Exam III Study Flashcards
(198 cards)
1
Q
What is the main purpose of telescopes
A
to collect as much light as possible in the shortest amount of time and resolve small details.
2
Q
What is a continuous spectrum
A
A spread of colors covering the entire visible region, depending on the temperature of the object
3
Q
What materials emit continuous spectra?
A
Hot, dense materials (solids) or highly dense gases
4
Q
What do continuous spectra depend on?
A
The temperature of the substance; the shape of the spectrum is universal but not alway symmetric.
5
Q
What is a discrete spectrum?
A
Separated bright lines with no background
6
Q
What materials emit discrete spectra
A
low-density materials (gases) at high temperatures
7
Q
What are discrete spectral lines connected to?
A
The energy transitions of electrons in the atoms that make up the object
8
Q
What is an absorption spectrum?
A
A combination of continuous and emission spectra- a continuous spectrum with dark lines overlaid.
9
Q
How are absorption spectra produced?
A
When a gold gas is in front of a hot gas which absorbs radiation
10
Q
How are spectral lines used?
A
They are unique to each element and used to identify the composition of distant astrophysical sources
11
Q
How else are spectral lines used in astronomy?
A
To determine the velocity and direction of astrophysical objects via the Doppler effect
12
Q
What is the Doppler effect
A
an increase (or decrease) in the frequency of light (namely) as the source and the observer move toward (or away from) each other
13
Q
what is redshift?
A
The shifting of shorter wavelengths toward longer wavelengths, indicating an object is moving away
14
Q
What is blueshift
A
the shifting of longer wavelengths toward shorter wavelengths indicating an object is moving toward the observer
15
Q
what are the terrestrial planets?
A
mercury, venus, earth, and mars; rocky planets in the interior
16
Q
What are the jovian planets?
A
Jupiter, saturn, uranus, and neptune (gaseous planets in the exterior)
17
Q
What is the shape of most planetary orbits
A
Nearly circular orbits
18
Q
Which planets have highly elliptical orbits?
A
Mercury and Mars
19
Q
How are elliptical orbits defined?
A
By eccentricity, or e, ranging from 0 (circular) to 1 (elliptical)
20
Q
How do planets orbit the sun in relation to one another
A
they all orbit on the same plane and nearly the same direction along the axis
21
Q
Where are dwarf planets located?
A
At large distances from the Sun
22
Q
How far is Pluto from the sun?
A
Around 40 AU
23
Q
Why is it important to compare planets?
A
It reveals patterns between them and helps gain a better understanding of how our planet fits in
24
Q
What is the goal of studying the solar system?
A
To quantify the solar system and build models of our observations to predict and identify objects beyond us
25
How much of the solar system's mass does the sun contain?
99% of all the mass in the solar system
26
What is the primary composition of the sun
70% H, 25% He where other % are negligible
27
What is plasma?
Ionized and charged particle gas
28
How does the sun produce energy?
Via nuclear fusion, converting hydrogen to helium via the proton+proton chain reaction
29
What temperature is required for nuclear fusion to occur in the Sun?
About 15 million degrees
30
Why cant Jupiter undergo nuclear fusion despite having a similar composition to the Sun?
It is not massive enough, so it cannot reach the temperatures needed to trigger fusion
31
What conditions in the Sun's core allow for the proton+proton reaction?
High pressures, high density, and high temperature
32
What is produced in the Sun's fusion process?
4 Protons are converted to helium, energy, positrons and neutrinos
33
Why is high temperature needed for fusion?
To overcome the electric repulsion between positively charged protons
34
What is the Sun's surface temperature?
Around 5700ºK
35
What is the sun's core temperature
in the 10s of millions of degrees
36
What two opposing forces keep the Sun in stable equilibrium?
Radiation pressure and gravitation
37
What are the three major layers of the Sun?
