Astronomy Exam #3
Explain the natural carbon dioxide cycle on Earth, including how carbon dioxide is removed from Earth's atmosphere and how carbon dioxide is returned to Earth's atmosphere. a. Atmospheric carbon dioxide is absorbed by seawater, forms sediments on the sea floor, then it is subducted to the mantle and returned to the atmosphere through volcanic eruptions. b. Atmospheric carbon dioxide is absorbed by seawater and decomposed because of the seawater salinity, but later it is returned to the atmosphere as a breathing product of living things. c. Atmospheric carbon dioxide is used by plants, then plants became soil, subducted to the mantle, and then, carbon dioxide is returned to the atmosphere through volcanic eruptions. d. Most of atmospheric carbon dioxide is used by plants and returned to the atmosphere as a breathing product of many living things.
A
If the Solar System formed as the result of a catastrophe, why would this suggest that planets are not common? a. Catastrophic events are unlikely. If our Solar System formed in such a way we would conclude that planetary systems around other stars would be unlikely. b. Catastrophic events are common for evolving stars, but the probability of planets forming during these events is low. c. Catastrophic events were common when our Solar System and the spiral galaxy were formed, but they are very rare now because most of the gas and dust was swept away. d. Catastrophic events usually occur in binary star systems, where they result in mass exchange and cataclysmic variability of brightness but not planet formation.
A
Look at the figure below. Rising from Earth's surface to the cloud layer shown, does the temperature increase, decrease, or stay the same? a. The temperature decreases from Earth's surface to the cloud layer. b. The temperature increases from Earth's surface to the cloud layer. c. The temperature from Earth's surface to the cloud layer depends on the season. d. The temperature remains the same from Earth's surface to the cloud layer.
A
Order the following steps in the formation of a Terrestrial planet chronologically: gravitational collapse, accretion, outgassing, condensation, and differentiation. Not all steps will necessarily be used. a. Condensation, accretion, differentiation, outgassing. b. Condensation, differentiation, gravitational collapse, outgassing. c. Gravitational collapse, condensation, differentiation, outgassing. d. Condensation, accretion, gravitational collapse, outgassing.
A
The Zeeman effect occurs when the atoms emitting or absorbing photons are which of the following? a. located in a magnetic field b. located in an electric field c. ionized d. very hot
A
What is the most significant kind of erosion that occurs on the Moon today? a. Micrometeorite impacts. b. Volcanism. c. Chemical erosion. d. Tectonics.
A
What kind of activity would the Sun have if it didn't rotate differentially? a. It would probably not have a strong magnetic field and resulting high-temperature gas above its photosphere. b. It would probably still have a strong magnetic field and resulting high-temperature gas below its photosphere. c. It would probably not have a strong magnetic field and resulting high-temperature gas below its photosphere. d. It would probably still have a strong magnetic field and resulting high-temperature gas above its photosphere.
A
What property of the Moon and Mercury has resulted in almost complete cessation of surface evolution on both those worlds, whereas Earth's surface evolution continues? a. Earth's surface evolution continues due to plate tectonics and erosion produced by its atmosphere and water. None of these processes operates on airless and inactive Mercury and the Moon. b. Earth's surface evolution continues due to its rapid rotation and erosion produced by its atmosphere and water. None of these processes operates on airless and tidally locked Mercury and the Moon. c. Earth's surface evolution continues due to its rapid rotation and the presence of developed life. None of these processes operates on lifeless and tidally locked Mercury and the Moon. d. Earth's surface evolution continues due to plate tectonics and the presence of developed life. None of these processes operates on inactive and lifeless Mercury and the Moon.
A
What is the evidence that planets orbit other stars? (Check all that apply.) a. Decrease in the brightness of a star during planetary transit. b. Planetary nebulae surrounding the remnants of stars. c. Doppler shifts in a star's spectrum due to the very small motion of the star as it and the planet orbit their center of mass. d. Brief magnification of a distant star's brightness due to gravitational lensing as the planet passes between Earth and the star.
A, C and D
According to the solar nebula theory, why is there a common direction of revolution and rotation for most objects in the Solar System? a. Massive objects with divergent rotation and revolution could not have stable orbits and would fly away or fall to the Sun a long time ago. b. Most objects in the Solar System have a common direction of revolution and rotation because they formed from the same rotating gas cloud. c. Revolution originated from the gravitational attraction of the Sun, and rotation originated from the Sun's tidal force. d. The solar wind affects the motion of planets greatly, and the solar wind's pattern is determined mostly by the Sun's surface rotation.
