Astronomy exam review #2
The more massive planets in the solar system tend to be less dense than the lower mass planets. a) true b) false
true
According to current evidence, Pluto is best explained as ________. a) a large member of the Kuiper belt b) a terrestrial planet that is surprisingly far from the Sun c) a very small jovian planet d) an escaped moon of Jupiter or Saturn
a
According to modern scientific dating techniques, approximately how old is the solar system? a) 4.5 billion years b) 10,000 years c) 4.6 million years d) 14 billion years
a
According to the laws of thermal radiation, hotter objects emit photons with ________. a) a shorter average wavelength b) a lower average energy c) a lower average frequency d) a higher average speed
a
All four of the giant outer planets-Jupiter, Saturn, Uranus, and Neptune-have rings. a) true b) false
a
All planets orbit the Sun in the same direction (counterclockwise as viewed from above Earth's North Pole). a) true b) false
a
At present, what is the primary way that the search for extraterrestrial intelligence (SETI) is carried out? a) by using radio telescopes to search for signals from extraterrestrial civilizations b) by using X-ray telescopes to search for exhaust from interstellar spacecraft c) by analyzing high-resolution images of nearby stars in search of evidence for structures that could not have developed naturally d) by seeking access to the secret records and alien corpses kept at the military's Area 51 in Nevada e) by searching for planets around distant stars
a
Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny? a) its size b) its distance from the Sun c) its composition d) whether or not it has liquid water
a
Consider a star with 2 planets. The mass of planet A is the same as the mass of planet B. The orbit of Planet A is on average, closer to the star than the orbit of Planet B. Which of the following statements is true? a) Planet A is, on average, moving faster than Planet B. b) Planet A is, on average, moving slower than Planet B c) The relative orbital speeds depend on the masses of the planets. d) Planet A moves with the same speed as Planet B.
a
In general, how does the size and location of a star's habitable zone depend on the star's mass? a) The smaller (less massive) the star, the smaller and the closer-in the habitable zone. b) The smaller (less massive) the star, the larger and the closer-in the habitable zone. c) The smaller (less massive) the star, the larger and the farther-out the habitable zone. d) The habitable zone is always about the same size, but its location moves inward for smaller stars.
a
In the context of planetary geology, what do we mean by outgassing? a) the release by volcanism of gases that had been trapped in a planetary interior b) the evaporation of water that adds water vapor (a gas) to an atmosphere c) the loss of atmospheric gas to outer space d) another name for a volcanic eruption
a
In which list are the jovian planets in order of increasing distance from the Sun? a) Jupiter, Saturn, Uranus, Neptune b) Jupiter, Saturn, Neptune, Uranus c) Saturn, Jupiter, Uranus, Neptune
a
Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen? a) The Sun would rotate faster than it does now. b) The Sun's rate of rotation would slow. c) The Sun's angular size in our sky would stay the same. d) This could never happen, because it is impossible for an object to shrink in size without an outside torque.
a
Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass? a) You'll have 0.25 kilogram of the radioactive substance remaining. b) All the material will have completely decayed. c) You'll have 0.5 kilogram of the radioactive substance remaining. d) You'll have 0.75 kilogram of the radioactive substance remaining.
a
The Antarctic ice-core plot of carbon dioxide (ppm) shows peaks and valleys at about the same times as the temperature plot has peaks and valleys, over 400,000 years. What can we conclude based on this fact alone? a) There is a correlation between the carbon dioxide concentration and the average temperature. b) Higher global average temperatures cause higher global carbon dioxide concentrations. c) Higher carbon dioxide concentrations cause higher global average temperatures. d) The carbon dioxide concentration is inversely related to the global average temperature.
a
The asteroid belt is located ________. a) between the orbits of Mars and Jupiter b) beyond the orbit of Neptune c) between the orbits of Jupiter and Saturn d) between the orbits of Earth and Mars
a
The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system? a) The diameter of Earth's Moon is about 1/4 that of Earth. b) Jupiter has a very small axis tilt. c) Venus does not have a moon. d) Saturn has no solid surface.
