Second Midterm Flashcards
(256 cards)
1
Q
The best way to study young stars hidden behind interstellar dust clouds would be to use
A
infrared light
2
Q
For a wave of constant velocity, wavelength is ___ to frequency
A
inversely proportional
3
Q
Radio telescopes would NOT represent a good choice for astronomical study of
A
ordinary stars
4
Q
Longest to shortest wavelength
A
radio, microwave, infrared, visible, UV, x-ray, gamma
5
Q
What is the primary advantage of techniques of radio interferometry?
A
an increase in resolving power
6
Q
Space zone observations
A
far-infrared, far-UV, x-ray, gamma
7
Q
Surface zone observations
A
visible and radio
8
Q
At radio and infrared wavelengths, it is necessary to build telescopes with very large ___ to obtain sufficient sensitivity to faint cosmic signals.
A
light-collecting areas
9
Q
At radio and infrared wavelengths, it is necessary to build telescopes with a very large signal sensing ___ to obtain maps of sufficient detail.
A
baselines
10
Q
Radio astronomers have pioneered the use of multiple telescopes working in concert that can produce maps of radio emission as detailed as optical images. These arrays of multiple telescopes are known as ___
A
interferometers
11
Q
Astronomical observations at radio and infrared wavelengths can be obtained even during ___
A
storms
12
Q
What do you need to obtain a successful x-ray image of a high-energy source?
A
1) a telescope designed and built to be launched into space 2) a cosmic source of high temperature
13
Q
T or F: Radio telescopes are large in part to improve their angular resolution, which is poor because of the long wavelengths at which they are used to observe the skies
A
True
14
Q
T or F: Gamma ray telescopes employ the same basic design that optical instruments use
A
False
15
Q
True statement about the used of infrared telescopes
A
the detector and telescope must be cooled to very low temperatures
16
Q
As telescopes become larger and larger, astronomers favor ___
A
reflecting telescopes, in part because large lenses and mirrors sag under their own weight, and it is easier to support a mirror along its entire back side than it is to support a lens only around its edge
17
Q
What property of a telescope influences it resolving power?
A
the size of the main mirror or lens
18
Q
Which of the following is an advantage of the Hubble Space Telescope has over ground-based telescopes?
A
there is no blurring due to atmosphere
19
Q
What fraction of the entire electromagnetic spectrum is spanned by visible light?
A
visible light covers a tiny fraction of the electromagnetic spectrum
20
Q
When multiple radio telescopes are used for interferometry, resolving power is most improved by increasing
A
the distance between telescopes
21
Q
Which of the following is true about observations at wavelengths other than optical or radio?
A
Space-based
22
Q
What is meant in astronomy by the phrase “active optics?”
A
Rapid modifications are made to the tilt and location of the elements of a telescope to correct for the effects of atmospheric and instrumental distortion.
23
Q
Surface figures of the optical elements themselves are controlled
A
adaptive optics
24
Q
The time it takes for a wave to travel from crest to crest
A
wave period
25
The distance of a wave from crest to crest
wavelength
26
Half the distance between a wave's crest and trough
amplitude
27
If you throw a rock into a pond, it creates a wave in the water. What is responsible for creating an electromagnetic wave?
a vibrating charged particle
28
Electromagnetic waves consist of co-oscillating electric and magnetic ___
fields
29
The wave amplitudes are directed ___ to the direction of wave motion.
perpendicular
30
Energy and information flows ___ to the direction of wave motion.
parallel
31
Electromagnetic waves are able to travel through a ___
vacuum
32
Electromagnetic waves travel at a speed of
300,000 km/s
33
T or F: The energy of a photon is inversely proportional to the wavelength of the radiation
True
34
EM radiation penetrates the atmosphere of Earth at what portions of the electromagnetic spectrum?
invisible, radio, and some IR
35
Which of the following is true about the Spitzer Space Telescope?
