Astro Fina
Which statement about photons of light is true? a. An infrared photon has less energy than an X-ray photon, but travels at the same speed. b. An infrared photon has less energy than an X-ray photon, and travels more slowly. c. An infrared photon has more energy than an X-ray photon, and travels more quickly. d. An infrared photon has more energy than an X-ray photon, but travels at the same speed.
An infrared photon has less energy than an X-ray photon, but travels at the same speed.
23) Under what circumstances can differentiation occur in a planet? A) The planet must have a rocky surface. B) The planet must be made of both metal and rock. C) The planet must have an atmosphere. D) The planet must be geologically active, that is, have volcanoes, planetquakes, and erosion from weather. E) The planet must have a molten interior.
E) The planet must have a molten interior.
5) Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? A) Due to Earth's tilt, the Northern Hemisphere is closer to the Sun than the Southern Hemisphere. B) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. C) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. D) It isn't; both hemispheres have the same seasons at the same time. Summer comes when Earth is nearest the Sun.
The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.
49) The stellar spectral sequence was originally based on which of the following? A) the composition of stars B) the mass of stars C) the strength of hydrogen lines in the spectra of stars D) the core temperature of stars E) the luminosity of stars
he strength of hydrogen lines in the spectra of stars
42) Which two quantities need to be measured in order to determine the density of an extrasolar planet? A) mass and composition B) orbital period and mass C) radius and orbital period D) radius and composition E) mass and radius
mass and radius
39) What is astrometry? A) measuring distances to stars B) searching for planets around stars C) measuring the positions of stars on the sky D) measuring the velocities of stars via the Doppler effect E) using metric units for distance (e.g., meters rather than light-years)
measuring the positions of stars on the sky
39) The Doppler method can be used to estimate the semimajor axis of a planet's orbit by A) measuring the speed at which the star orbits the mutual center-of-mass of the star and planet, and using Newton's theory of gravity. B) measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law. C) measuring the asymmetries in the velocity curve. D) measuring the amount by which the starlight is reduced when the planet transits.
measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law.
33) Where is Jupiter's strong magnetic field generated? A) rocky core B) metallic hydrogen layer C) liquid hydrogen layer D) gaseous hydrogen layer E) cloud tops
metallic hydrogen layer
26) Compared to the atmospheric pressure at sea level on Earth, the atmospheric pressure on Mars is A) about the same B) just slightly lower C) much higher D) much lower
much lower
The term observable universe refers to ________. A) that portion of the universe that we have so far photographed through telescopes B) the portion of the universe that can be seen by the naked eye C) the portion of the universe that is not hidden from view by, for example, being below the horizon D) that portion of the universe that we can see in principle, given the current age of the universe
that portion of the universe that we can see in principle, given the current age of the universe
22) What can we conclude from the fact that Neptune's large moon Triton orbits in a direction opposite to the direction in which Neptune rotates? A) Triton must be made mostly of ice. B) Triton must have formed as the result of a giant impact. C) Triton must have been captured by Neptune. D) Triton must have formed in place around Neptune. E) Triton must be more dense than Neptune.
C) Triton must have been captured by Neptune.
34) What is the approximate diameter of the largest asteroid? A) 1 km B) 10 km C) 100 km D) 1,000 km E) 10,000 km
D) 1,000 km
20) How does the Sun's mass compare with that of the planets? A) It is about a hundred times more massive than Earth. B) It is about a thousand times more massive than Earth. C) It is about a hundred times more massive than all the planets combined. D) It is about a thousand times more massive than all the planets combined. E) It is about as massive as all the planets combined.
D) It is about a thousand times more massive than all the planets combined.
30) What is the primary reason an icy moon is likely to be more geologically active than a rocky moon of the same size? A) Ice has a lower melting point than rock. B) Ice is less rigid than rock. C) Ice contains more radioactive elements than rock. D) Ice is affected by tidal forces to a greater extent than rock. E) Ice is less dense than rock.
Ice has a lower melting point than rock.
3) Relative to the age of the universe, how old is our solar system? A) It is about 1% as old as the universe. B) It is between about 5% and 10% as old as the universe. C) It is about one-third the age of the universe. D) It is nearly the same age as the universe.
It is about one-third the age of the universe.
