Astronomy AEGO Questions
The dwarf planet Erie orbits the Sun every 557 years. How does its average distance (67.7 a.u.) compare to that of Pluto? (aEris/aPluto)
1.72
Fm=5/Fm=10 = ? (HINT: use (100^1/5)^m2-m1
100
LM=-2/LM=8 = ? (HINT: (100^1/5)^M2-M1)
251.2
The dwarf planet Erie orbits the Sun every 557 years. What its average distance (semi majoraxis) from the Sun?
67.7 a.u.
A star with a parallax angle of 1/20 arc second is A. 20 parsecs away B. 1/20 parsec away C. 10 parsecs away D. 20 light-years away
A
A star's color is related to its surface temperature because A. stars emit thermal radiation B. stars have absorption lines in their spectra C. the colors of stars depend mainly on the emission lines in the spectra D. the color of a star depends on its mass, and mass is related to surface temperature
A
A star's luminosity is the A. total amount of light that the star radiates each second B. lifetime of the star C. apparent brightness of the star in our sky D. total amount of light that the star will radiate over its entire lifetime E. surface temperature of the star
A
Assume that Hubble's constant is 22 kilometers per second per million light-years. How fast would we expect a galaxy 100 million light-years away to be moving? (Assume the motion is due only to Hubble's law.) A. away from us at 2,200 km/s B. away from us at 220 km/s C. toward us at 2,200 km/s D. away from us at 22,000 km/s
A
At what positions(s) in its orbit would we see all of the Moon's daylight side and none of its night side? A. at the point on the far left B. at the two points at the top and bottom C. at the two points on the far left and far right D. at the point on the far right
A
Beijing and Philadelphia have about the same latitude but different longitudes. What can be said about the tonight's night sky in these two places? A. The sky will look about the same B. The sky will have completely different sets of constellations C. The sky will have partially different sets of constellations
A
Consider Earth and the Moon. As you should now realize, the gravitational force that Earth exerts on the Moon is equal and opposite to that which the Moon exerts on Earth. Therefore, according to Newton's second law of motion A. the Moon has a larger acceleration than Earth, because it has a smaller mass B. Earth has a larger acceleration than the Moon, because it has a larger mass C. the Moon and the Earth both have equal accelerations, because the forces are equal
A
During the time before fusion begins, a protostar's core gradually A. shrinks and heats B. shrinks and cools C. shrinks and maintains a constant temperature D. expands and cools
A
How do we learn the chemical composition of the interstellar medium? A. by studying spectra of interstellar gas clouds B. we use computer simulations of the interstellar medium C. we make an educated guess based on the Sun's composition D. we collect samples of gas and dust from interstellar space
A
Hubble's galaxy classification diagram (the "tuning fork") A. relates galaxies according to their shapes but not according to any evolutionary status B. explains active galactic nuclei C. shows how galaxies evolve from one form to another D. suggests the existence of black holes
A
If a star is extremely massive (well more than 100-solar masses), why isn't it likely to survive for long? A. it may blow itself apart because of radiation pressure B. it eventually divides into two lower-mass stars C. it explodes as a supernova after just a few dozen years D. its great mass will cause it to suck itself into becoming a black hole
A
If the distance between us and a star is doubled, the apparent brightness is decreased by a factor of 4 A. True B. False
A
In 1924, Edwin Hubble proved that the Andromeda Galaxy lay far beyond the bounds of the Milky Way, thus putting to rest the idea that it might have been a cloud within our own galaxy. How was he able to prove this? A. By observing individual Cepheid variable stars in Andromeda and applying the period-luminosity relation B. He was able to. measure the parallax of the Andromeda Galaxy C. He was the first person ever to look through a telescope at the object we now call the Andromeda Galaxy D. He found that the universe is expanding, and therefore concluded that Andromeda must lie outside our own galaxy
A
In science, a broad idea that has been repeatedly verified so as to give scientists great confidence that it represents reality is called A. a theory B. a hypothesis C. a paradigm D. a Ptolemaic model
A
Large telescopes often have small fields of view. For example, the Hubble Space Telescope's (HST's) advanced camera has a field of view that is roughly square and about 0.06 degree on a side. Calculate the angular area of the HST's field of view in square degrees. A. 0.0036 degrees B. 0.06 square degrees C. 0.006 square degrees D. 0.36 square degrees
A
On an H-R diagram, where would we find red giant stars? A. upper right B. lower right C. upper left D. lower left
A
On an H-R diagram, where would we find stars that have the largest radii? A. upper right B. lower right C. upper left D. lower left
A
Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude? A. Rigel has a higher surface temperature than Sirius B. Rigel has a higher core temperature than Sirius C. Sirius has a higher surface temperature than Rigel B. Sirius has a higher core temperature than Rigel
A
Suppose instead that we are looking at the gas cloud but the light source is off to the side instead of directly behind it. In that case, the spectrum would A. be an emission line spectrum B. appear as a continuous rainbow of colors C. still be an absorption spectrum D. appear completely dark
A
The age of the universe is related to the slope of the graph of Hubble's Law, and current data put the age of the universe at about 14 billion years. Suppose that future observations showed that the slope of Hubble's Law on the graph is actually steeper than that shown. In that case, the age of the universe would be ____ than 14 billion years because the universe is expanding ____ than current data suggest. A. younger / more rapidly B. younger / more slowly C. older / more rapidly D. older / more slowly
A
The approximate main-sequence lifetime of a star of spectral type O is A. 3 million years B. 300 million years C. 10 billion years D. 10,000 years
A
The graph of Hubble's Law shows that galaxies with high speeds as measured from Earth are A. moving AWAY from Earth and are FARTHER from Earth than galaxies with lower speeds B. moving TOWARD Earth and are FARTHER from Earth than galaxies with lower speeds C. moving AWAY from Earth and are CLOSER from Earth than galaxies with lower speeds D. moving TOWARD Earth and are CLOSER from Earth than galaxies with lower speeds
A
The observed relationship between the masses of central black holes and the bulge masses of galaxies implies that A. galaxy formation and supermassive black hole formation must be related somehow B. quasars were more common 10 billion years ago than they are today C. the black hole will eventually suck in the rest of the galaxy D. the biggest galaxies have the most luminous quasars
A
The white dwarf that remains when our Sun dies will be mostly made of A. carbon B. helium C. hydrogen D. neutrons
A
Under which circumstances can you be SURE that the thermal pressure within a gas cloud is increasing? A. the cloud's temperature and density are both increasing B. the cloud's temperature is decreasing and its density is increasing C. the cloud's temperature and density are both decreasing D. the cloud's temperature is increasing and its density is decreasing E. impossible to say
A
What are the standard units for luminosity? A. watts B. joules C. watts per second D. kilograms E. Newtons
A
What is the best way to determine a galaxy's redshift? A. Take a spectrum of the galaxy, and measure the difference in wavelength of spectral lines from the wavelengths of those same lines as measured in the laboratory B. Measure the magnitude of the galaxy, estimate its distance, and calculate its redshift using Hubble's Law C. Find the galaxy's apparent distance, and look up the redshift based on Hubble's Law D. Find the color of the galaxy, and estimate its distance based on how red the galaxy is
A
What two pieces of information would you need in order to measure the masses of stars in an eclipsing binary system? A. the time between eclipses and the average distance between the stars B. the period of the binary system and its distance from the Sun C. the velocities of the stars and the Doppler shifts of their absorption lines
A
What type of visible light spectrum does the Sun produce? A. an absorption line spectrum B. a continuous spectrum C. an emission line spectrum
A
Where along its orbit would the Moon also have its daylight side on the right and its night side on the left? A. everywhere along its orbit B. only at the point on the far left (the full moon position) C. only at the two points at the top and bottom (the first- and third-quarter positions) D. only at the point on the far right (the new moon position) E. only at the two points on the far left and far right (the new and full moon positions)
A
