Exploring the Cosmos - Galaxies and Large Scale Structure
1. Our Sun is situated
in a globular cluster in the halo of the galaxy.
in the disc of the galaxy close to the edge of the disc.
in a globular cluster in the galactic disc about half of its radius from the centre.
in the disc of the galaxy about two thirds of its radius from the centre.
2. Neutral hydrogen can be detected by astronomers because
it reflects blue light from nearby stars.
it glows with a bright blue colour.
it radiates a sharp 21 cm radio signal.
it forms dark clouds in the disc of a spiral galaxy.
3. Our Sun and solar system are
rotating about the centre of the Galaxy once every million years.
moving directly towards a supermassive black hole at the centre of the Galaxy and will merge into the centre in 240 million years.
stationary in our Galaxy.
rotating around the centre of the Galaxy once every 240 million years.
4. Recent observations have shown that there is much invisible matter in the outer regions of our Galaxy.
The observations have involved measurement of the velocities of stars in the spiral arms of the Galaxy.
The missing invisible material is likely to be completely accounted for by a large number of planets around stars.
The evidence has come from theoretical studies of black hole formation.
The current estimate is that around 50% of the mass of the Galaxy is in this invisible form.
5. The disk component of a spiral galaxy includes which of the following parts?
Globular clusters
Halo
Spiral arms
Bulge
6. By observing what astronomical objects was it first found that the Solar System is not located in the centre of the Milky Way?
Globular clusters
Cepheids
Absorption nebulae
Black holes
7. Our Sun is situated
in a globular cluster in the galactic disc about half of its radius from the centre.
in the disc of the galaxy close to the edge of the disc.
in a globular cluster in the halo of the galaxy.
in the disc of the galaxy about two thirds of its radius from the centre.
8. Of the stars in our galaxy
those in the spherical component move in elliptical orbits that have a random orientation.
those in the disc component move in circular orbits that have random orientations.
those in the spherical component move in circular orbits that have random orientations.
those in the nucleus orbit the centre in the opposite direction to those in the disc component.
9. The approximate position of the centre of the Milky Way galaxy was first found, using optical telescopes, by
measuring the position of visible open star clusters.
looking for the central bulge.
observing stars moving round the massive black hole in the centre.
measuring the position of visible globular clusters.
10. The diameter of the Milky Way Galaxy is
about 25 to 30 pc.
about 250 to 300 pc.
about 25 to 30 Mpc.
about 25 to 30 kpc.
11. Population II stars are
"metal" poor and typically found in the nucleus and halo of a spiral galaxy.
"metal" poor and typically found in the disc of a spiral galaxy.
"metal" rich and typically found in the disc of a spiral galaxy.
"metal" rich and typically found in the disc of a spiral galaxy.
12. Recent observations have shown that there is much invisible matter in the outer regions of our Galaxy.
The current estimate is that around 50% of the mass of the Galaxy is in this invisible form.
The evidence has come from theoretical studies of black hole formation.
The observations have involved measurement of the velocities of stars in the spiral arms of the Galaxy.
The missing invisible material is likely to be completely accounted for by a large number of planets around stars.
13. Several different measurements indicated that our galaxy is a spiral galaxy. Which of the following observations does not give evidence for the presence of spiral arms?
Infra-red measurements of the dust density in the Milky Way
Location of CO clouds within the galaxy
Location of nearby Globular clusters
Location of nearby O and B stars
14. The existence of dark matter was proposed to explain...
the formation of galaxies with extremely luminous galactic centres (active galaxies).
the shape of the orbits of halo stars and globular clusters.
the flat region of the rotation curve far from the galactic centre.
the observation of strong sources of x-rays and radio waves at the galactic centre.
15. In a galaxy such as ours, extremely young Population I stars are predominantly found...
in the disc component.
in the spiral arms.
in the nuclear bulge.
in the halo.
16. Globular clusters...
are usually found in the discs of galaxies and contain population I stars.
are usually found in the discs of galaxies and contain population II stars.
are usually found in the halos of galaxies and contain population II stars.
are usually found in the halos of galaxies and contain population I stars.
