Test 3 Flashcards
(149 cards)
0
Q
What happens in ice skater physics?
A
Pulling in then rapid spinning
1
Q
The Nebula Theory is about the origin of…
A
a solar system.
2
Q
What happens in pizza dough physics?
A
Flatten out; start to collapse into a disc
3
Q
Are planets common or rare?
A
Common
4
Q
What was the goal of the Kepler Mission?
A
To find planets around other stars
5
Q
By what process do planets form?
A
Accretion
6
Q
Accretion
A
Rocks and things collide, gravitational forces hold them together; it grows as it accretes more stuff
7
Q
Why does a red nebula appear red?
A
Spectral emission line from hydrogen gas
8
Q
Why does a blue nebula appear blue?
A
Dust grains; light from very hot stars bounces off of dust grains
9
Q
What are the dark areas in the Horsehead Nebula?
A
Dust
10
Q
Where is the Orion Nebula?
A
The center “star” of Orion’s sword in the Orion constellation
11
Q
What is the center star of Orion’s sword really?
A
newly formed Trapezium Star Cluster
12
Q
Giant molecular clouds are sites for…
A
star formation.
13
Q
What is a proplyd?
A
Protoplanetary disk
rotating disk of gas surrounding a newly formed solar system
14
Q
While studying radio waves in the Orion region, we can see…
A
molecules (carbon monoxide) and ionized hydrogen
15
Q
What is HII?
A
Ionized hydrogen
16
Q
How do stars get rid of extra material?
A
emit radio waves
17
Q
How is hydrogen ionized?
A
It loses an electron via UV light
18
Q
Super cool stars emit ___ light rather than red light.
A
infrared
19
Q
Why is it hard for astronomers to know the sequence of star formation?
A
all the stages present in the Orion Nebula are in the same position in the sky (from our point of view), rather than in a line.
20
Q
HII forms around hot (O and B) stars and emits a lot of ___ ___.
A
UV light
21
Q
Who was Macier? What did he do?
A
French astronomer in the 1800s
made a catalogue of things he could see through his telescope; he was looking for comets, so he just numbered everything that wasn’t a comet in the “Catalogue of Objects to be Ignored” (M-1, M-2, M-3, M-4, M-5, etc.)
22
Q
M-16 is also known as the ____ Nebula.
A
Eagle
23
Q
What is in M-16/ Eagle Nebula?
A
fairly massive O and B stars that emit a lot of UV light
“Pillars of Creation”
evaporative gaseous globules (EGG)
24
What are evaporative gaseous globules (EGG)?
baby solar systems
25
How do stars like the Sun get rid of excess or leftover material?
nearby O and B stars emit UV light to take care of it/ clean it up
26
What is a star's excess or leftover material?
nebula
27
How do T Tauri type stars get rid of excess material?
wild solar winds blow it away
28
evolution
slow change that takes place over a long period of time
29
stellar revolution
changes that take place quickly in one individual star
30
What is hydrostatic (gravitational) equilibrium?
In a star, if the forces of gravity and pressure balance exactly, the star is in equilibrium.
31
In a star, ___ pushes in and ___ pushes out.
gravity; pressure
32
The Sun and stars like it have __ solar mass.
1
33
What is the most important property in determining all the other properties of a star?
mass
34
What other property can also be important in determining all the other properties of a star?
chemical composition
35
A Red Giant with small mass produces ___ ___, leaving behind a ___ ___.
planetary nebula; white dwarf
36
A Red Giant with large mass produces ___ __ ___, leaving behind a ___ ___ or a ___ ___.
Type II supernova; neutron star; black hole
37
A white dwarf can slowly cool to become a ___ ___.
black dwarf
38
A white dwarf can accrete material to create a ___, leaving behind the ___ ___.
nova; white dwarf
39
A white dwarf can accrete material to create a ___, leaving behind ____.
Type I supernova; nothing
40
If a black hole has a ___ ___, it will accrete material and emit ___ ___.
binary companion, x-ray radiation
41
What is the approximate solar mass of a low-mass star?
less than 8 solar mass
42
The stellar core remaining in the middle of a low-mass star's planetary nebula is a ___ ___.
white dwarf
43
How does a low-mass star produce a planetary nebula?
It ejects its outer layers.
44
What is the approximate solar mass of a high-mass star?
more than 8 solar mass
45
The result of a Type II supernova depends on...
the original mass of the high-mass star that exploded as a Type II supernova
46
If a high-mass star is extremely massive, its resulting Type II supernova will leave behind a ___ ___. Otherwise, it will leave behind a ___ ___.
black hole; neutron star
47
If a white dwarf has a companion star, it can gravitationally attract material from its companion in a process known as ____.
accretion
48
Under what circumstances can a black hole be detected?
If the black hole has a binary companion star, the black hole's strong gravitational pull can accrete matter from its companion. The material spirals around the black hole and emits large amounts of X-ray radiation, detectable with X-ray telescopes.