a
The processes responsible for virtually all surface geology are ________. a) impact cratering, volcanisms, tectonics, and erosion b) accretion, differentiation, and radioactive decay c) convection, conduction, and radiation d) eruptions, lava flows, and outgassing
a
The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from? a) They were produced by stars that lived and died before our solar system was born. b) They were made by chemical reactions in interstellar gas. c) They were produced by gravity in the solar nebula as it collapsed. d) They have been present in the universe since its birth.
a
Thermal radiation is defined as ________. a) radiation with a spectrum whose shape depends only on the temperature of the emitting object b) radiation that is felt as heat radiation in the form of emission lines from an object c) radiation produced by an extremely hot object
a
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 ________. a) examining spectral lines from the atmospheres of distant planets b) determining the orbital properties of the planets c) sending spacecraft to study the planets up close d) examining high-resolution images of the planets made by orbiting telescopes
a
What do we mean by the frost line when we discuss the formation of planets in the solar nebula? a) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ice to condense. b) It is the altitude in a planet's atmosphere at which snow can form. c) It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds. d) It is another way of stating the temperature at which water freezes into ice.
a
What is the Great Red Spot? a) a long-lived, high-pressure storm on Jupiter b) a place where reddish particles from Io impact Jupiter's surface c) a hurricane that comes and goes on Jupiter d) a region on Jupiter where the temperature is so high that the gas glows with red visible light
a
What makes us think that Mars must once have had an atmosphere that was warmer and had higher surface pressure? a) The atmosphere is too cold and thin for liquid water today, yet we see evidence that water flowed on the surface in the past. b) We think it for purely theoretical reasons, based on calculations showing that the Sun has brightened with time. c) The presence of inactive volcanoes on Mars tells us that there must once have been a lot of outgassing, and hence a thicker atmosphere. d) The fact that parts of Mars have a lot of craters tell us that Mars must once have been much warmer.
a
What must be true in order for astronomers to be able to use the Doppler technique to determine a planet's mass? a) The planet's orbit must be viewed nearly edge on. b) The planet's orbit must be seen nearly face on. c) The planet must have a very low mass. d) The planet must have a very eccentric orbit.
a
When you see the bright flash of a meteor, what are you actually seeing? a) the glow from a pea-size particle and the surrounding air as the particle burns up in our atmosphere b) the flash that occurs when a speeding rock from space hits the ground c) emission of visible light from a particle that has not yet entered Earth's atmosphere d) a star that has suddenly shot across the sky
a
Which have more moons on average? a) jovian planets b) Terrestrial and jovian planets both have about the same number of moons. c) terrestrial planets
a
Which of the following best describes how the greenhouse effect works? a) A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere. b) The greenhouse effect is caused primarily by ozone, which absorbs ultraviolet light and thereby makes the atmosphere much hotter than it would be otherwise. c) Greenhouse gases absorb X-rays and ultraviolet light from the Sun, and this absorbed radiation then heats the atmosphere and the surface. d) Greenhouse gases absorb infrared light coming from the Sun, and this absorbed sunlight heats the lower atmosphere and the surface.
a
Which of the following changes did not occur during the collapse of the solar nebula? a) concentrating denser materials nearer the Sun b) heating up c) spinning faster
a
Which of the following gases is not a significant ingredient of the jovian planet atmospheres? a) carbon dioxide b) water c) helium d) hydrogen
a
Which of the following general statements about Earth's atmosphere is not true? a) The nitrogen and oxygen in Earth's atmosphere keep the surface pleasantly warm. b) Without the relatively rare gas called ozone, Earth's surface would be bathed in dangerous ultraviolet light from the Sun. c) The oxygen in our atmosphere was released by living organisms. d) Gas high in the atmosphere absorbs dangerous X-rays from the Sun.