17. The approximate position of the centre of the Milky Way galaxy was first found, using optical telescopes, by...
measuring the position of visible globular clusters.
measuring the position of visible open star clusters.
looking for the central bulge.
observing stars moving round the massive black hole in the centre.
18. Gas and dust in the interstellar medium (ISM) is often seen in diffuse clouds called nebulae.
The gas in emission nebulae typically emits pink light when it is excited by high energy light from nearby stars.
The Pleiades is an example of an emission nebula.
The difference in colour between emission and reflection nebulae arises from the Doppler effect and is due to their differing motion relative to us.
Reflection nebulae show up as pink, due to the reflection by dust of light coming from nearby stars.
19. The speed of stars as they orbit in a nearby spiral galaxy can be measured by...
using the red or blue shift of the spectrum from different parts of the disc.
observing them for a long period and measuring the change in their position.
determining their spectral class.
measuring the infra red spectrum from them.
20. Star clusters in our Galaxy that are...
globular clusters mainly contain hot, young stars.
open clusters typically occupy a volume of about 1 kpc across.
globular clusters mainly lie in the disk region.
open clusters typically contain up to a few thousand stars.
21. Which of the following processes does not contribute to the formation of 'metals' (elements heavier than Hydrogen and Helium)?
Planetary nebulae
Emission nebulae
Type 2 Supernovae
Type 1a Supernovae
22. Today we know that the Milky Way has two disc components. Which of the following statements is correct?
The stars of the thin disk have a stronger oscillatory motion than stars in the thick disc.
The stars in the thin disc have an iron to oxygen ratio that suggests they were formed later than the thick disk.
The stars of the two disc components move in opposite direction around the galactic centre.
The stars in the thick disc have an iron to oxygen ratio that suggests they were formed later than the thin disk.
23. Interstellar medium can be classified in four different categories, each of which has different densities. Which of the following statements is wrong?
Dark giant molecular clouds are denser than diffuse gas clouds.
Inter-cloud media have a lower density than diffuse gas clouds.
Very hot coronal gases have higher density than diffuse gas clouds.
Very hot coronal gas has lower density than inter-cloud media.
24. In the Universe
galaxies occur randomly in space.
galaxies tend to occur in super-clusters which, in turn, form even larger structures which stretch across much of the known universe.
galaxies tend to occur in super-clusters which occur randomly in space.
galaxies tend to occur in clusters which occur randomly in space.
25. The correct order of the distance ladder from close to far is
Spectroscopic parallax, Cepheid Variables, Supernovae 1a, Hubble’s Law.
Spectroscopic parallax, Cepheid Variables, Hubble’s Law, Supernovae 1a.
Supernovae 1a, Hubble’s Law, Spectroscopic parallax, Cepheid Variables.
Spectroscopic parallax, Supernovae 1a, Cepheid Variables, Hubble’s Law.
26. A type Sb galaxy is
a disc shaped galaxy with little gas and almost no new star formation.
a spiral galaxy with moderately tightly wound arms.
a barred spiral galaxy with moderately tightly wound arms.
a barred spiral galaxy with very open arms.
27. A Seyfert galaxy is
a galaxy that is emitting an unusually large amount of energy due to a black hole at its centre.
another name for a type SO galaxy.
a galaxy that does not have a black hole at its centre and is free to radiate large amounts of energy.
a galaxy that has been distorted by a close encounter with another galaxy so that there is a high rate of formation of new stars.
28. Cepheid variable stars are important for distance measurements because
their brightness pulsates in a well defined way that allows them to be identified and their average brightness is independent of their size.
from their pulsation rate of their brightness, we can deduce their intrinsic average brightness.
they emit radio waves whose frequency allows the calculation of their distance.
from their pulsation rate of their brightness, we can deduce their rotational speed.
29. An S0 galaxy is
a galaxy with intense star formation due to a collision with another galaxy.
a spiral galaxy with many arms.
a galaxy with a nucleus and a disc but little dust and gas.
a very elongated elliptical galaxy.