B
How can solar flares affect Earth? a. They emit large amounts of X-rays and ultraviolet radiation, which are caught by Earth's magnetic field and decrease the ionization of Earth's upper atmosphere. b. They emit large amount of X-rays and ultraviolet radiation that travel to Earth and increase the ionization of Earth's upper atmosphere. Flares also emit large amounts of charged particles that are caught by Earth's magnetic field. c. They are created by reconnection events when two arches on the Sun's surface cancel each other, so they do not affect Earth significantly. d. They emit large amounts of X-rays and ultraviolet radiation, but at such distance it does not affect Earth due to the inverse-square law.
B
How is the root cause of earthquakes in Hawai'i different from earthquakes in Southern California? a. Earthquakes near the Hawaiian Islands are associated with hot spots. The folding of plates causes earthquakes in Southern California. b. Earthquakes near the Hawaiian Islands are associated with hot spots. The slipping of plates causes earthquakes in Southern California. c. Earthquakes near the Hawaiian Islands are associated with plate subduction. The slipping of plates causes earthquakes in Southern California. d. Earthquakes near the Hawaiian Islands are associated with plate subduction. The folding of plates causes earthquakes in Southern California.
B
If the Moon was intensely cratered by the heavy bombardment and then formed great lava plains, why didn't the same thing happen on Earth? a. Earth had a liquid surface at the time of the heavy bombardment and all evidence of bombardment disappeared almost instantly. b. Earth was bombarded, but the moving plates long ago erased all evidence of such cratering and lava flows. c. Earth's crust is very dense and thick, so the heavy bombardment did not leave any evidence on Earth's surface. d. Earth was not bombarded because its gravitational field is much stronger and meteorites could not reach its surface.
B
Refer to the figures below. What kind of spectrum is shown in image A? What atmospheric layer(s) of the Sun is (are) associated with this spectrum? Image A. Image B. a. The continuous spectrum, which is produced by the corona. b. The absorption spectrum, which is produced by the photosphere. c. The continuous spectrum, which is produced by the photosphere and the chromosphere. d. The emission spectrum, which is produced by the chromosphere and the corona.
B
State one reason why an excess of CO2 and a deficiency of free oxygen would be harmful to all life on Earth in ways that go beyond mere respiration. a. It would increase the rate of wind erosion drastically. b. It would raise the surface temperature of Earth. c. It would destroy the magnetosphere protecting Earth from the solar wind. d. It would change the salinity of the oceans.
B
What caused Earth to be differentiated? During which stage of planetary development did that happen? a. The greenhouse effect due to a thick and carbon dioxide-rich atmosphere caused Earth's interior to melt and the densest material to sink to the core during the first stage of development, differentiation. b. Heat from a combination of radioactive decay and energy released by infalling matter caused Earth's interior to melt and the densest material to sink to the core during the first stage of development, differentiation. c. Impacts of heavy bombardment and increased flux from the Sun caused Earth's interior to melt and the densest material to sink to the core during the second stage of development, cratering. d. Radioactive elements reached the critical condition and intense nuclear fission caused Earth's interior to melt and the densest material to sink to the core during the second stage of development, cratering.
B
What keeps Earth's interior warm today? a. Radioactive decay and leftover heat of formation are the sources of heat, and Earth's oceans and water vapor in the atmosphere insulate deeper layers. b. Radioactive decay and leftover heat of formation are the sources of heat, and Earth's crust insulates deeper layers. c. A magnetic dynamo in the core is the source of heat, and Earth's oceans and water vapor in the atmosphere insulate deeper layers. d. A magnetic dynamo in the core is the source of heat, and Earth's crust insulates deeper layers.
B
Which atmospheric layer(s) is (are) associated with the Sun's continuous spectrum? With its absorption spectrum? With its emission spectrum? a. The continuous spectrum—the photosphere and the chromosphere. The absorption spectrum and the emission spectrum—the corona. b. The continuous and the absorption spectra—the photosphere. The emission spectrum—the chromosphere and the corona. c. The continuous spectrum—the photosphere. The absorption spectrum—the chromosphere. The emission spectrum—all the layers. d. The continuous spectrum—the corona. The absorption spectrum—the chromosphere. The emission spectrum—the photosphere.
