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Astro 1 Unit 1 Exam > Unit 4 Exam > Flashcards

Unit 4 Exam Flashcards

1
Q

Which is the smallest object?
A: a neutron star
B: the Solar System
C: the Sun
D: a dwarf galaxy
E: the Eagle nebula

A

A

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2
Q

A galaxy has an H-alpha emission line observed at a wavelength 10 percent larger than the rest wavelength of H-alpha. What is the redshift of the galaxy?
A: 10
B: 0.001
C: 0.1
D: 1
E: -0.001

A

C

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3
Q

Which is the most luminous?
A: nova
B: supernova
C: quasar
D: the Sun
E: white dwarf

A

C

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4
Q

What is in this image? (circular blue,red,yellow thing)
A: supernova remnant
B: irregular galaxy
C: planetary nebula
D: globular star cluster
E: star forming region

A

A

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5
Q

Which contains the most stars?
A: an open star cluster
B: a globular star cluster
C: a spiral galaxy
D: the Solar System
E: the alpha Centauri star system

A

C

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6
Q

Galaxy A appears twice the angular size of Galaxy B. Assuming the two galaxies have the same physics size in kiloparsecs, which of the following is true?
A: Galaxy A is 2 times farther away than Galaxy B.
B: Galaxy B is 2 times farther away than Galaxy A.
C: Galaxy A and B are at the same distance.
D: Galaxy A is 4 times farther away than Galaxy B.
E: Galaxy B is 4 times farther away than Galaxy A.

A

B

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7
Q

What fundamental particles make a Helium-3 atom?
A: 2 up quarks, 1 down quark, 1 electron
B: 6 up quarks, 6 down quarks, 2 electrons
C: 3 up quarks, 3 down quarks, 3 electrons
D: 1 proton, 2 neutrons, 1 electron
E: 5 up quarks, 4 down quarks, 2 electrons

A

E

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8
Q

What type of galaxy is in this image? (Loose spiral arms, small bulge, barred)
A: E5
B: Irr
C: Sa
D: Sc
E: SBc

A

E

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9
Q

Which statement is FALSE?
A: planetary nebulae can have layers because of pulsating stars
B: planetary nebulae usually last tens of thousands of years
C: a planetary nebula will be part of the end state of the Sun
D: planetary nebulae usually have black holes at their centers
E: planetary nebulae are a few light years in size

A

D

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10
Q

Which statement is TRUE?
A: Stars form in molecular clouds, where temperatures are about 10 degrees
Kelvin.
B: A cloud will collapse and form stars if its mass is a lot less than its Jeans
mass.
C: A nova outburst typically only happens once in a star’s life.
D: Stars usually form in isolation, far away from other stars
E: The Crab supernova, in our galaxy, went off about 8 years ago.

A

A

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11
Q

How tiny a spot is the Hubble Deep Field?
A: About 1/2 of the entire sky.
B: About 1/5 of the entire sky.
C: About 1/10 of the entire sky.
D: About 1/50 of the entire sky.
E: The size of President Roosevelt’s eye on a dime held at arm’s length.

A

E

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12
Q

Among these choices, what is the last thing that happens in the history of the
Universe.
A: electrons join with nuclei to make atoms
B: quarks join together to make protons and neutrons
C: nucleosynthesis
D: the Planck epoch
E: The Big Bang expansion begins

A

A

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13
Q

If a galaxy had no dark matter, we would observe …
A: the entire galaxy would approach us at a faster velocity, and we would
observe a redshift
B: the entire galaxy would recede from us at a faster velocity, and we would
observe a redshift
C: the rotation velocity would remain constant with increasing distance
D: the rotation velocity would decrease with increasing distance like the Keplerian curve in our Solar System
E: the rotation velocity would increase with increasing distance like the
Keplerian curve in our Solar System

A

D

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14
Q

How many times bigger is the Local Group of galaxies in which the Milky Way resides than the Milky Way itself?
A: it is not bigger than the Milky Way
B: about 100 times bigger
C: about 1040 times bigger
D: about 1010 times bigger
E: about 1 million times bigger

A

B

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15
Q

Which one of the following is FALSE?
A: Irregular galaxies, although small, often have a lot of star formation taking
place in them.
B: Barred spiral galaxies have similar properties to normal spirals, except for
the “bar” feature.
C: Galaxy collisions destroy most of the stars in the galaxies involved.
D: Most galaxies appear to be receding from the Milky Way Galaxy
E: Most elliptical galaxies contain only old stars.

