© 2017 Pearson Education, Inc.

Question 1 Based on their shapes and stars, elliptical galaxies are most like the Milky Way’s disk and spiral arms. halo. central bulge. open clusters. companion galaxies, the Magellanic Clouds. Answer: b © 2017 Pearson Education, Inc.

Question 1 Based on their shapes and stars, elliptical galaxies are most like the Milky Way’s disk and spiral arms. halo. central bulge. open clusters. companion galaxies, the Magellanic Clouds. Explanation: Like the stars and globular clusters in our halo, elliptical galaxies contain little or no gas and dust to make new stars. © 2017 Pearson Education, Inc.

Question 2 What property is shared by spiral galaxies? Ongoing star formation A disk, bulge, and halo Globular clusters in the halo Open clusters in the disk All of the above Answer: e © 2017 Pearson Education, Inc.

Question 2 What property is shared by spiral galaxies? Ongoing star formation A disk, bulge, and halo Globular clusters in the halo Open clusters in the disk All of the above Explanation: M-51, a Type Sb spiral © 2017 Pearson Education, Inc.

Question 3 The Magellanic Clouds are giant globular clusters in the halo. small irregular galaxies that orbit the Milky Way. large molecular clouds in the disk of our Galaxy. the brightest ionized hydrogen regions in our Galaxy. spiral nebulae originally discovered by Herschel. Answer: b © 2017 Pearson Education, Inc.

Question 3 The Magellanic Clouds are giant globular clusters in the halo. small irregular galaxies that orbit the Milky Way. large molecular clouds in the disk of our Galaxy. the brightest ionized hydrogen regions in our Galaxy. spiral nebulae originally discovered by Herschel. © 2017 Pearson Education, Inc.

Question 4 Hubble took spectra of galaxies in the 1930s. What did he find? Most galaxies showed redshifts. All galaxies showed blueshifts. Galaxies showed about half redshifts and half blueshifts. Galaxies showed no line shifts at all. Some galaxies showed a redshift that changed into a blueshift at other times. Answer: a © 2017 Pearson Education, Inc.

Question 4 Hubble took spectra of galaxies in the 1930s. What did he find? Most galaxies showed redshifts. All galaxies showed blueshifts. Galaxies showed about half redshifts and half blueshifts. Galaxies showed no line shifts at all. Some galaxies showed a redshift that changed into a blueshift at other times. Explanation: Redshifts of galaxies indicate they are moving away from us. © 2017 Pearson Education, Inc.

Question 5 Hubble’s law is based on more distant galaxies showing greater blueshifts. distant quasars appearing proportionally dimmer. more distant galaxies showing greater redshifts. slowly varying Cepheid variables appearing brighter. more distant galaxies appearing younger. Answer: c © 2017 Pearson Education, Inc.

Question 5 Hubble’s law is based on more distant galaxies showing greater blueshifts. distant quasars appearing proportionally dimmer. more distant galaxies showing greater redshifts. slowly varying Cepheid variables appearing brighter. more distant galaxies appearing younger. © 2017 Pearson Education, Inc.

Question 6 Hubble’s constant measures the density of galaxies in the universe. luminosity of distant galaxies. reddening of light from dust clouds. speed of a galaxy. rate of expansion of the universe. Answer: e © 2017 Pearson Education, Inc.

Question 6 Hubble’s constant measures the density of galaxies in the universe. luminosity of distant galaxies. reddening of light from dust clouds. speed of a galaxy. rate of expansion of the universe. Explanation: Hubble’s law relates how fast galaxies are moving away from us at different distances. A larger value for H0 implies a faster expansion rate. velocity = H0 x distance © 2017 Pearson Education, Inc.

Question 7 To calibrate Hubble’s constant, astronomers must determine the size of the universe. distances to galaxies. the speed of recession of galaxies. the density of matter in the universe. the temperature of the Big Bang. Answer: b © 2017 Pearson Education, Inc.

Question 7 To calibrate Hubble’s constant, astronomers must determine the size of the universe. distances to galaxies. the speed of recession of galaxies. the density of matter in the universe. the temperature of the Big Bang. Explanation: Distances to galaxies are determined using a variety of “standard candles,” including Cepheid variables, supernova explosions, model galaxies, and model clusters. © 2017 Pearson Education, Inc.

Question 8 Hubble’s discovery of galaxy redshifts means the universe is static. the universe is collapsing. the universe is expanding. the Milky Way is the center of the universe. There is no accepted interpretation. Answer: c © 2017 Pearson Education, Inc.

Question 8 Hubble’s discovery of galaxy redshifts means the universe is static. the universe is collapsing. the universe is expanding. the Milky Way is the center of the universe. There is no accepted interpretation. © 2017 Pearson Education, Inc.

Question 9 Quasars are “quasi-stellar” because they generate energy partly through H to He fusion like stars. they show spectra similar to extremely bright O stars. their luminosity varies like eclipsing binary stars. in short-exposure photographs, their images appear stellar. they are dense concentrations of millions of stars. Answer: d © 2017 Pearson Education, Inc.

Question 9 Quasars are “quasi-stellar” because they generate energy partly through H to He fusion like stars. they show spectra similar to extremely bright O stars. their luminosity varies like eclipsing binary stars. in short-exposure photographs, their images appear stellar. they are dense concentrations of millions of stars. Explanation: Although short-exposure images can appear starlike, many quasars show jets or other signs of intense activity. © 2017 Pearson Education, Inc.

Question 10 Seyfert and radio galaxies could be powered by supermassive black holes at their cores. dark matter. self-sustaining star formation. spiral density waves. hypernova explosions. Answer: a © 2017 Pearson Education, Inc.

Question 10 Seyfert and radio galaxies could be powered by supermassive black holes at their cores. dark matter. self-sustaining star formation. spiral density waves. hypernova explosions. Explanation: The Circinus Galaxy, a Seyfert galaxy about 4 Mpc away © 2017 Pearson Education, Inc.

Question 11 In active galaxies, the central engine can be “fed” by sudden bursts of star formation. supernova chain reactions in the core. the collapse of the core into a larger black hole. close encounters with a nearby galaxy. dark matter becoming visible and emitting light. Answer: d © 2017 Pearson Education, Inc.

Question 11 In active galaxies, the central engine can be “fed” by sudden bursts of star formation. supernova chain reactions in the core. the collapse of the core into a larger black hole. close encounters with a nearby galaxy. dark matter becoming visible and emitting light. © 2017 Pearson Education, Inc.