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Astronomy Final
Test 1, Test 2, and Last Section
227
Astronomy
Undergraduate 2
12/08/2009

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Term
How many stars exist in the solar system?
Definition
1 ( the sun)
Term
Which object is not a member of the solar system?
-comet haley
-I0 (satellite of jupiter)
-Proxima Centauri
-433 Eros (asteroid between earth & mars orbit)
Definition
Proxima Centauri
Term
The solar system is about _____ as old as the universe itself
Definition
1/3
Term
The nearest star to the planey Neptune is
Definition
Proxima Centauri
Term
Planets are different from stars in that planets...
Definition
are composed mostly of liquid and solid materials.
Term
The most massive object in the Solar System is ____. This object is a _____
Definition
The Sun. A Star.
Term
What planet has a solid surface most affected by the greenhouse effect?
Definition
Venus
Term
What planet does not appear to have a solid surface?
Definition
Saturn
Term
The diameter of the sun is approximatly ____ the diameter of Earth
Definition
100 times
Term
How far does light travel in 10 seconds?
Definition
1,860,000 miles
Term
If the sun is reduced to the size of a ping pong ball (and all other sizes scaled down proportionatly) then the distance to the sun's nearest neighbor star is about.
Definition
700 miles
Term
A light year could also be expressed in terms of what other units?
Definition
Kilometers
Term
What shape most closely resembles the shape of our Milky Way Galaxy
Definition
Fried Egg
Term
The solar neighborhood is defined as
Definition
the region of space in our galaxy including the nearest few tens of thousands of stars
Term
which statement below about the motion of the Solar System in the Galaxy is correct?
Definition
The solar system is moving outward from the center of the Galaxy aling a spiral path.
Term
If the solar system is reduced in size such that the orbit of neptune is about the diameter of a ping pong ball, then the diameter of the milky way galaxy would be about the size of
Definition
North America
Term
The Milky Way Galaxy is apart of what larger system of material?
Definition
The local group
Term
The virgo cluster belongs to what larger system of material
Definition
The local supercluster
Term
which astronomical systems of matter are listed below in order of increasing size?
Definition
Solar Neighborhood, Milky Way Galaxy, Local Group, Local Supercluster
Term
Imagine a sudden astronomical event, that actually occurred about the time of the birth of Christ. If this even is observed int he present epoch, then we can conclude that the event occurred at a distance of about ______ from Earth.
Definition
2000 light years.
Term
If the entire history of the universe collapsed into one year, about when did the solar system form?
Definition
September 1
Term
As seen in Lexington, the north celestial pole appears about where in the sky?
Definition
about 40 degrees above the north horizon point
Term
Imagine a time exposure photograph of the sky in which each star left a trail. Each trail is an arc of about 90 degrees. In this case, the exposure time of the photograph is about
Definition
6 hours
Term
If the sky is represented as a sphere, what fraction of the sphere is above the horizon (in a flat location?)
Definition
1/2
Term
the celestial sphere appears to rotate 360 degrees in
Definition
24 hours
Term
suppose you observe that the south celestial pole is straight overhead, where are you on earth?
Definition
the south pole
Term
The city of Melbourne, Austrailia has a lattitude of 38 degrees south. Where in the skies of Melbourne would find the south celestial pole?
Definition
38 degrees about the south point of the horizon
Term
where on earth do both the north and the south celestial poles lie on the horizon?
Definition
the equator
Term
which object is not a wandering star identified by the ancients?
Definition
Uranus
Term
From the perspective of ancient astronomers, an example of a fixed star is _____ an example of a "wandering" star is ____
Definition
Proxima Centauri, The Sun
Term
THe sun is seen in the constellation Libra in October and in Scorpio in November. Why the change?
Definition
The earth orbits the sun
Term
The path traced out by the sun in the sky over the course of a full year is called the _____
Definition
Ecliptic
Term
The sun appears to move____ degree(s)____ in 24 hours as a result of Earth's rotation.
Definition
360, westward
Term
The sun appears to move ___degree(s)____ in 24 hours a sa resutl of Earth orbital motion.
Definition
1, eastward
Term
Constellations of the zodiac (of astrological importance) are different from other constellations in the sky in that zodiac constellations
Definition
lie along the eliptic
Term
the dates f the year associated with the sun signs of astrology are different now from what they were in the ancient times. This change is the result of the
Definition
wobbling of the earths rotational axis
Term
Owing to its annual apparent motion, about how long does the sun take to "move" from one constellation to the next?
