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QUESTION 01. Figure 1 shows a view of the Moon, which is on the meridian, at sunset, with the Sun setting due west. What is the phase of the Moon shown here, and what would be the phase about 1 week later? a.1st quarter; new moon b.1st quarter; full moon c.3rd quarter; new moon d.3rd quarter; full moon Figure 1 - The Moon located due south at sunset ANSWER 01. Figure 1 shows a view of the Moon, which is on the meridian, at sunset, with the Sun setting due west. What is the phase of the Moon shown here, and what would be the phase about 1 week later? a.1st quarter; new moon b.1st quarter; full moon c.3rd quarter; new moon d.3rd quarter; full moon Figure 1 - The Moon located due south at sunset QUESTION A. Sun, Earth, Moon - parallel shadows B. Sun, Earth, Moon - Earth’s shadow is perpendicular C. Sun, Earth, Moon - Earth with huge shadow D. Sun, Earth, Moon - Moon is in Earth’s shadow Figure 2 - Four different geometries for the Sun - Earth - Moon system from an overhead view. 02. Examine Figure 2 above that shows 4 choices for shadows of the Earth and Moon at the same phase of the Moon given in question 1. However, only 1 figure is correct. Which one and what evidence does it provide? a. The geometry of A is correct; Moon phases are NOT caused by Earth’s shadow. b. The geometry of B is correct; the dark (left) side of this phase IS caused by Earth’s shadow. c. The geometry of C is correct; the Earth’s shadow is VERY large and causes moon phases. d. The geometry of D is correct; this Moon phase involves its passing IN Earth’s shadow. ANSWER A. Sun, Earth, Moon - parallel shadows B. Sun, Earth, Moon - Earth’s shadow is perpendicular C. Sun, Earth, Moon - Earth with huge shadow D. Sun, Earth, Moon - Moon is in Earth’s shadow Figure 2 - Four different geometries for the Sun - Earth - Moon system from an overhead view. 02. Examine Figure 2 above that shows 4 choices for shadows of the Earth and Moon at the same phase of the Moon given in question 1. However, only 1 figure is correct. Which one and what evidence does it provide? a. The geometry of A is correct; Moon phases are NOT caused by Earth’s shadow. b. The geometry of B is correct; the dark (left) side of this phase IS caused by Earth’s shadow. c. The geometry of C is correct; the Earth’s shadow is VERY large and causes moon phases. d. The geometry of D is correct; this Moon phase involves its passing IN Earth’s shadow. (Called a lunar eclipse, not a phase.) QUESTION 03. We define or characterize light - electromagnetic radiation - by its a. energy b. wavelength c. frequency d. All of these. ANSWER 03. We define or characterize light - electromagnetic radiation - by its a. energy b. wavelength c. frequency d. All of these. QUESTION 04. Which one of the following lists the wavelengths of light from the longest to the shortest? a. radio, gamma ray, infrared, visible, ultraviolet, X-ray b. radio, infrared, visible, ultraviolet, X-ray, gamma ray c. gamma ray, X-ray, ultraviolet, visible, infrared, radio d. gamma ray, infrared, radio, ultraviolet, visible, X-ray ANSWER 04. Which one of the following lists the wavelengths of light from the longest to the shortest? a. radio, gamma ray, infrared, visible, ultraviolet, X-ray b. radio, infrared, visible, ultraviolet, X-ray, gamma ray c. gamma ray, X-ray, ultraviolet, visible, infrared, radio d. gamma ray, infrared, radio, ultraviolet, visible, X-ray QUESTION 05. Which one of the following lists the corresponding energy of the photons of light from the lowest energy to the highest? a. radio, gamma ray, infrared, visible, ultraviolet, X-ray b. radio, infrared, visible, ultraviolet, X-ray, gamma ray c. gamma ray, X-ray, ultraviolet, visible, infrared, radio d. gamma ray, infrared, radio, ultraviolet, visible, X-ray ANSWER 05. Which one of the following lists the corresponding energy of the photons of light from the lowest energy to the highest? a. radio, gamma ray, infrared, visible, ultraviolet, X-ray b. radio, infrared, visible, ultraviolet, X-ray, gamma ray c. gamma ray, X-ray, ultraviolet, visible, infrared, radio d. gamma ray, infrared, radio, ultraviolet, visible, X-ray QUESTION 06. Kepler’s first law states that orbits of the planets are a. eclipses of the planets by the Earth. b. ellipses