A

C

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16
Q

If a galaxy is moving away from us the wavelength of the light it emits will be …
A: unaffected.
B: blueshifted.
C: increased.
D: decreased.
E: distorted.

A

C

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17
Q

If light takes 4 billion years to reach us from a distant galaxy, how many times
farther away is the distant galaxy than the Andromeda galaxy, which is 2 million
light years away?
A: 4 billion times
B: 200 times
C: 20 times
D: 2,000 times
E: 2 million times

A

D

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18
Q

The stars in the halo of our Milky Way Galaxy are
A: in a very flat distribution.
B: very close together compared to stars in the disk.
C: older and bluer than those in the disk.
D: never in globular clusters.
E: older and redder than those in the disk.

A

E

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19
Q

The supermassive black hole in the center of the Milky Way has a mass of
A: 10 solar masses
B: 1,000 solar masses
C: 4 million solar masses
D: 100 billion solar masses
E: 100 solar masses

A

C

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20
Q

Which force has as its boson the photon?
A: strong
B: weak
C: electromagnetic
D: gravity
E: none of the forces do

A

C

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21
Q

Which mysterious phenomena do scientists attribute to dark energy?
A: The increasing rate of expansion of the Universe.
B: Mysterious bonding that holds atoms together.
C: The creation of the cosmic microwave background.
D: The formation of Helium through nucleosynthesis.
E: Dark energy causes all of the above.

A

A

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22
Q

Why can we NOT see back the whole way to the time the Big Bang expansion began?
A: Not enough photons were produced.
B: Radiation is blueshifted out of the visible range.
C: Our telescopes could never be powerful enough.
D: The radiation scatters off matter frequently so the Universe is opaque.
E: It would take too long for light to travel that far.

A

D

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23
Q

What are the standard candles that were used to determine the Universe is accelerating?
A: spiral galaxies
B: elliptical galaxies
C: Type Ia supernovae
D: light bulbs
E: Type II supernovae

A

C

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24
Q

An older star cluster …
A: contains hotter stars than a younger star cluster.
B: has a main sequence turnoff farther to the left on the H-R diagram.
C: has a main sequence turnoff farther to the right on the H-R diagram.
D: would never be located in the halo of a galaxy.
E: has a bluer color than a younger star cluster.

A

C

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25
Q

Which of the following statements is TRUE?
A: One or two supernovae are observed to go off in the Milky Way galaxy each year.
B: Type II supernovae are produced by the death of a massive star.
C: Type Ia supernovae show a lot of strong hydrogen lines in their spectra.
D: Type Ia supernovae are produced when a neutron star collapses to become a
black hole.
E: When a planetary nebula is produced it can outshine an entire galaxy.

A

B

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26
Q

Which types of clusters have hundreds, up to thousands, of stars/ its stars formed at about the same time, from the same initial gas & dust cloud/ it clusters only stars bound by gravity for a few million years?(Loosely-arranged collections of stars, dominated by few bright, blue (and therefore young) stars.)

A

Open Star Clusters

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27
Q

Open Star Clusters have lots of which types of stars visible? Why?

A

Blue stars
relatively young ages and blue stars vastly outshine red stars

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28
Q

The “Pleiades” is a notable example of which type of cluster?

A

Open Star Clusters

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29
Q

Which type of clusters include hundreds of thousands, to millions, of stars/ tend to be yellow, with several red giants/ many have ages around 10 billion years — overall considered old clusters(More-densely packed collections of a greater number of stars than open clusters, tend to have a dense “core” of stars)

A

Globular Clusters

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30
Q

“47 Tucanae” is an example of which type of cluster?

A

Globular Clusters

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31
Q

How can the age of star clusters be determined?

A

by seeing what spectral class of star has most recently “turned off” the main sequence, in the cluster’s H-R diagram

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32
Q

Many stars formed in clusters later …, leaving more stars isolated.

A

dispersed

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33
Q

This occurs when a low-mass star runs out of core nuclear fuel, and blows off outer layers, and its stars can pulsate and eject gas in layers (leading to a sort of shell- or ring-like appearance)(very colorful)

A

Planetary Nebulae

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34
Q

What leads to the symmetry that results in nebulae?

