ASTRO FINAL Flashcards
(294 cards)
1
Q
How old is the universe
A
14 billion years
2
Q
How many kilometers make up a light-year?
A
10*10^12
3
Q
How many galaxies are present in the Local Group?
A
40
4
Q
Is there ever a time when we on Earth are not in some type of motion?
A
No
5
Q
How far away are the nearest stars, excluding the Sun?
A
a least 4 light-years away
6
Q
T or F. The elements hydrogen & helium were created during the Big Bang
A
True
7
Q
T or F. The expansion of the universe refers to the increase in the average distance between galaxies as time progresses
A
True
8
Q
If the Galaxy were shrunk to the size of a football field, how far apart would the Sun and its nearest neighboring stars be?
A
a few millimeters
9
Q
How is Earth moving in our solar system?
A
1- The Earth orbits the Sun once each year 2- The Earth orbits the Sun once each year 3- The Earth rotates on its axis once each day 4- The Earth orbits an average distance of 1 AU from the Sun
10
Q
How is our solar system moving in the Milky Way Galaxy?’’
review
A
The Sun takes about 230 million years (or 230 x 10^6 years) to orbit the Milky Way
11
Q
How big is the Milky Way Galaxy?
A
100,000 light-years across or 100 x 10^3
12
Q
How do galaxies move within the Local Group of galaxies?
A
in a random manner
13
Q
What is rotation?
A
It is the spinning of an object on its axis
14
Q
How many kilometers is one Astronomical Unit (AU)?
A
150 million km (150*10^6)
15
Q
How many stars are there in the Milky Way Galaxy, including the Sun?
A
100 billion (100*10^9)
16
Q
How many galaxies are present in the observable universe?
A
100 billion (100*10^9)
17
Q
What is a comet?
A
Relatively small & icy object?
18
Q
How were most of the elements of the periodic table created?
A
by stars
19
Q
T or F. A star is a glowing ball of gas that generates energy through nuclear fusion
A
True
20
Q
From the mid-latitudes on Earth, which of the following is true of stars in the sky in the direction of the celestial equator?
A
Those stars appear to rise in an easterly direction, set in a westerly direction
21
Q
About how many stars can be seen with our eyes in the night’s sky from a dark site?
A
6000
22
Q
T or F. The Moon-Earth system orbits the Sun.
A
True
23
Q
For a specific viewing location on the Earth, which of the following is equal to the altitude of the north celestial pole at that same viewing location?
A
latitude
24
Q
What is the celestial sphere?
A
It is an imaginary sphere with the earth at its center & all the stars appear to be at the same distance
25
T or F. The phase of the Moon on any given day depends on its relative position to the Sun and the Earth.
True
26
How many official constellations are used as regions to divide up the celestial sphere?
88
27
What is a parallax?
It is a change in the apparent position of an object caused by a change in the observer's line of sight
28
When does a lunar eclipse occur?
It occurs when the Earth lies directly between the Sun & the Moon
29
When the third quarter moon rises, approximately what time is it?
midnight
30
By about how many degrees a day does the Sun appears to drift along the ecliptic?
1.0
31
What causes a full moon to occur?
The Sun & the Moon are in the opposite directions as seen from Earth
32
What is precession?
It is a gradual wobble that alters the orientation of Earth’s axis in space
33
T or F. The angle of the meridian to the zenith and the Earth’s distance from the Sun together cause the seasons
False
34
Why doesn't a lunar or solar eclipse happen every month?
The Moon's orbital plane is inclined a few degrees to the ecliptic
35
What is the angle (in degrees) between the ecliptic & the celestial equator?
23.5
36
What is the period of the Moon’s orbit around the Earth?
27.3 days
37
What is the celestial equator?
It is a projection of Earth's equator into space?
38
Which of the following is a true statement about circumpolar stars?
They never rise or set?
39
T or F. The stars in the celestial sphere appear to move in circles around the celestial pole, when viewed from a fixed point on Earth, during a 24 hour rotation period.
True
40
Before the invention of the compass, what did people use to tell North during the night?
Polaris
41
Before the invention of the compass, people used the direction of which of the following to tell North during the day?