with the Sun at one focus. c. equatorials aligned with the celestial equator. d. ecliptics or orbits aligned with the Sun. ANSWER 06. Kepler’s first law states that orbits of the planets are a. eclipses of the planets by the Earth. b. ellipses with the Sun at one focus. c. equatorials aligned with the celestial equator. d. ecliptics or orbits aligned with the Sun. QUESTION Figure 3 - A sketch of the Milky Way and one of its orbiting globular clusters Kepler’s laws also apply to globular clusters as they orbit the center of the Milky Way (the focus of the orbit). Figure 3 sketches the counterclockwise orbit of one of the globular clusters on a highly eccentric orbit. 07. The globular cluster will spend the longest amount of time at which location, A or B? 08. At which location will the globular cluster be orbiting the fastest, A or B? ANSWER Figure 3 - A sketch of the Milky Way and one of its orbiting globular clusters Kepler’s laws also apply to globular clusters as they orbit the center of the Milky Way (the focus of the orbit). Figure 3 sketches the counterclockwise orbit of one of the globular clusters on a highly eccentric orbit. 07. The globular cluster will spend the longest amount of time at which location, A or B? A 08. At which location will the globular cluster be orbiting the fastest, A or B? B QUESTION Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 09. Which one of these stars is the closest to us? a. Sirius b. Canopus c. Alpha Centauri A d. Alpha Centauri B e. Arcturus ANSWER Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 09. Which one of these stars is the closest to us? a. Sirius b. Canopus c. Alpha Centauri A d. Alpha Centauri B e. Arcturus QUESTION Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 10. Which one of these stars is the most luminous? a. Sirius b. Canopus c. Alpha Centauri A d. Alpha Centauri B e. Arcturus ANSWER Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 10. Which one of these stars is the most luminous? a. Sirius b. Canopus c. Alpha Centauri A d. Alpha Centauri B e. Arcturus QUESTION Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 11. Sirius, Alpha Centauri A, and Alpha Centauri B are all main sequence stars. Which of these stars will live the longest on the main sequence? a. Sirius b. Alpha Centauri A c. Alpha Centauri B ANSWER Table 1 - Six of the Brightest Stars in the Sky Star Name Spectral Class Parallax (arc seconds) Apparent Magnitude absolute magnitude Sirius A1 V 0.379 -1.46 1.43 Canopus F0 II 0.011 -0.72 -5.60 Alpha Centauri A G2 V 0.755 -0.01 4.34 Alpha Centauri B K1 V 0.797 1.33 5.68 K1.5 III 0.015 -0.04 -0.30 Arcturus V = main sequence; III = giant; II = in between giant and supergiant 11. Sirius, Alpha Centauri A, and Alpha Centauri B are all main sequence stars. Which of these stars will live the longest on the main sequence? a. Sirius b. Alpha Centauri A c. Alpha Centauri B QUESTION 12. Figure 4 shows the color magnitude diagrams (CMDs) of two open clusters (actual data). Which cluster is the younger one? a. NGC 1960 b. NGC 2355 c. They are both the same age. d. Not enough information is given to answer this question. ANSWER 12. Figure 4 shows the color magnitude diagrams (CMDs) of two open clusters (actual data). Which cluster is the younger one? a. NGC 1960 b. NGC 2355 c. They are both the same age. d. Not enough information is given to answer this question. QUESTION 13. What else can be inferred from the graph for each of the CMDs shown in Figure 4? a. The locations or coordinates on the celestial sphere where the clusters are located. b. How fast each cluster is moving relative to Earth; i.e., spectral redshifts or blueshifts. c. The value of Hubble’s constant by fitting a slope to the main sequence. d. The approximate masses of main sequence stars based on the turn-off B - V value. ANSWER 13. What else can be inferred from the graph for each of the CMDs shown in Figure 4? a. The locations or coordinates on the celestial sphere where the clusters are located. b. How fast each cluster is moving relative to Earth; i.e., spectral redshifts or blueshifts. c. The value of Hubble’s constant by fitting a slope to the main sequence. d. The approximate masses of main sequence stars based on the turn-off B - V value. QUESTION 14. One of these clusters still has massive