49
Which live longer, high-mass or low-mass stars?
low-mass
50
What is a protostar?
the object that initially forms when a cloud of dust and gas begins to collapse inward to form a star
51
What is the process of the Sun's evolution?
The Sun collapses onto the Main Sequence. It releases its solar nebula. The Sun is sustained on nuclear fusion reactions (4 H -> 1 He). Eventually, the hydrogen is exhausted, and it must burn helium instead. The Sun is now at the first Red Giant stage. There will be a helium flash. Now, the Sun has reached the second Red Giant stage. It is very unstable. It blows up its outer shell and ejects planetary nebula. Helium burning ceases. The planetary nebula dissipates into space, and the core collapses into a white dwarf. Eventually, it will cool to a black dwarf.
52
When does a star officially become a star?
when hydrogen is converted to helium in the core
53
A star expands when ___ runs out.
hydrogen
54
___ and ___ overcome the repulsive force between electrons during the Main Sequence stage, causing nuclear fusion reactions.
Heat; pressure
55
Hydrogen and helium both have a ___ charge.
positive
56
When hydrogen runs out and the star expands, the ___ core will begin to collapse and the ___ shell outside that core will expand and cool.
helium; hydrogen
57
Because helium and hydrogen have the same charge (positive) and like charges repel, heat and pressure are needed to force ___ ___ reactions.
nuclear fusion
58
When the helium core is contracting or collapsing, gravity wins. The temperature of the helium core ___. A new nuclear fusion reaction occurs: helium -> ____. This is known as the ___ ___.
increases; carbon; Triple-alpha Process
59
helium flash
all the nuclear fusion reactions start igniting at once
60
Triple-alpha Process
set of nuclear fusion reactions by which helium is transformed into carbon
61
Stars with 1 solar mass can't generate enough heat or inward ____ force to generate carbon fusion reactions, so they collapse into the ___ ___ stage.
gravitational; white dwarf
62
variable star
stars that change in brightness
63
What evidence do we have to prove the theoretical predictions regarding stellar evolution?
variable stars
64
A Cepheid star is a ___ star.
variable
65
The universe isn't old enough for any less-massive __ stars to have evolved off the main sequence yet.
M
66
A Cepheid star has a ___ day cycle of bright -> faint -> bright -> faint.
5 1/2
67
catalyst
expedites reaction
68
Any fission reactions with elements lighter than iron (Fe) ___ energy rather than ___ energy.
require; produce
69
List carbon, hydrogen, silicon, and iron in order from most to least massive.
Fe, Si, C, H
70
___ is the line between fission and fusion.
Iron (Fe)
71
A supernova emits as much energy in a few years as the Sun does in ____ years.
10 billion
72
A supernova recycles stardust and...
seeds a new age of stars.
73
Sirius is a ___ ___ star.
white dwarf
74
Sirius doesn't move in a straight line across the sky, because it is...
orbiting something in a binary system.
75
Sirius A is ___ than Sirius B. They are in a ___ orbit.
brighter; binary
76
A white dwarf is about the size of ___.
Earth; about 10,000 miles diameter
77
large mass in small volume equals
high density
78
Degenerate Electron Gas
electrons are packed as tight as possible
79
White dwarfs have different laws, because they are made of ___ ___ ___.
degenerate electron gas
80
Typical ___ laws do not apply to degenerate electron gases.
gas
81
degenerate electron gas: The proportions of ___, ___, and ___ are not constrained. Changing one does not affect the others.
pressure, volume, temperature
82
Adding more mass to white dwarfs decreases their ___, because no ___ is pushing out.
size; pressure
83
There are no nuclear reactions going on in a white dwarf star whatsoever. How do we know?
It there were, it would constantly be exploding. As pressure increases in a white dwarf, size does not increase.
84
As pressure increases in a white dwarf, ___ does not increase.
size
85
Chandrasekhar Limit
upper mass limit for white dwarfs
| If a white dwarf is more than 1.4 solar mass, it is unstable and will collapse into a neutron star.
86
If a white dwarf is more than ___ solar mass, it is unstable and will collapse into a neutron star.
1.4
87
neutron star
big ball of neutrons condensed into the nucleus of an atom
a ball of neutrons (neutral charge) can be squeezed tighter than a ball of protons (positive charge) or electrons (negative charge)
88
When it comes to protons and electrons, opposites ___.
attract
89
Who discovered neutron stars? When?
Jocelyn Bell-Burnell
| 1967
90
How did Jocelyn Bell-Burnell discover neutron stars?
by accident while studying twinkling stars and interplanetary medium
She found a "bit of scruff" in her data (radio waves chart) accurate to a billionth of a second. It was bright then faint, etc.