30. A possible explanation of the formation of a giant elliptical galaxy is
it was formed by the merger of two or more galaxies.
a giant spiral galaxy used up the gas and dust in its disc so that the generation of new stars ceased and the arms slowly broke up.
it has a giant black hole at its centre that attracts many stars.
a giant spiral galaxy evolved into an elliptical galaxy.
31. Which of the following is not a characteristic of rich galaxy clusters?
Collisions of galaxies are likely to happen.
High density of galaxies.
The cluster at the centre is often formed by one or more giant elliptical galaxies.
Contains a large fraction of spiral galaxies.
32. A super-massive black hole would be most likely found in our galaxy
in the nucleus.
in one of its arms.
in one of the open clusters of stars.
at the centre of a globular cluster.
33. Astronomers have been able to measure the speeds of stars near the centre of our galaxy using
infrared telescopes.
radio telescopes.
modern optical telescopes.
X-ray telescopes.
34. A bright red region observed round a bright star in our galaxy is usually
a dust cloud scattering the light of a red giant star.
a region in which hydrogen atoms in a gas cloud are being excited and ionised by the very luminous nearby star and are emitting the red light.
coloured dust ejected by a nearby supernova.
a dust cloud that is absorbing the blue part of the light from the very luminous star and allowing only the red light to pass.
35. Population II stars are
metal rich and typically found in the nucleus and halo of a galaxy.
metal rich and typically found in the spiral arms of a galaxy.
metal poor and typically found in the nucleus and halo of a galaxy.
metal poor and typically found in the spiral arms of a galaxy.
36. On average the density of gas in the interstellar medium (ISM) is
similar to that at the surface of the Sun.
in the region of 1 hydrogen atom per cubic centimetre.
in the region of 1 hydrogen atom per cubic metre.
similar to that in the Earth's atmosphere.
37. Which of the following comprise the oldest members of the Milky Way?
The Sun and other solar mass stars.
Red giant stars in spiral arms.
Globular clusters.
Type O stars.
38. What can cause a galactic fountain?
Multiple supernovae occurring together.
The combined effect of spiral density waves.
A supernova occurring in the halo.
Winds and jets from newly-formed protostars.
39. Two stars, A and B, have the same intrinsic brightness. The distance to A is two-thirds of the distance to B. Compared to B, A will appear to be
two-thirds as bright as B.
as bright as B.
2.25 (or 9/4) times brighter than B.
1.5 times brighter than B.
40. The Great Wall is
a dense concentration of galaxies that stretches across much of the visible universe.
an unusually dense concentration of stars, gas and dust in a nearby spiral arm of our galaxy.
a dense concentration of galaxies in the nearby Virgo cluster.
a mechanism that explains the formation of the density waves that cause the creation of new stars in a spiral galaxy.
41. What two observable properties of a Cepheid variable are directly related to one another?
Its luminosity and its mass.
The period between its peaks of brightness and its luminosity.
The period between its peaks of brightness and its distance.
Its mass and its distance.
42. Which of the following terms does not refer to one of the major galaxy classes?
Spiral
Barred Spiral
Elliptical
Barred Elliptical
43. Which of the following conditions can be responsible for the creation of an irregular galaxy?
A super-massive black hole in the centre of the galaxy
Collision of two galaxies
A quasar in the centre of the galaxy
Continuous inflow of atomic Hydrogen from outside the galaxy
44. Which of the following characteristics is true for elliptical Galaxies?
Lots of interstellar medium is present in elliptical galaxies.
Elliptical galaxies mainly feature Population I stars.
In elliptical galaxies there is very little active star formation.
Elliptical galaxies often rotate fast.
45. An S0 galaxy can evolve into which of the following galaxy types?
Galaxies cannot evolve from one type into another
SBb
Sa
Sc
46. What two observable properties of a Cepheid variable are directly related to one another?
The period between its peaks of brightness and its distance.
Its luminosity and its mass.
The period between its peaks of brightness and its luminosity.
Its mass and its distance.
47. What can cause a galactic fountain?
Winds and jets from newly-formed protostars.