B
Why are debris disks evidence that planets have already formed? a. Such disks usually have high temperatures; this means that a star system is active and has already formed planets. b. Debris disks are not hot and dense enough for planet formation. They are produced by collisions among comets, asteroids, and KBOs, and where you find these objects, you should also find planets. c. They are usually produced by large planets' gravitational fields; therefore, you should also find planets in such a system. d. Debris disks are held by planets' gravitational fields. If a star system did not have planets, such debris would disappear.
B
Why do planetary scientists hypothesize that the Moon formed with a molten surface? a. All of the rock samples from the Moon are sedimentary, meaning that they were formed by the solidification of molten rock. b. All of the rock samples from the Moon are igneous, meaning that they were formed by the cooling and solidification of molten rock. c. All of the rock samples from the Moon contained less than percent water, meaning that they were formed by the cooling of underground molten rock. d. All of the rock samples from the Moon were dark-colored, meaning that they were formed after the cooling of molten rock by meteorite impacts.
B
Why is it not surprising that there is no evidence of plate tectonics on Mercury's surface? a. Mercury is the densest planet in the Solar System, so its crust is very durable. b. The crust of Mercury is thick and heat flowing outward is unable to drive plate tectonics. c. Mercury is not a differentiated world. It consists of evenly distributed metal and metal oxides. d. Mercury has orbital-rotation resonance with the close Sun, so plates cannot have their own motion.
B
Why is the solar nebula theory considered a theory rather than a hypothesis? a. It solves the angular momentum problem, which is the main problem of Solar System formation research. b. It has extensive evidence and explains many observations of different objects. c. It is based on mathematical models and previous calculations of molecular and particle properties. d. It is accepted by most scientists nowadays, and it is conventionally named as a theory.
B
Why was the nebular hypothesis of the Solar System origin not fully accepted by astronomers in the th and early th centuries? a. Only giant gas planets should be generated during the gas condensation process described in the hypothesis. b. The Sun rotates relatively slowly and most of the angular momentum of the Solar System is contained in the orbits of the planets. c. The Sun rotates relatively rapidly and that fast rotation does not correspond to fairly slow planetary motions and small angular momenta. d. Angular momenta of the Sun and the planets should compensate each other, but the Sun and planets rotate in almost one plane and in one direction.
B
Why would you include the Moon in a comparison of the Terrestrial planets? a. The Moon shows tectonic and erosion processes on its surface and has a very thin but detectable atmosphere like other Terrestrial planets. b. The Moon is small compared with the Jovian planets. It is also dense with a rock and iron composition and a solid surface and is located in the inner Solar System like other Terrestrial planets. c. The chemical composition and material age of the Moon's surface are very similar to those on Earth. The Moon also shows tectonic processes like other Terrestrial planets. d. The Moon is classified with the Terrestrial planets to provide a contrasting example. Its density, composition, and surface characteristics are not similar to those of Terrestrial planets.
B
Does Mercury have volcanism today? How do you know? a. Yes. Mercury has a large and partially molten core which should produce magma eruptions. b. Yes. The bright color of lava plains suggests that they are young and that volcanism on Mercury is still active. c. No. The surface of Mercury shows us old craters and lobate scarps, which would be recycled if active volcanism existed. d. No. The rotation-orbit resonance of Mercury with the close Sun blocks lava and gaseous eruptions through the breaks of the crust.
C
Earth shows few craters on its surface. What is the explanation for this? a. Earth did not avoid heavy bombardment, but its surface was less cratered because Earth's crust is thicker and has higher density than that of other Terrestrial planets. b. Earth avoided most heavy bombardment because the relatively large Moon, in a tidal lock, worked as a shield and took the hits instead of Earth. c. Earth did not avoid heavy bombardment, but its surface has been heavily reworked and processed by erosion and plate tectonics. d. Earth avoided most heavy bombardment because of its great magnetic field and oxygen-rich atmosphere, which caused partial deflection and burning of meteoroids.
C
How are astronomers able to explore the layers of the Sun below the photosphere? a. Astronomers study solar wind produced by the Sun. b. Astronomers study formation of granules and changes in the chromosphere and the corona. c. Astronomers study vibrations of the surface of the Sun caused by movements deep in the Sun and propagated outward like sound waves. d. Astronomers study strong spectral lines of the Sun in the UV and the X-ray regions.