16) Consider the spectra of the four objects shown beneath the laboratory spectrum. Based on these spectra, what can you conclude about Object 4? A) It is a star with a thin upper atmosphere. B) It is moving toward us. C) It is composed mostly of hydrogen, helium, and iron. D) It is a very hot object, with a temperature above 1 million K. E) It is moving away from us
It is moving toward us.
58) Consider the H-R diagram for a star cluster shown on the right. The dotted lines correspond to the location of a 1-solarmass star. Now consider the star to which the arrow points. Which of the following statements about this star is not true? A) It is significantly less massive than the Sun. B) It is larger in radius than the Sun. C) It is brighter than the Sun. D) Its surface temperature is lower than the Sun's. E) Its core temperature is higher than the Sun's.
It is significantly less massive than the Sun.
26) Which of the following best describes convection? A) It is the process by which rocks sink in water. B) It is the process in which warm material expands and rises while cool material contracts and falls. C) It is the process in which warm material gets even warmer and cool material gets even cooler. D) It is the process in which a liquid separates according to density, such as oil and water separating in a jar. E) It is the process in which bubbles of gas move upward through a liquid.
It is the process in which warm material expands and rises while cool material contracts and falls.
9) What is the significance of the photograph on the right? A) It was taken Jan. 1, 2000 to commemorate the turn of the millennium. B) It shows the first person ever to land on Mars. C) It shows the first person ever to go into space. D) It shows a person standing on the most distant world ever visited by a human being.
It shows a person standing on the most distant world ever visited by a human being.
74) This painting shows a futuristic spacecraft powered by the detonation of small hydrogen bombs. If we actually had such a spacecraft, what would it allow us to do? A) It would allow us to travel from Earth to Mars in less than an hour. B) It would allow us to travel roundtrip to almost anywhere in the Milky Way galaxy in just a few years' time. C) It would allow us to make a one-way trip to the nearest star besides the Sun in about a century. D) It would allow us to travel up to several times faster than the speed of light.
It would allow us to make a one-way trip to the nearest star besides the Sun in about a century.
34) What causes the "gaps" observed in the asteroid belt between Mars and Jupiter? A) There are very few asteroids with diameters between 1 and 100 kilometers, creating a gap in the size distribution. B) Asteroids cluster together due to their mutual gravity and this creates gaps in their distribution. C) There is a large population of asteroids too faint to see called the "gap" asteroids. D) Jupiter's gravity causes orbital resonances that nudge asteroids out of these areas. E) There are either pure metal or pure rock asteroids, but no mixtures. Thus there is a "gap" in the composition of asteroids.
Jupiter's gravity causes orbital resonances that nudge asteroids out of these areas.
10) He discovered that the orbits of planets are ellipses. A) Tycho Brahe B) Copernicus C) Kepler D) Galileo E) Ptolemy
Kepler
21) Which planet has the most extreme temperature difference between day and night? A) Mercury B) Venus C) Earth D) Mars E) Jupiter
Mercury
24) According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets? A) Our theory is not quite correct because it cannot explain these exceptions. B) Most of the exceptions are the result of giant impacts or close gravitational encounters. C) The exceptions probably represent objects that formed recently, rather than early in the history of the solar system. D) The exceptions probably represent objects that were captured by our solar system from interstellar space. E) The exceptions are probably the result of the Sun passing very close to another star billions of years ago.
Most of the exceptions are the result of giant impacts or close gravitational encounters.
13) Study the diagram on the right, which shows why we see phases of Venus, as first observed by Galileo. When should we expect to see a full Venus in our night sky? A) At midnight, when Venus is on the opposite side of its orbit from Earth. B) Never. C) Only when Earth is at the opposite side of the Sun from what is shown in this diagram. D) At midnight, when Venus is on the same side of its orbit from Earth.
Never
43) What is the solution to the solar neutrino problem? A) The electron neutrinos created in the Sun's core change into another type of neutrino that we did not originally detect. B) The Sun is generating energy other than by nuclear fusion. C) The Sun is generating much less energy than we think it is. D) We did not know how to detect neutrinos. E) Not all fusion reactions create neutrinos.
The electron neutrinos created in the Sun's core change into another type of neutrino that we did not originally detect.