stars on the main sequence. Which region of the Milky Way galaxy is it most likely to be found? a. Near the supermassive black hole at the center. b. Far out in the halo. c. Within a spiral arm of the disk. d. Within the orbit of Pluto. ANSWER 14. One of these clusters still has massive stars on the main sequence. Which region of the Milky Way galaxy is it most likely to be found? a. Near the supermassive black hole at the center. b. Far out in the halo. c. Within a spiral arm of the disk. d. Within the orbit of Pluto. QUESTION Figure 5 - CMD for globular cluster NGC 1851; actual image taken with an Artemis 285 digital camera Match the names of the regions of this CMD with its identifying letter. 15. Main sequence of stars _____ 16. Subgiant branch _____ 17. Red giant branch _____ 18. Main sequence turn-off _____ 19. Horizontal branch. _____ ANSWER Figure 5 - CMD for globular cluster NGC 1851; actual image taken with an Artemis 285 digital camera Match the names of the regions of this CMD with its identifying letter. 15. Main sequence of stars __D___ 16. Subgiant branch __C___ 17. Red giant branch __A___ 18. Main sequence turn-off __E___ 19. Horizontal branch. __B___ QUESTION 20. Somewhere between 3 and 6 billion years from now the Sun will run out of hydrogen in its core and move to the subgiant branch. What does this mean for the Sun? a. Its surface temperature will decrease. b. Its luminosity will increase. c. Its radius will increase d. All of these statements are true. ANSWER 20. Somewhere between 3 and 6 billion years from now the Sun will run out of hydrogen in its core and move to the subgiant branch. What does this mean for the Sun? a. Its surface temperature will decrease. b. Its luminosity will increase. c. Its radius will increase d. All of these statements are true. QUESTION 21. When nuclear fusion of hydrogen to helium shuts down in the Sun’s core, there is no longer enough pressure to support the rest of the star. What happens in and around the core? a. The core expands, cools, and fusion of helium to carbon shell fusion begins. b. The core has a carbon flash, and the fusion of carbon to oxygen begins. c. The core shrinks and releases heat starting hydrogen to helium shell fusion. d. The core shrinks until electron degeneracy becomes the means of support. ANSWER 21. When nuclear fusion of hydrogen to helium shuts down in the Sun’s core, there is no longer enough pressure to support the rest of the star. What happens in and around the core? a. The core expands, cools, and fusion of helium to carbon shell fusion begins. b. The core has a carbon flash, and the fusion of carbon to oxygen begins. c. The core shrinks and releases heat starting hydrogen to helium shell fusion. d. The core shrinks until electron degeneracy becomes the means of support. QUESTION 22. Planetary nebulae provide excellent examples of the range colors that can be produced by processes occurring in atoms. What kind of spectra do we expect to see from planetary nebulae? a. Continuous spectra with the peak wavelength occurring in the ultraviolet. b. Emission spectra from elements like carbon, nitrogen, oxygen, and hydrogen. c. Absorption spectra indicating most electrons of the atoms cannot gain energy. d. Highly redshifted spectra originating from the ejection of gas from the star. ANSWER 22. Planetary nebulae provide excellent examples of the range colors that can be produced by processes occurring in atoms. What kind of spectra do we expect to see from planetary nebulae? a. Continuous spectra with the peak wavelength occurring in the ultraviolet. b. Emission spectra from elements like carbon, nitrogen, oxygen, and hydrogen. c. Absorption spectra indicating most electrons of the atoms cannot gain energy. d. Highly redshifted spectra originating from the ejection of gas from the star. QUESTION 23. How is it that the core of a massive star is able to fuse heavier and heavier elements without any of these stages resulting in degeneracy or any flashes like the helium flash that occurs in solar-type stars? a. The cores of massive stars are so hot, have such high densities and pressures, that these stars fuse all elements simultaneously; that is, all at the same time. b.The strong gravitational force contracts the core at the end of each fusion cycle, causing