A

bipolar jets

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35
Q

What lasts tens of thousands of years/ can be a few light years in size/ leaves the core of the former star, a white dwarf, left behind at the center

A

Planetary Nebulae

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36
Q

True or False:
Planetary Nebulae will be part of the end state of the Sun, in about 5 billion years

A

True

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37
Q

What is caused by a binary star, wherein one star of the two
evolves faster than the other?

A

Nova

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38
Q

In a nova the faster-evolving star, perhaps already a …, can be close enough to still be partly surrounded by a … … . … from its nearby companion star (which evolves more slowly, but still eventually reaches its own red-giant phase)

A

white dwarf
common envelope of gas

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39
Q

In a nova mass transfer of what from the companion star onto a carbon white dwarf temporarily causes extra burning on the white dwarf’s surface?

A

hydrogen

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40
Q

In a nova the white dwarf plus the new material added suddenly …; this can happen periodically, repeatedly.

A

brightens

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41
Q

“V838 Monocerotis” is what kind of Milky Way content?

A

“light echo” pattern nova

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42
Q

What occurs when massive stars die — the kinds that lead to neutron
stars or black holes?

A

Type II supernovae

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43
Q

What occurs when very large amounts of material are suddenly added
to a white dwarf from a binary companion; the resulting burst destroys the white dwarf?

A

Type Ia supernovae

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44
Q

The observed spectra of Type II supernovae contain prominent … lines.

A

Hydrogen

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45
Q

Type Ia spectra do not contain …, since they come from white dwarfs primarily made of …

A

Hydrogen
carbon

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46
Q

Supernovae are … luminous than novae, but only happen … since the star is basically destroyed; novae can be a repeating process.

A

more
once

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47
Q

“Crab Nebula” and “Cassiopeia A” are remnants of what type of Milky Way content? (have a filamentary
or shredded appearance)

A

Supernova

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48
Q

Supernovas have different what because of different chemicals? Also, with a blue haze from electron glow.

A

colors

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49
Q

The supernova which eventually formed the Crab Nebula was seen on Earth in the year …; the Cassiopeia A supernova was about … years ago

A

1054
340

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50
Q

When do we generally expect a supernova in the Milky Way to happen?

A

once every couple hundred
years

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51
Q

Where do stars form?

A

molecular clouds

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52
Q

What Star-Forming Region typically contains several million times the sun’s mass worth of gas and dust?

A

molecular clouds

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53
Q

What are the characteristics of molecular clouds?

A

dark/dusty and cool, only about 10 degrees Kelvin

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54
Q

The “Jeans mass” tells you what about a molecular cloud?

A

if a cloud will collapse to form stars

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55
Q

If the mass molecular cloud is … than Jean’s mass, gravity dominates over internal gas pressure and it will collapse.

A

greater

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56
Q

If the mass of a molecular cloud is … than Jean’s mass, internal pressure dominates and it will not collapse.

A

smaller

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57
Q

When sections of the molecular cloud collapse into clumps, where do individual stars form in?

A

they form in with protoplanetary disks

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58
Q

“Orion Nebula” and the “Eagle Nebula” are examples of which Milky Way content?

A

Star-Forming Regions

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59
Q

Where is the Galactic Center located?

A

towards the constellation of Sagittarius, called “Sag A*”

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60
Q

What is at the center of the Galactic Center that leads to a faster stellar motion their?

A

a supermassive black hole

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61
Q

What is the mass and radius of the black hole at the center of the Galactic Center?

A

4 million solar masses
100 Astronomical Units

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62
Q

How has the supermassive black hole at the center of the Galactic center grown?

A

by accreting mass from other objects over time

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63
Q

How many stars does the Milky Way Galaxy include?

A

400 billion

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64
Q

A vast majority of stars in the Milky Way Galaxy are what types of stars?

A

red, M-type stars

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65
Q

The relatively few blue stars in the Milky Way are vastly more …, so the blue ones can … all the red ones.

A

luminous
outshine

66
Q

The empty space between stars is …; the universe is … empty space between stars.

A

vast
mostly

67
Q

What are the three components of the Milky Way Galaxy?

A

Bulge, Disk, and Halo

68
Q

What is 100,000 light years in diameter — spiral pattern; young, where blue stars dominate

A

The disk of the Milky Way Galaxy

69
Q

In the disk, our Sun is how many light years out from the galaxy center, in the disk?