43) What is the solution to the solar neutrino problem? A) The Sun is generating energy other than by nuclear fusion. B) The Sun is generating much less energy than we think it is. C) We did not know how to detect neutrinos. D) Not all fusion reactions create neutrinos. E) The electron neutrinos created in the Sun's core change into another type of neutrino that we did not originally detect.
The electron neutrinos created in the Sun's core change into another type of neutrino that we did not originally detect.
28) Why is Jupiter denser than Saturn? A) It is made of a different composition than Saturn, including a higher proportion of hydrogen compounds and rocks. B) The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn. C) Its core is much larger than Saturn's. D) It has a greater proportion of helium to hydrogen compared to Saturn. E) Scientists do not know why this is so.
The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn.
36) Why aren't small asteroids spherical in shape? A) The force of gravity in small asteroids is less than the resistance of the rock to deform. B) Small asteroids have odd shapes because they were all chipped off larger objects. C) Large asteroids were once molten and therefore became spherical, but small asteroids were never molten. D) Large asteroids became spherical because many small collisions chipped off pieces until only a sphere was left; this did not occur with small asteroids.
The force of gravity in small asteroids is less than the resistance of the rock to deform.
4) What is a circumpolar star? A) a star that is close to the north celestial pole B) a star that is close to the south celestial pole C) a star that always remains above your horizon D) a star that makes a daily circle around the celestial sphere E) a star that is visible from the Arctic or Antarctic circles
a star that always remains above your horizon
6) The celestial sphere is A) the central spherical region of the Milky Way Galaxy, dense with stars. B) a spherical galaxy, centered on the Sun. C) a useful illusion used to map the stars and other objects in the sky. D) the star-sphere discovered by the Greeks and other ancient civilizations which shows the physical location in space of the nearby stars. E) the orb of the Sun; a normal star
a useful illusion used to map the stars and other objects in the sky.
57) Degeneracy pressure stops the crush of gravity in all the following except A) a brown dwarf. B) a white dwarf. C) a neutron star. D) a very massive main-sequence star. E) the central core of the Sun after hydrogen fusion ceases but before helium fusion begins.
a very massive main-sequence star.
73) The 1420 MHz (21 cm) radio line generated by neutral hydrogen atoms is a good choice for interstellar communications because A) it is the easiest radio frequency to generate B) all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency C) it is the only radio frequency that is not blocked by interstellar matter D) it is the only frequency to which radio telescopes can be tuned
all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency
63) What is a standard candle? A) an object whose luminosity we know B) an object for which we can easily measure its apparent brightness C) a class of objects that we know all have exactly the same apparent brightness D) any star for which we know its exact apparent brightness E) a unit of luminosity used by astronomers
an object whose luminosity we know
25) The Cassini mission to Saturn consists of ________. A) an orbiter that orbits Saturn and a probe that descended to the surface of Titan B) a large spacecraft that flew by Saturn on its way to other planets C) an orbiter that orbits Saturn and a probe that descended into Saturn's atmosphere D) a spacecraft that orbits Saturn and a sample return mission that landed on Titan, scooped up a surface sample, and will return it to Earth
an orbiter that orbits Saturn and a probe that descended to the surface of Titan
61) What produces the 21-cm radio emission line that can be used to map the Milky Way Galaxy? A) atomic hydrogen B) ionized hydrogen C) molecular hydrogen D) carbon monoxide E) helium
atomic hydrogen
2) Why do the patterns of the stars in our sky look the same from year to year? A) because the stars in the constellations are so far away B) because the stars in the constellations are not moving C) because the stars in the constellations all move at the same speeds and in the same directions, so they don't change their relative positions D) because the stars in the constellations move so slowly—typically about the speed of a snail— that their motions are not noticeable
because the stars in the constellations are so far away
56) Helium fusion directly results in the formation of A) hydrogen. B) oxygen. C) carbon. D) nitrogen. E) iron.
carbon
75) The adoption of very similar streamlined body shapes by both sharks and dolphins provides evidence for A) cross-breeding B) convergent evolution C) genetic mutations D) life originating in the oceans
convergent evolution
51) What condition is necessary in an interstellar gas cloud for it to begin collapsing? A) a low density B) a low temperature C) a high temperature D) a high heavy element content E) a low heavy element content
low temperature
Which of the following stellar properties has the greatest range in values? A) mass B) radius C) core temperature D) surface temperature E) luminosity
luminosity
6) Ancient people who knew the saros cycle could A) completely predict every lunar eclipse. B) completely predict every solar eclipse. C) predict what type of eclipse would occur. D) predict when they'd see the next total solar eclipse in their area. E) predict when an eclipse would happen, but not necessarily what type and where it would be visible.
predict when an eclipse would happen, but not necessarily what type and where it would be visible.
