large, violent storms swirling in counterclockwise directions ice crystals being sprayed out into space 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 river valleys feeding into surface lakes of very cold liquids active volcanoes

Suppose you had the misfortune of finding yourself outside on Titan without a spacesuit. Which would probably kill you first? the lack of oxygen the cold temperature the toxic effects of the predominant gas in Titan's atmosphere the high atmospheric pressure

the cold temperature

The habitable zone refers to ________. the regions on a planet where life could potentially exist the range of distances from a star within which a planet could potentially have surface oceans of liquid water the range of distances from a star at which a planet or moon could potentially have surface or subsurface oceans of liquid water the regions around a star in which Earth-size planets exist

the range of distances from a star within which a planet could potentially have surface oceans of liquid water

The bandwidth of a radio transmission is a measure of ________. the dominant frequency in the transmission the amount of power carried by the transmission the signal-to-noise ratio in the transmission the range of frequencies that carry information in the transmission

the range of frequencies that carry information in the transmission

Any particular location on Earth experiences __________. two high tides and two low tides each day two sets of high and low tides in the ocean, but only one set on land two high tides and two low tides each month one high tide and one low tide each month one high tide and one low tide each day

two high tides and two low tides each day

Temperatures on Mercury are ________. very hot in the day and very cold at night very hot in the summer and very cold in the winter always much hotter than those on Venus always slightly hotter than those on Venus

very hot in the day and very cold at night

For a solar sail to be useful in accelerating a spacecraft, the sail would need to be ________. very lightweight (low mass) and very large in area very lightweight (low mass) and very compact in size heavy (high mass) and very compact in size heavy (high mass) and very large in are

very lightweight (low mass) and very large in area (The large area is necessary to collect a lot of sunlight, and the low mass is necessary so it doesn't take much energy to accelerate the sail itself.)

The energy that warms Earth's surface comes primarily in the form of __________. visible light from the Sun infrared light from the Sun heat from Earth's interior ultraviolet light from the Sun heat from the Sun

visible light from the Sun

Titan shares all of the following geological features with Earth except ________. rivers and lakes wind-blown erosion volcanoes erupting with molten rock boulders smoothed by liquid erosion

volcanoes erupting with molten rock

Compared to the planets of our solar system, the composition of a ------ most resembles the compositions of Uranus and Neptune.

water world