Where does a 1 solar-mass protostar appear on an H-R diagram? A. to the right of the main-sequence and higher up than the Sun B. nowhere; only stars that have fusion in their cores can be shown on H-R diagrams C. to the right of the main-sequence and lower down than the Sun D. to the left of the main-sequence and higher up than the Sun
A
Which event marks the beginning of a supernova? A. the sudden collapse of an iron core into a compact ball of neutrons B. the beginning of neon burning in an extremely massive star C. the sudden initiation of the CNO cycle D. the onset of helium burning after a helium flash
A
Which has a greater luminosity, a star with absolute magnitude -2 or a star with absolute magnitude 8? A. A star with absolute magnitude -2 B. A star with absolute magnitude 8
A
Which of the following correctly lists our "cosmic address" from small to large? A. Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe B. Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy, universe C. Earth, Milky Way Galaxy, solar system, Local Group, Local Supercluster, universe
A
Which of the following is NOT true about differences between novae and supernovae? A. supernovae eject gas into space but novae do not B. novae occur only in binary star systems, whereas supernovae can occur both among single stars and among binary star systems C. the same star can undergo novae explosions more than once but can undergo only a single supernova D. novae are much less luminous than supernovae
A
Which of the following statement about spectral types of stars is NOT generally true? A. the spectral type of a star can be used to determine its distance B. the spectral type of a star can be determined by identifying lines in its spectrum C. the spectral type of a star can be used to determine its surface temperature D. the spectral type of a star can be used to determine its color
A
Which of the following statements about various stages of core nuclear burning (hydrogen, helium, carbon, etc.) in a high-mass star is NOT true? A. Each successive stage lasts for approximately the same amount of time B. As each stage ends, the core shrinks and heats further C. Each successive stage creates an element with a higher atomic number and atomic mass number D. As each stage ends, the reactions that occurred in previous stages continue in shells around the core
A
Which of these stars has the greatest surface temperature? A. a 30MSun main-sequence star B. a supergiant A star C. a Cepheid variable star
A
Which of these stars is the most massive? A. a main-sequence A star B. a main-sequence G star C. a main-sequence M star
A
Which statement best describes how variation in the Earth-Sun distance affects the seasons? A. The variation in Earth-Sun distance over the course of each year has virtually no effect on the seasons B. No matter where you live or what the seasons, it is generally hotter when Earth is closer to the Sun and colder when Earth is farther from the Sun C. Summer occurs when Earth is closer to the Sun and winter occurs when Earth is farther from the Sun
A
Why does the rotation of a protostar slow down over time? A. magnetic fields can transfer angular momentum to the protostellar disk and protostellar winds can carry angular momentum away B. magnetic fields of other stars interact with the magnetic fields of the protostars, slowing its rotation C. the onset of fusion causes the rotation ate to slow dramatically D. all rotating objects slow down over time
A
Why is a 1 solar-mass red giant more luminous than a 1 solar-mass main sequence star? A. Fusion reactions are producing energy at a greater rate in the red giant B. The red giant has a hotter core C. The red giant is more massive D. The red giant's surface is hotter
A
Why should galaxy collisions have been more common in the past than they are today? A. galaxies were closer together int he past because the universe was smaller B. galaxies attracted each other more strongly in the past because they were more massive; they had not yet turned most of their mass into stars C. galaxies were more active in the past and therefore would have collided with each other more frequently D. galaxies were much bigger in the past because they had not contracted completely
A
What conditions must exist for a lunar eclipse to occur? Select all that apply. A. it must be full moon B. the Moon must be passing through Earth's orbital plane C. it must be new moon D. it must be near the time of the summer or winter solstice E. the Moon must be below Earth's orbital plane
A and B
Which of the following changes would cause the fusion rate in the Sun's core to increase? Check all that apply A. an increase in the core temperature B. an increase in the core radius C. a decrease in the core temperature D. a decrease in the core radius
A, D
The total annual U.S. energy consumption is about 2 x 10^20 joules. With current technologies and solar collectors on the ground, the best we can hope for is that solar cells will generate an average (day and night) power of about 190 watts/m^2. What total area would we need to cover with solar cells to supply all the power needed for the United States? Give your answer in both square meters and square kilometers.
Atotal = 3.17 x 10^10 m^2, Atotal = 3.17 x 10^4 km^2
A spinning neutron star has been observed at the center of a A. red supergiant B. supernova remnant C. planetary nebula D. protostar
B
About what percentage of the mass of a molecular cloud is in the form of dust? A. 50% B. 1% C. 10% D. 98%
B
According to current understanding, how did the first generation of stars differ from stars born today? A. they contained much more hydrogen and helium than stars born today B. they were much more massive than most stars born today C. they were much cooler in temperature than most stars born today D. they were much more likely to be members of binary star systems than stars are born today
B
Angular momentum plays an important role in star formation. Which of the following characteristics of a protostellar system is probably NOT strongly affected by the star's angular momentum? A. the strength of protostellar winds B. the onset of core hydrogen fusion C. the existence of protostellar jets D. the formation of a protostellar disk
B
At what position(s) in the Moon's orbit would we see exactly half of the Moon's daylight face and exactly half of its night face? A. at the point on the far right B. at the two points at the top and bottom C. at the point on the far left D. at the two points on the far left and far right
B
Binary star systems are thought to form when A. the protostellar disk around a protostar has enough material to form a second star B. gravity pulls two neighboring protostars quite close together, but angular momentum causes them to orbit each other rather than colliding C. two interstellar gas clouds happen to contract so close together that there's no room for a disk or planets D. a protostar emits two jets, each of which turns into a star
B
Careful measurements reveal that a star maintains a steady apparent brightness at most times, except that at precise intervals of 73 hours the star becomes significantly dimmer for about 2 hours. The most likely explanation is that A. the star is a Cepheid variable B. the star is a member of an eclipsing binary star system C. the star is a white dwarf D. the star is periodically ejecting gas into space, every 73 hours
B
How did astronomers discover the relationship between spectral type and mass for main sequence stars? A. by comparing stars with the same spectral type but different luminosities B. by measuring the masses and spectral types of main-sequence stars in binary systems C. by measuring stellar radii with powerful telescopes D. by using computer models of hydrogen fusion and stellar structure
B
How does an accretion disk around a neutron star differ from an accretion disk around a white dwarf? A. the accretion disk around a neutron star is more likely to give birth to planets B. the accretion disk around a neutron star is much hotter and emits higher-energy radiation C. the accretion disk around a neutron star always contains much more mass D. the accretion disk around a neutron star is made mostly of helium, whereas the accretion disk around a white dwarf is made mostly of hydrogen
B
How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope? A. two times B. four times C. six times
B
If the star Alpha Centauri were moved to a distance 10 times farther than it is now, its parallax angle would A. get larger B. get smaller C. stay the same
B
Imagine that when we looked out into the universe we found that the light from all galaxies was blueshifted (rather than redshifted) and that the light from the most distant galaxies was blueshifted by the greatest amount. Which statement best describes what we would conclude about the motions of galaxies in this case? A. All are moving toward Earth, with nearby galaxies moving faster than distant galaxies B. All are moving toward Earth, with distant galaxies moving faster than nearby galaxies C. All are moving away from Earth, with nearby galaxies moving faster than distant galaxies D. All are moving away from Earth, with distant galaxies moving faster than nearby galaxies
B
In the Greek geocentric model, the retrograde motion of a planet occurs when: A. Earth is about to pass the planet in its orbit around the Sun B. The planet actually goes backward in its orbit around Earth C. The planet is aligned with the Moon in our sky