The shortest shadow cast by an object
42
Kepler's Second Law says that as a planet moves around its orbit, it sweeps out:
equal area in the equal time
43
Why are there 7 days in a week?
Only 7 objects were known to change their positions on the celestial sphere
44
Perihelion:
is the closest distance to the Sun
45
What claim does the geocentric model make to explain retrograde motion?
Planets really do reverse their direction of motion when they are in retrograde, and they become brighter because they are closer to the Earth correct
46
What does Kepler's First Law say about the orbits of the planets?
They are ellipses with the Sun at one focus
47
The ancient Greeks discovered that:
1- the Moon is round 2- The size of the Earth 3- Earth is round
48
What did Tycho use to build the biggest instruments in the world for his observatory?
Metal
49
In what ways do we use scientific thinking in everyday life?
We combine trial-and-error experiments with testable predictions
50
Kepler's third law states that:
period squared equals semimajor axis cubed
51
East is defined by the direction of:
Sunrise at equinox
52
A planet moves:
fastest at perihelion & slowest at aphelion
53
How did the Greeks explain planetary motion?
with a geocentric circles-on-circles model
54
Why did the heliocentric model of Copernicus fail to predict the position of the planets better than the geocentric model?
Copernicus used perfect circles for orbits
55
How did astronomy benefit ancient societies?
1- It helped them to keep track of the day of the year 2- It helped them to define directions 3- It helped them to determine the time of day or night
56
T or F. A semimajor axis is the distance from the center to the edge along the sorter axis of an ellipse
False
57
T or F. Galileo observed sunspots on the Sun, mountains on the Moon, the moons of Jupiter, and all the phases of Venus to solidify the Copernican revolution.
True
58
Why was Ptolemy's geocentric model widely accepted for 1600 years?
It accurately predicted the positions of the planets
59
T or F. The Moon is always falling toward the Earth
True
60
What keeps a planet rotating & orbiting the Sun
Conservation of angular momentum
61
Kepler & Galileo speculated that Kepler's Laws could be explained using:
magnetic fields
62
Mass:
is a fixed amount of material
63
T or F. Tides cause the moon to move farther away from the Earth
True
64
During spring tides at full & new moons, the Sun & Moon are:
working together
65
Newton's Law of Gravity says every object attracts every other object with a force that is proportional to the:
product of their masses & declines with square of the distance between them
66
A force is in the direction of:
the change in motion
67
Newton's First Law says an object at rest remains at rest and an object in motion
remains in motion along a straight line
68
Conservation of energy means:
energy cannot be created or destroyed
69
Temperature measures
the speed of the particles
70
Velocity is:
speed in a specified direction
71
What does doubling the mass of one object do to the gravitational force between the object and another object?
Doubles the force
72
Newton's Second Law says a force is:
mass multiplied by acceleration
73
Gravity causes tides because
it pulls on the near side harder than it does on the far side
74
Acceleration is
a change in velocity
75
Newton's version of Kepler's third law allows us to measure:
mass
76
Astronauts in orbit around the Earth experience “weightlessness” because:
They are in continual free-fall
77
Speed is
the rate at which an object is moving
78
Which of the following is the main cause of tides on Earth
Moon
79
How much stronger are the tides from the Sun compared to the tides from the Moon
One third as strong
80
What is the angle between the ecliptic & the celestial equator
23.5 degrees
81
What is the ecliptic?
The Sun's apparent annual path on the celestial sphere
82
What is the acceleration on Earth due to gravity
10 m/s^2
83
Which of the following best describes an asteroid that orbits a star?
A relatively small & rocky object
84
T or F. The altitude of the Sun above the horizon changes over the course of a year
True
85
Which of the following is a reason for the change in the apparent daily path of the Sun as the seasons progress?
The tilted axis of the Earth
86
Which of the following defines a planet in our solar system?
It has cleared objects from its orbital path
87
Which of the following is created when the Sun crosses the celestial equator moving north, sometime around March
The vernal equinox
88
What does a force change?
Motion
89
Why do objects move at a constant velocity if no force acts on them?
Conservation of momentum
90
What causes the seasons?
The tilt of the rotation axis relative to the ecliptic
91
What is a zenith?