18) In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate? A) infrared B) visible C) ultraviolet D) X-ray E) radio
radio
12) If an interstellar gas cloud shrank in size, what does the law of conservation of angular momentum predict will happen? It will A) heat up. B) slow down in its rotation. C) cool off. D) continue shrinking. E) rotate faster.
rotate faster.
58) Consider an X-ray binary system in which the compact object is surrounded by an accretion disk. All of the following statements about such accretion disks are true except A) X-rays are emitted by the hot gas in the accretion disk. B) the accretion disk consists of material that spills off the companion star. C) the compact object may be either a neutron star or a black hole. D) several examples of flattened accretion disks being "fed" by a large companion star can be seen clearly in photos from the Hubble Space Telescope. E) the radiation from an accretion disk may vary rapidly with time.
several examples of flattened accretion disks being "fed" by a large companion star can be seen clearly in photos from the Hubble Space Telescope.
2) Sunspots are cooler than the surrounding gas in the photosphere because A) they are regions where convection carries cooler material downward. B) strong magnetic fields slow convection and prevent hot plasma from entering the region. C) magnetic fields trap ionized gases that absorb light. D) there is less fusion occurring there. E) magnetic fields lift material from the sunspot and quickly cool the material
strong magnetic fields slow convection and prevent hot plasma from entering the region.
27) An image of Mars taken with the Hubble Space Telescope shows a small Northern polar cap and a large Southern Polar cap. What season is it in the Northern hemisphere? A) spring B) fall C) summer D) winter
summer
8) Which of the four ellipses shown below has the least eccentricity? A) 1 B) 2 C) 3 D) 4
1
1) The farthest galaxies that modern telescopes are capable of seeing are up to A) 10 million light-years away. B) 1 billion light-years away. C) 5 billion light-years away. D) 10 billion light-years away . E) 1 trillion light-years away.
10 billion light-years away
67) How long after the Big Bang was the Planck time, the time at which our current theories become completely unable to describe conditions any earlier in the universe? A) 10-10 seconds B) 10-35 seconds C) 10-43 seconds D) 3 minutes E) 380,000 years
10-43 seconds
44) What is the approximate temperature of the Sun's core? A) 5,800 K B) 10,000 K C) 1 million K D) 15 million K E) 150 million K
15 million K
2) According to astronomers, how old is Earth? A) 4.5 billion years old B) 4.5 trillion years old C) 1.5 million years old D) 14 billion years old
4.5 billion years old
18) One of the absorption lines of hydrogen has a rest wavelength of 656 nm (at rest means with respect to the observer, like in a lab). You observe several stars and measure the wavelength of this same hydrogen absorption line in each star. Based on the measured wavelength of this line, which star is moving towards the Earth the fastest? A) 630 nm B) 640 nm C) 656 nm D) 670 nm E) 690 nm
630 nm
69) Why do scientists suspect that life first arose near deep-sea volcanic vents or similar environments with abundant chemical energy? A) A deep ocean environment would have protected early organisms from ultraviolet radiation before the formation of the ozone layer. B) All organisms have similar DNA, with further relations having greater differences. C) Deep-sea volcanic vents would have been the only source of energy present on Earth when life was forming. D) all of the above
A deep ocean environment would have protected early organisms from ultraviolet radiation before the formation of the ozone layer.
15) Considering Einstein's equation relating mass and energy, E = mc2, which of the following statements is true? A) Mass can be turned into energy, but energy cannot be turned back into mass. B) It takes a large amount of mass to produce a small amount of energy. C) A small amount of mass can be turned into a large amount of energy. D) You can make mass into energy if you can accelerate the mass to the speed of light. E) One kilogram of mass represents 1 joule of energy.
A small amount of mass can be turned into a large amount of energy.