a
Which of the following is considered by biologists to be a likely place where life might have first arisen on Earth? a) in hot water near undersea volcanoes b) deep in Earth's core c) on land surfaces that got moderately heavy rainfall d) on meteorites that landed on Earth
a
Which of the following kinds of object resides closest to the Sun on average? a) asteroids b) jovian planets c) comets
a
Which planet listed below has the most extreme seasons? a) Uranus b) Jupiter c) Mars d) Earth
a
Which statement is not thought to be true of all comets in our solar system? a) Comets always have tails. b) All comets orbit the Sun. c) All comets are icy in composition. d) All comets are leftover planetesimals that originally condensed beyond the frost line in the solar nebula.
a
Why are planets with long orbital periods among the last to be discovered? a) Astronomers have to watch a long time before they repeat their orbits. b) They are harder to see against the bright light of the host star. c) Very few of these planets exist. d) They will never block any of the light from their host star.
a
Why do scientists say that evolution is a "theory"? a) because it explains a great deal about life and is supported by an enormous body of evidence b) because it's really just a guess about how life developed on Earth c) because it is supported by only a small amount of evidence d) because they are not very confident that it really happened
a
Why does Earth have so little carbon dioxide in its atmosphere compared to Venus? a) Earth has just as much carbon dioxide as Venus, but most of it is locked up in carbonate rocks rather than being free in the atmosphere. b) Earth once had a lot of carbon dioxide, but it was lost to space during the heavy bombardment early in our solar system's history. c) Chemical reactions turned Earth's carbon dioxide into nitrogen. d) Earth's volcanoes outgassed far less carbon dioxide than those on Venus.
a
A terrestrial world's lithosphere is ________. a) a thin layer of rock that lies between the mantle and crust b) a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle c) the interior region in which the planet's magnetic field is generated d) a layer of hot, molten rock encompassing the core and part of the mantle
b
According to our theory of solar system formation, what are asteroids and comets? a) chunks of rock or ice that were expelled from planets by volcanoes b) leftover planetesimals that never accreted into planets c) the shattered remains of collisions between planets d) chunks of rock or ice that condensed after the planets and moons finished forming
b
According to our theory of solar system formation, why did Uranus and Neptune end up to be much less massive than Jupiter and Saturn? a) The colder gas in the outer regions of the solar nebula had less gravity and therefore could not gather up into such large balls as it could closer in. b) Particles in the solar nebula were more spread out at greater distances, so that accretion took longer and there was less time to pull in gas before the solar wind cleared the nebula. c) Ices were able to condense at the distance of Jupiter and Saturn, but only rock and metal could condense at the distances of Uranus and Neptune. d) The size differences are thought to be a random coincidence.
b
According to the nebular theory, where should jovian planets form? a) at the inner edge of the planet forming disk, where even metal and rock evaporate b) in the cold outer regions of the disk, where rocks, metals, and ices can condense c) within the inner few AU of the disk, where only rocks and metals can condense
b
All the planets in the solar system have at least one moon. a) true b) false
b
All the planets in the solar system rotate in the same direction as they orbit the Sun. a) true b) false
b
From center to surface, which of the following correctly lists the interior layers of a terrestrial world? a) core, crust, lithosphere b) core, mantle, crust c) mantle, crust, core d) mantle, core, crust
b
How can astronomers measure the composition of an extrasolar planet's atmosphere? a) by measuring the composition of the host star; the planet must have formed from the same initial material b) by comparing spectra for when the planet is in transit or eclipse with spectra taken at other times c) by measuring how brightly the planet glows in infrared light d) by measuring the Doppler shift of the host star
b
If we someday find life on Mars, we expect to find it a) in dried-up riverbeds. b) underground. c) near the polar ice caps.
b
In what way is Venus most similar to Earth? a) Both planets have similar surface geology. b) Both planets are nearly the same size. c) Both planets have warm days and cool nights. d) Both planets have very similar atmospheres.