Straight up 90º from the horizon
92
Approximately what time is it if a full moon is directly overhead?
midnight
93
Which of the following best describes momentum?
Velocity multiplied by mass
94
Why are astronauts weightless if they are on a space station that is in orbit around the Earth
they are continually falling
95
What does doubling the distance between 2 objects do to the gravitational force between the objects?
it changes the force by a factor 1/4
96
When does a solar eclipse occur?
When the moon lies directly between the Sun & the Earth
97
How is the direction of the West determined?
By the sunset at equinox
98
What is an aphelion?
It is the farthest distance from the Sun
99
What are the main phases of matter?
Solid, liquid, gas, plasma
100
T or F. A continuous spectrum looks like a smooth continuous rainbow of light
True
101
An absorption line spectrum looks like:
a smooth continuous rainbow of light punctured by dark regions
102
What do astronomers use light for?
spectroscopy, imagining & timing
103
How many times smaller is the nucleus compared to an atom?
10^5
104
How does matter affect light?
Matter can emit, absorb, transmit & scatter light
105
Over a very long time, tidal forces cause the Earth to:
rotate more slowly
106
The length of an Earth day is determined by the time required for approximately one:
Earth rotation
107
T or F. An emission line spectrum looks like a smooth continuous rainbow of light punctured by dark regions.
False
108
An atom has a diameter of about
10^-10m
109
A hot opaque object emits a:
continuous spectrum
110
A hot opaque object viewed through a cooler gas shows:
an absorption line spectrum
111
Timing:
measures changes in time
112
Gas viewed without a hot opaque object in the line of sight shows:
an emission line spectrum
113
What is the relationship between wavelength & frequency?
Wavelength multiplied by frequency is speed
114
When an atom absorbs a single particle of light, how is that energy stored in the atom?
An electron in the atom jumps to a higher energy level
115
The energy of a photon is
its frequency multiplied by Planck's constant
116
Imaging:
takes a picture
117
The first step in spectroscopy is:
dispersion of light into its component colors
118
Power is
Energy per time
119
Light can show us that an object is rotating when one side is moving toward us and one side is moving away using:
the Doppler effect
120
How is the peak wavelength related to temperature, 'T'?
Peak wavelength is inversely proportional to the temperature (1/T)
121
How does Earth’s atmosphere affect ground-based observations?
It limits observing at visible light wavelengths to nighttime
122
T or F. Spectral lines shift to redder wavelengths for objects moving towards us to bluer wavelengths for objects moving away from us
False
123
How does your eye form an image?
By focusing light on your retina
124
T or F. We put telescopes in space to be able to observe all wavelengths of light
True
125
Radio telescopes use:
metal dishes
126
X-ray telescopes use:
Grazing incidence reflections
127
A refracting telescope forms an image by
Focusing light with a lens
128
What are the characteristic wavelength and energy of photons emitted by hotter objects
Shorter wavelength, higher energy
129
The faster an object rotates, the:
wider the spectral line
130
Which of the following allows multiple telescopes to be linked together to obtain the angular resolution of a much larger telescope?
Interferometry
131
How is the power emitted related to the temperature 'T'
The power emitted is proportional to the temperature to the 4th (T^4)
132
What are the 2 most important properties of a telescope?
Collecting area & angular resolution
133
Which of the following is a characteristic of an object whose temperature is rapidly increasing?
It becomes brighter
134
What is the color difference between hotter & cooler objects?
Hotter objects look bluer, cooler objects look redder
135
Hotter objects emit more light
per unit surface area
136
A sample return:
returns samples from another world to Earth
137
The Sun is powered by:
hydrogen burning in its core
138
Which of the following is the most volcanically active place in the solar system
Io
139
How long is a day on Mercury?
3 months
140
In which direction do all the planets orbit the Sun when viewed from above the Sun's northern hemisphere
Counterclockwise
141
The pressure on the surface of Venus is equivalent to
1 km beneath the surface of the ocean on Earth
142
All planetary orbits in our Solar System lie nearly the same:
ecliptic plane
143
A flyby:
visits another world usually just once
144
The planet in our solar system that rotates backward is:
Venus
145
All the planets in our Solar system move in:
elliptical orbits
146
An orbiter:
goes into orbit around a world
147
The Sun is mainly made of
hydrogen & helium
148
All of the Jovian Planets with rings are:
Saturn, Jupiter, Neptune, Uranus
149
How old is the Sun?