35) What characteristic distinguishes a meteorite from a terrestrial rock? A) A meteorite is usually covered with a dark crust from burning in Earth's atmosphere. B) A meteorite usually has a high metal content. C) Meteorites have different isotope ratios of particular elements when compared to terrestrial rocks. D) Meteorites often contain rare elements that terrestrial rocks do not. E) All of the above are true.
All of the above are true.
48) Which of the following statements about apparent and absolute magnitudes is true? A) The magnitude system that we use now is based on a system used by the ancient Greeks over 2,000 years ago that classified stars by how bright they appeared. B) A star with an apparent magnitude of 1 appears brighter than a star with an apparent magnitude of 2. C) The absolute magnitude of a star is dependent upon its luminosity. D) A star's absolute magnitude is the apparent magnitude it would have if it were at a distance of 10 parsecs from Earth. E) All of the above are true.
All of the above are true.
47) The "butterfly" diagram above shows the progression of sunspots during the last several solar cycles. Why is each set of "butterfly wings" slanting downward and to the right? A) As each solar cycle progresses, sunspots form closer to the solar equator. B) The distribution of sunspots during each solar cycle is random. C) As each solar cycle progresses, it becomes more and more difficult to form large sunspots. D) As each solar cycle progresses, sunspots form at higher and higher latitudes. E) As each solar cycle progresses, atmospheric drag causes sunspots to move closer to the solar equator
As each solar cycle progresses, sunspots form closer to the solar equator.
60) Which of the following does not accurately describe what we observe toward the galactic center? A) At radio wavelengths, we see giant gas clouds threaded by powerful magnetic fields. B) At infrared wavelengths, we see a massive star cluster. C) At optical wavelengths, we see a cluster of old, red stars. D) At X-rays, we see faint emission from an accretion disk around a black hole.
At optical wavelengths, we see a cluster of old, red stars.
25) When we see a region of a planet that is not as heavily cratered as other regions, we conclude that A) there is little volcanic activity to create craters. B) the planet is rotating very slowly and only one side was hit by impactors. C) the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals. D) the surface in the region is younger than the surface in more heavily cratered regions. E) the surface in the region is older than the surface in more heavily cratered regions.
D) the surface in the region is younger than the surface in more heavily cratered regions.
29) Why does Jupiter have several distinct cloud layers? A) Different layers represent clouds made of gases that condense at different temperatures. B) Different layers represent the various regions where the temperature is cool enough for liquid water to condense. C) Different gases are present at different altitudes in Jupiter's atmosphere. D) Winds prevent clouds from forming at some altitudes, so we see clouds only at the other altitudes. E) Clouds form randomly, so on average there are always several layers.
Different layers represent clouds made of gases that condense at different temperatures.
71) Notice the gray ovals (such as those indicated by the arrows) in this image of a galaxy cluster. The oval structures are not really located where they appear to be, but instead are multiple images of a single galaxy that lies directly behind the cluster. What do we call the process that creates these multiple images? A) Cluster image distortion B) Dark energy C) The arc effect D) Gravitational lensing E) Dark matter
Gravitational lensing
62) Why are we unlikely to find Earth-like planets around halo stars in the galaxy? A) Planets around stars are extremely rare in our galaxy. B) Halo stars formed from gas containing few heavy elements, which are needed to create terrestrial planets like the Earth. C) Halo stars formed from gas containing lots of heavy elements and few of the light elements needed to create terrestrial planets like the Earth. D) Halo stars are all very low mass stars that cannot hold onto planets. E) Halo stars formed directly from gas in the halo without forming a planetary disk.
Halo stars formed from gas containing few heavy elements, which are needed to create terrestrial planets like the Earth.
1) How are galaxies able to recycle the material of stars? A) As the stars burn, they grow smaller. The gravity of the galaxy joins them together. B) As a galaxy rotates, the stars cycle around the galaxy center again and again, returning to where they started. C) New stars are continuously being formed in galaxies out of the gas that has been ejected during the evolution of a previous generation of stars. D) New galaxies are continuously being formed from gas that remains after the explosion of previous galaxies. E) In the formation of a star, no matter is wasted. All excess material ends up recycled into orbiting planets
New stars are continuously being formed in galaxies out of the gas that has been ejected during the evolution of a previous generation of stars.