Multiple supernovae occurring together.
A supernova occurring in the halo.
The combined effect of spiral density waves.
48. Quasars are seen to be unusual because they are very
compact distant galaxies with a large red shift that have many bright O type stars that makes them very luminous.
small stars with an extremely low luminosity because their mass is so small the almost failed to become stars.
small bright objects whose large red shift indicates that they are very distant.
bright stars near the centre of our galaxy whose light is very red-shifted by the intense gravitational field from the super-massive black hole at the centre.
49. A Seyfert galaxy is a
disc shaped galaxy with a central bulge, little gas and dust and a low rate of generation of new stars.
spiral galaxy whose nucleus is a very strong emitter of radio waves and sometimes X-rays.
spiral galaxy with a high rate of creation of new stars.
large elliptical galaxy with jets of matter that are ejected at high speed from its centre.
50. Elliptical galaxies are believed to have been formed by
the merger of two or more elliptical or other types of galaxies.
the collapse of a very large spiral galaxy.
matter that collected round a very massive black hole.
the very rapid collapse of a super-massive cloud of dust and gas.
51. The "Local Group" of galaxies
contains the galaxies of the Virgo cluster.
has our Galaxy as one of the smaller members.
contains galaxies that are spread in a volume that is nearly 10 million light years in diameter.
consists of about 200 galaxies.
52. Which class of galaxies predominantly contains Population II stars and little or no gas and dust?
Seyfert galaxies.
Spirals.
Barred spirals.
Elliptical galaxies.
53. If a galaxy’s disc rotates in the direction opposite to the rotational direction of the core, this is a likely indication of
a spiral galaxy.
a merger of two galaxies.
a galaxy with a large recessional velocity.
a supermassive black hole in the centre of the galaxy.
54. The existence of dark matter was proposed to explain
the flat region of the rotation curve far from the galactic centre.
the shape of the orbits of halo stars and globular clusters.
the observation of strong sources of X-rays and radio waves at the galactic centre.
the formation of active galaxies.
55. Rich clusters typically contain a high fraction of
Sa, Sb and Sc galaxies.
SBa, SBb and SBc galaxies.
elliptical (E) and S0-type galaxies.
grand design galaxies.
56. Assuming a value of H0 = 70km/s/Mpc for the Hubble constant, and a measured recessional velocity of a galaxy of v = 350km/s, what is the distance to this galaxy according to Hubble’s law?
24.5Gpc
none of the above
5Mpc
0.2Mpc
57. The distance to a Cepheid variable star can be determined by using the relation between
its mass and its velocity.
its pulsation period and its velocity.
its mass and its luminosity.
its pulsation period and its luminosity.
58. The theory of density waves explains the structure of
flocculent galaxies.
Seyfert galaxies.
grand design galaxies.
elliptical galaxies.
59. Galaxies of type Sa have
a large nucleus and tightly wound spiral arms.
a small nucleus and loosely wound spiral arms.
a large nucleus and loosely wound spiral arms.
a small nucleus and tightly wound spiral arms.
60. In a galaxy such as ours, extremely young Population I stars are predominantly found
in the spiral arms.
in the halo.
in the disc component.
in the nuclear bulge.
61. Which of the following properties does not apply to typical Type I Seyfert galaxies?
The emission spectra show broad spectral lines of highly ionized atoms.
The galactic centres are strong emitters of x-rays and ultraviolet radiation.
The sources of the emitted radiation, the active galactic nuclei, are extremely large.
The velocity of matter near their centres is much higher than in normal galaxies.
62. The spectra of Seyfert galaxies show:
broad emission lines from highly ionised atoms.
narrow emission lines from highly ionised atoms.
narrow absorption lines from highly ionised atoms.
broad absorption lines from highly ionised molecules,
63. Which of the following statements about quasars is wrong?
Optically, quasars seem to be a single star.
Spectra from quasars are strongly red-shifted.
Quasars are very distant galaxies.
In the radio band, quasars look like single stars.
64. The period of Cepheid variable stars is about
1 to 60 seconds.
1 to 60 minutes.