it orbits the Sun a little behind Earth
36
Most commonly used by professional astronomers today
reflecting
37
World's largest optical telescope
reflecting
38
The HBT is what type of optical telescope
reflecting
39
Galileo used what type of optical telescope
refracting
40
what type of optical telescope: incoming light passes through glass
refracting
41
what type of optical telescope: very large telescopes become "top-heavy"
refracting
42
what type of optical telescope: the world's largest 1-meter in diameter
refracting
43
The number of waves that pass a point each second measures ___
frequency
44
T or F: The term "seeing" is used to describe how faint an object can be detected by a telescope
False
45
If we double the diameter of a telescope's mirror, what happens to its light-gathering ability?
it quadruples
46
What is the main reason that UV astronomy must be done in space?
earth's atmosphere absorbs most UV wavelengths
47
Which of the following photons is most energetic?
gamma ray
48
A star much cooler than the Sun would appear
red
49
In non-ionized hydrogen, for instance, what does a higher orbital state have more of than a lower orbital state?
energy
50
Wien's law states that the wavelength of the peak radiation emitted by a blackbody is ___ the temperature of a blackbody
inversely proportional to
51
Rank from farthest to closest to Sun: Mercury, Saturn, Earth, Mars, Pluto, Jupiter
Pluto, Saturn, Jupiter, Mars, Earth, Mercury
52
Rank from highest to lowest mass: Earth, Jupiter, Mars, Mercury, Pluto, Sun
Sun, Jupiter, Earth, Mars, Mercury, Pluto
53
Rank from largest to smallest radius: Earth, Jupiter, Mars, Mercury, Pluto, Sun
Sun, Jupiter, Earth, Mars, Mercury, Pluto
54
An object with a temperature of 1000 K emits mostly
IR light
55
When an electron goes from a higher energy level back down to the ground state, what is the most accurate way to describe the light it emits?
One or more photons, equal in total energy to the energy the electron absorbed to move up to the higher level
56
About a trillion comets are thought to be located far, far beyond Pluto in the ___
Oort cloud
57
The bright spherical part of a comet observed when it is close to the Sun is the ___
coma
58
A comet's ___ stretches directly away from the Sun
plasma tail
59
A comet's ___ is the frozen portion of a comet
nucleus
60
Particles ejected from a comet can cause a ___ on Earth
meteor shower
61
The ____ extends from about beyond the orbit of Neptune to about twice the distance of Neptune from the Sun
Kuiper belt
62
T or F: Imagine an emission spectrum produced by a container of hydrogen gas. Changing the amount of hydrogen in the container will change the colors of the lines in the spectrum.
False
63
Black background with specific lines
emission spectrum
64
Colorful background with black lines
absorption spectrum
65
A hot, high-density light source (hot bulb)
continuous spectrum
66
A hot, low-density light source (heated hydrogen gas)
emission spectrum
67
A hot, high-density light source shining through a cool, low-density medium (hot bulb behind a cool gas)
absorption spectrum
68
A cloud of hot, interstellar gas glowing as a result of one or more nearby young stars that ionize gas
emission nebula (emission spectrum)
69
A glowing cloud of hot, low-density gas that is ejected from a red-giant star
planetary nebula (emission spectrum)
70
a glowing ball of extremely dense gas powered by nuclear fusion in its core, but surrounded by a low-density, cooler atmosphere
Sun (absorption spectrum)
71
layer of cool, low density gas confined close to the surface of Titan
atmosphere on Titan (absorption spectrum)
72
visible light meets clear glass
transmission
73
cell phone signal passes through walls
transmission
74
visible light does not pass through a black wall
absorption
75
blue light hits a red sweatshirt
absorption
76
white light hits a white piece of paper
reflection or scattering
77
red light hits a red sweatshirt
reflection or scattering
78
light comes from a light bulb
emission
79
light comes from your computer screen
emission
80
T or F: Imagine an emission spectrum produced by a container of hydrogen gas. Changing the gas in the container from hydrogen to helium will change the colors of the lines occurring in the spectrum.