10) The controversial book On the Revolutions of the Celestial Spheres of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun. A) Tycho Brahe B) Nicolas Copernicus C) Johannes Kepler D) Galileo Galilei E) Claudius Ptolemy
Nicolas Copernicus
5) Has Polaris always been the "North Star", also known as the "Pole Star"? A) Yes, because stars position change little over many centuries. B) No, because the Earth's axis slowly changes the direction it points. C) No, because it is a young star which formed only a few hundred years ago. D) No, because the Milky Way blocked our line of site to it for a long time.
No, because the Earth's axis slowly changes the direction it points.
14) The photos on the right show two different astronomical objects. Which object is bigger, and by about how much? A) Object 2 is approximately 1,000 times as large as Object 1. B) Object 1 is about 10 times as large as Object 2. C) Object 2 is more than a trillion times as large as Object 1. D) Both objects are about the same size. E) Object 2 is about 10 times as large as Object 1.
Object 2 is more than a trillion times as large as Object 1.
How do observations of galaxies at different distances help us learn about galaxy evolution? A) Observations of different distances show galaxies of different ages and therefore different stages of evolution. B) We can see the primordial clouds of gas that formed the galaxies. C) We can observe the evolution of a single galaxy over time. D) We can observe galaxies at different distances merge, helping us learn how mergers affect evolution. E) We can see what our galaxy used to look like over time, helping us theorize about the physical processes that led to its current appearance.
Observations of different distances show galaxies of different ages and therefore different stages of evolution.
41) Why haven't we detected low-mass planets close to their stars and high-mass planets far from their stars? A) We have not been observing for a long enough time. B) We have not been looking at stars similar to our Sun. C) Our techniques are not yet sensitive enough and we have not been observing for a long enough time. D) Our techniques are not yet sensitive enough. E) Such systems cannot form, as the material in dust disks is densest close to their stars.
Our techniques are not yet sensitive enough and we have not been observing for a long enough time.
19) Why do astronomers need different telescopes at different locations to observe across the electromagnetic spectrum? A) There are not enough telescopes to fill the need, so telescopes are grouped, and each group is allocated to one band of the electromagnetic spectrum. B) Visible light specifically requires refracting telescopes that use lenses to bend light. C) Photons of different wavelengths behave differently and so require different collection strategies. D) Light pollution is worse at radio wavelengths than visible wavelengths. E) Visible light telescopes require a ground environment and radio telescopes require a space environment.
Photons of different wavelengths behave differently and so require different collection strategies.
38) What is the chief difficulty in attempting to detect planets around other stars? A) Even the largest planets are thousands of times smaller than their host stars. B) Planets do not emit visible light, and they are typically at least a billion times fainter than their host stars. C) Planets do not glow in the infrared, so infrared telescopes cannot be used to study them, either. D) As viewed from Earth, planets often hide behind their stars and cannot be seen. E) all of the above
Planets do not emit visible light, and they are typically at least a billion times fainter than their host stars.
What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane? A) Solar eclipses would be much rarer. B) Solar eclipses would be much more frequent. C) Total solar eclipses would last much longer. D) Both A and C E) Both B and C
Solar eclipses would be much more frequent.
59) Why is there an upper limit to the mass of a white dwarf? A) White dwarfs come only from stars with masses less than 1.4 solar masses. B) The more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, and no more mass can be supported. C) The more massive the white dwarf, the higher its temperature and hence the greater its degeneracy pressure. Near 1.4 solar masses, the temperature becomes so high that all matter effectively melts into subatomic particles. D) The upper limit to the masses of white dwarfs was determined through observations of white dwarfs in binary systems, but no one knows why the limit exists.
The more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, and no more mass can be supported.
63) What evidence supports the existence of a very massive black hole at the center of our galaxy? A) We observe an extremely bright X-ray source at the center of our galaxy. B) We can see gas falling into an accretion disk and past the event horizon of a black hole. C) The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region no larger than our solar system. D) We observe a large, dark object that absorbs all light at the center of our galaxy. E) all of the above
The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region no larger than our solar system.