b
Suppose Earth were to cool down a little. How would the carbon dioxide cycle tend to restore temperatures to normal? a) Cooler temperatures cause volcanoes to become more active, so they release more carbon dioxide into the atmosphere than they do when temperatures are warmer. b) Cooler temperatures mean less rain and so lead to slower formation of carbonate minerals in the ocean, so carbon dioxide released by volcanism builds up in the atmosphere and strengthens the greenhouse effect. c) Cooler temperatures mean more ice and more erosion, which somehow makes the planet warm up. d) Cooler temperatures allow carbon dioxide to form rain and rain out of the atmosphere.
b
Suppose that Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be ________. a) slightly cooler, but still above freezing b) well below the freezing point of water c) about the same as it is now d) slightly warmer, but still well below the boiling point of water
b
Suppose we represent Earth with a basketball. On this scale, most of the air in Earth's atmosphere would fit in a layer that is ________. a) about a half-inch thick b) about the thickness of a sheet of paper c) about an inch thick d) about 6 inches thick
b
A habitable world is a world that a) has life of some kind. b) is potentially capable of having an advanced civilization. c) is potentially capable of having life.
c
Suppose you could float in space just a few meters above Saturn's rings. What would you see as you looked down on the rings? a) a solid, shiny surface, looking much like a piece of a DVD but a lot bigger b) countless icy particles, ranging in size from dust grains to large boulders c) dozens of large "moonlets" made of metal and rock, each a few kilometers across d) Nothing-up close; the rings would be so completely invisible that you'd have no way to know they are there. They can be seen only from a distance.
b
The choices below describe four hypothetical planets. Which one's surface would you expect to be most crowded with impact craters? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.) a) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. b) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. c) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. d) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.
b
The outer layers of most jovian moons are made primarily of a) hydrogen and helium. b) ices. c) rock and metal.
b
What do we mean when we say that the terrestrial worlds underwent differentiation? a) They lost interior heat to outer space. b) When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces. c) The five terrestrial worlds all started similarly but ended up looking quite different. d) Their surfaces show a variety of different geological features resulting from different geological processes.
b
What is the leading hypothesis for the origin of the Moon? a) It split off from a rapidly rotating Earth. b) It formed from the material ejected by a giant impact on Earth. c) It formed at the same time as Earth.
b
When we analyze whether a world is a possible home to life, the key thing we look for is ________. a) the presence of organic molecules such as amino acids b) the past or present existence of liquid water c) evidence of atmospheric oxygen d) surface coloration changes that could indicate vegetative growth
b
Which ingredients made up about 98% of the solar nebula? a) hydrogen compounds b) hydrogen and helium c) rock and metal
b
Which moon has a thick atmosphere made mostly of nitrogen? a) Ganymede b) Titan c) Europa d) Triton
b
Which of the following best describes how the Drake equation is useful? a) It allows us to calculate the masses of planets orbiting other stars. b) It helps us understand what we need to know in order to determine the likelihood of finding other civilizations. c) It tells us what wavelengths of light will be most useful to examine in the search for extraterrestrial intelligence. d) It has allowed us to determine the number of civilizations in the Milky Way Galaxy.
b
Which of the following best explains why many jovian moons have been more geologically active than the Moon or Mercury? a) Because of their greater distances from the Sun, the jovian moons receive much less heat from the Sun. b) Jovian moons are made mostly of ice that can melt or deform at lower temperatures than can the rock and metal that make up the Moon and Mercury. c) The jovian moons are considerably larger than the Moon and Mercury and therefore have retained much more internal heat. d) The jovian moons probably have far more internal heat generated by radioactive decay than do the Moon or Mercury.
b
Which of the following is an example of convection? a) rocks sinking in water b) warm air expanding and rising while cooler air contracts and falls c) different kinds of material separating by density, like oil and water d) gas bubbling upward through a liquid
b
Why do astronomers believe that Triton is a captured moon? a) Triton appears to be made mostly of ice. b) Triton orbits Neptune in a direction opposite that of Neptune's rotation. c) Triton is too large to have been formed in the "miniature solar nebula" thought to have surrounded Neptune in its very early history. d) Triton is very small and potato-shaped, which is common of captured moons.