B
Our solar system is located in the center of the Milky Way Galaxy A. True B. False
B
Recall that one of the laws of thermal radiation states that a higher-temperature object emits photons with higher average energy (Wien's law). This law is illustrated by the fact that for a higher temperature object, the graph peaks at A. a longer wavelength B. a shorter wavelength C. a higher intensity
B
Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called A. bright B. circumpolar C. celestial D. seasonal
B
Suppose an elliptical galaxy is so far away that we cannot see even its brightest stars individually. Which of the following techniques might allow us to measure its distance? A. We could use radar ranging B. We could use a white dwarf supernova as a standard candle C. We could use parallax D. We could use Cepheid variables as standard candles
B
Suppose that hydrogen, rather than iron, had the lowest mass per nuclear particle. Which of the following would be true? A. Stars would be brighter B. Nuclear fusion could not power stars C. Stars would be less massive D. All stars would be red giants
B
Suppose that you measure the parallax angle for a particular star to be 0.5 arc second. The distance to this star is A. 0.5 parsec B. 2 parsecs C. 5 light-years D. 0.5 light-year E. 5 parsecs
B
Suppose we observe a Cepheid variable in a distant galaxy. The Cepheid brightens and dims with a regular period of about 10 days. What can we learn from this observation? A. it will allow us to determine the mass of the galaxy B. we can learn the distance to the galaxy C. it will allow us to calculate the rotation rate of the galaxy D. under the rules of the International Astronomical Union, we will be entitled to naming rights for the galaxy
B
Suppose we observe a source of X rays that varies substantially in brightness over a period of a few days. What can we conclude? A. the X-ray source contains a black hole with an accretion disk B. the X-ray source is no more than a few light-days in diameter C. the X-ray source is a quasar D. the X-ray source must have a strong, rapidly varying magnetic field
B
Suppose you are in an elevator car when the elevator cable breaks. Which of the following correctly describes what happens and why. A. You will crash your head into the elevator car ceiling because Earth's gravity will be pulling the car down faster than it pulls you down B. You float weightlessly within the elevator car because you and the elevator both begin to accelerate downward at the same rate C. You will crash your head into the elevator car ceiling because the car will be falling rapidly away from you D. You float weightlessly within the elevator car because Earth's gravity is no longer tugging on you E. You will remain stuck to the elevator floor as you and the elevator plunge downward toward a horrific crash
B
Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be A. equal to your normal weight at rest B. greater than your normal weight at rest C. less than your normal weight at rest
B
The core of a protostar that will eventually become a brown dwarf shrinks until A. it radiates brown light B. the type of pressure called degeneracy pressure becomes important C. it forms a rocky core D. its central temperature is high enough to support fusion reactions
B
The loopback time of the cosmological horizon is A. the Big Bang B. the age of the universe C. 10 billion years D. 1 billion years
B
The most basic difference between elliptical galaxies and spiral galaxies is that A. spiral galaxies lack anything resembling the distribution of stars in an elliptical galaxy B. elliptical galaxies lack anything resembling the disk of a spiral galaxy C. elliptical galaxies lack anything resembling the halo of a spiral galaxy D. elliptical galaxies are old and spiral galaxies are young
B
The solar system contains about 100 billion stars A. True B. False
B
The spectral sequence sorts stars according to A. radius B. surface temperature C. core temperature D. luminosity E. mass
B
To calculate the masses of stars in a binary system, we must measure their A. luminosities and distance from Earth B. orbital period and average orbital distance C. absolute magnitudes and luminosities D. spectral types and distance from Earth
B
Two ways in which the starting conditions in a protogalactic cloud might cause it to become an elliptical (rather than spiral) galaxy are if the cloud begins with either A. relatively low mass and a relatively high abundance of heavy elements B. relatively little angular momentum or relatively high density C. relatively high angular momentum or relatively low density D. relatively high mass and a relatively low abundance of heavy elements
B
We can study how galaxies evolve because A. we can watch as they interact in real time B. the farther away we look, the further back in time we see C. galaxies are transparent to visible light D. we are really smart astronomers
B
We do not know for certain whether the general trends we observe in stellar birth masses also apply to brown dwarfs. But if they do, then which of the following would be true? A. brown dwarfs would be responsible for most of the overall luminosity of our Milky Way Galaxy B. brown dwarfs would outnumber all ordinary stars C. most of the brown dwarfs in the Milky Way Galaxy would be quite young in age D. brown dwarfs would be extremely rare
B
What do astronomers mean by a constellation? A. A constellation is any random grouping of stars in the sky B. A constellation is a region in the sky as seen from Earth C. A constellation is a group of stars related through an ancient story D. A constellation is a group of stars that are all located in about the same place in space
B
When you are standing on a scale in an elevator, what exactly does the scale measure? A. your mass B. the force you exert on the scale C. the gravitational force exerted on you by Earth
B
Which 2 processes can generate energy to help a star or gas cloud maintain its internal thermal pressure? A. nuclear fusion and supernova B. nuclear fusion and gravitational contraction C. nuclear fission and supernova D. nuclear fusion and nuclear fission
B
Which characteristic is NOT generally true of a starburst galaxy? A. the observed features that cause us to classify it as a "starburst" must be only temporary phenomena in the galaxy's history B. the observed features of the starburst are thought to be caused by the presence of a supermassive black hole in the galaxy's center C. supernovae occur so frequently that their effects combine to drive a galactic wind that blows material into the intergalactic space D. its rate of star formation is many times higher than the rate of star formation in the Milky Way
B
Which is brighter in our sky, a star with apparent magnitude 5 or a star with apparent magnitude 10? A. A star with apparent magnitude 10 B. A star with apparent magnitude 5
B
Which of the following best describes why a white dwarf cannot have a mass greater than the 1.4-solar-mass limit? A. White dwarfs are made only from stars that have masses less than the 1.4-solar-mass limit B. Electron degeneracy pressure depends on the speeds of electrons, which approach the speed of light as a white dwarf's mass approaches the 1.4-solar-mass limit C. White dwarfs get hotter with increasing mass, and above the 1.4-solar-mass limit they would be so hot that even their electrons would melt D. The upper limit to a white dwarf's mass is something we have learned from observations, but no one knows why this limit exists
B
Which of the following best summarizes the reason we see phases of the Moon? A. Earth casts a shadow into space, and the Moon's phase depends on how much of Earth's shadow is touching the Moon B. Half the Moon is always illuminated by the Sun, but the phase we see depends on how much of this half we are l looking at from Earth C. The amount of the Moon that is illuminated by sunlight varies as it orbits the Earth, thereby determining the phase that we see
B
Which of the following describes a star with a hydrogen-burning shell and an inert helium core? A. It is what is known as a helium-burning star, which has both helium fusion in its core and hydrogen fusion in a shell B. It is a sub giant that grows in luminosity until helium fusion begins in the central core C. It is a red giant that grows in luminosity until it dies in a planetary nebula D. It is a sub giant that gradually grows dimmer as its hydrogen-burning shell expands and cools
B
Which of the following observations would NOT be likely to provide information about the final, explosive stages of a star's life? A. studying the light rings around Supernova 1987A in the Large Magellanic Cloud B. decades of continuous monitoring of red giants in a globular cluster C. neutrino detections from nearby supernovae D. observing th structures of planetary nebulae
B
Which of the following statements about degeneracy pressure is NOT true? A. degeneracy pressure can continue to support an object against gravitational collapse even if the object becomes extremely cold B. degeneracy pressure can arise only from interactions among electrons C. degeneracy pressure arises from a quantum mechanical effect that we don't notice in our daily lives D. black holes form when gravity overcomes. neutron degeneracy pressure
B