You observe a star very similar to our own Sun in size and mass. This star moves very slightly back and forth in the sky once every 4 months, and you attribute this motion to the effect of an orbiting planet. What can you conclude about the orbiting planet? A) The planet must be closer to the star than Earth is to the Sun. B) The planet must have a mass about the same as the mass of Jupiter. C) The planet must be farther from the star than Neptune is from the Sun. D) You do not have enough information to say anything at all about the planet.
The planet must be closer to the star than Earth is to the Sun.
37) Why does the plasma tail of a comet always point away from the Sun? A) Radiation pressure from the Sun's light pushes the ions away. B) The solar wind pushes the plasma ions directly away from the Sun. C) The conservation of the angular momentum of the tail keeps it always pointing away from the Sun. D) Gases from the comet, heated by the Sun, push the tail away from the Sun. E) The particles in the plasma tail are more massive than those in the dust tail.
The solar wind pushes the plasma ions directly away from the Sun.
Why did the era of nuclei end when the universe was about 380,000 years old? A) All the free particles had combined to form the nuclei of atoms. B) The universe had expanded and cooled enough for stable, neutral atoms to form. C) Atomic nuclei were finally able to escape the plasma of the early universe. D) Photons were finally able to escape the plasma of the early universe and were no longer available to produce hydrogen and helium nuclei. E) The nucleosynthesis era that produced the nuclei heavier than helium ended.
The universe had expanded and cooled enough for stable, neutral atoms to form.
29) Why do we think Mercury has so many tremendous cliffs? A) They were probably carved in Mercury's early history by running water. B) They were probably formed by tectonic stresses when the entire planet shrank as its interior cooled. C) They probably formed when a series of large impacts hit Mercury. D) They are probably volcanic in origin, carved by flowing lava. E) They were probably formed by convection occurring in Mercury's mantle.
They were probably formed by tectonic stresses when the entire planet shrank as its interior cooled.
1) Earth is made mostly of metals and rocks. Where did the elements (carbon, silicon, iron, etc.) that make up these materials form? A) They were produced by the Big Bang. B) They are a product of chemical reactions in interstellar gas clouds. C) They were produced by nuclear fusion in stars. D) They were produced by nuclear fusion in our Sun. E) They were produced by nuclear fission of uranium and other radioactive materials in space.
They were produced by nuclear fusion in stars.
45) At the time the hypothesis was suggested, what major problem was identified with the idea that the Sun was powered by gravitational contraction? A) Contracting objects cool down rather than heat up. B) This process would power the Sun for only about 25 million years, but geologists already had evidence the Earth was much older than that. C) This process could not possibly lead to the observed power output of the Sun. D) 19th century astronomers should have been able to measure the required change in the Sun's size.
This process would power the Sun for only about 25 million years, but geologists already had evidence the Earth was much older than that.
31) Which moon did the Huygens spacecraft land on? A) Ganymede B) Callisto C) Europa D) Titan E) Triton
Titan
61) From a physical standpoint, what is a pulsar? A) a star that alternately expands and contracts in size B) a rapidly rotating neutron star C) a neutron star or black hole that happens to be in a binary system D) a binary system that happens to be aligned so that one star periodically eclipses the other E) a star that is fusing iron in its core
a rapidly rotating neutron star
70) What evidence suggests that the Milky Way contains dark matter? A) We observe clouds of atomic hydrogen far from the galactic center orbiting the galaxy at higher speeds than they would have if they felt only the gravitational attraction from objects that we can see. B) We see many lanes of dark material blocking out the light of stars along the band of the Milky Way. C) We see many dark voids between the stars in the halo of the Milky Way. D) When we observe in different wavelengths, such as infrared or radio, we see objects that don't appear in visible-light observations. E) When we look at the galactic center, we are able to observe a large black hole that is composed of dark matter.
We observe clouds of atomic hydrogen far from the galactic center orbiting the galaxy at higher speeds than they would have if they felt only the gravitational attraction from objects that we can see.
72) How is the "Fermi Paradox" normally stated? A) Why are we here? B) Who are we? C) Where are we? D) Where is everybody?
Where is everybody?