The core, radiative zone, and convective zone
38
What happens in the sun's core?
nuclear reactions generate vast amounts of energy at approximately 15 million degrees
39
How is energy transported through the radiative zone?
Via photon diffusion (scattering and absorption)
40
How long does it take energy to exit the Sun?
more than 100,000 years
41
What is the photosphere?
A very thin (only a few hundred kms) layer that forms the "surface" that we see
42
What is the corona?
The wispy outer layer of the sun that carries charged particles via solar wind
43
Where is Mercury relative to the sun?
The closest planet to the Sun
44
What is Mercury composed of?
Metal and rock, it is highly cratered
45
Why does Mercury remain heavily cratered?
Because it has practically no atmosphere
46
Why does Mercury have extreme temperature changes between day and night?
Extreme temperature changes occur metallic and rocky composition is highly conductive, so it gains and loses heat quickly
47
What is unusual about Mercury's orbit?
It is highly elliptical compared to other planets
48
What is Venus' atmosphere composed of?
Very dense CO2
49
What makes venus so hot
It suffers an extreme greenhouse effect due to its highly absorptive CO2 atmosphere that traps infrared radiation
50
What other factors contribute to venus' heat trapping?
It rotates fairly slowly
51
How hot does Venus get?
Temperatures reach about 500ºC - high enough to melt most metals on earth
52
What is earth's atmosphere composed of?
N2 and O2
53
What protects Earth from solar wind?
Our significant magnetic field, generated by the molten metallic core
54
What is solar wind?
Energetic particles emanating from the Sun
55
What happens to solar wind when they reach the earth?
They are redirected by the magnetic field to the northern and southern poles, saving Earth from a direct hit and preserving life
56
What conditions are needed for Earth's core to produce a magnetic field
A flow of charge and high heat
57
What conditions are needed for Earth's core to produce a magnetic field
A flow of charge and high heat
58
What causes Earth's seismic activity and significant weather?
The core and inner molten layers generate heat and volcanic activity
59
How far away is Mars from the Sun
1.5 AU
60
What are some of Mars' notable surface features?
Huge canyons and polar caps
61
What do Mars' polar caps contain?
H2O ice and carbon dioxide ice
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How do Mars' solar caps change
They grow and shrink according to climate change
63
What types of weather occurs on Mars?
Month-long sandstorms
64
What causes Mars' sandstorms?
Temperature changes and its light atmosphere
65
What is Mars' atmosphere composed of?
CO2, not directly breathable, but sufficient to cause weather patterns
66
What gives Mars its reddish-brown color?
Dust in the atmosphere
67
Why is Mars the most studied planet besides Earth?
Potential remnants of water and polar caps give it the potential to hold life
68
What type of life might be found on Mars?
Likely bacterial or single-cell organisms found deep in the polar caps
69
How does Mars' orbit affect its climate ?
Its significant elliptical orbit causes changes in temperature and helps create wind storms due to variation in the sunlight it recieves
70
What is Jupiters standing in the solar system?
It is the most massive and largest planet, located at 5AU
71
What is located between Mars and Jupiter?
The asteroid belt, a significant feature of small rock-like asteroids orbiting the Sun
72
What is Jupiter composed of?
Gaseous, mostly H/He
73
Why doesn't Jupiter undergo nuclear fusion despite its compisition?
It is not massive enough, which doesn't allow the interior to reach the necessary 15 million degrees for proton+proton chain reaction
74
What is Jupiter's surface like?
Deep layers of gas; ammonia, methane, and sulfur dioxide
75
What is the Red Giant Spot?
A long lasting storm that has survived for centuries due to the frictionless environment and lack of surface that would normally dissipate such storms
76
What powers the Red Giant Spot?
Heat generated from gravitational contraction
77
What indicates the presence of liquid and metallic-like behavior of hydrogen in Jupiter?
Its very dense and extensive magnetic field
78
How does Jupiter generate internal heat?
Gravitational contraction
79
Aside from its moons, what surrounds Jupiter?