b
Are planets common around other stars? Choose the best answer. a) No, planets are very rare. b) Terrestrial and gas-rich planets are both common c) Planets are not particularly rare, but terrestrial planets are extremely rare.
c
Earth has been gradually warming over the past few decades. Based on a great deal of evidence, scientists believe that this warming is caused by ________. a) the fact that our politicians spout a lot of hot air b) the increase in forest fires during recent years c) human activities that are increasing the concentration of greenhouse gases in Earth's atmosphere d) the human release of chemicals called CFCs into the stratosphere
c
From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? a) gamma rays, X-rays, visible light, ultraviolet, infrared, radio b) infrared, visible light, ultraviolet, X-rays, gamma rays, radio c) gamma rays, X-rays, ultraviolet, visible light, infrared, radio d) radio, infrared, visible light, ultraviolet, X-rays, gamma rays
c
How did oxygen (O2) get into Earth's atmosphere? a) It was outgassed from volcanoes. b) It came from chemical reactions with surface rocks. c) It was released by life through the process of photosynthesis. d) It was captured from the solar nebula.
c
How many of the planets orbit the Sun in the same direction as Earth does? a) a few b) most c) all
c
In which list are the major steps of solar system formation in the correct order? a) gravitational collapse of the solar nebula, accretion, condensation b) accretion, condensation, gravitational collapse of the solar nebula c) gravitational collapse of the solar nebula, condensation, accretion
c
Planetary orbits are a) fairly circular but oriented in random directions. b) very eccentric (stretched-out) ellipses and in the same plane. c) fairly circular and in the same plane.
c
Suppose we had a device that allowed us to see Earth's interior. If we looked at a typical region of the mantle, what would we see happening? a) dense metals falling downward while low-density rock rises upward b) a rapid, up and down churning of the material in the mantle c) Not much-on human time scales, the mantle looks like solid rock. d) hot molten rock rising upward throughout the mantle and cool, solid rock falling downward
c
The impact of a 100 meter asteroid could kill many people if it struck a major city. Suppose the probability of such an impact in any single year is 1 in 1,000, and suppose we know (somehow) that it has been 1200 years since the last impact. What would that tell us? a) We are now due for such an impact, so the actual probability for the coming year must be much higher than 1 in 1000. b) The prediction must be wrong, since the time since the last impact has been 1200 years. c) Nothing, we would still presume that the chance of such an impact during the next year is 1 in 1000. d) We are overdue for such an impact, so we should expect to be hit by something even larger during the next few years.
c
The planet in our solar system with the highest average surface temperature is ________. a) Mercury b) Earth c) Venus d) Neptune
c
This figure shows the orbital periods and radii of all planet candidates identified from Kepler data as of early 2013. Which of the following size planets were most detected? a) planets less than 1 Earth radius in size b) planets between 4 Earth radii and 10 Earth radii in size c) planets between 1 Earth radius and 4 Earth radii in size d) planets greater than 10 Earth radii in size
c
Uranus and Neptune have methane clouds but Jupiter and Saturn do not. Which factor explains why? a) Jupiter and Saturn do not contain any methane gas. b) The stronger gravity on Jupiter and Saturn pulls methane downward so that it can't form clouds. c) Temperatures on Jupiter and Saturn are too high for methane to condense. d) The rapid rotation of Jupiter and Saturn prevents methane clouds from forming.
c
What atmospheric constituent is responsible for the blue color of Uranus and Neptune? a) ammonia b) water c) methane d) hydrogen
c
What is an "extrasolar planet"? a) a planet that is larger than the Sun b) a planet that is extra large compared to what we'd expect c) a planet that orbits a star that is not our own Sun d) a planet that is considered an "extra," in that it was not needed for the formation of its solar system
c
What is the giant impact hypothesis for the origin of the Moon? a) The Moon formed just like Earth, from accretion in the solar nebula. b) The Moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than Earth. c) The Moon formed from material blasted out of Earth's mantle and crust by the impact of a Mars-size object. d) The Moon formed when two gigantic asteroids collided with one another.