Which of the following statements provides observational evidence for the claim "the corona is hotter than the photosphere?" A. The corona emits much less total light than the photosphere B. The corona primarily emits X rays while the photosphere primarily emits visible light C. The corona is higher in the Sun's atmosphere than the photosphere D. The corona has a much lower gas density than the photosphere
B
Which of these star clusters is oldest? A. a cluster whose brightest main-sequence stars are white B. a cluster whose brightest main-sequence stars are yellow C. a cluster containing stars of all colors
B
Which statement about pulsars is NOT thought to be true? A. a pulsar must have a strong magnetic field and rotate quite rapidly B. pulsars can form only in close binary systems C. all pulsars are neutron stars, but not all neutron stars are pulsars D. pulsars are kept from collapsing by neutron degeneracy pressure
B
Why can't we see past the cosmological horizon? A. The cosmological horizon is infinitely far away, and we can't see to infinity B. Beyond the cosmological horizon, we would be looking back to a time before the universe was born C. We do not have big enough telescopes D. Every galaxy in the entire universe (not just the observable universe) exists within the cosmological horizon, so there's nothing to see beyond it
B
Will our Sun ever undergo a white dwarf supernova explosion? Why or why not? A. Yes, right at the end of its double-shell burning stage of life B. No, because it is not orbited by another star C. No, because the Sun's core will never be hot enough to fuse carbon and other heavier elements into iron D. Yes, about a million years after it becomes a white dwarf
B
Which of the following must occur for a star's core to reach equilibrium after an initial change in fusion rate? Check all that apply A. If the fusion rate initially decreases, then the core expands B. If the fusion rate initially increases, then the core expands C. If the fusion rate initially decreases, then the core contracts D. If the fusion rate initially increases, then the core contracts
B, C
A television advertisement claiming that a product is light-years ahead of its time does not make sense because A. a light-year is an astronomically large unit, so a product could not possibly be so advanced B. light-years can only be used to talk about light C. it uses "light-years" to talk about time, but a light-year is a unit of distance D. it doesn't specify the number of light-years
C
According to present understanding, a nova is caused by A. a white dwarf that gains enough mass to exceed the 1.4-solar-mass limit B. carbon fusion in the core of a white dwarf C. hydrogen fusion on the surface of a white dwarf D. hydrogen fusion on the surface of a neutron star
C
All of the following observations are real. Which one does NOT support the model in which active galactic nuclei are powered by accretion disks around massive black holes? A. the total luminosity of an active galactic nucleus can be as high as about 10 billion times that of the Sun B. X-ray emission from active galactic nuclei can vary significantly in times as short as a few days C. the most luminous active galactic nuclei have huge redshifts D. spectra of active galactic nuclei show that clouds of gas are orbiting a central object at a high speed
C
By looking at the graph of Hubble's law, what can we say about the galaxies that have the lowest speeds? A. They are moving AWAY from Earth and are FARTHER from Earth than galaxies with high speeds B. They are moving TOWARD Earth and are FARTHER from Earth than galaxies with high speeds C. They are moving AWAY from Earth and are CLOSER from Earth than galaxies with high speeds D. They are moving TOWARD Earth and are CLOSER from Earth than galaxies with high speeds
C
Consider a large molecular cloud that will give birth to a cluster of stars. Which of the following would you expect to be true? A. all the stars int he cluster will have approximately the same luminosity and surface temperature B. all the stars in the cluster will become main-sequence stars at about the same time C. a few massive stars will form, live, and die before the majority of the star's clusters even complete their protostar stage D. all the stars in the cluster will be of about the same mass
C
Earth is closer to the Sun in January than in July. Therefore, in accord with Kepler's second law: A. It is summer in January and winter in July B. Earth travels faster in its orbit around the Sun in July than in January C. Earth travels faster in its orbit around the Sun in January than in July
C
Generally speaking, a main-sequence star is ___ than it was during the time it was a protostar A. hotter and brighter B. cooler and dimmer C. hotter and dimmer D. cooler and brighter
C
Given that the universe is about 14 billion years old, which of the following statements is logically valid? A. All galaxies that we see have an age that is approximately equal to the age of the universe today, minus the loopback time (or light travel time) corresponding to the redshift of that galaxy B. All galaxies that we can see are about 14 billion years old C. The oldest galaxies we see at great distances are younger than the oldest galaxies we see nearby D. All galaxies nearby us are about 14 billion years old
C
If the distance between us and a star is doubled, with everything else remaining the same, the luminosity A. is decreased by a factor of 4, and the apparent brightness is decreased by a factor of 4 B. is decreased by a factor of 4, but the apparent brightness remains the same C. remains the same, but the apparent brightness is decreased by a factor of 4 D. is decreased by a factor of 2, and the apparent brightness is decreased by a factor of 2 E. remains the same, but the apparent brightness is decreased by a factor of 2
C
In a photo like the Hubble eXtreme Deep Field (Figure 20.1 in your text), we see galaxies in many different stages of their lives. In general, which galaxies are seen in the earliest (youngest) stages of their lives? A. the galaxies that are nearest to us B. the galaxies that have the most hot, young O and B stars C. the galaxies that are farthest away D. the galaxies that are the reddest in color
C
Interactions among galaxies also are thought to influence a galaxy's type in at least some cases. Which of the following does NOT support the idea that interactions can shape galaxies? A. computer modeling of collisions between galaxies B. the fact that galaxies with distorted appearances are more common at great distances than nearby C. the fact that more distant galaxies have larger redshifts D. the presence of features such as "tails" extending out of galaxies, bridges between galaxies, and rings of stars around galaxies
C
Most active galactic nuclei are found at large distances from us, with relatively few nearby. What does this imply? A. active galactic nuclei can form only at large distances from the Milky Way B. the jets seen in many active galactic nuclei must cause them to move far away from us C. active galactic nuclei exist tend to become less active as they age D. supermassive black holes existed only when the universe was young, and no longer exist today
C
On an H-R diagram, where on the main-sequence would we find stars that have the greatest mass? A. upper right B. lower right C. upper left D. lower left
C
One possible explanation for a galaxy's type invokes the angular momentum of the protogalactic cloud from which it formed. Suppose a galaxy forms from a protogalactic cloud with a lot of angular momentum. Assuming its type has not changed due to other interactions, we'd expect this galaxy to be A. an elliptical galaxy B. a torn and incoherent galaxy C. a spiral galaxy D. an irregular galaxy
C
Our Sun is considered to be a A. brown dwarf B. intermediate-mass star C. low-mass star D. high-mass star
C
Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. If this hypothesis is correct, what else should we in principle be able to detect from such mergers? A. significant disruption of gas thousands of light-years away in the surrounding galaxy B. gravitational waves C. an "afterglow" of bright visible light, lasting for weeks D. X-ray bursts
C
Spectral lines from Galaxy B are redshifted from their rest wavelengths 2x as much as the spectral lines from Galaxy A. According to Hubble's Law, what can you say about their approximate relative distances? A. Galaxy B is 4x as far as Galaxy A B. Galaxy A is 2x as far as Galaxy B C. Galaxy B is 2x as far as Galaxy A D. Galaxy A is 4x as far as Galaxy B E. Not enough information to say; you need to know Hubble's constant to answer this question
C
Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be A. greater than your normal weight at rest B. equal to your normal weight at rest C. less than your normal weight at rest
C
The more massive a white dwarf, the A. higher its temperature B. larger its radius C. smaller its radius D. higher its luminosity
C
To calculate the dashed orbits from the stellar positions, astronomers had to assume that A. if they observed for many more years, the dots would trace out parabolas B. the central object has a mass of about 4 million solar masses C. if they observed for many more years, the dots would trace out ellipses D. the stars are all main-sequence stars