1 to 60 days.
1 to 60 weeks.
65. Which of the following objects is usually not used as a standard candle?
Seyfert galaxies.
0 class stars.
Planetary nebulae
Supernovae Ia.
66. The Tully-Fisher relation relates
the rotation rate of a galaxy to its apparent luminosity.
the rotation direction of a galaxy to its apparent luminosity.
the rotation direction of a galaxy to its intrinsic luminosity.
the rotation rate of a galaxy to its intrinsic luminosity.
67. The correct order of the distance ladder from close to far is
Spectroscopic parallax, Cepheid Variables, Hubble’s Law, Supernovae 1a.
Supernovae 1a, Hubble’s Law, Spectroscopic parallax, Cepheid Variables.
Spectroscopic parallax, Cepheid Variables, Supernovae 1a, Hubble’s Law.
Spectroscopic parallax, Supernovae 1a, Cepheid Variables, Hubble’s Law.
68. Interstellar medium can be classified in four different categories, each of which has different densities. Which of the following statements is wrong?
Dark giant molecular clouds are denser than diffuse gas clouds.
Very hot coronal gases have higher density than diffuse gas clouds.
Inter-cloud media have a lower density than diffuse gas clouds.
Very hot coronal gas has lower density than inter-cloud media.
69. What evidence supports the hypothesis that a super-massive black hole is in the centre of the galaxy?
We can directly see the black hole using infrared telescopes.
The stars close to the centre of the Milky Way move at very high speed.
We can directly observe the black hole by detecting the gravitational waves it emits.
Black holes regularly swallow stars close to the centre of the Milky Way.
70. The Milky Way features two discs. Which of the following statements is wrong?
The stars in the thick disc have more circular orbits than the ones in the thin disc.
The stars in the thin disc have more circular orbits than the ones in the thick disc.
The stars in the thin disc are younger than ones in the thick disc.
New stars are formed mainly in the thin disc.
71. Which of the following four objects does not contribute to the production of metals?
Quasars
Planetary Nebulae
Supernovae Type 1a
Supernovae Type 2
72. Which of the following is not a characteristic of Population I stars
Population I stars are often found in open clusters.
Population I stars are 'metal rich'.
Population I stars are 'metal poor'.
Population I stars often have a bluish colour.
73. Which of the following items can be explained by the density wave theory?
Irregular galaxies
Elliptical galaxies
Grand design galaxies
Flocculent galaxies
74. Which of the following statements is correct?
Our galaxy is currently not active, but has been active in the past.
Our galaxy currently shows features of being an active Seyfert galaxy.
Our galaxy has never been active.
Our galaxy can be classified as a quasar.
75. Which of the following is not a characteristic of rich galaxy clusters?
High density of galaxies.
Collisions of galaxies are likely to happen.
Contains a large fraction of spiral galaxies.
The cluster at the centre is often formed by one or more giant elliptical galaxies.
76. Which of the following objects cannot be used as a standard candle for measuring distances?
Supernovae, Type II
RR Lyrae
Cepheids
Supernovae, Type Ia
77. Which of the following is the correct sorting for distance measurement methods from far to near?
Hubble’s law, Spectrospic parallax, parallax method, Tully Fisher.
Tully Fisher, Hubble’s law , Spectrospic parallax, parallax method.
Spectrospic parallax, Hubble’s law, parallax method, Tully Fisher.
Hubble’s law, Tully Fisher, Spectrospic parallax, parallax method.
78. Which of the following is a characteristic of elliptical galaxies?
Relatively strong emission of the 21cm line.
Contains Population I and II stars.
Active stellar recycling.
Relatively weak emission of the 21cm line.
79. Which of the following statements is correct?
Spiral galaxies are as common as irregular galaxies.
Spiral galaxies are more common than elliptical galaxies.
Elliptical galaxies are as common as spiral galaxies.
Spiral galaxies are more common than irregular galaxies.
80. Which of the following galaxy types features no disc?
Sba
Sa
E0
S0
81. Which of the following statements is incorrect?
In the centre of our galaxy sits a super massive black hole of 2.6 million solar masses.