the pressure and temperature to increase enough to fuse heavier elements. c.Massive stars have enough hydrogen throughout their interiors and atmospheres that they never run out of hydrogen to fuse and avoid flashes. d.After the stellar-mass black hole forms in the core of a massive star it pulls in all of the fusion shells that have been formed, preventing flashes. ANSWER 23. How is it that the core of a massive star is able to fuse heavier and heavier elements without any of these stages resulting in degeneracy or any flashes like the helium flash that occurs in solar-type stars? a. The cores of massive stars are so hot, have such high densities and pressures, that these stars fuse all elements simultaneously; that is, all at the same time. b.The strong gravitational force contracts the core at the end of each fusion cycle, causing the pressure and temperature to increase enough to fuse heavier elements. c.Massive stars have enough hydrogen throughout their interiors and atmospheres that they never run out of hydrogen to fuse and avoid flashes. d.After the stellar-mass black hole forms in the core of a massive star it pulls in all of the fusion shells that have been formed, preventing flashes. QUESTION 24. Observationally, what is the difference between a neutron star and a pulsar? a. Not all neutron stars are beaming radiation in our direction and pulsing. b. Neutron stars always rotate much faster than pulsars. c. Neutron stars usually rotate much slower than pulsars. d. Pulsars are much larger than neutron stars and thus give off more light. ANSWER 24. Observationally, what is the difference between a neutron star and a pulsar? a. Not all neutron stars are beaming radiation in our direction and pulsing. b. Neutron stars always rotate much faster than pulsars. c. Neutron stars usually rotate much slower than pulsars. d. Pulsars are much larger than neutron stars and thus give off more light. QUESTION 25. Unfortunately, we will never, ever be able to actually "see" what is going on inside the event horizon of a black hole, including the singularity. Why not? a. Singularities are theoretical possibilities and we can't *see* theoretical things. b. Everything that gets sucked in is destroyed so there's nothing left TO see. c. Inside the event horizon, the escape velocity exceeds that of light. d. Our telescopes fail to detect Hawking radiation emitted from the event horizon. ANSWER 25. Unfortunately, we will never, ever be able to actually "see" what is going on inside the event horizon of a black hole, including the singularity. Why not? a. Singularities are theoretical possibilities and we can't *see* theoretical things. b. Everything that gets sucked in is destroyed so there's nothing left TO see. c. Inside the event horizon, the escape velocity exceeds that of light. d. Our telescopes fail to detect Hawking radiation emitted from the event horizon. QUESTION A. Identify the galaxies shown in Figure 6. Each type is used just once. B. 26. Irregular or peculiar _____ 27. Spiral _____ 28. Elliptical _____ 29. Barred Spiral _____ C. C 30. What is the type of galaxy that the Milky Way is most widely thought to resemble: A, B, C, or D? Figure - 6 Four galaxies for classifying A C B D ANSWER A. Identify the galaxies shown in Figure 6. Each type is used just once. B. 26. Irregular or peculiar __D___ 27. Spiral _C____ 28. Elliptical __B___ 29. Barred Spiral __A___ C. 30. What is the type of galaxy that the Milky Way is most widely thought to resemble: D? A, B, C, or Figure - 6 Four galaxies for classifying A C B D QUESTION 31. Around 1975 there was a definite disagreement in the accepted value for the Hubble constant (Ho): about 100 km/s per megaparsec versus 50 km/s per megaparsec. If the calculated age of the Universe with a Hubble constant of 50 km/sec per megaparsec was 20 billion years, what would be the implied age of the Universe for Ho = 100 km/s/Mpc? a. 10 billion years b. 40 billion years c. 15 billiion years d. 5 billion years ANSWER 31. Around 1975 there was a definite disagreement in the accepted value for the Hubble constant (Ho): about 100 km/s per megaparsec versus 50 km/s per megaparsec. If the calculated age of the Universe with a Hubble constant of 50 km/sec per megaparsec was 20 billion years, what would be the implied age of