A

26,000

70
Q

Where do stars form in molecular clouds? Molecular clouds are strewn about what part of the disk of the Milky Way Galaxy? What else tends to be found in the disk?

A

“density waves”
the spiral arms
open clusters

71
Q

What part of the Milky Way Galaxy is the spherical region in the center of the disk with older yellow stars?

A

The bulge of the Milky Way Galaxy

72
Q

What part of the Milky Way Galaxy is the larger, spherical region around whole galaxy with old stars and few heavy elements?

A

The halo of the Milky Way Galaxy

73
Q

What types of clusters live in the halo?

A

globular star clusters

74
Q

What are the satellite dwarf
galaxies of the Milky Way that are visible at night in the southern hemisphere?

A

“Large Magellanic Cloud” and “Small Magellanic Cloud”

75
Q

How many stars do dwarf galaxies have?

A

tens of millions to 1 billion stars

76
Q

What galaxy is similar to the Milky Way Galaxy?

A

Andromeda Galaxy

77
Q

How far is the Andromeda Galaxy from the Milky Way Galaxy?

A

2.5 million light years

78
Q

True or False:
Andromeda Galaxy does not have dwarf satellite galaxies

A

False

79
Q

The “Local Group” contains which two galaxies? How many dwarf satellite galaxies are in the “Local Group”?

A

Andromeda Galaxy and Milky Way Galaxy
40

80
Q

When will the Andromeda and Milky Way collide and form a single galaxy?

A

5 billion years

81
Q

What type of galaxies have more gas, more dust, and more new star formation, and have very noticeable disks (disks have bluer color on account of younger stars)?

A

Spiral

82
Q

What type of galaxies do not have very noticeable disks (more older stars, yellower colors)?

A

Elliptical

83
Q

What type of galaxies are the largest galaxies?

A

Ellipticals

84
Q

If the spiral galaxy has a central bar they are classified as what?

A

SB galaxies

85
Q

If the spiral galaxy does not have a central bar what is it classified as?

A

S galaxies

86
Q

Spirals are classified as …, …, and …

A

a,b,c

87
Q

Type C spiral galaxies have what characteristics?

A

loose, lumpy arms and a smaller bulge than ”a”

88
Q

An “SBa” galaxy is what type of galaxy?

A

barred spiral with tight, smooth arms and a relatively large bulge

89
Q

Elliptical galaxies range from what to what depending on their shape on the sky.

A

from E0 (circular) to E7 (elongated)

90
Q

You might remember the types of elliptical galaxies by remembering the number “0” being … than a “7”

A

rounder

91
Q

Some galaxies have a more irregular structure and cannot be classified as spiral or elliptical; what are these are called?

A

irregular galaxies

92
Q

how many galaxies are in the observable universe?

A

50-100 billion galaxies

93
Q

how many stars are there per galaxy in the observable universe? how many in total?

A

1-100 billion
10^22 stars(50-100 billion) and most have planets

94
Q

How were we made to estimate how many galaxies and stars there is in the observable universe?

A

“Hubble Deep Field”

95
Q

What is the tiny patch of sky that the Hubble Space Telescope imaged for 10 full days called?

A

“Hubble Deep Field”

96
Q

Looking into the distance means looking … … …, because the speed of light determines how long an image takes to reach us; 1 light year is how far light travels in 1 year; a galaxy 2 million light years away appears as what?

A

back in time
it was 2 million years ago

97
Q

In the nearby/recent universe what types of galaxies are common; there are also … galaxies grouped around the larger galaxies

A

spiral and elliptical galaxies
dwarf

98
Q

In the earlier universe, what types of galaxies were much more common? Why is this?

A

irregular galaxies
galaxies were still in the process of being assembled
” Tadpole Galaxy”

99
Q

What is left behind because of the gravitational pull of one colliding galaxy on another?

A

tidal debris

100
Q

How are new star clusters formed so that we often see young, massive blue stars

A

gas in galaxy collisions

101
Q

Sometimes galaxy collisions can cause which type of galaxy that has a fast rate of star formation.