C
Two stars that are in the same constellation A. must both be part of the same cluster of stars in space B. must both have been discovered at about the same time C. may actually be very far away from each other
C
What conditions must exist for a solar eclipse to occur? Select all that apply. A. it must be new moon B. it must be full moon C. the Moon must be passing through Earth's orbital plane D. the Moon must be above Earth's orbital plane E. it must be near the time of the spring or fall equinox
C
What do we mean by a geocentric model of the universe? A. the name given to sphere-shaped models that show all the constellations as they appear in our sky on the celestial sphere B. a model designed to explain what we see in the sky while having Earth orbit the Sun C. a model designed to explain what we see in the sky while having Earth located in the center of the universe D. a model of the Milky Way Galaxy that has our solar system located at its center
C
What do we need to measure in order to determine a star's luminosity? A. apparent brightness and mass B. apparent brightness and temperature C. apparent brightness and distance
C
What statement does NOT use the term "light-year" in an appropriate way? A. It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year B. A light-year is about 10 trillion kilometers C. It will take me light-years to complete this homework assignment D. The Milky Way Galaxy is about 100,000 light-years in diameter E. It's about 4 light-years from here to Alpha Centauri
C
Which is more common: a star blows up as a supernova, or a star forms a planetary nebula/white dwarf system? A. They both occur in about equal numbers B. It is impossible to say C. Planetary nebula formation is more common D. Supernovae are more common
C
Which of the following is always true about images captured with X-ray telescopes? A. They show us light with extremely long wavelengths compared to the wavelengths of visible light B. They always are made with adaptive optics C. They are always shown with colors that are NOT the true colors of the objects that were photographed D. They always have very high angular resolution
C
Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope? A. Reflecting telescopes make much clearer images than can refracting telescopes of the same size B. A refracting telescope produces refracted images while a reflecting telescope produces reflected images C. A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light D. It is much easier to make a large refracting telescope than a large reflecting telescope
C
Which of the following statements is NOT an assumption used in models of galaxy formation? A. the universe started out filled ALMOST uniformly with hydrogen and helium B. some regions in the universe were slightly more dense than others C. gas contracted to form the disks of galaxies before any stars were born D. the universe is expanding
C
Which of the following types fo data provide evidence that helps us understand the life tracks of low-mass stars? A. observing a low-mass star over many years B. H-R diagrams of open clusters C. H-R diagrams of globular clusters D. spacecraft observations of the Sun
C
Which of these stars has the coolest surface temperature? A. an A star B. an F star C. a K star
C
Which of these stars has the largest radius? A. a supergiant A star B. a giant K star C. a supergiant M star
C
Which of these stars has the longest lifetime? A. a main-sequence A star B. a main-sequence G star C. a main-sequence M star
C
Which statement below correctly describes the relationship between expansion rate and age for the universe? A. the faster the rate of expansion, the older the age of the universe B. age is independent of the expansion rate C. the faster the rate of expansion, the younger the age of the universe
C
Why do the Sun's rays become parallel at the end of the video? A. The rays that reach Earth and the Moon come from only one very small spot on the Sun B. The video is incorrect; the Sun's rays actually converge on the Moon from all directions, not just as parallel rays C. The Sun is so far away compared to the size of the Moon's orbit that all the rays reaching the orbit come from essentially the same direction D. Rays from the Sun that start out going in different directions turn toward Earth as they travel away from the Sun
C
You observe a star in the disk of the Milky Way, and you want to plot the star on an H-R diagram. You will need to determine all of the following, except the A. spectral type of the star B. distance to the star C. rotation rate of the star D. apparent brightness of the star in our sky
C
You observe the peak brightness two white dwarf supernovae. Supernova A is only 1/4 as bright as Supernova B. What can you say about their relative distances? A. Supernova A is 4x as far away as Supernova B B. Supernova B is 2x as far away as Supernova A C. Supernova A is 2x as far away as Supernova B D. Supernova B is 4x as far away as Supernova A E. We can't say anything about their relative distances because we do not have enough information
C
In reality, the Moon's orbit about Earth is tilted (by about 5°) with respect to Earth's orbit about the Sun. As a result, the actual number of solar eclipses that occur each year is approximately A. 0 B. 1 C. 2 D. 12 E. 24
C. 2
A quasar's spectrum is hugely redshifted. What does this large redshift tells us about the quasar? A. the type of host galaxy in which the quasar resides B. the composition of the quasar C. the mass of the quasar's central, supermassive black hole D. the distance to the quasar
D
A solar model is used to calculate interior conditions based on certain "known" characteristics of the Sun, such the Sun's total mass. How do we know the Sun's mass? A. We first measure the Sun's size and density, then use these measurements to calculate the Sun's mass B. We can calculate it by using the law of conservation of energy with the measured amount of light that the Sun emits C. We infer the mass from a model of the Sun D. We can calculate it by applying Newton's version of Kepler's third law with Earth's orbital period (1 year) and Earth's average distance from the Sun (1 AU)
D
All stars are born with the same basic composition, yet stars can differ greatly in appearance. Which two factors are most important in determining the current appearance of a star? A. age and location in the galaxy B. mass and surface temperature C. luminosity and stage of life D. mass and stage of life E. apparent brightness and luminosity
D
Carbon fusion occurs in high-mass stars but not in low-mass stars because A. carbon fusion can occur only in the stars known as carbon stars B. the cores of low-mass stars never contain significant amounts of carbon C. only high-mass stars do fusion by the CNO cycle D. the cores of low-mass stars never get hot enough for carbon fusion
D
Central black holes can be efficient for converting the mass-energy of in-falling matter to thermal energy in the accretion disk. Roughly what percentage of the mass-energy can be converted to other forms of energy as matter falls into a black hole? A. 100% B. 0.7% C. 1-4% D. 10-40%
D
Does Hubble's law work well for galaxies in the Local Group? Why or why not? A. No, because we do not know the precise value fo Hubble's constant B. No, because Hubble did not know the Local Group existed when he discovered his law C. Yes, it works so well that we have never detected any measurable deviations from its predictions D. No, because galaxies in the Local Group are gravitationally bound together
D
If the Andromeda Galaxy collided with the Milky Way, what would most likely happen to Earth? A. the Sun will turn into a red giant and explode B. the Sun and all its planets would be crushed by collisions with stars and planets from the Andromeda Galaxy C. the Sun would not be disturbed, but the solar system would be ripped apart D. nothing
D
If we wanted to show the Moon's orbit on the scale of this starting frame, we would need to draw a circle that A. is about twice the size of the white dot representing the Sun B. has a diameter that is about a quarter of the distance between Earth's orbit and Venus's orbit C. has a diameter that is about half the distance between Earth's orbit and Venus's orbit D. is smaller than one of the green dashes that show Earth's orbit
D
Observations indicated that over billions of years, galaxies in general tend to change from A. smaller and redder to larger and bluer B. larger and bluer to smaller and redder C. larger and redder to smaller and bluer D. smaller and bluer to larger and redder
D
Observations show that elements with atomic mass numbers divisible by 4 (such as oxygen-16, neon-20, and magnesium-24) tend to be more abundant in the universe than elements with atomic mass numbers in between. Why do we think this is the case? A. the apparent pattern if thought to be a random coincidence B. this pattern in elemental abundances was apparently determined during the first few minutes after the Big Bang C. elements with atomic mass numbers divisible by 4 tend to be more stable than elements in between D. at the end of a high-mass star's life, it produces new elements through a series of helium capture reactions
D
On an H-R diagram, where would we find white dwarfs? A. upper right B. lower right C. upper left D. lower left