c
What is the importance of the carbon dioxide (CO2) cycle? a) It makes the growth of continents possible. b) It allows for an ultraviolet-absorbing stratosphere. c) It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate. d) It will prevent us from suffering any consequences from global warming.
c
What is the transit method of finding extrasolar planets? a) observing a star during the rare occasion of another star passing directly in front of it; slight changes in how the light is bent by gravity can indicate the presence of planets around the closer star b) measuring the spectrum of the star for a periodic variation in its Doppler shift c) monitoring a star to detect periodic dips in its brightness from the planet passing in front of and behind the star
c
What mechanism explains the presence of "hot Jupiters" around many other stars? a) evaporation of the disk by the stellar wind removes gas that was holding the planet at a large radius b) gravitational attraction by terrestrial planets that formed at small radii attract the giant planets inward c) planetary migration caused by gravitational interactions between the planet and disk d) rapid formation of the gas giant from evaporated rock and metal at the inner disk edge
c
What's the fundamental reason that Mars, unlike the Earth, has become virtually geologically dead? a) its large size compared to the Earth b) its closer distance than Earth to the Sun c) its small size compared to Earth d) its rapid rotation compared to the Earth e) its farther distance than Earth to the Sun
c
When we see a meteor shower, it means that ________. a) the solar wind is unusually strong b) an Earth-approaching asteroid has recently come very close to our planet c) Earth is crossing the orbit of a comet d) you should duck and run for cover to avoid being blasted on the head by a rock from space
c
Which of the following are examples of planets that will be very difficult to detect in other solar systems? a) Cold Jupiters b) Super Earths c) Mini-Earths d) Mini-Neptunes
c
Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)? a) They have different atomic mass numbers b) They have different names. c) They have different numbers of protons in their nucleus. d) They have different numbers of electrons.
c
Which of the following best describes the geological histories of the Moon and Mercury? a) Impact cratering shaped these worlds early in their histories. Then, during the past few million years, they were reshaped by episodes of volcanism and tectonics. b) Impact cratering is the only major geological process that has affected their surfaces. c) Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all. d) All four geological processes were important in their early histories, but only impact cratering still reshapes their surfaces today.
c
Which of the following is not considered crucial for life to exist on some world? a) liquid water b) a source of energy that can be used by life c) an atmosphere d) a source of nutrients
c
Which of the following lists the planets of our solar system in the correct order from closest to farthest from the Sun? a) Earth, Mars, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune b) Mercury, Earth, Venus, Mars, Jupiter, Saturn, Neptune, Uranus c) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune d) Mercury, Venus, Mars, Earth, Saturn, Jupiter, Neptune, Uranus
c
Which of the following objects are probably not located in the same general region of the solar system in which they originally formed? a) Pluto b) Kuiper belt comets c) Oort cloud comets d) asteroids of the asteroid belt
c
Which of the following statements best describes the size of the largest asteroid, Ceres? a) It is no larger than a typical mountain on one of the terrestrial planets. b) It is smaller than the jovian planets but larger than the terrestrial planets. c) It is a little less than half the diameter of our Moon. d) It is about the size of a terrestrial planet.
c
Which of the following types of material can condense into what we call ice at low temperatures? a) rock b) hydrogen and helium c) hydrogen compounds d) metal
c
Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth? a) active volcanism and active tectonics b) life and atmospheric oxygen c) plate tectonics and liquid water oceans d) life and active volcanism
c
All of the statements below are true. Which one gives the primary reason why the surface of Venus today is some 450°C hotter than the surface of Earth? a) Venus is only about 73% as far from the Sun as Earth b) Venus has a higher atmospheric pressure than Earth. c) Venus has a much higher reflectivity than Earth. d) Venus has a much stronger greenhouse effect than Earth.
d
All the following statements are true. Which one is most important in explaining the tremendous tidal heating that occurs on Io? a) Io exhibits synchronous rotation, meaning that its rotation period and orbital period are the same. b) Io is the closest to Jupiter of Jupiter's large moons. c) Io orbits Jupiter in the Io torus, and therefore has a surface that is bombarded by many charged particles. d) Io orbits Jupiter on an elliptical orbit, due to orbital resonances with other satellites.