A

“starburst galaxies”

102
Q

True or False:
When galaxies collide, the odds are extremely high that individual stars and/or planets would collide

A

False, given the relatively small sizes of stars and planets in comparison to the spaces between them

103
Q

A merger of two spiral galaxies may give rise to which types of galaxies

A

elliptical galaxy or an irregular galaxy

104
Q

What appeared on Earth 225 million years ago, more than 13 billion years after the Big Bang expansion began?

A

First mammals and dinosaurs

105
Q

When did humans begin roaming the Earth?

A

100,000 years ago

106
Q

When did our Sun and Earth form?

A

about 4.5 billion years ago

107
Q

What lights up at the centers of many forming galaxies, as nearby fuel feeds the supermassive black holes

A

Quasars

108
Q

Stars and galaxies start to form via …

A

gravity

109
Q

This is how … form: photons turn into particle/anti-particle pairs, and vice versa.

A

quarks

110
Q

Quarks bind together into … and … (with … different colors joining

A

protons and neutrons
three

111
Q

Protons and neutrons bind together to form … …. What is this called?

A

helium nuclei
nucleosynthesis

112
Q

Before the Big Bang (actually before 10−36 seconds, during the “… …”) do we know what happened? The current laws of physics are not able to draw
conclusions, but the matter was dense like the singularity in a black hole, and the energies of photons were very high.

A

“Planck time”
no

113
Q

… percent of the mass was converted to helium nuclei at that time. The universe is still a hot, dense plasma at this time (about 100 seconds), like
as in the core of a star. It is still … so that light cannot freely go through it.

A

25%
opaque

114
Q

… join with nuclei to form complete atoms. The universe becomes …, so radiation could here after pass more freely through space. We see the microwave background radiation — equivalent to 2.73 degrees Kelvin, now — coming from this time, about … … after the Big Bang began.

A

Electrons
transparent
300,000 years

115
Q

What are the four forces?

A

gravity, electromagnetism, and “strong” and “weak” nuclear forces

116
Q

have not been discovered yet, but are thought to be the bosons that
carry the force of gravity, and act on mass

A

Gravitons

117
Q

bosons that carry the electromagnetic force, and act on electric charge

A

photons

118
Q

bosons that carry the “strong” force, that holds atomic nuclei together

A

gluons

119
Q

what bosons carry the “weak” force? The weak force is responsible for
radioactive decay.

A

W+, W–, and Z

120
Q

What is exchanged between particles in order to make the forces work?

A

bosons

121
Q

Everything we can see on Earth, or in the Universe that is made of atoms, but atoms are not fundamental particles

A

Conventional matter

122
Q

What are the fundamental particles that cannot be broken up into smaller units, as far as we know?

A

quarks, leptons, and bosons

123
Q

What are the “Flavors,” or types, of quarks?

A

“up,” “down,” “charm,” “strange,” “top,” and “bottom”

124
Q

How many types of quarks and anti-quarks are there?

A

6 quarks
6 antiquarks

125
Q

For each quark there is also a corresponding, …-…, …-…: anti-up, anti-down, anti-charm, anti-strange, anti-top, and anti-bottom.

A

oppositely-charged
anti-quark

126
Q

what are the lighter fundamental particles that includes electrons and neutrinos? How many types leptons are there?

A

leptons
6 types of leptons
6 types of anti-leptons

127
Q

The nucleus of an atom contains … and …; a complete atom of a chemical element contains a nucleus with … around it

A

neutrons and protons
electrons

128
Q

What does a proton contain?

A

2 up quarks and 1 down quark (or, “ p = uud”)(must have different colors)

129
Q

What does a neutron contain?

A

2 down quarks and an up quark (or, “ n = udd”)(must have different colors)

130
Q

What are the 30 types of fundamental particles

A

12 quarks/anti-quarks
12 leptons/anti-leptons
6 bosons

131
Q

Almost everything we observe in nature is made of … …, … …, and … The other particles are either not very stable and/or do not interact much
with other matter.

A

up quarks, down quarks, and electrons

132
Q

Dark energy comprises about …% of the overall energy density of the Universe

A

71%

133
Q

Type Ia supernovae (powerful explosions produced when a lot of new matter falls onto a white dwarf, from a companion star) are good “… …” which means that they have well-known luminosities which do not depend on the time in the universe’s history that they go off.

A

standard candles

134
Q

Knowing the luminosity of a standard candle, we can measure its apparent
… and calculate its … from the Inverse-Square Law.