D
Our solar system consists of A. a few hundred billion stars, bound together by gravity B. the Sun and several nearby stars, as well as the planets and other objects that orbit these stars C. the Sun and the planets, and nothing else D. the Sun and all the objects that orbit it
D
Quasar spectra often show many absorption lines that all appear to be due to the same electron transition (such as level 1 to level 2 in hydrogen) but that fall at different wavelengths in the spectrum. Why do we think this is the case? A. no one knows; it remains perhaps the greatest mystery about quasars B. quasars are rotating rapidly, and this rotation produces spectral lines with a wide variety of Doppler shifts C. the lines fall at different wavelengths because they are produced by different chemical elements D. we are seeing absorption lines from clouds of gas that lie between us and the quasar, and therefore each cloud has a different redshift
D
Since all stars begin their lives with the same basic composition, what characteristic most determines how they will differ? A. luminosity they are formed with B. time they are formed C. color they are formed with D. mass they are formed with E. location where they are formed
D
Star A is identical to Star B, but Star A is twice as far from us as Star B. Therefore, A. both stars have the same luminosity, but the apparent brightness of Star A is 4x that of Star B B. both stars have the same luminosity, but the apparent brightness of Star B is 2x that of Star A C. both stars have the same apparent brightness, but the luminosity of Star B is 4x that of Star A D. both stars have the same luminosity, but the apparent brightness of Star B is 4x that of Star A
D
Suppose that galaxy B is twice as far from Earth as galaxy A. Hubble's law predicts that galaxy B will be moving away from Earth with approximately A. the same velocity as galaxy A B. four times the velocity of galaxy A C. half the velocity of galaxy A D. twice the velocity of galaxy A
D
Suppose that instead of being inclined to Earth's orbit around the Sun, the Moon's orbit was in the same plane as Earth's orbit around the Sun. In this hypothetical situation, approximately how many solar eclipses would occur each year? A. 0 B. 1 C. 2 D. 12 E. 24
D
Suppose you lived on the Moon. Which of the following would be true? A. Both your weight and your mass would be less than they are on Earth B. Your mass would be less than your mass on Earth, but your weight would be the same as it is on Earth C. Both your weight and your mass would be the same as they are on Earth D. Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth
D
Suppose you measure the parallax angle for a particular star to be ).1 arcsecond. The distance to this star is A. 10 light-years B. impossible to determine C. 0.1 light-year D. 10 parsecs E. 0.1 parsec
D
The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is the youngest? A. the diagram shows main-sequence stars of every spectral type except O, along with a few giants and supergiants B. the diagram shows main-sequence stars of all the spectral types except O and B, along with a few giants and supergiants C. the diagram shows no main-sequence stars at all, but it has numerous supergiants and white dwarfs D. the diagram shows main-sequence stars of spectral types G, K, and M, along with numerous giants and white dwarfs
D
The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is the youngest? A. the diagram shows no main-sequence stars at all, but it has numerous supergiants and white dwarfs B. the diagram shows main-sequence stars of spectral types G, K, and M, along with numerous giants and white dwarfs C. the diagram shows main-sequence stars of all the spectral types except O and B, along with a few giants and supergiants D. the diagram shows main-sequence stars of every spectral type except O, along with a few giants and supergiants
D
Tidal forces are important to the Algol system today but were not important when both stars were still on the main sequence. Why not? A. main-sequence stars are too big to be affected by tidal forces B. main-sequence stars are too massive to be affected by tidal forces C. main-sequence stars are unaffected by tidally induced mass transfer D. main-sequence stars in a system like the Algol system are small compared to their physical separation
D
What does cosmological redshift do to light? A. makes it slow down B. makes all light infrared C. makes it brighter D. stretches its wavelength
D
What happens to the visible light radiated by stars located within a dusty gas cloud? A. it is reflected by dust back to the star from when it came B. it is blocked by dust and its energy is thereby lost C. it passes through the cloud unaffected D. it is absorbed by dust, which heats the dust grains so that they emit the absorbed energy as infrared light
D
What is the cause of the seasons? A. The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and vice versa in winter B. The seasons are caused by variation in the amount of rainfall (or snowfall) in different places at different times of year C. Earth's speed varies in its orbit around the Sun, giving us summer when Earth is moving fastest and winter when Earth is moving slowest D. The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year
D
What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? A. The Sun's core would not start to cool down, and the rate of fusion would decrease B. The Sun's core would reach a new equilibrium at a lower temperature C. The Sun's core would reach a new equilibrium at a higher temperature D. The Sun's core would start to heat up, and the rate of fusion would increase even more
D
Where would a brown dwarf be located on an H-R diagram? A. in the upper right corner of the H-R diagram B. in the lower left corner of the H-R diagram C. above and to the left of the highest part of the main sequence D. below and to the right of the lowest part of the main sequence
D
Which of the following is a general difference between a planet and a star? A. Planets are brighter than stars B. Planets are larger than stars C. All planets are made of rock and all stars are made of gas D. Stars glow in infrared and visible light, while planets glow only in the infrared
D
Which of the following observatories is most likely to discover a black hole in a binary system? A. the SOFIA airborne infrared observatory B. the Arecibo Radio Observatory C. the Hubble Space Telescope D. the Chandra X-Ray Observatory
D
Which of the following phenomena are NOT thought to be results of collisions or other interactions between galaxies? A. starbursts B. the presence of large, central dominant galaxies in clusters of galaxies C. the fact that elliptical galaxies are more common in clusters of galaxies than outside clusters D. the fact that spiral galaxies have both disk and halo components
D
Which of the following statements about gamma rays is NOT true? A. gamma ray bursts are among the most luminous events that ever occur in the universe B. gamma ray bursts were originally discovered by satellites designed to look for signs of nuclear bomb tests on Earth C. many gamma ray bursts are associated with supernovas in distant galaxies D. the events responsible for gamma ray bursts apparently produce ONLY gamma rays, and no other light that we can hope to detect
D
Which of the following statements about types of galaxies is NOT true? A. large elliptical galaxies are more common in clusters of galaxies than they are outside of clusters B. Among the large galaxies in the universe OUTSIDE of clusters, most are spiral C. Spiral galaxies have both young and old stars, whereas elliptical galaxies have only old stars D. Elliptical galaxies are bluer and contain more dust than spiral galaxies
D
Which of the following statements best describes the two principle advantages of telescopes over eyes? A. Telescopes can collect far more light with far greater magnification B. Telescopes have much more magnification and better angular resolution C. Telescopes collect more light and are unaffected by twinkling D. Telescopes can collect far more light with far better angular resolution
D
Which process is required to allow a gravitationally-collapsing gas cloud to CONTINUE to collapse? A. new dust particles must continually be made in the cloud B. the cloud must trap most of its thermal energy C. the cloud must collide with other clouds D. the cloud must radiate away much of its thermal energy
D
Which statement about accretion disks is NOT true? A. the gas in the inner parts of the disk is hotter than the gas in the outer parts of the disk B. accretion disks are made primarily of hydrogen and helium gas C. the gas in the inner parts of the disk travels faster than the gas in the outer parts of the disk D. the primary factor determining whether a white dwarf has an accretion disk is the white dwarf's mass
D
Which statement concerning black hole masses and Schwartzschild radii is NOT true? A. for black holes produced in massive star supernovae, Schwartzschild radii are typically a few to a few tens of kilometers B. even an object as small as you could become a black hole if there were some way to compress you to a size smaller than your Schwartzschild radius C. the more massive the black hole, the larger the Schwartzschild radius D. in a binary system with a black hole, the Schwartzschild radius depends on the distance from the black hole to the companion star