35) What is a meteorite? A) a streak of light caused by a star moving across the sky B) a streak of light caused by a small particle from space burning up in Earth's atmosphere C) a fragment of material from the solar system that has fallen to Earth's surface D) a small moon that orbits one of the giant planets E) a comet that burns up in Earth's atmosphere
a fragment of material from the solar system that has fallen to Earth's surface
11) Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that A) a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun. B) a planet's period does not depend on the eccentricity of its orbit. C) planets that are farther from the Sun move at slower average speeds than nearer planets. D) the period of a planet does not depend on its mass. E) planets have circular orbits.
a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.
66) What is the main idea of the Big Bang theory? A) the idea that the universe formed from the collapse of a previous universe B) the idea that all matter and energy in the universe began in an unimaginably dense state, and then space itself began expanding in all directions C) the idea that the universe as we see it formed from the singularity in a black hole D) the idea that a massive explosion about 14 billion years ago created all matter and energy that rushed out to fill the surrounding space
the idea that all matter and energy in the universe began in an unimaginably dense state, and then space itself began expanding in all directions
46) Which layer is considered the "surface" of the Sun? A) the corona B) the chromosphere C) the photosphere D) the tachycline E) none of the above
the photosphere
24) The lithosphere of a planet is the layer that consists of A) material above the crust. B) material between the mantle and the core. C) the rigid rocky material of the crust and uppermost portion of the mantle. D) the softer rocky material of the mantle. E) the lava that comes out of volcanoes.
the rigid rocky material of the crust and uppermost portion of the mantle.
15) The names of the seven days of the week are based on ________. A) the names of the seven planets closest to the Sun B) the seven most prominent constellations in the summer sky C) the names of prophets in the Bible D) the seven naked-eye objects that appear to move among the constellations
the seven naked-eye objects that appear to move among the constellations
39) The reason that most extrasolar planets discovered by the Doppler method are found close to their parent stars is A) they transit more frequently, and have thus been more likely to be detected in the short time we have been searching for them. B) more of the starlight is blocked by the planet when it transits the star. C) the wavelength shift of the star's spectrum is larger. D) the closer to a star, the hotter and therefore brighter the planet is. E) planets that are close to a star are heated up and therefore larger.
the wavelength shift of the star's spectrum is larger.
33) Which of the following applies to Europa? A) the most volcanically active body in the solar system B) thought to have a deep, subsurface ocean of liquid water C) probably a captured Kuiper Belt object D) the only moon of a jovian planet with an atmosphere thicker than Earth's atmosphere
thought to have a deep, subsurface ocean of liquid water
19) What is the purpose of adaptive optics? A) to reduce blurring caused by atmospheric turbulence for telescopes on the ground B) to allow several small telescopes to work together like a single larger telescope C) to increase the amount of light gathered by allowing the telescope's computer to reconfigure the pathways of observed light D) to allow ground-based telescopes to observe ultraviolet light that normally does not penetrate all the way to the ground
to reduce blurring caused by atmospheric turbulence for telescopes on the ground
40) Which planet search technique is currently best suited to finding Earth-like planets? A) Doppler B) astrometric C) transit D) gravitational lensing E) combining all of the above
transit
49) Which stars produce most of their energy by the CNO cycle? A) Protostars B) upper main-sequence stars C) protostars and lower main-sequence stars D) protostars and upper main-sequence stars E) lower main-sequence stars
upper main-sequence stars
What two quantities did Edwin Hubble compare for a sample of galaxies to discover the expansion of the universe? A) luminosity and distance B) velocity and temperature C) velocity and distance D) luminosity and temperature E) age and distance
velocity and distance
32) Which of the following best describes the composition of the particles forming Saturn's rings? A) methane ice B) water ice C) metallic grains D) volcanic rock E) hydrogen and helium
water ice
30) Suppose Earth's atmosphere had no greenhouse gases. This would cause Earth's average surface temperature to be A) well below the freezing point of water. B) at the freezing point of water. C) at the boiling point of water. D) the same temperature as it is now. E) slightly warmer than it is now.
well below the freezing point of water.
52) What can we learn about a star from its life track on an H-R diagram? A) how long ago it was born B) when it will die C) where it is located D) what surface temperature and luminosity it will have at each stage of its life E) all of the above
what surface temperature and luminosity it will have at each stage of its life
12) Earth is farthest from the Sun in July and closest to the Sun in January. During which Northern Hemisphere season is Earth moving fastest in its orbit? A) winter B) spring C) summer D) fall
winter