C
How are the histories of the Moon and Mercury similar? a. They formed in the inner Solar System, passed through intense cratering, have orbits tidally locked into resonances, and show evidence of intense erosion of their surfaces. b. They formed in the outer Solar System and were then gravitationally captured, did not pass through differentiation, and show evidence of intense erosion of their surfaces. c. They formed in the inner Solar System, passed through intense cratering, have orbits tidally locked into resonances, and their surface evolution is limited to micrometeorite impacts. d. They formed in the outer Solar System and were then gravitationally captured, did not pass through differentiation, and their surface evolution is limited to micrometeorite impacts.
C
How does the large-impact hypothesis explain the Moon's lack of iron? a. The collision between the proto-Moon and another large planetesimal ripped out the proto-Moon's core containing most of the Moon's iron. b. The material that formed the Moon originated from a further part of the solar nebula and was driven to the area of Earth by an impact between two large planetesimals. c. The material that formed the Moon would be mostly iron-poor crust and mantle material, ripped from proto-Earth it was struck by a large planetesimal. d. The collision between proto-Earth and another large planetesimal produced a density wave in a surrounding disk of low-density particles that formed the Moon.
C
How does the solar nebula theory help you understand the location of the asteroid belt? a. The asteroid belt is the region where planetesimals actually formed a planet, but that planet was destroyed by Jupiter's tidal forces and became moons and asteroids long ago. b. The area of transition between rocky Terrestrials and liquid-icy Jovians should have less matter, and that amount of matter is not enough to form a single planetary body. c. Gravitational disturbances from Jupiter in the region of the asteroid belt were strong enough to disrupt accretion of planetesimals there, so the planetesimals did not coalesce into a single planet. d. Gravitational resonance between the Sun and Jupiter results in certain positions in the Solar System where solid objects concentrate without accretion.
C
How has the presence of liquid water on Earth affected the ability of scientists to discern the planet's history? a. Liquid water produced climatic changes that correspond to past changes of Earth's magnetic field. The ocean's salinity reveals some information about the chemical composition of the ocean floor in the past. b. Liquid water produces climatic changes that correspond to past changes of Earth's magnetic field. The oceans cover important features of the crust. c. Liquid water produced significant erosion that altered the surface and erased the evidence of our planet's early history. The vast oceans cover important features of the crust. d. Liquid water produced significant erosion that altered the surface and erased the evidence of our planet's early history. The ocean's salinity reveals some information about the chemical composition of the ocean floor in the past.
C
State two processes that could melt the interior of a forming planet. a. Radioactive decay and gravitational collapse. b. Outgassing and gravitational collapse. c. Radioactive decay and heat of formation. d. Heat of formation and gravitational collapse.
C
The greenhouse effect is only bad for Earth's climate. True or false? Explain your answer. a. True. Because of the greenhouse effect, many species of animals have disappeared. b. False. Because of the greenhouse effect, there are more animal species that are able to breathe carbon dioxide. c. False. Without the greenhouse effect, Earth would be colder and uninhabitable for water-based life. d. True. The greenhouse effect has made Earth's surface hot enough to melt ice; therefore, the sea level rises.
C
This image of the Sun was recorded in the extreme ultraviolet by the SOHO spacecraft. Explain the features you see. a. The far UV light image shows that the Sun rotates differentially. b. The far UV light image shows that the magnetic activity of the Sun varies with time. c. The far UV light image shows bright regions of extremely hot gas trapped in magnetic fields above active regions. d. The far UV light image shows that the upper photosphere and the chromosphere consist of high-density and high-temperature gases.
C
What evidence can you give that the Atlantic Ocean is growing wider? a. The analysis of clouds and storm patterns observed from satellites. b. The width of the Atlantic Ocean on old maps differs from the width based on modern measurement. c. The difference in time for laser flashes reflecting from the Moon for European and American observatories. d. The Doppler redshift of signals sent from one coast of the Atlantic Ocean to another.
C
What evidence can you give that the Solar System formed about billion years ago? a. We use the estimate derived from the solar nebula theory because this theory has extensive evidence and explains properties and observations of various objects precisely. b. We can estimate the age of the Solar System by observing the comets, which have an analog of annual rings, and calculating their orbital periods. c. Radioactive dating of meteorites. Dating of the oldest rocks from Earth and the Moon shows lesser ages but they are consistent with the estimate from meteorites. d. We obtain the age estimate from the Sun's structure by modeling and comparing it with actual observations of the spectrum, activity, and nuclear fusion of the Sun.