the Universe for Ho = 100 km/s/Mpc? a. 10 billion years b. 40 billion years c. 15 billiion years d. 5 billion years QUESTION 32. What was one of the important contributions that Cepheid variable stars made to our determining distances in the Universe? a. One observed in the Andromeda galaxy was determined to be millions of light years away. b. This kind of variable star has a well defined period-luminosity relationship that we use. c. They are so luminous that they can be observed in galaxies over 25 million light years away. d. Each one of these answers relates to the contributions Cepheids have made. ANSWER 32. What was one of the important contributions that Cepheid variable stars made to our determining distances in the Universe? a. One observed in the Andromeda galaxy was determined to be millions of light years away. b. This kind of variable star has a well defined period-luminosity relationship that we use. c. They are so luminous that they can be observed in galaxies over 25 million light years away. d. Each one of these answers relates to the contributions Cepheids have made. QUESTION 33. What is the theory behind the observations that the halo stars - such as those found in globular clusters - are all "metal-poor," meaning that they have a very low percentage of elements heavier than helium, while stars located in the disk of the Galaxy have higher, and sometimes much higher, abundances of "heavy elements,” such as carbon, nitrogen, oxygen, iron, magnesium, etc. a, Halo stars formed shortly after the Big Bang when the composition of the Universe was mainly hydrogen and helium. b. Disk stars have compositions enriched with heavy elements from supernovae explosions, planetary nebulae, and stellar winds. c. Star formation in the disk happened later than that in the halo and is still an ongoing process. c. All of these answers are part of the theory of the chemical enrichment of the Milky Way. ANSWER 33. What is the theory behind the observations that the halo stars - such as those found in globular clusters - are all "metal-poor," meaning that they have a very low percentage of elements heavier than helium, while stars located in the disk of the Galaxy have higher, and sometimes much higher, abundances of "heavy elements,” such as carbon, nitrogen, oxygen, iron, magnesium, etc. a, Halo stars formed shortly after the Big Bang when the composition of the Universe was mainly hydrogen and helium. b. Disk stars have compositions enriched with heavy elements from supernovae explosions, planetary nebulae, and stellar winds. c. Star formation in the disk happened later than that in the halo and is still an ongoing process. c. All of these answers are part of the theory of the chemical enrichment of the Milky Way. QUESTION 34. Which one of the following answers provides convincing evidence that there is a supermassive black hole at the center of the Milky Way? a. Observations at radio wavelengths indicate extreme gravitational redshifts. b. High velocity stars whose orbits indicate a mass of millions of suns within a small volume. c. Large volumes of stars, gas, clusters, and dust seem to be “hovering” for eternity. d. Large extensive jets of ionized material shooting straight up from the center of the Galaxy. ANSWER 34. Which one of the following answers provides convincing evidence that there is a supermassive black hole at the center of the Milky Way? a. Observations at radio wavelengths indicate extreme gravitational redshifts. b. High velocity stars whose orbits indicate a mass of millions of suns within a small volume. c. Large volumes of stars, gas, clusters, and dust seem to be “hovering” for eternity. d. Large extensive jets of ionized material shooting straight up from the center of the Galaxy. QUESTION 35. What aspect about globular clusters and our measurements of the distances to them using RR Lyrae variable stars modified our view of the Milky Way Galaxy and our place in it? a. Some of the globular clusters are very far away and must belong to the Andromeda Galaxy. b. We found out that there are hundreds of globular clusters hidden by columns of dust. c. The most distant globular clusters are metal-rich and so must have originated in the disk. d. They all orbit the center of the Galaxy, and the center of their distribution is