true
81
Astronomers analyze starlight to determine a star's
motion, composition, temperature
82
T or F: An electron moves to a higher energy level in an atom after absorbing a photon of a specific energy.
true
83
Form a coma when near the sun
comets
84
visible in the sky as a fuzzy patch of light that rises and sets with the stars
comets
85
most are located either in the Kuiper belt or Oort cloud
comets
86
dust particles entering the Earth's atmosphere at high speed
meteors
87
visible in the sky as a bright streak of light for only a few seconds
meteors
88
compositions similar to that of terrestrial planets
asteroids
89
typically orbit the sun at approximately 3 Au
asteroids
90
What kind of spectrum does the Sun have?
absorption
91
length of comet's tail depends on
the distance of the comet from the sun, longer when it is closer to the sun
92
What will happen to the absorption and/or emission spectral lines of an object moving away from Earth at high speed?
they will be shifted to the red end of the spectrum
93
Stefan's law states that the total energy radiated by a blackbody depends on the ________ power of the temperature of the blackbody.
fourth
94
The effect of a cool, dilute gas between an observer and a continuous hot source is that ________.
dark absorption lines will appear in the spectrum
95
Rank from closest to farthest from the sun (shortest to longest orbital period): Kuiper belt object, trojan asteroid, Oort cloud object, asteroid in asteroid belt
asteroid in asteroid belt, trojan asteroid, Kuiper belt object, Oort cloud object
96
formed nearest to farthest from sun: asteroid in asteroid belt, Kuiper belt object, Oort cloud object
asteroid in asteroid belt, Oort cloud object, Kuiper belt object
97
Which of the planets below has the greatest tilt of its rotation axis?
uranus
98
Greatest to least gravitational tidal forces exerted on the moon by Earth (Moon's near side, midway, and far side)
near side, midway, far side
99
Gravitational forces from Earth causes the Moon to have
a deformation of its shape known as a tidal bulge and tidal locking (Moon's rotation and orbital periods are synchronized, one side of the Moon's tidal bulge faces the earth as it orbits)
100
Rank from longest to shortest period: Earth's orbital period, Earth's rotation period, Moon's orbital period, Moon's rotation period
Earth's orbital period, Moon's orbital period = moon's rotation period, Earth's rotation period
101
Rank from highest to lowest average surface temperature: Earth, Mars, Mercury, Jupiter, Neptune, Venus
Venus, Mercury, Earth, Mars, Jupiter, Neptune
102
Rank from longest to shortest orbital period:Earth, Mars, Mercury, Jupiter, Neptune,
Neptune, Jupiter, Mars, Earth, Mercury
103
Kepler's third law
orbital period increases with distance from the Sun
104
Rank from highest to lowest number of orbiting moons: Earth, Mars, Mercury, Jupiter
Jupiter, Mars (2), Earth, Mercury
105
In relation to the density of Earth's Moon, Mercury's density suggests that the planet
has a dense metal core
106
Jupiter is noticeably oblate (flattened) rather than spherical primarily because of which of the following physical effects?
rapid motion (turn into a pancake if not for its strong gravitational field)
107
What is the primary component of the atmosphere of Jupiter?
hydrogen
108
The wide variation in the lunar surface temperature is due to its lack of which of the following?
an atmosphere
109
What effect has the greenhouse effect had on the surface environment of Venus?