C
What evidence can you give to support the theory of plate tectonics? a. Continental drift, volcanism and earthquakes near plate borders, heat coming from Earth's interior, abundance of oxygen and nitrogen in the atmosphere. b. Bow shocks and radiation belts, erosion on Earth's surface, folded mountain chains, magnetic patterns of basalt at midocean rises. c. Continental drift, volcanism and earthquakes near plate borders, folded mountain chains, rift valleys, magnetic patterns of basalt at midocean rises. d. Bow shocks and radiation belts, erosion on Earth's surface, heat coming from Earth's interior, abundance of oxygen and nitrogen in the atmosphere.
C
What evidence leads astronomers to conclude that some stars have chromospheres and coronae like those of the Sun? a. Telescopes are able to make images of the atmospheres of stars. The images show that many stars have chromospheres and large coronae. b. Many stars have the same temperature, same size, and the same composition as that of the Sun. c. The spectra of many stars contain emission lines in the far ultraviolet and X-ray region. Those lines are formed in low-density, high-temperature gases of a chromosphere and corona. d. All stars have the same nature and structure as the Sun, so they also should have chromospheres and coronae.
C
What evidence leads astronomers to conclude that temperature increases with height in the chromosphere and corona? a. The atoms in the corona are less ionized than atoms in the photosphere. Atoms in the chromosphere are even less ionized. b. The atoms in the corona are more highly ionized than atoms in the photosphere. Atoms in the chromosphere are even more highly ionized. c. The atoms in the chromosphere are more highly ionized than atoms in the photosphere. Atoms in the corona are even more highly ionized. d. The atoms in the chromosphere are less ionized than atoms in the photosphere. Atoms in the corona are even less ionized.
C
Why did the first Apollo missions land on the maria? Why were the other areas of more scientific interest? a. Maria are the most difficult sites for landing; it was important to test lunar module systems on a hard surface for future flights. Other areas such as highlands represented different parts of the Moon's history. b. Maria have the most geologically important samples that could tell much about the Moon's origin. Other areas could possibly contain a lot of minerals. c. Maria are relatively smooth, so they were safe landing sites. Other areas such as highlands represented different parts of the Moon's history. d. It was suggested that microorganisms could be found in maria. Other areas have a lot of minerals which could tell about the Moon's origin and evolution.
C
Why does Earth's atmosphere contain little carbon dioxide and lots of oxygen? a. CO2 dissolves in oceans and combines with minerals in seawater; ultraviolet radiation destroys water in oceans producing oxygen faster than chemical reactions can remove it. b. CO2 mostly leaked away to space due to a large impact during Earth's formation; green plants release oxygen into Earth's atmosphere faster than chemical reactions can remove it. c. CO2 dissolves in oceans and combines with minerals in seawater; green plants release oxygen into Earth's atmosphere faster than chemical reactions can remove it. d. CO2 mostly leaked away to space due to a large impact during Earth's formation; ultraviolet radiation destroys the water in oceans producing oxygen faster than chemical reactions can remove it.
C
Why is almost every solid surface in the Solar System scarred by craters? a. Most craters result from high-energy particles of the solar wind striking the objects' surfaces. Most objects in the Solar System lack thick dense atmospheres that could protect their surfaces from those collisions. b. Craters are the result of strong meteorite bombardments caused by another star passing near the Solar System after planet formation. Most objects in the Solar System lack thick dense atmospheres that could protect their surfaces from those collisions. c. Most craters formed by impacts of planetesimals left over from planet formation during the heavy bombardment period. Most objects in the Solar System lack enough surface activity to erase these craters. d. Most craters formed by convection currents occurred when heat of formation melted the objects' surfaces during the condensation and differentiation stages. Most objects in the Solar System lack enough surface activity to erase these craters.
C
As viewed from outside the Earth-Moon system, how many times does the Moon rotate in one orbit? How do you know? a. The Moon rotates 29.5 times per orbital period, because its orbital period is 29.5 days and it rotates once per day. b. As viewed from outside the system, the Moon does not appear to rotate because it is tidally coupled to Earth. c. The Moon rotates 27.3 times per orbital period, because its orbital period is 27.3 days and it rotates once per day. d. The Moon appears to rotate once per orbital period, because its orbital and rotation periods are the same.
