Astronomy Final

What do these observations likely imply about the very center of our galaxy? A. Most of the mass in the center of our galaxy is invisible. B. Gravity works differently in the central region of the galaxy, so Newton's and Kepler's laws should not be used to calculate mass there. C. Most of the mass in the center of the galaxy is contained within many very-high-mass stars. D. Most of the mass in the center of the galaxy is contained within a large number of low-mass stars.

Which of the following objects is most likely to exist at the very center of our galaxy, considering your knowledge of the properties of these objects? A. a clump of dark matter B. a globular cluster C. a supermassive black hole D. a giant molecular cloud E. an extremely massive star

This interactive shows views of the Milky Way galaxy, the galaxy we reside in, from various angles. After examining these views, determine which of the following everyday objects best matches the shape of the Milky Way. A. aluminum soda can B. soccer ball ("football" outside the United States) C. book D. pencil E. dinner plate

How did dust affect Shapley's RR Lyrae measurements? A. The periods were longer than they would be if there were no dust. B. The apparent brightnesses were brighter than they would be if there were no dust. C. The periods were shorter than they would be if there were no dust. D. The apparent brightnesses were fainter than they would be if there were no dust.

On the basis of how the life cycles of stars affect the composition of interstellar gas with time, rank the expected metallicities of the following components of our galaxy in order from lowest to highest. Thin Disk Bulge Halo

Study the distribution and ages of stars in the figure, and use your observations to determine which of the following statements are correct. A. New stars are currently being born throughout the entire galaxy. B. Globular clusters formed before the gas from which our galaxy formed had time to collapse into a disk. C. The thin disk of our galaxy formed at the same time as the bulge. D. The cloud of gas from which our galaxy formed was originally spheroidal in shape.

With which of the four fundamental forces must dark matter interact? A. electromagnetism B. gravity C. strong nuclear force D. weak nuclear force E. none

Which of the following measurements would allow you to determine each cluster's distance from us? A. the period and luminosity of RR Lyraes in each cluster B. the angular distance of each cluster from the center of the Milky Way in our sky C. the right ascension and declination of the RR Lyraes in each cluster D. the period and apparent brightness of RR Lyraes in each cluster

Which statement(s) about galaxy groups is/are true? A. Tidal streams can result from galaxy interactions. B. Interactions between massive and less-massive galaxies affect only the smaller galaxies. C. Galaxies in a group are all moving away from each other. D. The largest galaxies tend to have satellite galaxies. E. Galaxy mergers are rare in galactic evolution.

Using star counts, William and Caroline Herschel concluded that A. the Milky Way Galaxy is disk-shaped. B. there are fewer massive stars than smaller stars. C. stars are not evenly distributed in our galaxy. D. stars differ in mass. E. the Milky Way is made of stars.

Which of the following observations support the idea that the only place in the Milky Way where active star formation is occurring today is in the spiral arms? A. Globular clusters contain no gas and have no high-mass stars. B. OB associations consist of very hot stars with extremely short lifetimes. C. Spiral arms in the Milky Way's disk are traced out by higher gas density, OB associations, and open clusters. D. The halo of the Milky Way has almost no gas or dust. E. Open clusters are extremely old star clusters consisting solely of low-mass stars.

The age of the Milky Way Galaxy is about 13 billion years, but our Solar System is less than 5 billion years old. If the Sun had been one of the very first stars, how would the Sun and its evolution differ? A. The Sun would have a lower mass. B. The Sun would have lower metallicity. C. The Sun would be able to fuse carbon. D. The Sun would have a larger magnetic field. E. The Sun would have more rapid rotation.

What is at the very center of our galaxy? This question is difficult to answer because the center is completely obscured to our eyes behind a large amount of dust. On the basis of what you know about dust from previous chapters, what can be done to improve our view of the galaxy's center? A. Observe it with a blue filter. B. Observe it with a higher-resolution telescope. C. Observe it with a space telescope. D. Calculate how much light has been absorbed by the dust and mathematically add it back into images of the center. E. Observe it in the infrared.

Which of the following is not evidence of spiral arms in the Milky Way? A. the appearance of spiral arms in similar galaxies B. the distribution of hydrogen seen via the 21-cm line C. patterns of O and B stars D. CO (carbon monoxide gas) maps of the galaxy E. the path of the Sun on the sky

Our Solar System orbits the center of the galaxy with approximately what period? A. 200 million years B. 1 year C. 4.5 billion years D. 13 billion years E. 24 hours

Given that Shapley calculated the size of the Milky Way based on the stars' apparent brightness, how did not including the effects of gas and dust affect Shapley's calculation? A. The distance calculated to each globular cluster was too large, and thus his size for the Milky Way was too small. B. The distance calculated to each globular cluster was too large, and thus his size for the Milky Way was too large. C. The distance calculated to each globular cluster was too small, and thus his size for the Milky Way was too large. D. The distance calculated to each globular cluster was too small, and thus his size for the Milky Way was too small.

What role did interstellar dust play in the quest to determine the shape and size of our galaxy? A. It played no role; dust is not important on a galactic scale. B. It obscured some regions and made others appear dimmer and redder. C. It outlined the Milky Way's structure. D. It magnified the light from stars, making them appear closer. E. It made stars appear bluer.