not where we are. ANSWER 35. What aspect about globular clusters and our measurements of the distances to them using RR Lyrae variable stars modified our view of the Milky Way Galaxy and our place in it? a. Some of the globular clusters are very far away and must belong to the Andromeda Galaxy. b. We found out that there are hundreds of globular clusters hidden by columns of dust. c. The most distant globular clusters are metal-rich and so must have originated in the disk. d. They all orbit the center of the Galaxy, and the center of their distribution is not where we are. QUESTION 36. An observer far outside our galaxy would best describe our galaxy and the Sun's position in it as a a. disk of stars roughly centered on our Solar System. b. disk of stars with our Solar System located in the bulge. c. gigantic sphere of stars centered on our Solar System. d. disk of stars with the Sun approximately 25,000 light years from the center. ANSWER 36. An observer far outside our galaxy would best describe our galaxy and the Sun's position in it as a a. disk of stars roughly centered on our Solar System. b. disk of stars with our Solar System located in the bulge. c. gigantic sphere of stars centered on our Solar System. d. disk of stars with the Sun approximately 25,000 light years from the center. QUESTION 37. Here is a diagram that depicts some of the electron transitions in a hydrogen atom. Which transition results in a red photon being emitted? a. wavelength = 121.6 nm b. wavelength = 656.3 nm c. wavelength = 486.2 nm d. wavelength = 434.1 nm e. wavelength = 420.2 nm Figure 7 - Five transitions for electrons in a hydrogen atom. ANSWER 37. Here is a diagram that depicts some of the electron transitions in a hydrogen atom. Which transition results in a red photon being emitted? a. wavelength = 121.6 nm b. wavelength = 656.3 nm c. wavelength = 486.2 nm d. wavelength = 434.1 nm e. wavelength = 420.2 nm Figure 7 - Five transitions for electrons in a hydrogen atom. QUESTION 38. Figure 8 shows a planetary nebula that is called (amazingly enough) the red rectangle. The image was taken in visible light by the Hubble Space Telescope, and almost all of the diffuse gas that was ejected from the star glows red. This red color is most likely due to a. warm dust glowing at infrared wavelengths. b. excited atoms that are emitting light at ultraviolet wavelengths. c. electrons in hydrogen atoms transitioning from energy level 3 to 2. d. interstellar reddening due to dust scattering blue light. ANSWER 38. Figure 8 shows a planetary nebula that is called (amazingly enough) the red rectangle. The image was taken in visible light by the Hubble Space Telescope, and almost all of the diffuse gas that was ejected from the star glows red. This red color is most likely due to a. warm dust glowing at infrared wavelengths. b. excited atoms that are emitting light at ultraviolet wavelengths. c. electrons in hydrogen atoms transitioning from energy level 3 to 2. d. interstellar reddening due to dust scattering blue light. QUESTION 40. Using the concept of look-back time, which one of the following answers is correct? a. The galaxies with the highest redshifts will look the oldest. b. The most distant galaxies will look the youngest. c. The closest galaxies to us will look the youngest. d. The galaxies with the highest redshifts will be the oldest. ANSWER 40. Using the concept of look-back time, which one of the following answers is correct? a. The galaxies with the highest redshifts will look the oldest. b. The most distant galaxies will look the youngest. c. The closest galaxies to us will look the youngest. d. The galaxies with the highest redshifts will be the oldest. QUESTION 41. Light has a finite speed. We are able to gain insight as to how galaxies evolve over time by studying the galaxies at various redshifts in the Hubble Deep Fields because the farther away a galaxy is the longer its light takes to reach us. a.galaxies at larger and larger redshifts will look progressively younger and younger. b.since the Big Bang, galaxies have been gradually evolving from spiral to elliptical types. c.galaxies were all born at roughly the same time, but the closest ones are the youngest. ANSWER 41. Light has a finite speed. We are able to gain insight as to how galaxies evolve