It has raised the surface temperature by hundreds of degrees
110
What material is rare in the atmosphere of Earth, but common in the atmospheres of Mars and Venus?
carbon dioxide
111
Kepler's second law
planets move faster when closer to the Sun
112
Kepler's first law
planets have elliptical orbits with the sun at one focus
113
Ice age periods of heavier ice __ and less ice ___
glacial and interglacial
114
What appears at its highest level at present in past 500,000 years based on ice cores and is historically correlated with high surface temperatures
CO2
115
Climate has many systems affect by ___ and is difficult to model
nonlinear feedback
116
A possible outcome of the melting of Arctic ices
abrupt climate cooling in N. Atlantic (glaciation, 10 years)
117
Earth's atmosphere composition
78% N2, 21% O2 + trace other, composition linked to life O2, oceans lack CO2
118
Moderate greenhouse effect is ___, due to ___ absorption
good, water
119
Climate is affected b y
oceans and solar energy
120
Earth's mean density
5.5
121
Earth's crust density
3.3
122
Earth layered structure
dense core, mantle, less dense crust
123
Earth has a ___ surface
young
124
plate tectonics and evolving "young surface" is driven by
convection by hot core (hot from radioactive decay and heat formation)
125
source of magnetic fields
conducting currents in molten core + earth's rotation
126
Protects Earth against solar wind; causes van Allen belts and aurorae
magnetic field
127
Moon size in relation to Earth
1/81 M and 0.3 R (relatively large moon compared to the size of earth
128
Because the moon has no atmosphere
can see stars in the day, large day/night temperature variations
129
Moon's "old surface"
craters from meteor impacts and micrometeorites.
| no plate tectonics, no volcanoes
130
Maria is __ than highlands, but still > 3 Gyr
younger
131
like the moon except denser and warmer
Mercury
132
NASA's Messenger space probe discovered that Mercury's surface
is old and cratered like our moon but some evidence of other tectonic processes (cooling)
133
Rembrandt crater with scarp
shriveling due to cooling
134
Hesiod crater: pyroclastic vents
outgassing
135
Where the sun doesn't shine (Mercury's south pole)
has ice brought may comets
136
1989 NASA's Magellan visits Venus
radar mapping of Venus to see beneath the clouds
137
Venus surface
is young about 500 million years no obvious activity now, because of hot core, volcanoes
138
interior heating by
radioactive decay and residual heat from formation
139
core of Earth and Venus
6000K
140
core of Mercury and moon
fairly cool/cold since they are small
141
a frozen world but not unlike our own
Mars
142
Mar's atmosphere and surface
THIN atmosphere (1% of earth's) water ice, ice clouds, no liquid water at present
143
A planet's atmosphere has to do with its
temperature and escape velocity
144
It is easier to planets and moons to hang onto
heavier, more slowing moving molecules (CO2, O2, N2) than light fast molecules (H2 or He)
145
more massive and/or cold planets hang on gases
much more easily
146
the molecules in warmer atmospheres move
faster and gases can escape the pull of gravity
147
lighter and/or warmer planets will have atmospheres with
heavy molecules
148
Valles Marineras
scarp? 2 Gyr
149
Olympus Mons
biggest volcano in the solar system 25 km in height nonmoving crust
150
Mars appears to have lost
most of its atmosphere and its liquid water (planets evolve)
151
NASA's Mars Reconnaissance Orbiter finds
buried glaciers on Mars (radar imaging: 3 times larger than LA)
152
Like the moon, no air, 100/700K, rotation 58.6 d, no geology, old surface
Mercury
153
earth-sized, thick CO2 atmosphere, very hot 735K, old volcanoes but no plate tectonics, newish surface (500Myr), rotation retrograde 243d
Venus
154
N2/O2 atmosphere, 185/331 K, water, weather, erosion, active geology, magnetic field, young surface, life
Earth
155
thin CO2 atmosphere, 186/268K, some geology, no plate tectonics, water ice evidence for previous liquid water, 24.6h rotation
Mars
156
getting to the planets
Hohmann transfer orbits
157
Rocket leaves Earth at transfer orbit aphelion
transfer orbit perihelion coincides with other planet's orbit
158
Voyagers 1 and 2 used
gravity assist
159
Jupiter's atmosphere
thick 90% H2, He
160
Jupiter's clouds
ammonia, methane, water
161
light bands
zones
162
redder layers, deeper into atmosphere and warmer
belts
163
Jupiter's core
rocky metallic H, pressures are very high = interior is very hot
164
What did Galileo spacecraft discover on Jupiter?