Star orbits around the galactic centre with a period as low as 15 years have been observed.
The super massive black hole at the galactic centre swallows on average 30 stars per year.
Stars close to the galactic centre feature velocities of about 3 million miles per hour.
82. Which of the following is a characteristic of Population I stars?
Population I stars are 'metal rich'.
Population I stars are 'metal poor'.
Population I stars are often found in globular clusters.
Population I stars often have a reddish colour.
83. Which of the following is a source of heavy elements?
Planetary nebulae.
Dark nebulae.
Reflection nebulae.
Emission nebulae.
84. Which of the following galaxy types belongs to the barred spiral galaxies?
E4
SBa
S0
Sb
85. Which of the following parts of our Galaxy can we not observe using visible light?
Open clusters
Galactic centre
Globular clusters
Spiral arms
86. Which of the following characteristics is true for elliptical Galaxies?
Elliptical galaxies mainly feature Population I stars.
Elliptical galaxies often rotate fast.
Lots of interstellar medium is present in elliptical galaxies.
In elliptical galaxies there is very little active star formation.
87. Which part of our galaxy features strong star formation?
Globular clusters
Central bulge
Halo
Spiral arms
88. An S0 galaxy can evolve into which of the following galaxy types?
SBb
Sc
Galaxies cannot evolve from one type into another.
Sa
89. Which of the following are not active galaxies?
Radio galaxies
Quasars
Seyfert galaxies
Infrared galaxies
90. Which of the following statements is not correct?
The central bulge is thicker than the galactic disk.
The halo components move in nearly circular orbit around the centre of the galaxy.
Our Galaxy has two disks.
Open clusters are mainly found in the disk.
91. Which of the following statements is correct?
The position of the solar system within our galaxy was first determined using the position of globular clusters.
The position of the solar system within our galaxy was first determined using the position of nearby O and B stars.
The position of the solar system within our galaxy was first determined using the 21 cm line.
The position of the solar system within our galaxy was first determined using the position of open clusters.
92. How does the solar system move with respect to the galactic centre?
It is spiralling inwards to the galactic centre
It does not move in respect to the galactic centre
It moves in a nearly circular orbit around the galactic centre
It moves in a strongly elliptical orbit around the galactic centre
93. Which of the following is a characteristic of Population II stars?
Population II stars are 'metal rich'
Population II stars are 'metal poor'
Population II stars are usually very young
Population II stars are often O or B class stars
94. Which of the following processes does not contribute to the creation of 'metals' (elements heavier than Hydrogen and Helium)?
Supernova, Type 1a
Supernova, Type 2
Planetary nebulae
Emission nebulae
95. By observing what astronomical objects was it first found that the Solar System is not located in the centre of the Milky Way?
Globular clusters
Black holes
Absorption nebulae
Cepheids
96. Which of the following terms does not refer to one of the major galaxy classes?
Barred Elliptical
Barred Spiral
Elliptical
Spiral
97. Which of the following characteristics is true for Spiral Galaxies?
In spiral galaxies there is very little active star formation
Very little interstellar medium is present in spiral galaxies
Spiral Galaxies feature Population II stars as well as Population I stars
Spiral Galaxies mainly feature Population II stars.
98. Several different measurements indicated that our galaxy is a spiral galaxy. Which of the following observations does not give evidence for the presence of spiral arms?
Location of nearby O and B stars
Location of nearby Globular clusters
Location of CO clouds within the galaxy
Infra-red measurements of the dust density in the Milky Way
99. Which of the following conditions can be responsible for the creation of an irregular galaxy?
Collision of two galaxies
Continuous inflow of atomic Hydrogen from outside the galaxy
A super-massive black hole in the centre of the galaxy
A quasar in the centre of the galaxy
100. Which of the following Galaxy types does not belong to the Spiral Galaxies?
Sc
Sa
SBb
S0
101. Today we know that the Milky Way has two disk components. Which of the following statements is correct?
The stars in the thin disc have an iron to oxygen ratio that suggests they were formed later than the thick disk.