Faint rings
80
How many significant moons does Jupiter have?
Four, Galilean Moons
81
What is special about Io
it is the most geologically active object in the solar system, with volcanoes constantly spewing gas
82
What causes Io's intense volcanic activity?
It is internally torn by gravitational pull from Jupiter and outer moons - tidal pushing and pulling - tugging its interior to cause seismic shifting - this causes tidal heating which drives Io's volcanic activity
83
What surrounds Io?
Io is immersed in Jupiter's magnetic fields, with charged particles swirling with released volcanic gas
84
Why is Europa of extreme interest?
Due to evidence of large amounts of water under a hard surface
85
What is Europa's surface like?
A thin crust forms the outer surface
86
What might exist under Europa's surface?
Possibly an ocean
87
What evidence supports the conviction that there is water on Europa?
Spacecraft have taken images of water spewing out from the surface like Earth's geysers, and surface features shift over time, suggesting something is floating on the surface
88
How does Saturn compare to Jupiter?
It's giant and gaseous like Jupiter, primarily a H/He mixture
89
What element dictates features and properties particular to Saturn?
Heloum
90
What unusual storms occur on Saturn?
Helium rainstorms
91
Why is helium significant on Saturn?
Its highly conductive and fluid at lower temperatures
92
How does Saturn's magnetic field compare to Jupiter's
It shows less metallic hydrogen at the inner layers and its magnetic field is not as extensive
93
What are saturn's rings composed of?
particles, ice, or rock chunks- spacecraft can move through them
94
Why are Saturn's rings highly reflective?
Ice particles
95
What is unique about Titan?
It is the only moon with a substantial atmosphere of N2 (like earth)
96
How do we know about Titan"
It has been photographed by Callisto
97
What is Titan's surface like?
Hard with some indication of fluid flow
98
Why is water unlikely to be found on Titan
Its low temperatures would likely freeze water
99
What is the likely composition of Titan's fluid?
Most likely methane and ethane carbon chains. which behave like water at low temperatures, possibly creating oil like features
100
What is Uranus composed of
H/He gas and hydrogen compounds (H2O vapor, ammonia, NH3, CH4)
101
What is unusual about Uranus' axis
It has an extreme axis tilt, making for interesting weather patterns and seasons. Most planets are tilted vertically with respect to the plane, but Uranus' is horizontal
102
What surrounds Uranus?
Many moons and faint rings
103
How does Neptune compare to Uranus?
Similar except not as extreme an axis tilt; also has moons and rings
104
What gives Neptune its color?
Methane composition
105
What are dwarf planets composed of?
Primarily ice and rokc
106
What is the primary dwarf planet?
Pluto!
107
How many moons does Pluto have?
2, similar in size to pluto itself
108
How far is Pluto from the Sun?
about 40 AU
109
What surface features does Pluto have?
Icy and rock-like features that suggest some geological activity
110
Why doesn't Pluto show cratered features?
It appears polished, suggesting it is undergoing erosion
111
What might explain Pluto's erosion?
Potential radioactive materials in the interior
112
What characteristics describe dwarf planets orbits?
They are in elliptical orbits and very distant from the Sun
113
What is Eris?
Another dwarf planet, smaller than Pluto but similar in construction
114
What other objects exist in the solar system?
Comets and asteroids
115
What four features do solar system models attempt to explain?
1) patterns of large bodies: orbits move in the same direction and along the same plane
2) Two types of planes: jovian and terrestrial
3) Existence of smaller bodies: asteroids and comets
4) Notable exceptions to the usual patterns
116
What are the notable exceptions to the usual patterns in the solar system?
Rotation of Uranus and Venus, patterns of orbits, earth's moon
117
What laws explain orbital patterns?
Kepler's laws and Newton's third law
118
What is the core idea of the nebular model?