4.6*10^9 years old
150
What gives Uranus & Neptune their blueish colors?
Methane
151
The solar system contains very, very large numbers of:
comets & asteroids
152
An object is a planet if it is in orbit around the sun, has enough mass to become spherical &
has cleared its orbit
153
The Kuiper belt begins near
Neptune
154
The eight official planets clearly divide into 2 groups:
Terrestrial & Jovian
155
The Oort Cloud extends:
about halfway to the nearest stars
156
What feature explains the general differences between the Terrestrial & Jovian planets
Temperature
157
What property of our solar system must a formation theory explain?
Patterns of motion
158
When did the planets begin to form?
4.6*10^9 years ago
159
What explains the existence of our moon?
The Moon resulted from a giant impact with the Earth
160
What process set explains the orderly pattern of motion in our solar system?
Heating, spinning & flattening
161
What characteristic of a young Sun sweeps away material not yet accreted onto the planets?
Strong stellar wind
162
What is formed outside the frost line?
Jovian planets
163
What does the era of heavy bombardment explain?
Exceptions to the general patterns
164
The formation of a gas from a solid is called:
sublimation
165
T or F. Asteroids are the ice-rich leftover planetesimals of the inner solar system
False
166
Summer in Phoenix AZ is hotter than winter because:
Earth's Northern Hemisphere is tilted toward the Sun
167
The formation of a liquid from gas is called:
condensation
168
An unimportant property of a telescope is its:
magnifications
169
Radiometric dating:
measures the proportions of a radioactive isotope with its decay products
170
What does a collapsing cloud do as it shrinks
It heats up, spins faster & flattens out
171
What is formed inside the frost line?
Terrestrial planets
172
What process represents conservation of angular momentum in action as the solar nebula cloud collapses?
Faster spinning
173
What process represents energy conservation in action when the solar nebula cloud collapses?
Heating
174
The Oort Cloud:
where icy leftover planetesimals are found
175
T or F. When viewing the solar system above the Sun's northern hemisphere, most planets rotate counterclockwise
True
176
How does a reflecting telescope form an image?
By focusing light with mirrors
177
What is a lander primarily designed to do?
Probes the surface or atmosphere
178
Which of the following planet’s axis of rotation is the most tilted?
Uranus
179
How is the composition of a distance object determine?
Identifying the spectral lines
180
The Doppler shift formula measures?
The speed of an object is proportional to the change in the wavelength
181
What are the best objects to study in order to learn about the composition of the early solar system?
Asteroids & comets
182
T or F. Observations made from space can observe all wavelengths of light
True
183
According to the nebular theory, how did the solar system form?
By the collapse of a cloud of gas & dust
184
What planet still retains its primary atmosphere from birth?
Jupiter
185
What does spectroscopy reveal about an object?
The composition
186
As the solar nebula cloud collapsed, which natural consequence caused it to flatten into a disk?
Collisions
187
The temperature of an object has a specific meaning as it relates to the object's atoms. In this case, what does a high temperature mean?
The atoms are moving fast
188
What are astronomy’s detectors according to the historical order?
Eye, film, photomultiplier & ccd
189
What geological processes shaped Mercury?
Cratering & volcanism
190
A crater has a width
10 times the size of the impactor
191
What fundamental property of a planet determines its geological activity?
Size
192
How do we know that Earth's surface is in motion?
The continents fit together & creation of new sea crust, composition differences between seafloor & crust, & GPS measurements
193
What are the major processes that shape planetary surfaces after solar system formation
Cratering, volcanism, tectonics & erosion
194
T or F. Volcanism is more likely on a planet with high internal temperatures & a thin lithosphere
True
195
Compared to smaller planets, larger planets retain their interior heat:
longer
196
The 3 ways to heat a terrestrial interior are:
accretion, differentiation & radioactive decay
197
3 ways to cool a terrestrial interior are:
convection, conduction & raditation
198
Which of the following layers, being thinner, allows for more geological activity?