The stars of the two disc components move in opposite direction around the galactic centre.
The stars in the thick disc have an iron to oxygen ratio that suggests they were formed later than the thin disk.
The stars of the thin disk have a stronger oscillatory motion than stars in the thick disc.
102. Which of the following comprise the oldest members of the Milky Way?
Globular clusters.
The Sun and other solar mass stars.
Type O stars.
Red giant stars in spiral arms.
103. What makes up the interstellar medium?
O and B stars
Gas and dust
Open clusters
K and M stars
104. How does the interstellar medium obscure our view of most of the galaxy?
It reflects most light from far distances of the galaxy away from our line of sight.
It absorbs visible, ultraviolet, and some infrared light.
It absorbs all wavelengths of light.
It produces so much visible light that it is opaque and blocks our view of anything beyond it.
105. How can we see through the interstellar medium?
By using telescopes above the Earth’s atmosphere.
By observing at high-energy wavelengths such as X rays and long wavelengths of light such as radio waves.
By observing only the brightest visible sources.
By using only the biggest telescopes.
106. Where are heavy elements made?
In none of the above.
In the Big Bang, when the universe first began.
In the interstellar medium.
In stars and supernovae.
107. What can cause a galactic fountain?
A supernova occurring in the halo.
The combined effect of spiral density waves.
Winds and jets from newly-formed protostars.
Multiple supernovae occurring together.
108. Compared with our Sun, most stars in the halo are
young, red, and dim and have fewer heavy elements.
old, red, and dim and have much more heavy element material.
young, blue, and bright and have much more heavy element material.
old, red, and dim and have fewer heavy elements.
109. The disk component of a spiral galaxy includes which of the following parts?
Spiral arms
Bulge
Globular clusters
Halo
110. What evidence suggests that the protogalactic cloud that formed the Milky Way resulted from several collisions among smaller clouds?
Halo stars differ in age and heavy-element content, but these variations do not seem to depend on the stars’ distance from the galactic centre.
The Milky Way resembles an elliptical galaxy more than other spirals do.
The stars in the halo of the Milky Way are organized into several dense clusters arranged throughout the halo.
The bulge of the Milky Way is surrounded by many globular clusters, just as elliptical galaxies are.
111. What two observable properties of a Cepheid variable are directly related to one another?
The period between its peaks of brightness and its luminosity.
Its mass and its distance.
The period between its peaks of brightness and its distance.
Its luminosity and its mass.
112. The age of our galaxy is about
100 to 150 thousand million years.
1.0 to 1.5 million million years.
100 to 150 million years.
10 to 15 thousand million years.
113. Our Sun is
in one of the arms of the disc of our galaxy, close to its edge.
in a globular cluster in the spherical component of our galaxy.
a halo star in the disc of our galaxy about a third of the distance in from its edge.
in one of the arms of the disc of our galaxy about a third of the distance in from its edge.
114. In our galaxy, dense concentrations gas and dust are found
in the central bulge.
everywhere in the disc.
everywhere in the galaxy.
in the thin disc.
115. Population I stars are found in the
spherical component of a spiral galaxy and have weak absorption lines in their spectra.
arms of a spiral galaxy and have strong absorption lines in their spectra.
arms of a spiral galaxy and have weak absorption lines in their spectra.
spherical component of a spiral galaxy and have strong absorption lines in their spectra.
116. Elliptical galaxies are believed to have been formed by
matter that collected round a very massive black hole.
the very rapid collapse of a super-massive cloud of dust and gas.
the collapse of a very large spiral galaxy.
the merger of two or more elliptical or other types of galaxies.
117. A Seyfert galaxy is a
spiral galaxy whose nucleus is a very strong emitter of radio waves and sometimes X-rays.
disc shaped galaxy with a central bulge, little gas and dust and a low rate of generation of new stars.
spiral galaxy with a high rate of creation of new stars.
large elliptical galaxy with jets of matter that are ejected at high speed from its centre.