D
Describe the first two stages of Terrestrial planet development. a. Cratering, when debris falls to a planet and forms impact craters on the solid surface. Basin flooding, when magma rises through the cracks of the crust and ponds in large crater basins. b. Differentiation, when materials separate by density. Slow surface evolution, when the planet's surface is changed by plate tectonics and erosion. c. Basin flooding, when magma rises through the cracks of the crust and ponds in large crater basins. Slow surface evolution, when the planet's surface is changed by plate tectonics and erosion. d. Differentiation, when materials separate by density. Cratering, when debris falls to a planet and forms impact craters on the solid surface.
D
Describe the last two stages of Terrestrial planet development. a. Cratering, when debris falls to a planet and forms impact craters on the solid surface. Basin flooding, when magma rises through the cracks of the crust and ponds in large crater basins. b. Differentiation, when materials separate by density. Cratering, when debris falls to a planet and forms impact craters on the solid surface. c. Differentiation, when materials separate by density. Slow surface evolution, when the planet's surface is changed by plate tectonics and erosion. d. Basin flooding, when magma rises through the cracks of the crust and ponds in large crater basins. Slow surface evolution, when the planet's surface is changed by plate tectonics and erosion.
D
Does the Moon have volcanism today? How do you know? a. No, because volcanoes cannot be observed from Earth even with the strongest telescopes. b. Yes, because the Moon's surface is constantly changing. c. Yes, because several volcanoes are observed from Earth with the strongest telescopes. d. No, because the entire surface appears old with a lot of craters.
D
How do you think the Sun's appearance would differ if it had no convection inside? a. Mixing of the material within the Sun would be slower and have alternate forms, which would affect the nuclear fusion of hydrogen in the interior of the Sun. b. The Sun's matter would become much less transparent to radiation. So less energy would reach the surface, and the luminosity of the Sun would significantly decrease. c. Without a convective zone, energy would have to come out via radiation alone. So, the Sun's spectrum would consist of only emission lines, without any absorption lines. d. There would be no visible granules or supergranules on the Sun. The sunspot cycle would be much different.
D
How does the Babcock model explain the sunspot cycle? a. Single sunspots should occur where the north poles of the tubes of the concentrated magnetic energy burst through the Sun's surface. b. It states that the sunspots occur in the areas of the strong magnetic flow. c. Single sunspots should occur where the south poles of the tubes of the concentrated magnetic energy burst through the Sun's surface. d. Pairs of sunspots should occur where the tubes of concentrated magnetic energy burst through the Sun's surface during the magnetic cycle.
D
How does the solar nebula theory explain the significant density difference between the Terrestrial and Jovian planets? a. The inner part of the forming Solar System contained only heavy elements, therefore, planets formed there were relatively dense Terrestrials. The outer part contained only light elements, which condensed to form low-density Jovian planets. b. Revolution in the inner part of the forming Solar System was faster, so only heavy elements could condense there and form Terrestrial planets with high densities. In the outer part, low-density Jovian planets formed from slowly moving gases and ice. c. The Sun's gravity is stronger in the inner part of the Solar System, so light materials like gases were mostly absorbed by the Sun in the area where Terrestrial planets formed. d. In the hotter inner part of the forming Solar System only materials with high melting points could condense, forming dense Terrestrial planets. In the cooler outer part, low-melting-point materials could also condense to form Jovian planets.
D
Look at the figure below. To what height and which atmospheric layer does the red color correspond? a. It corresponds to a height of 500 km and lower (the corona). b. It corresponds to a height of 2300 km and lower (the corona). c. It corresponds to a height of from 500 km to 2200 km (the chromosphere). d. It corresponds to a height of 2300 km and higher (the corona).
D
The two images here show two solar phenomena. What are they, and how are they related? How do they differ? a. Both images are of the same type object, a filament/prominence. When seen in the H-alpha-wavelength, the object appears to be dark, and in usual light, it looks like a bright prominence. b. Both images are of the same type object, a filament. A dark filament occurs in regions where the opposed magnetic fields meet and cancel each other. c. Both images are of the same type object, a prominence. One of the images of the prominence was made by a coronagraph (or during the eclipse), so the object looks brighter. d. Both images are of the same type object, a filament/prominence. When seen against the disk of the Sun, the object appears to be a dark filament, when against the dark background of space—a bright prominence.