A

brightness
distance

135
Q

The relationship between the apparent brightnesses and redshifts for Type Ia supernovae can be used to measure the … of space

A

geometry

136
Q

parallel light rays will continue along parallel paths if the geometry is what?

A

“flat”

137
Q

parallel light rays diverge if the geometry is what?

A

“open”

138
Q

parallel light rays converge if the geometry is what?

A

“closed”

139
Q

Observations of Type Ia supernovae in distant galaxies show that the universe is not just expanding, but that the expansion is …

A

accelerating

140
Q

not only are the spaces between galaxies getting larger over time, but now the rate at which those spaces are getting larger is itself …

A

increasing

141
Q

Dark energy, a sort of ”…-…,” causes the acceleration of the universe.
(We really do not know what it is yet)

A

anti-gravity

142
Q

Dark energy is … in space, but there is only a … … per unit volume; only because of the hugeness of space does it add up.

A

everywhere
small amount

143
Q

Dark energy may have to do with Einstein’s “… …” (which he
invented and then abandoned, thinking it was wrong)( the energy density that may fill empty space)

A

cosmological constant

144
Q

The Universe is 4.6 %… 24 % … … and 71.4 % … …

A

atoms
dark matter
dark energy

145
Q

Dark matter comprises about …% of the overall energy density of the universe.

A

24

146
Q

What is known to exist through the observed large rotation velocities in galaxy disks, motions of galaxies in clusters, and by the way that light is bent by galaxies and galaxy clusters?

A

dark matter

147
Q

What emits no radiation of any form we can observe — no visible light, no
heat, no X-rays, etc. We know about it through the gravitational influence of its mass on ordinary matter? (must be some kind of unknown particle that has not been discovered yet)

A

dark matter

148
Q

What charts how fast the stars and gas in the disk rotate as a function of their distance from galaxy center? (The more mass, the faster the material rotates. There needs to be much more mass present than we can see, thus we infer the presence of dark matter)

A

The rotation curve of a spiral galaxy

149
Q

Essentially we are using … … … to find dark matter — in the same way as we determine the mass of the supermassive black hole in the center of our galaxy.

A

Kepler’s third law

150
Q

Our Universe is …, in the sense that … is being added everywhere in between the galaxies.

A

expanding
space

151
Q

All galaxies throughout the universe would measure … from galaxies distant from them.

A

redshifts

152
Q

There is no … to the universe, nor is there an … It is likely that the universe is infinite.

A

center
edge

153
Q

The Big Bang expansion began about … … years ago. At that time, the
universe was very hot and dense. All matter and energy in our observable universe was then compressed into a single point of space.

A

13.8 billion

154
Q

What explains how a neutron star is 10,000x bigger than a person, earth is 10 mil bigger than a person, stars are 10-100x bigger in diameter of Earth, Nebulae can be million x bigger than individual stars, Galaxies are billion-trillion x bigger than individual stars, Andromeda is 10 of times the diameter of a galaxy away, Galaxy cluster is 100s x bigger than an individual galaxy, Observable Universe is a million x bigger than the Milky Way Galaxy

A

“Powers of Ten”

155
Q

… to galaxies can be estimated using “standard candles,” like Cepheid
variables or Type Ia supernovae seen in other galaxies

A

Distances

156
Q

Distances to galaxies can also be crudely estimated by taking the assumed real size in … divided by the apparent angular size measured in … The answer comes out in … (millions of parsecs).

A

kiloparsecs
milliradians
Megaparsecs

157
Q

What is the shifting of the lines in the spectrum of an object to longer
wavelengths (to redder colors), due to its motion away from the observer called? (alternatively, “blueshift” would be seen for an object moving toward the observer)

A

redshift

158
Q

Specifically, redshift ( “Z” ) is …
Z = ?

A

( observed(wavelength symbol) – rest(wavelength symbol) ) / (rest)(wavelength symbol)

159
Q

Object’s velocity, v = ?

A

redshift x speed of light

160
Q

The redshifts of galaxies are found to be … the farther away the galaxies are

A

larger

161
Q

Hubble’s Law (where v is the velocity of recession, H0 is Hubble’s constant, and D is the distance to the galaxy)

A

v = H0 × D

162
Q

Hubble’s constant is effectively the … … of our universe, at present

A

expansion rate

Astro 1 Unit 1 Exam (5 decks)

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