gale force winds 400mph
165
formed by coagulation of planetesimals
terrestrial planets
166
formed by like stars, inner core was big enough to accrete gases
Jovian planets
167
Jupiter radiates __ as much energy as it receives from the sun
twice
168
Jupiter's hot core + rotation -->
magnetic field
169
Loss of equatorial wind belt and evidence for another comet hit
dark belt gone now a lighter zone
170
Saturn's shepherd moons cause
fine structure
171
forward scattering
backlit Saturn
172
Uranian equator is always cold because of
pole-on rotation
173
Red areas (false color) on Neptune
methane gas
174
white methane ice cloud
Scooter
175
5.2 AU, 12 eyrs, 318 M, 11R, 1.3g/cc, 10 h rotation, 59km/s escape velocity, H, He atmosphere, 125K, 66 moons and a ring
Jupiter
176
9.5 AU, 29 eyrs, 95M, 0.5R, 0.7 g/cc, 35km.s escape velocity, H, He atmosphere, 95K, 62+moons, and a ring
Saturn
177
1781 William Herschel, 19.2 AU, 84 eyrs, 14M, 4R, 1.3gm/cc, 21 km/s escape velocity, H, He, methane, ammonia, 57K, 27 moons and a ring
Uranus
178
1846 Galle, Adams, Leverrier, 30 AU, 165 eyrs, 17M, 4R, 1.3gm/cc, 23 km/s escape velocity, H, He, methane (blue), 59K 13 moons and ring
Neptune
179
Moons are mostly
an outer solar system phenomenon (except Earth and Mars)
180
youngest surface in solar system
Io (hot interior due to tidal heating, active volcanoes)
181
Galilean moons of Jupiter
Io, Europa, Gaymede, Callisto
182
warm interior: tidal heating, possible salty liquid ocean beneath ice (magnetic field)
Europa
183
largest moon in the solar system
ganymede
184
farthest and oldest surface moon
Callisto
185
Saturn's largest moon, bigger than Mercury, Earth-like atmosphere near a big city (smoggy N2 + methane "lakes")
Titan
186
Titan's temperature and pressure are near
the triple point of methane
187
which Saturn moon has ice geysers and may be the origin of Saturn's E ring
Enceladus
188
discovered in 1930, 2nd largest dwarf planet,very bright because of icy surface
Pluto
189
discovered in 2005, 27% more massive than Pluto, eccentric orbit, 98AU and 38 AU
Eris
190
discovered 1801 similar in size to Pluto, asteroid, 2.7 AU
Ceres
191
Haumea, Sedna, Makemake
other dwarf planets
192
Moons Charon, Hydra, Nix
Pluto
193
The planets are all in a
thin disk
194
the planets all ___ around the Sun (ex. Uranus and Venus, believed to have had collisions)
rotate in the same direction as they revolve
195
the planets close to the sun are __, far from the sun are ___ (if big enough) __
rocky, gassy, icy
196
the distant planets are
giants
197
caused by rotation, angular momentum at "equator" of original gas cloud hindered collapse in equatorial region, no hindrance at poles
flat disk
198
rotation, revolution in same sense
all derived from rotation of original gas cloud
199
young sun's heat scoured the inner solar nebula of ices, gases only ___ left
rocky elements
200
Newton derived Kepler's equations to derive __ between two bodies
elliptical orbits
201
the three-body system ___
has no solution
202
five stable points where a small body can co-rotate with two larger bodies
Lagrange points
203
Solve many body problem
given mass --> force--> accelerations--> velocity--> positions
204
computational limitations
rounding errors and precision
205
computer simulation of how the solar system may have evolved (migration of planets)
Nice Model
206
the solar system objects __ with the sun
formed together
207
solar system flattening is caused by
rotation (angular momentum)
208
outer planets beyond the "frost line" at asteroid belt can retain
volatiles
209
Inner to outer of Sun
Core, Radiation zone, convection zone, photosphere, chromosphere, transition zone
210
Triton
Neptune's moon
211
Dactyl
Ida's moon
212
NASA moon missions -of Jupiter
Galileo
213
NASA moon missions of Saturn
Cassini
214
newer sunspots appear __ to the equator and older ones are at __