over time by studying the galaxies at various redshifts in the Hubble Deep Fields because the farther away a galaxy is the longer its light takes to reach us. a.galaxies at larger and larger redshifts will look progressively younger and younger. b.since the Big Bang, galaxies have been gradually evolving from spiral to elliptical types. c.galaxies were all born at roughly the same time, but the closest ones are the youngest. QUESTION 42. The spectrum of the cosmic microwave background radiation is the signature of what the Universe was like at 380,000 years after the Big Bang when atoms finally formed. The radiation from this early time is the closest thing we have observed to a perfect blackbody spectrum. This spectrum tells us that the early universe was a.opaque b.dense c.of nearly uniform, hot temperature d.All of these conditions were present. ANSWER 42. The spectrum of the cosmic microwave background radiation is the signature of what the Universe was like at 380,000 years after the Big Bang when atoms finally formed. The radiation from this early time is the closest thing we have observed to a perfect blackbody spectrum. This spectrum tells us that the early universe was a.opaque b.dense c.of nearly uniform, hot temperature d.All of these conditions were present. QUESTION 43. The group of astronomers that discovered that the expansion of the universe is not slowing down but is rather speeding up, or accelerating in its expansion, used a standard candle that you should be familiar with by now. What did they use? a. Hubble’s Law using a sample of 1000 distant elliptical galaxies. b. RR Lyrae variables in the globular clusters of distant galaxies. c. Type Ia supernovae in very distant galaxies. d. A large sample of Cepheid variable stars. ANSWER 43. The group of astronomers that discovered that the expansion of the universe is not slowing down but is rather speeding up, or accelerating in its expansion, used a standard candle that you should be familiar with by now. What did they use? a. Hubble’s Law using a sample of 1000 distant elliptical galaxies. b. RR Lyrae variables in the globular clusters of distant galaxies. c. Type Ia supernovae in very distant galaxies. d. A large sample of Cepheid variable stars. QUESTION 44. Suppose that a number of galaxies are grouped closely together in the sky (as seen in the image of the Hubble Deep Field North), but have very different redshifts. From this, you can conclude that a. b. c. d. the nearness in the sky is just coincidence. the galaxies are actually close together in space. the galaxies are all moving in different directions. the galaxy motions are dominated by peculiar velocities. Figure 10 - A small section of the Hubble Deep Field North with some redshifts noted ANSWER 44. Suppose that a number of galaxies are grouped closely together in the sky (as seen in the image of the Hubble Deep Field North), but have very different redshifts. From this, you can conclude that a. b. c. d. the nearness in the sky is just coincidence. the galaxies are actually close together in space. the galaxies are all moving in different directions. the galaxy motions are dominated by peculiar velocities. Figure 10 - A small section of the Hubble Deep Field North with some redshifts noted QUESTION State whether you are describing gravity as a. Newton or as b. Einstein would. 45. Gravity is a force that simultaneously acts between objects. 46. The structure of space determines how mass moves. 47. The amount of mass in an object determines how much space curves. 48. Force of gravity is the product of two masses divided by the radius squared. 49. Gravitation is the result of the shape of spacetime an object moves through. 50. Gravitational lensing is probably caused by the distortion of spacetime. ANSWER State whether you are describing gravity as a. Newton or as b. Einstein would. 45. Gravity is a force that simultaneously acts between objects. A 46. The structure of space determines how mass moves. B 47. The amount of mass in an object determines how much space curves. B 48. Force of gravity is the product of two masses divided by the radius squared. A 49. Gravitation is the result of the shape of spacetime an object moves through. B 50. Gravitational lensing is probably caused by the distortion of spacetime. B