D
Which units are appropriate for measurement of apparent brightness? A. joules B. newtons C. watts D. watts per square meter
D
Why are white dwarf supernovae more useful than massive star supernovae for measuring cosmic distances? A. White dwarf supernovae are much more common than massive star supernovae B. We can see only white dwarf supernovae in distant galaxies, not massive star supernovae C. White dwarf supernovae follow a period-luminosity relation, whereas massive supernovae do not D. White dwarf supernovae all have roughly the same true peak luminosity, whereas massive supernovae come in a wide range of peak luminosities
D
You observe a star and you want to plot it on an H-R diagram. You will need to measure all of the following, EXCEPT the star's A. apparent brightness B. distance C. spectral type D. mass
D
For which of the following other motions would your weight also be greater than your normal weight? A. The elevator moves upward with constant velocity B. The elevator moves downward while increasing in speed C. The elevator moves downward with constant velocity D. The elevator moves upward while slowing in speed E. The elevator moves downward while slowing in speed
E
Suppose you see two main-sequence stars of the SAME spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude? (Neglect any effects that might be caused by interstellar dust and gas.) A. the luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2 B. Star 1 is 10x more distant than Star 2 C. Star 1 is 100x nearer than Star 2 D. without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other E. Star 1 is 100x more distant than Star 2
E
What is an astronomical unit? A. the length of time it takes Earth to revolve around the Sun B. the diameter of Earth's orbit around the Sun C. the average speed of Earth around the Sun D. any basic unit used in astronomy E. the average distance from Earth to the Sun
E
Which of the following celestial objects do NOT rise in the East and set in the West, as viewed from the Earth? (Assume that all of these objects are visible from your location on Earth, and that none of them are circumpolar) A. the Sun B. stars C. galaxies D. the Moon E. All of these objects rise in the East and set in the West
E
A solar model is used to calculate the expected temperature and density at all depths within the Sun. These results are then used to calculate the expected fusion rate within the Sun. We have confidence that the model is correct because it agrees with the observed characteristics of the Sun. Which of the following observations can be used to check that we really do know the Sun's internal fusion rate? Select all that apply A. Observations of neutrinos coming from the Sun B. Observations of the total X-ray emission from the Sun's corona C. Measurement of the Sun's mass D. Measurements of the varying number of sunspots on the Sun over time E. Measurements of the Sun's total energy output into space
Measurements of the Sun's total energy output into space, observations of neutrinos coming from the Sun
Large telescopes often have small fields of view. For example, the Hubble Space Telescope's (HST's) advanced camera has a field of view that is roughly square and about 0.06 degree on a side. The angular area of the entire sky is about 41,250 square degrees. How many pictures would the HST have to take with its camera to obtain a complete picture of the entire sky?
N = 1.1 x 10^7 pictures
The total annual U.S. energy consumption is about 2 x 10^20 joules. What is the average power requirement for the United States, in watts? (HINT: 1 watt = 1 joule/s)
Paverage = 6.34 x 10^12 W
REVIEW ALL PARTS OF H-R DIAGRAM
REVIEW ALL PARTS OF H-R DIAGRAM
REVIEW ASTEROIDS
REVIEW ASTEROIDS
REVIEW BLACK HOLES
REVIEW BLACK HOLES
REVIEW CONTINUOUS, EMISSION LINE, AND ABSORPTION LINE SPECTRUMS
REVIEW CONTINUOUS, EMISSION LINE, AND ABSORPTION LINE SPECTRUMS
REVIEW DOPPLER SHIFT, BLUESHIFTS, AND REDSHIFTS; MOTION OF STARS
REVIEW DOPPLER SHIFT, BLUESHIFTS, AND REDSHIFTS, MOTION OF STARS
REVIEW EARTH'S AXIS TILTS
REVIEW EARTH'S AXIS TILTS
REVIEW GALAXY EXPANSION
REVIEW GALAXY EXPANSION
REVIEW GRAVITATIONAL FORCE
REVIEW GRAVITATIONAL FORCE
REVIEW HUBBLE'S LAW
REVIEW HUBBLE'S LAW
REVIEW MILKY WAY GALAXY AND ITS PARTS
REVIEW MILKY WAY GALAXY AND ITS PARTS
REVIEW MOON PHASES
REVIEW MOON PHASES
REVIEW PRE-MAIN SEQUENCE STAGES
REVIEW PRE-MAIN SEQUENCE STAGES
umbra
The darkest part of a shadow
penumbra
The part of Earth's shadow surrounding the darkest part
node
a point at which the Moon crosses Earth's orbital plane
annular eclipse
a solar eclipse that occurs when the new moon is too far from Earth to completely cover the Sun
Which of the following statements correctly summarize key differences between the disk and the halo? Check all that apply A. Stars in the disk all orbit in the same direction and nearly the same plane, while halo stars have more randomly oriented orbits B. Clusters of young stars are found only in the disk C. Gas and dust are abundant in the disk but not in the halo D. Disk stars come in a broad range of masses and colors, while halo stars are mostly of low mass and red
all of them
total solar eclipse
can occur only when the Moon is new and has an angular size larger than the Sun in the sky
Listed following are various physical situations that describe how light interacts with matter. Match these to the appropriate category. TRANSMISSION - visible light meets clear glass - visible light does not pass through a black wall - red light hits a red sweatshirt - light comes from your computer screen - cell phone signals pass through walls - blue light hits a red sweatshirt - white light hits a white piece of paper - light comes from a light bulb
cell phone signals pass through walls, visible light meets clear glass
Which of the following layers of the Sun can be seen with some type of telescope? Consider all forms of light, but do not consider neutrinos or other particles. Select all that apply - photosphere - radiation zone - core - convection zone - chromosphere - corona
chromosphere, photosphere, corona
In which of the following layer(s) of the Sun does nuclear fusion occur? Select all that apply - corona - photosphere - radiation zone - convection zone - core - chromosphere
core
Rank the following layers of the Sun based on the pressure within them, from highest to lowest - photosphere - radiation zone - core - convection zone
core, radiation zone, convection zone, photosphere
Rank the following layers of the Sun based on their temperature, from highest to lowest - radiation zone - photosphere - convection zone - core
core, radiation zone, convection zone, photosphere
Rank the layers of the Sun based on their density, from highest to lowest - radiation zone - convection zone - chromosphere - core - photosphere - corona
core, radiation zone, convection zone, photosphere, chromosphere, corona
Following are the different layers of the Sun's atmosphere. Rank them based on the order in which a probe would encounter them when traveling from Earth to the Sun's surface, from first encountered to last - photosphere - corona - chromosphere
corona, chromosphere, photosphere
Rank the layers of the Sun's atmosphere based on their temperature, from highest to lowest - corona - photosphere - chromosphere
corona, chromosphere, photosphere
Rank the layers of the atmosphere based on the energy of the photons that are typically emitted there, from highest to lowest - photosphere - chromosphere - corona
corona, chromosphere, photosphere
Listed following are the different layers of the Sun. Rank these layers based on their distance from the Sun's center, from greatest to least - core - photosphere - convection zone - chromosphere - radiation zone - corona
corona, chromosphere, photosphere, convection zone, radiation zone, core
convection zone
energy moves through here by means of the rising of hot gas and falling of cooler gas
We divide the electromagnetic spectrum into six major categories of light, listed below. Rank these forms of light from left to right in order of increasing wavelength - ultraviolet - infrared - gamma rays - radio waves - visible light - X rays
gamma rays, X rays, ultraviolet, visible light, infrared, radio waves
Listed following are various physical situations that describe how light interacts with matter. Match these to the appropriate category. EMISSION - visible light meets clear glass - visible light does not pass through a black wall - red light hits a red sweatshirt - light comes from your computer screen - cell phone signals pass through walls - blue light hits a red sweatshirt - white light hits a white piece of paper - light comes from a light bulb
light comes from a light bulb, light comes from your computer screen
The total mass of the Sun is about 2 x 10^30 kg, of which about 76% was hydrogen when the Sun formed. However, only about 13% of this hydrogen ever becomes available for fusion in the core. The rest remains in layers of the Sun where the temperature is too low for fusion. Use the given data to calculate the total mass of hydrogen available for fusion over the lifetime of the Sun. Express your answer using two significant figures.