closer, higher latitudes
215
number of sunspots
zero to 100-200 at max solar activity
216
the fact that Europa orbits Jupiter twice for every one orbit of Ganymede is an example of
orbital resonance
217
Granulation is evidence of
convection in the solar interior (convection just below photosphere = hot material wells up from within the Sun then sinks back down into the interior)
218
source of ionized gas in the donut-shaped charge particle belt around Jupiter
Io
219
hot, glowing lava visible in some photos
Io
220
volcanos currently erupting = smooth surface
Io
221
ice covered surface with few impact craters
Europa
222
heavily cratered terrain adjacent to much younger terrain
Ganymede
223
theory of origin
circular orbits, highly differentiated, rotate in the same sense as the sun, orbits lie in the same plane
224
primary source of energy for the sun
hydrogen fusion
225
surface temperature of Saturn's moon Titan
94K much cooler than Earth's
226
__ are caused by magnetic disturbances in the lower atmosphere of the sun
flares
227
approximate age of the solar system
4.6 Gyr
228
Saturn's rings are composed of
lots of individual particles of ice and rock
229
Saturn's rings look bright because
light from the Sun reflects off the material in the rings
230
From which region of the Sun does the solar wind originate?
corona
231
hot coronal gas escaping the gravity of the Sun
solar wind
232
occurs about 11 years after a solar max, solar flares are most common, auroras, orbiting satellites are more at risk, numerous sunspots
solar max
233
occurs about 5 to 6 years after solar max
solar min
234
nuclear fusion of hydrogen into helium occurs in
core
235
energy moves through the sun's __ by means of rising of hot gas and falling of cooler gas
convection
236
nearly all the visible light we see from the sun
photosphere
237
Most of the Sun's UV light is emitted from the narrow layer called __ where T increases with altitude
chromosphere
238
we can see the sun's __ most easily during total solar eclipses
corona
239
the __ is the layer of the sun between is core and convection zone
radiation zone
240
what causes the Io's orange surface color?
sulfur compounds
241
surface T of the Sun
5780 K
242
common cause of sunspots, flares, and prominences
magnetic fields
243
atm pressure of Titan
is about 1.5 times greater than Earth's
244
surfaces dramatically altered during the heavy bombardment
terrestrial planets
245
formed in regions cold enough for water to freeze and with lower orbital speeds
Jovian planets
246
What causes the fusion rate in the Sun's core to increase?
increase in core T and decrease in core radius
247
if the fusion rate initially increases
then the core expands
248
if the fusion rate initially decreases
then the core contracts
249
What would happen if the fusion rate in the core of the Sun were increased but the core could not expand?
The Sun’s core would start to heat up and the rate of fusion would increase even more.
250
Compared with Earth's diameter, the Sun's diameter is about
one hundred times larger.
251
What is the term for loops or sheets of glowing gas ejected from active regions on the solar surface?
Prominences
252
During periods of low solar activity just after solar minimum, what is true of the location and distribution of sunspots?
They tend to cluster at high solar latitudes
253
Why do sunspots appear dark?
They have relatively lower temperatures than the brighter, background photosphere
254
Kuiper belt objects have __when observed from Earth.
a low relative brightness
255
Jupiter's moon Europa might harbor life because it has which of the following conditions?
A liquid water subsurface layer
256
Which of the following statements about solar sunspots is NOT true?
They are distributed approximately uniformly over the Sun's surface both in position and in time.