118. In elliptical galaxies
the star move round the centre on random orbits, there is little gas and dust and very little formation of new stars.
the stars move round the centre on random orbits, there is much gas and dust but very little formation of new stars due to the lack of a disc structure.
there is a disc and a central bulge but little generation of new stars due to a lack of gas and dust.
there is much formation of new stars that is triggered by the formation of the galaxy in a collision of two or more galaxies.
119. Two stars, A and B, have the same intrinsic brightness. The distance to A is twothirds of the distance to B. Compared to B, A will appear to be
as bright as B.
two-thirds as bright as B.
1.5 times brighter than B.
2.25 (or 9/4) times brighter than B.
120. The Great Wall is
an unusually dense concentration of stars, gas and dust in a nearby spiral arm of our galaxy.
a dense concentration of galaxies that stretches across much of the visible universe.
a mechanism that explains the formation of the density waves that cause the creation of new stars in a spiral galaxy.
a dense concentration of galaxies in the nearby Virgo cluster.
121. Quasars are seen to be unusual because they are very
compact distant galaxies with a large red shift that have many bright O type stars that makes them very luminous.
small stars with an extremely low luminosity because their mass is so small the almost failed to become stars.
bright stars near the centre of our galaxy whose light is very red-shifted by the intense gravitational field from the super-massive black hole at the centre.
small bright objects whose large red shift indicates that they are very distant.
122. Our galaxy
is a barred spiral galaxy with the Solar System between a half and two thirds the way out from the centre towards the edge of the nucleus.
is a barred spiral galaxy with the Solar System between a half and two thirds the way out towards the visible edge of the disc.
is a grand design galaxy with the Solar System between a half and two thirds the way out from the centre to the visible edge of the disc.
is a grand design galaxy with the Solar System between a half and two thirds the way out from the centre to the edge of the nucleus.
123. A type Sb galaxy is
a spiral galaxy with moderately tightly wound arms.
a barred spiral galaxy with moderately tightly wound arms.
a barred spiral galaxy with very open arms.
a barred spiral galaxy with very open arms.
124. Globular clusters
are usually found in the discs of galaxies and contain population I stars.
are usually found in the halos of galaxies and contain population I stars.
are usually found in the discs of galaxies and contain population II stars.
are usually found in the halos of galaxies and contain population II stars.
125. Cepheid variable stars are important for distance measurements because
their brightness pulsates in a well defined way that allows them to be identified and their average brightness is independent of their size.
from their pulsation rate of their brightness, we can deduce their rotational speed.
they emit radio waves whose frequency allows the calculation of their distance.
from their pulsation rate of their brightness, we can deduce their intrinsic average brightness.
126. The inverse square law of light propagation means that a star that is half the distance of another identical star will appear to be
two times as bright as the other star.
equally as bright as the other star.
four times as bright as the other star.
a quarter as bright as the other star.
127. Population I stars in our galaxy are
typically found in regions with new star formation and are "metal" poor.
typically found in regions with little new star formation and are "metal" poor.
typically found in regions with little new star formation and are "metal" rich.
typically found in regions with new star formation and are "metal" rich.
128. Spiral galaxies are more easily seen than other types of galaxy because
they are much bigger than any other kind of galaxy.
they have a very large and prominent nucleus that contains bright O and B stars.
they have bright O and B stars in their arms.
they are free of dust which obscures the light from stars in other galaxies.
129. The Large and Small Magellanic Clouds are
irregular galaxies close to our own galaxy.
dark dust clouds obscuring part of the Milky Way.
reflection nebulae in Orion.
emission nebulae in the disc of our galaxy.
130. A "starburst" galaxy is
one in which stars are colliding.
one in which the stars are being thrown outwards, away from the centre.
one with intense new star formation due to a close interaction with another galaxy.
one with unusually intense new star formation due to the collision of two of its spiral arms.
131. The distance to very remote galaxies can be measured by
identifying the spectral classes of their stars and then using spectral parallax.
measuring the apparent brightness of a type 1a supernova in them and / or measuring the red shift of the light from them.
measuring the angular size of their globular clusters and then by using trigonometry.
measuring the period and apparent brightness of their Cepheid variables.
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