Lithosphere
199
Which of the following processes led to the formation of tremendous tectonic cliffs on Mercury?
Cooling of planets
200
Subduction occurs at:
ocean trenches
201
Which of the following features accounts for similar internal structures between the terrestrial planets?
Gravity
202
How do impact craters reveal a surface’s geological age?
More craters indicate an older surface
203
New seafloor crust is created at
mid-ocean ridges
204
T or F. The polar ice caps provide geological evidence of the fact that water once flowed on Mars
False
205
A planetary magnetic field requires 3 items:
electrically conductive fluid, convection, core rotation
206
Erosion is defined as:
the breakdown & transport of rocks by volatiles
207
Tectonic activity on Earth is always accompanied by
earthquakes
208
Does Venus have ongoing plate tectonics
We do not see any
209
The three factors that determine if a gas molecule achieves thermal escape are:
temperature, the mass of particles & planet mass
210
The weather on Mars is driven largely by:
condensation & sublimation at the poles
211
T or F. Without an atmosphere, surface temperatures on a planet are set by its distance from the Sun, how much sunlight it absorbs & its rotation rate
True
212
The Earth's climate stays relatively stable due to:
the feedback processes that counter warming or cooling trends
213
The thermosphere is where
solar x-rays are absorbed
214
How does the greenhouse effect warm a planet?
By the atmosphere absorbing & re-admitting infrared radiation
215
3 primary sources of atmospheric gases are:
outgassing, evaporation & surface ejection
216
A magnetic field protects am atmosphere by shielding it from
solar wind
217
What is one of the main reasons the atmosphere on Mars changed?
Mars has too little gravity to hold an atmosphere
218
How many convection cells per hemisphere does the Coriolis effect cause Earth to have
3
219
What processes remove gases from the atmosphere and keep them trapped on the planet's surface?
chemical reactions & condensation
220
The troposphere is where:
Greenhouse warming & weather changes take place
221
The stratosphere is where:
the ozone absorbs ultraviolet light
222
On the Earth, most of the outgassed carbon dioxide is converted to:
limestone
223
What is an atmosphere?
A layer of gas surrounding a world
224
Why is the sky blue?
Blue light is the most likely to be scattered so we can see it from all directions
225
What led to the ultimate runaway greenhouse effect on Venus?
Distance from the Sun
226
Jupiter’s moon Europa may have a deep, liquid water ocean under its icy crust due to:
Tidal heating
227
Which Jovian planets have magnetospheres?
Jupiter, Saturn, Uranus, Neptune
228
Neptune's moon Triton has:
a geologically young surface
229
The rings of Jovian planets have particles that are a result of:
dismantling of small moons
230
How many times stronger is Jupiter’s magnetic field compared to that of Earth’s?
20,000 times
231
Saturn's moon Titan shows:
thick atmosphere & hydrocarbon lakes
232
Saturn's rings are made up of:
objects ranging from the size of dust grains to boulders
233
Uranus and Neptune are made mostly of:
hydrogen compounds with metals & rock
234
The Great Red Spot is:
a high-pressure storm
235
The Jovian planets are squashed due to:
rapid rotation
236
The cores of the Jovian planets differ in their:
rotation rates
237
Within the rings of Jovian planets, on average, how long does it take for basketball-sized particles to ground to dust?
5*10^7 (50 million) years
238
Within the rings of Jovian planets, on average, how long does it take for basketball sized particles to ground to dust?
REVIEW QUESTION
hydrogen & helium
239
Jupiter’s moon Io has its interior primarily kept hot by:
tidal heating
240
On average, collisions between objects within Saturn’s rings happen every:
every few hours
241
Jupiter’s zones and belts correspond to:
clouds of different compositions at different heights
242
T or F. Icy volcanism can occur at low temperatures.
True
243
Moons within & beyond the rings of Jovian planets create:
gaps
244
The Iridium layer is:
rich in iridium & soot found worldwide
245
Impacts in the solar system are usually linked to the gravitational influence of:
Jupiter
246
Processed meteorites are:
fragments of planetesimals
247
T or F. In the Kuiper belt, Pluto is one of the largest icy dwarf planets
True
248
We observed the impacts of comet Shoemaker-Levy 9 on:
Jupiter
249
Approximately how many small bodies are orbiting the Sun?