Our solar system formed from the gravitational collapse of a giant interstellar gas cloud - the solar nebula
119
What did the first solar nebula contain
Primordial elements equivalent to all the mass currently within the solar system
120
How long did it take for gravity to collapse the solar nebula?
Millions or billions of years
121
Is the close encounter model widely accepted today?
No
122
What is the idea behind the close encounter model?
The sun was formed first and another object around the size of the sun came in close contact with it
123
Why was the close encounter model dismissed?
It cannot explain observed motion and types of planets
124
What is galactic recycling?
Elements of planets are formed within stars (first from primordial gases). Stars eventually die over millions of years and explode as supernovae, throwing material into outer space
125
Where is evidence of galactic recycling found
in regions of large amounts of gas where we can see collapse taking place
126
How are elements formed in stellar systems?
Majority of elements are formed in the nuclear fusion process with heavier elements (beyond iron) formed during supernova explosions
127
What happens to momentum as nebular system collapses?
Overall momentum stays the same, but particles can gain/lose momentum
128
What happens to speed as a cloud contracts?
The speed increases as the cloud contracts due to conservation of angular momentum
129
How is energy conserved during a nebular collapse
Gravitational potential energy (mgh) decreases as the system collapses (h) and is transferred into kinetic energy (speeds up) and thermal energy (heats up)
130
What causes the flattening of a nebular system?
the collisions of particles result in flattening. The cloud begins as a spherical shape, then flattens into a disk by virtue of collisions
131
How do collisions affect particle motion
Collisions between gas particles reduce up and down motions
132
Where can evidence of nebular collapse be found?
In images from ALMA
133
What is the frost line?
A boundary in the solar system thought of in terms of both energy and temperature
134
What conditions exist inside the frost line?
Temperatures are too hot for hydrogen compounds to form ices, only heavier compounds (metallic and rock-like materials) survive as solids
135
What conditions exist outside the frost line?
Hydrogen compounds thrive, freezing into ice forms
136
What is accretion?
The process by which small particles join together to form larger bodies
137
How did terrestrial planets form?
Small particles of rock and metal present inside the frost line formed planetismals of rock and metal, which through gravity assembled into terrestrial planets
138
How did Jovian planets form?
Ice formed small particles outside the frost line, which created large planetismals able to form through gravity
139
What is the Orien Belt in relation to planet formation?
A nursery of stellar birth where disks and plaetesimals are formed
140
How were moons formed?
Also through the accretion process
141
What happened to the sun's rotation over time?
It is thought to have spun much faster in its younger form but is now rotating relatively slower
142
What caused the Sun's rotation to slow?
Friction between the solar magnetic field and the solar nebula
143
What are asteroids and comets, according to the nebular model?
leftovers from the accretion process - rocky asteroids inside the frost line, icy comets outside the frost line
144
What is one theory about the origin of earth's water?
Water may have come to earth by way of icy plaetesimals being kicked inward
145
What probability does the icy planetesimal theory for earth's water face?
Probability issues
146
What is an alternative explanation for earth's water?
Earth was formed outside the frost line, suffered a collision, changed orbit and pushed it into the interior
147
How was earth's moon formed?
From a collision with earth
148
How might mars and jupiter's moons been formed?
They could have been captured planetesimals, as they reside close to the asteroid belt
149
What might explain the different rotation axes of planets?
Giant impacts
150
What determines the age of the solar system?
Carbon dating
151
What is the relationship between force, mass, and acceleration
Force is equal to mass times acceleration
152
What is required for terrestrial or astronomical motion?
Net force to act on an entity (Newon's 3rd law)
153
Why does the sun remain relatively unmoved despite gravitational forces from planets?
because the sun is much more massive than earth, though it does wobble around the center of the mass
154
How can the presence of planets around distant stars be detected
By observing the small wobbling motion of the star (gravity!)