91
Crab Nebula Pulsar
bright and faint every .033 seconds (the star is "turning on and off" 33 times per second)
92
pulsars
neutron stars
93
What happened in space on July 4, 1054 AD?
Type II supernova explosion
| It was so bright, it was visible during the day for a month.
94
rapidly rotating neutron star
When magnetic poles (north and south) point toward us, the star is "on." Otherwise, it's "off."
95
Synchrotron Radiation
the radio waves emitted along the direction of an electron's motion; electromagnetic radiation emitted when charged particles are accelerated radially
96
neutron star mass limit
between 2-3 solar mass
97
What happens if a neutron star exceeds the mass limit?
it's unstable and becomes a black hole
98
Adding mass does not ____ size.
increase
99
nova
exploding; relatively small explosion
100
A nova only involves the ___ ___ of a white dwarf.
surface layers
101
What shape is the binary system orbit of a red giant and white dwarf?
figure 8
102
Type II supernovas are the result of...
massive red giants with iron cores.
103
Type I supernovas come from...
white dwarfs the exceed the Chandrasekhar limit.
104
Supernovas are ____.
explosions
105
Both types of supernovas blow ___ into space and make heavy ___.
atoms; elements
106
What do the atoms blown out by supernovas do?
combine with other stuff to make Earth and other things
107
What is a static black hole?
a black hole that doesn't move and is isolated
108
escape velocity
minimum speed needed to escape an object; minimum speed to throw something into orbit from a planet
109
The escape velocity increases if the ___ ___ increases.
gravitational force
110
How would the gravitational force increase?
compress the body
111
If you compress something so much that the escape velocity exceeds the speed of light, what is produced?
a black hole
112
___ can go faster than the speed of light.
Nothing
113
Orbit depends on ___ not ___.
size; mass
114
If the Sun somehow became a black hole, what would the Earth do?
It would stay in orbit, no change
115
If something is in a stable orbit around a star that becomes a black hole, it will...
stay in orbit.
116
The event horizon is also known as the ___ ___.
Schwarzschild Radius
117
The escape velocity at the event horizon equals...
exactly the speed of light.
118
You can cross ___ at the event horizon, but you can't cross ___.
inward; outward
119
How would one escape the event horizon?
travel at the speed of light
120
The singularity is a ___ ___.
geometric point
121
What is the radius and volume of the singularity?
0
122
Approximately, what is the mass of the singularity?
a lot
123
What is the density of the singularity?
infinity
124
What are the three parts of a black hole?
singularity, event horizon/Schwarzschild Radius, photon sphere
125
How can light escape a black hole?
if it is emitted from the exitcone axis, it will escape on a straight path
126
What happens to light that unsuccessfully tries to escape a black hole?
it orbits the black hole
127
Black holes in ___ orbits can be seen with ___ telescopes.
binary; x-ray
128
The spinning speed of a neutron star is measured in ___.
milliseconds
129
What are the three characteristics of a rapidly spinning black hole?
singularity, ergosphere, stationary limit
130
What will happen if you are in the ergosphere of a rapidly spinning black hole?
you will spin along with the black hole
131
It is possible to extract energy from a rapidly spinning black hole, but the black hole will...
slow down
132
How do you extract energy from a rapidly spinning black hole?
go past the stationary limit, gain energy by spinning along with the black hole, and eject from the ergosphere with more energy than you went in with
133
What is the theory about the center of galaxies?
there is a supermassive black hole there emitting energy by spinning
134
Stephen Hawking combined ___ ___ and ___ ___ to study ___ ___.
general relativity; quantum mechanics; black holes
135
Stephen Hawking concluded that primordial black holes ___.
evaporate
136
primordial black hole
hypothetical type of black hole that is less massive and formed by the extreme density of matter present during the universe's early expansion (rather than by the gravitational collapse of a large star)
137
Quantum mechanics is based on ___.
probability
138
The singularity of a black hole is predicted through quantum mechanics. The farther from the black hole's center, the ___ likely the singularity is to be there.
less
139
According to Hawking, what will happen if the singularity is outside the event horizon/Schwarzschild Radius?
the black hole will explode/evaporate and emit gamma rays
140
How long would it take for a less massive or primordial black hole to evaporate?
longer than the age of the universe
141
What are the four parts involved with a wormhole?
black hole (our universe), singularity, Einstein-Rosen Bridge (the actual wormhole), white hole (other universe)
142
white hole
things can come out, but they can't go in (the opposite of a black hole)
143
How fast would you have to go to get through a wormhole? Why?
faster than the speed of light; the singularity oscillates
144
Gravitational force depends on ___ and ___.
mass; distance
145
An accretion disk gets really ___ and emits ___ radiation.
hot; x-ray
146
An x-ray source may be a ____ ____.
black hole
147
A neutron star has ___ mass than a black hole.
less
148
What does a neutron star have in common with a black hole?
both have accretion disks that emit x-ray radiation