Trillions (10^12)
250
The fragments in the asteroid belt did not form a planet because:
Orbital resonances kept occurring with Jupiter
251
T or F. Comets come from the Kuiper Belt and the Oort cloud.
True
252
On average, a 10-km-sized object impacts Earth every:
10^8 (100 million) years
253
On average, a 1-km sized object impacts Earth every:
10^6 (million) years
254
How many years ago did a major impact coincide with the mass extinction of dinosaurs?
65*10^6 (65 million)
255
Primitive meteorites are valued because they are:
original material from the solar nebula
256
On average, a 10-meter sized object impacts Earth every:
year
257
When do meteor showers occur?s
When the earth passes through the path of a comet
258
T or F. Jovian planets have more moons than a terrestrial planet
True
259
What is the weather like on Jovian planets?
Multiple cloud layers, fast winds & large storms
260
What are comets famous for delivering to Earth
A significant fraction of the current supply of water
261
How is Io's interior kept hot?
tidal heating
262
Why are zonal winds on Jovian planets stronger than those on terrestrial planets?
The Jovian planets rotate faster
263
What is a similarity between Europa and Titan?
They are both targets in the search for life
264
What is one reason for Pluto to be classified as a dwarf planet?
It has not cleared the neighborhood of its orbit
265
Why did materials in the asteroid belt not form a planet?
It was prevented by orbital resonances with Jupiter
266
What is the main reason for the different colors of the clouds on Jupiter?
Its composition
267
How many tails does a comet have?
2
268
Astrometry is best for finding massive planets that are:
Very close to their host stars
269
T or F. Most known exoplanets orbit far from their stars and have large rotation axis tilts.
False
270
Most of the Hot Jupiters were probably:
born on Jovian-like orbits & migrated inwards
271
How many times brighter are stars typically when compared to the light reflected from a planet orbiting it?
10^9 times
272
How do most of the known exoplanets differ from Earth?
They are more massive
273
Which method does the NASA's Kepler mission use to find other Earths?
Transit photometry
274
Transit Photometry:
detects the periodic dimming of the star due to a planet crossing
275
The Doppler Method detects:
the periodic shift in a star's spectrum
276
T or F. The overall exoplanet situation for known exoplanetary systems is remarkably unlike what we find in our solar system.
True
277
Direct Imaging
Takes a picture of the orbiting planet
278
Which exoplanetary detection method can most easily be used with amateur telescopes?
Transit photometry
279
Astrometry detects:
the periodic wobble of the stars position
280
The habitable zone is the region where a planet can exist around a star where:
It's the right temperature to have liquid water
281
T or F. Humans know if Earth-like planets are rare or common.
False
282
Chemical rockets could reach maximum speeds of about:
0.1% the speed of light
283
Nuclear fusion rockets could reach maximum speeds of about:
10% the speed of light
284
Light sails could reach maximum speeds of about:
50% the speed of light
285
Which of these signals from Earth could most easily be detected by intelligent life on nearby stars?
Radio & TV waves intended for communication of Earth
286
The Miller-Urey experiment showed that if materials matching the chemical composition of the Early Earth are put in a sealed container and energy is added to it (sparks from lightning), then we would observe:
the formation of organic molecules
287
T or F. The Voyager record contains music, pictures of Earth, and greetings in many languages.
True
288
What is one of the spacecrafts from Earth that intentionally included messages to extraterrestrials?
Pioneer
289
In general, life on Earth seems to require only three things:
Nutrients, a source of energy & liquid water
290
What is the Waterhole?
A range of radio wavelength between the 21 cm line of hydrogen & the 18 cm line of hydroxyl
291
According to fossil evidence, approximately how many years ago did life originate on Earth?
3.5*10^9 years ago
292
The most likely method of contact with extraterrestrial intelligence is:
Radio waves
293
The Drake equation gives an estimate for the number of:
civilizations that we could communicate with in the Milky Way
294
Matter-antimatter rockets could reach maximum speeds of about:
90% the speed of light