155
What is the gravitational force between two objects proportional to
the product of two masses
156
How does distance affect gravitational force?
it is inversely proportional to the distance between the objects squared
157
How does gravitational force compare to other forces?
it is very weak relatively, however it is long ranged and actors over astronomical distances
158
What other forces exist besides gravity?
electromagnetic and nuclear forces
159
What are bound orbits
circular and elliptical
160
What is an unbound orbit
hyperbolic
161
What factors determine the type of orbit
the energy and momentum of the orbiting object
162
How are orbital properties quantified
Using kepler's laws
163
What does the main Kepler's law allow us to determine
the mass of the combined system
164
Why does this method typically give us the mass of a stellar obejct
because the mass of a planet is very small compared to a stellar object
165
How does radar work to measure distances?
It uses electromagnetic waves travelling at the speed of light to measure the transit time of pulses reflected from sources
166
What other method allows measurement of distant astronomical objects
the use of parallax
167
What is luminosity?
the power stars emit, independent of their distance
168
How does luminosity differ from bightness?
Brightness depends on distance and is a measure of how much radiative power reaches the observer
169
How are luminosity and distance related?
By the inverse square law: brightness is proportional to luminosity and is inversely proportional to the distance squared
170
What is the electromagnetic spectrum
The measure of electromagnetic radiation as a function of wavelength (frequency)
171
What is the relationship between wavelength and frequency?
C = (frequency)(wavelength); since c is constant, wavelength and frequency are inversely related
172
How does temperature affect radiation?
Cold objects radiate in low frequencies; hot objects radiate in high frequencies
173
What types of radiation does the sun emit?
Visible light, UV, and some X-Rays
174
What type of radiate do planets emit?
Infrared (long wavelengths not visible to the human eye)
175
What is the visible light wavelength range for the human eye?
400-700 nanometers
176
What is the composition of Earth's atmosphere
80% N2, 20% O2
177
How high does earth's atmosphere extend
to 100km in altitude, but most is concentrated in the lowest 10km (thermosphere)
178
What does the stratosphere contain?
The ozone (O3) layer
179
Why is Ozone important?
It absorbs harmful UV radiation
180
How do atmospheres affect liquid water?
they create pressure that determines whether liquid water can exist on a planet's surface
181
How do atmospheres interact with light
They absorb and scatter light
182
What weather phenomena do atmosphere's create?
Wind, weather, and climate
183
How do atmospheres interact with solar wind?
They create a magnetosphere
184
How can atmospheres affect planetary temperature?
they make surfaces warmer through the greenhouse effect
185
What is the greenhouse effect
the warming of the planetary surface via absorption of the infrared radiation
186
What gases typically contribute to the greenhouse effect?
CO2 and H2O
187
How would Earth's temperature be different without the greenhouse effect
it would be 30º colder
188
Which planet is most affected by the greenhouse effect?
Venus, because it has a very dense CO2 Atmosphere
189
What causes long-term climate changes?
1. Solar brightening (or dimming
2. changes in reflectivity of a planet's surface
3. changes in the axis tilt of a planet
4. changes in greenhouse gas abundance
190
How does surface material affect reflectivity and planetary temperature
more trees are less reflective (warmer), ice is more reflective (colder)
191
What makes the surface of Io appear red and orange?
Sulfur expelled by volcanic eruptions
192
Why are there no impact craters on the surface of Io?
Impact craters have been buried by lava flows
193
Where do scientists think that Jupiter's strong magnetic field is generated?
In its metallic hydrogen layer
194
Why do jovian planets budge around their equators?
Their rapid rotation flings mass near the equator outward
195
Why is Jupiter denser than Saturn?
Jupiter's mass compresses its interior to a greater extent than of Saturn
196
How big is Jupiter's great red spot?
twice as wide as Earth
197
Which Jovian planets have compositions dominated by hydrogen compounds such as methane, ammonia, and water?
Uranus and Neptune
198
Key evidence that Jupiter contains a lot of internal heat comes from the fact that
Jupiter emits about twice as much energy as it receives from the sun