D
What evidence indicates that Earth has a liquid metal core? a. Liquid magma pokes through the crust and produces volcanism. Earth's magnetic field suggests a liquid core by the dynamo effect. b. Liquid magma pokes through the crust and produces volcanism. Measurable continental drift suggests a liquid core. c. Shear seismic waves (S waves) do not pass through the core. Measurable continental drift suggests a liquid core. d. Shear seismic waves (S waves) do not pass through the core. Earth's magnetic field requires a liquid core by the dynamo effect.
D
What is the difference between condensation and accretion? a. A particle grows by condensation when it adds matter from a surrounding gas. Separation of materials according to various density is called accretion. b. Condensation is the process when gas transforms into the solid phase without the liquid phase. Accretion is the sticking together of solid particles. c. Condensation is the process when gas transforms into the solid phase without the liquid phase. Separation of materials according to various density is called accretion. d. A particle grows by condensation when it adds matter from a surrounding gas. Accretion is the sticking together of solid particles.
D
What is the evidence that Earth went through an early stage of cratering? a. A lot of old impact craters can be detected under the soil on the continents and on the ocean floor by seismological observations and deep drilling. b. Earth's crust consists of substances of obviously extraterrestrial origin according to their composition and age. The infall of these substances must have created impact craters on Earth. c. The solar nebula theory is proper evidence of Earth's stages of evolution, including cratering. So we don't need more evidence. d. Every old solid surface in our Solar System has impact craters. If cratering happened to other worlds in the Solar System, it must have happened to Earth too.
D
Whenever there is a total solar eclipse, you can see something like the image shown below. Explain why the shape and extent of the glowing gases are observed to be different for each eclipse. a. The Sun rotates on its axis. During each eclipse, it shows different sides. b. The uneven light emission due to sunspots on the surface of the Sun affects the shape of the corona. c. The shape of the corona changes due to thermodynamic fluctuations of the gas. d. The activity on the surface of the Sun changes the shape of the corona.
D
Which type of seismic wave cannot pass through Earth's core? What does that indicate about the composition of the core? a. P waves. It indicates that the core is at least partially molten. b. S waves. It indicates that the core contains primarily iron and nickel. c. P waves. It indicates that the core contains primarily iron and nickel. d. S waves. It indicates that the core is at least partially molten.
D
Why are there two kinds of planets in our Solar System? a. Gas giants formed from the envelope of the Sun's past binary partner, after it passed the red giant stage. Small dense inner planets formed from its core. b. Gas giants formed when nuclear fusion inside the Sun had not begun. Then low-density gases were swept away by the radiation pressure and inner planets formed only from heavy substances. c. The substances in the disk around the forming Sun were sorted by density. Low-density gases were blown to the outer solar nebula and heavy particles were gravitationally attracted closer to the Sun. d. Near the Sun only metals and silicates can condense and form dense small planets. In outer solar nebula, ice molecules can condense and form objects large enough to capture gas directly.
D
Why doesn't the Moon have a magnetic field? a. The dense core of the Moon is large and does not contain enough solidified iron to produce a magnetic field. b. The Moon has very low density. Only high-density planets can have magnetic fields. c. The Moon is not a differentiated body so it does not have a core. d. The dense core of the Moon is small and does not contain enough molten iron to produce a magnetic field.
D
Astronomers can measure the strength of a magnetic field by observing which of the following? a. the separation of the spectral line components b. any of these c. the intensity of the spectral line components d. the Doppler shifts in the spectral line components
A
From looking at images of the Moon's near side, how can you tell that Copernicus is a young crater? a. It is located on a mare and has bright rays of ejecta extending from it. b. It consists of highland matter regardless of its location on a mare. c. It is a relatively large crater with clear edges and is visible from Earth. d. Astronomers observed how this crater was produced not so long ago.
A
Life on Earth exists because of oxygen in Earth's atmosphere. True or false? Explain your answer. a. False, because life could originate only from the places without free oxygen. b. False. There is oxygen in Earth's atmosphere because of life; except for the minority of creatures, including us, most life forms on Earth do not need oxygen. c. True. Life on Earth exists because of oxygen in Earth's atmosphere, because the majority of creatures, including us, need oxygen. d. True. Life on Earth exists because of a large amount of water (H2O), which contains oxygen.
B
State the two most important processes that cleared the solar nebula and ended planet formation. a. Radiation pressure and sweeping up of debris by the planets. b. The solar wind and ejection of material from the Solar System by close encounters with planets. c. Radiation pressure and the solar wind. d. Ejection of material from the Solar System by close encounters with planets and sweeping up of debris by the planets.
C