d
Based on DNA studies, it seems that all life on Earth ________. a) arose from one of five distinct ancestors that lived about two billion years ago b) belongs to one of just two kingdoms: plants and animals c) requires oxygen to survive d) shares a common ancestor
d
Complete this statement. The larger the decrease in the star's brightness as the planet transits in front of a star, _______. a) the larger the distance to the star. b) the larger the size of the planet's orbit. c) the larger the size of the star. d) the larger the size of the planet.
d
If the hypothesis tracing the extinction of the dinosaurs to an impact is correct, the dinosaurs died off largely because ________. a) the impact caused massive earthquakes worldwide b) of injuries suffered from direct hits of pieces of the asteroid or comet c) radiation from iridium in the asteroid caused the dinosaurs to die of cancer d) of global climate effects initiated by dust and smoke that entered the atmosphere after the impact
d
If we could put all the asteroids together, their total mass would be ________. a) about the mass of Earth b) about the mass of Mercury c) greater than the mass of Earth but less than the mass of Jupiter d) much less than the mass of any terrestrial planet
d
In essence, the Kepler mission is searching for extrasolar planets by____________. a) observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet b) obtaining high-resolution photographs of other star systems c) identifying spectral lines that look like what we expect to see from a planet rather than a star d) monitoring stars for slight dimming that might occur as unseen planets pass in front of them
d
In science fiction movies, spaceships are often shown dodging through large numbers of closely spaced, boulder-size objects. Which of the following real things in our solar system would look most like such science fiction dangers? a) the asteroid belt b) the atmosphere of Jupiter c) the Oort cloud d) the rings of Saturn
d
Overall, Jupiter's composition is most like that of ________. a) an asteroid b) a comet c) Earth d) the Sun
d
Recent evidence suggests that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth? a) Mars rotates much slower than the Earth. b) Mars is too far from the Sun to have a global magnetic field. c) The Martian core is made of rock, while Earth's core is made of metal. d) Mars's interior has cooled so much its molten core layer no longer undergoes convection.
d
The choices below describe four hypothetical planets. Which one would you expect to have the hottest interior? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.) a) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. b) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. c) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. d) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.
d
The cores of the terrestrial worlds are made mostly of metal because ________. a) the terrestrial worlds as a whole are made mostly of metal b) over billions of years, convection gradually brought dense metals downward to the core c) the core contained lots of radioactive elements that decayed into metals d) metals sunk to the centers a long time ago when the interiors were molten throughout
d
What are the two main differences between extrasolar planetary systems discovered to date and our Solar System? a) Extrasolar planet orbits tend to be closer and more circular than in our Solar System. b) Extrasolar planet orbits tend to be more eccentric and inclined than in our Solar System. c) Extrasolar planets tend to be more massive and dense than Jupiter. d) Extrasolar planet orbits tend to be closer and more eccentric than in our Solar System. e) Extrasolar planets tend to be bigger and denser than Jupiter.
d
What extrasolar planet discoveries were initially surprising? a) planets with large eccentricities b) Jupiter-like planets orbiting very close to their stars c) systems with only one planet d) Jupiter-like planets orbiting very close to their stars and planets with large eccentricities e) Jupiter-like planets orbiting very close to their stars and systems with only one planet
d
What is a so-called "hot Jupiter"? a) a planet with a mass and composition similar to what we would expect if Jupiter were hotter b) a Jupiter mass planet orbiting a star that is more massive and hotter than the Sun c) a planet with a mass similar to Jupiter but composition similar to Mercury d) a planet with a mass similar to Jupiter but very close to the central star and therefore hot
d
What mechanism likely accounts for whether a large icy planetesimal becomes a "water world" or a gas giant? a) the amount of heavy metals initially present in the disk b) the presence of other planets to make its orbit highly eccentric c) the migration of larger planets through the disk d) the timing of when the stellar wind blows away the remaining gas of the planet forming nebula
d
Which new idea has been added into our theory of solar system formation as a result of the discoveries of extrasolar planets? a) In addition to the categories of terrestrial and jovian, there must be an "in-between" category of planet that has the mass of a jovian planet but the composition of a terrestrial planet. b) In some star systems, it is possible for jovian planets to form in the inner solar system and terrestrial planets to form in the outer solar system. c) Some of the "exceptions to the rules" in our own solar system are likely to have been the result of giant impacts. d) Planets can migrate from the orbits in which they are born.