What property of these stars can we measure to determine how much mass is at the center of the galaxy? A. their ages B. their average spectral type C. their total luminosity D. their velocities as they orbit the center

Hubble's law says that A. all galaxies are expanding. B. all galaxies that will ever exist already do exist. C. larger galaxies rotate faster. D. the larger the galaxy is, the faster it is receding. E. the more distant the galaxy is, the faster it appears to be receding from us.

Considering how the predictions compare to the observations, what does this imply about the mass distributed in the galaxy? A. The observations and predictions match, so the total mass distribution in the galaxy is accurately described by the top graph. B. The observations show higher velocities throughout the entire galaxy than is predicted, indicating that there is more mass than we can see, and this invisible mass is distributed evenly throughout the galaxy. C. The observations show higher velocities than predicted, mostly in the central regions, indicating that there is more mass in the central region than we can see. D. The observations show higher velocities than is predicted, mostly in the outer regions of the galaxy, indicating that there is more mass in the outer regions than we can see.

Think about what you have learned about stars and galaxies so far, and determine which of the following statements is correct. A. Red stars form in between the spiral arms, whereas blue stars form inside them. B. Both red and blue stars form inside the spiral arms. Then both stars begin to move out of the arms, but the blue stars die before they can get very far. C. Both red and blue stars form everywhere equally within the disk of the galaxy, then something happens to clear the blue stars out from in between the arms. D. Both red and blue stars form inside the spiral arms. Then the red stars move out of the arms, while the blue stars stay inside them.

Which method of determining distance would be most appropriate for a ground-based observer trying to find accurate distances out to approximately 100 parsecs? (Choose the lowest applicable rung on the cosmic distance ladder.) A. Tully-Fisher law B. Cepheid variables C. spectroscopic parallax D. parallax E. Type Ia supernovas

The nearly edge-on view of the spiral galaxy shown gives us some clues as to why the level of recent star formation is different between bulges and disks. Consider the type of environment in which new stars form, and use your observations of the picture to choose the statement that best describes why there is more star formation in the disk. A. There is more cold, dense gas in the disk than in the bulge. B. It is too bright in the bulge for new stars to form. C. Stars can only form in flattened disks. D. There is more hot gas in the disk than in the bulge.

The unified model of AGNs A. says that the various AGNs have different physical characteristics. B. is based on observations of the Milky Way's AGN. C. says that all galaxies have AGNs. D. explains all variations in observations of the various types of AGNs, except those of quasars. E. says that the orientation of the observer accounts for the differences among the types of AGNs.

A galaxy is observed to be spheroid and to have increasing stellar density toward the center. What is its galaxy classification? A. lenticular B. spiral C. barred spiral D. elliptical E. irregula

Galaxy A is receding from us at x km/s, while galaxy B's recession velocity is 3x km/s. Based on Hubble's law, which statement is true? A. B is 1/3 as far from us as A. B. The relative positions of A and B depend on the types of galaxies they are. C. The relative positions of A and B depend on their size. D. B is 9 times as far from us as A. E. A is 1/3 as far from us as B.

Which of the following describe(s) characteristics of AGNs that point to a black hole as the central engine? A. short timescales for variability in brightness B. rapid star formation C. abundance of dark matter D. relativistic velocity of jets E. compact size of the core

On the basis of the colors and lifetimes of different types of stars, which of the following statements best describes the current state of the bulge and disk? A. New stars are forming mostly in the disk. B. It is impossible to tell whether new stars are forming just from color alone. C. New stars are forming inside both the disk and the bulge at about the same rate. D. New stars are forming mostly in the bulge.

Given that elliptical galaxies are relatively round, ranging in shape from spheres to more squished spheroids similar to an American football, which of the following statements most accurately describes the orbits of stars in an elliptical galaxy? A. The stars in half the galaxy all orbit in one direction around the center, and the stars in the other half orbit together in the opposite direction. B. The stars take spiral orbits from the bottom to the top of the galaxy, and then back down again. C. All the stars orbit in the same direction around the center of the galaxy. D. The stars all have irregular orbits in all directions about the center.

How did Herschel determine his model for the Milky Way? A. He saw the outline of the spiral arms surrounding Earth. B. He saw that the stars in the night sky rotated together in fixed patterns around Earth. C. He counted all the stars at various brightnesses that he could see in all direction.

What was surprising about the globular cluster distribution discovered by Shapley? A. Globular clusters were distributed in a large spherical region of space with the solar system at the center. B. Globular clusters were distributed in a large spherical region of space which was not centered on the solar system. C. Globular clusters were randomly located in the sky with no apparent pattern.

The pulsation period of RR Lyrae (typically found in globular clusters) is typically less than a? A. month B. week C. day D. year

Unlike Cepheid Variables who show a linear luminosity-pulsation period relationship, the RR Lyrae have: A. a luminosity that depends on the pulsation period squared. B. constant luminosity about 100x of the Sun. C. an exponentially decaying luminosity.

Why is gravitational lensing such an important tool for astronomers? A. It provides very narrow spectral emission lines. B. It helps make the Tully-Fisher Law yield more accurate results. C. It provides very accurate redshifts. D. It allows astronomers to locate dark matter and probe expansion of the universe.