m = 1.97 x 10^29 kg
chromosphere
most of the Sun's ultraviolet light is emitted from this narrow layer where temperature increases with altitude
photosphere
nearly all the visible light we see from the Sun is emitted from here
Listed the following are events or phenomena that occur during either the part of the sunspot cycle known as solar minimum or the part known as solar maximum. Match these items to the correct part of the sunspot cycle. SOLAR MINIMUM - solar flares are most common - occurs about 5 to 6 years after a solar maximum (on average) - sunspots are most numerous on the Sun - orbiting satellites are most at risk - auroras are most likely in Earth's skies - occurs about 11 years after a solar maximum (on average)
occurs about 5 to 6 years after a solar maximum (on average)
Rank the layers of the Sun's atmosphere based on their density, from highest to lowest - corona - chromosphere - photosphere
photosphere, chromosphere, corona
Rank these forms of light from left to right in order of increasing energy - ultraviolet - infrared - gamma rays - radio waves - visible light - X rays
radio waves, infrared, visible light, ultraviolet, X rays, gamma rays
Rank these forms of light from left to right in order of increasing frequency - ultraviolet - infrared - gamma rays - radio waves - visible light - X rays
radio waves, infrared, visible light, ultraviolet, X rays, gamma rays
Listed following are various physical situations that describe how light interacts with matter. Match these to the appropriate category. REFLECTION OR SCATTERING - visible light meets clear glass - visible light does not pass through a black wall - red light hits a red sweatshirt - light comes from your computer screen - cell phone signals pass through walls - blue light hits a red sweatshirt - white light hits a white piece of paper - light comes from a light bulb
red light hits a red sweatshirt, white light hits a white piece of paper
Listed the following are events or phenomena that occur during either the part of the sunspot cycle known as solar minimum or the part known as solar maximum. Match these items to the correct part of the sunspot cycle. SOLAR MAXIMUM - solar flares are most common - occurs about 5 to 6 years after a solar maximum (on average) - sunspots are most numerous on the Sun - orbiting satellites are most at risk - auroras are most likely in Earth's skies - occurs about 11 years after a solar maximum (on average)
solar flares are most common, sunspots are most numerous on the Sun, orbiting satellites are most at risk, auroras are most likely in Earth's skies, occurs about 11 years after a solar maximum (on average)
Rank the seasons for the Southern Hemisphere based on Earth's distance from the Sun when each season begins, from closest to farthest
summer, fall, spring, winter
The total mass of the Sun is about 2 x 10^30 kg, of which about 76% was hydrogen when the Sun formed. However, only about 13% of this hydrogen ever becomes available for fusion in the core. The rest remains in layers of the Sun where the temperature is too low for fusion. Use the given data to calculate the total mass of hydrogen available for fusion over the lifetime of the Sun. The Sun fuses about 600 billion kg of hydrogen each second. Base on your result from part A, calculate how long the Sun's initial supply of hydrogen can last. Give your answer in both seconds and years. Express your answer using two significant figures.
t = 3.04 x 10^17 s, t = 9.64 x 10^9 years
The total mass of the Sun is about 2 x 10^30 kg, of which about 76% was hydrogen when the Sun formed. However, only about 13% of this hydrogen ever becomes available for fusion in the core. The rest remains in layers of the Sun where the temperature is too low for fusion. Use the given data to calculate the total mass of hydrogen available for fusion over the lifetime of the Sun. Given that our solar system is now about 4.6 billion years old, when will we need to worry about the Sun running out of hydrogen for fusion? Express your answer using two significant figures.
t = 9.2 x 10^9 billion years
To understand the interplay of observations and models you must first be able to distinguish between things that we observe and things that we infer from models. Consider the following statements about the Sun. Classify each statement as an observation or as an inference based on the current, accepted model for the Sun. INFERENCES - The Sun generates energy by fusing hydrogen into helium in its core - The Sun emits neutrinos - The convection zone is cooler than the radiation zone - The photosphere is made mostly of hydrogen and helium - The composition of the photosphere is the same as that of the gas cloud that gave birth to our solar system - The corona is hotter than the photosphere - The photosphere emits mostly visible light - The core temperature is 10 million K
the Sun generates energy by fusing hydrogen into helium in its core, the convection zone is cooler than the radiation zone, the composition of the photosphere is the same as that of the gas cloud that gave birth to our solar system, the core temperature is 10 million K
radiation zone
the layer of the Sun between its core and convection zone
To understand the interplay of observations and models you must first be able to distinguish between things that we observe and things that we infer from models. Consider the following statements about the Sun. Classify each statement as an observation or as an inference based on the current, accepted model for the Sun. OBSERVATIONS - The Sun generates energy by fusing hydrogen into helium in its core - The Sun emits neutrinos - The convection zone is cooler than the radiation zone - The photosphere is made mostly of hydrogen and helium - The composition of the photosphere is the same as that of the gas cloud that gave birth to our solar system - The corona is hotter than the photosphere - The photosphere emits mostly visible light - The core temperature is 10 million K
the photosphere emits mostly visible light, the photosphere is made mostly of hydrogen and helium, the corona is hotter than the photosphere, the Sun emits neutrinos
Rank these forms of light from left to right in order of increasing speed - ultraviolet - infrared - gamma rays - radio waves - visible light - X rays
they are all the same speed
Listed following are various physical situations that describe how light interacts with matter. Match these to the appropriate category. ABSORPTION - visible light meets clear glass - visible light does not pass through a black wall - red light hits a red sweatshirt - light comes from your computer screen - cell phone signals pass through walls - blue light hits a red sweatshirt - white light hits a white piece of paper - light comes from a light bulb
visible light does not pass through a black wall, blue light hits a red sweatshirt
corona
we can see this part of the Sun most easily during total solar eclipses
total lunar eclipse
when the Moon passes entirely through the umbra
core
where nuclear fusion of hydrogen into helium occurs
Rank the seasons for the Northern Hemisphere based on Earth's distance form the Sun when each season begins, from closest to farthest
winter, spring, fall, summer