d
Which of the following best describes natural selection? a) It is a guess made by scientists about how life develops, but it has no hard evidence to support it. b) It is the idea that organisms naturally increase in complexity and intelligence with time. c) It is the idea that the strong survive and the weak die off. d) It is the idea that organisms with genetic traits that improve their ability to reproduce are more likely to pass those traits on to future generations.
d
Which of the following best explain what we think happened to outgassed water vapor on Venus? a) Water was removed from the atmosphere by chemical reactions with surface rock. b) It is frozen as water ice in craters near the poles. c) It turned into carbon dioxide by reacting with nitrogen in Venus's atmosphere. d) Ultraviolet light split the water molecules, and the hydrogen then escaped to space.
d
Which of the following is not a general characteristic of the four jovian planets in our solar system? a) They are composed mainly of hydrogen, helium, and hydrogen compounds. b) They lack solid surfaces. c) They are much more massive than any of the terrestrial planets. d) They are higher in average density than are the terrestrial planets.
d
Which of the following is the most basic definition of a greenhouse gas? a) a gas that reflects a lot of sunlight b) a gas that makes a planet much hotter than it would be otherwise, even in small amounts c) a gas that keeps warms air from rising, and therefore warms the surface d) a gas that absorbs infrared light
d
Which of the following places is not generally considered a potential home for life in our solar system? a) Mars b) Europa c) Titan d) Jupiter's atmosphere
d
Which statement about Io is true? a) It is the only moon in the solar system with a thick atmosphere. b) It is thought to have a deep, subsurface ocean of liquid water. c) It is the largest moon in the solar system. d) It is the most volcanically active body in our solar system.
d
Which two factors are most important to the existence of plate tectonics on Earth? a) oxygen in the atmosphere and mantle convection b) the existence of life and oxygen in the atmosphere c) Earth's liquid outer core and solid inner core d) mantle convection and a thin lithosphere
d
Why didn't a planet form where the asteroid belt is now located? a) There was not enough material in this part of the solar nebula to form a planet. b) The temperature in this portion of the solar nebula was just right to prevent rock from sticking together. c) There was too much rocky material to form a terrestrial planet, but not enough gaseous material to form a jovian planet. d) Gravitational tugs from Jupiter prevented material from collecting together to form a planet.
d
Why is Europa considered a good candidate for the possible existence of life? a) It is located within our Sun's habitable zone. b) It has a thick atmosphere with a surface pressure greater than that on Earth. c) The Galileo spacecraft found strange seasonal changes on its surface that look like they could be due to life. d) Strong evidence suggests that it has a deep, subsurface ocean of liquid water.
d
Why is the sky blue (on Earth)? a) because deep space is blue in color b) because molecules scatter red light more effectively than blue light c) because the Sun emits mostly blue light d) because molecules scatter blue light more effectively than red light e) No one knows-this is one of the great mysteries of science.
d
The _____ is designed as a way of estimating the number of intelligent civilizations in the Milky Way.
drake equation
Which of the following is not a characteristic of the outer planets? a) Their orbits are separated by relatively large distances. b) They all have rings. c) They are primarily made of hydrogen and helium. d) They all have large quantities of gas. e) They have very few, if any, satellites.
e
High-mass main-sequence stars have a more distant and wider ________ than low-mass stars.
habitable zone
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
Sky surveys looking for radio signals generated by technology are part of the _________
search for extraterrestrial intelligence
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