Definition
One month
Term
As a traveler moves north in the northern hemisphere
Definition
the north celestial pole (NCP) rises higher about the horizon
Term
the angle of the north celestial pole above the horizon was known by ancient astronomers to change as a traveler moved north or south. The information was used by ancient astronomers to infer
Definition
that the is spherical
Term
What astronomical phenomenon is caused by the shadow of the earth?
Definition
a lunar eclipse
Term
imagine using Eratosthenes method of estimating the size of the earth based upon two cities along a north-south line. Suppose the sun angle at high noon is 36 degrees different between two cities located 3000 units apart. In this case, the estimated diameter of the Earth is about ____ units
Definition
10,000
Term
suppose eratosthenes has been mistaken about the distance between alexandria and syene. in particular suppose he mistakenly thought the two cities were twice as far apart as they actually are In this case, his estimate of the diameter of earth would have been
Definition
two times larger then the correct value
Term
in modern times, the occasional retrograde motion of mars and other planets is explained by the fact that mars
Definition
moves more slowly in its orbit than earth
Term
aproximatly how often does the planet jupiter exhibit retrograde motion?
Definition
once per 12 years
Term
in the ancient times, the retrograde motion of mars and other planets was explained by the fact that Mars
Definition
moves on a small circle called an epicycle
Term
according to the solar system model of ptolemy, which objects take exactly the same time to go around the earth as does the sun?
Definition
venus and mercury
Term
according to Ptolemy, the ____ is at the center of the solar system, and the ____ is the closest celestial neighborhood to the earth
Definition
earth, moon
Term
in what period did Copernicus publish his book describing a sun-centered Solar system?
Definition
1500's
Term
an important (and physically correct) objection raised by the contemporaries of Copernicus regarding his model of the solar system was that
Definition
nearer stars should shift positions relative to more distant stars if the earth moved about the sun
Term
Ptolemy's model of the solar system is a(n) _____ model, while Copernicus's model is a(n) _____ model
Definition
Geocentric, Heliocentric
Term
what was the significance of Galileos observations of the satellites of Jupiter?
Definition
The observations established that some objects in the solar system do not orbit the earth.
Term
why (according to the model of Copernicus) does Venus always appear close to the Sun in the sky?
Definition
it is closer to the sun than the earth
Term
why were the phases of venus not used as an argument against the Solar System model of Ptolemy prior to the time of Galileo?
Definition
the phases of Venus could not be observed prior to galileo
Term
Careful study of the phases of venus establishes that
Definition
venus orbits the sun
Term
What was the principal contribution of Tycho Brahe to the Copernican Revolution?
Definition
He measured the positions of the planets relative to the background stars
Term
which scientist made use of the astronomical records kept by Brahe to infer important new information about the solar system?
Definition
Kepler
Term
what astronomical instruments did Tycho Brahe construct
Definition
mechanical models of the celestial sphere that predicted future positions of planets relative to the constellations
Term
what is the significance of Kepler's discovery regarding the shapes of the planetary orbits?
Definition
they are not circles, or combinations of circles
Term
the average distance between a planet and the sun is the _____ of the planets orbit.
Definition
semi-major axis
Term
according to keplers 1st law, one focus of a planeys orbits is the location of ____ while the other focus is the location of ______
Definition
The sun, nothing
Term
in general, an ellipse has____ special point(s) within it. These points lie____
Definition
2, along the major axis
Term
in general, an ellipse has____ special point(s) within it. These points lie____
Definition
2, along the major axis
Term
what is the significance of Kepler's second law of planetarymotion (equal areas law)?
Definition
A given planet moves faster in its orbit when it is closer to the sun.
Term
the longest dimension across the orbit of the earth is
Definition
2 astronomical units
Term
what is the significance of Keplers 3rd Law (Psquared=acubed)
Definition
planets closer to the sun take less time to orbit the sun than planeys further from the sun
Term
according to Keplers 3rd law, which planet has the longest period?
Definition
Jupiter (farthest from the sun)
Term
which example below illustrates uniform motion?
Definition
Marathon runner moving along a straight path at a constant speed.
Term
which object is acted upon by no net force?
Definition
elevator moving down the elevator shaft at a constant speed
Term
An appropriate unit of acceleration is ___, an appropriate unit of force is ____
Definition
meters per sec per sec, newtons
Term
consider a train moving along a straight track at a constant speed. What can you conclude about this train?
Definition
the net force acting upon the train is zero.
Term
what controls on an automobile can create an acceleration of the vehicle?
Definition
accelerator, brake and steering wheel.
Term
Suppose an object is falling downward under the acceleration of earths gravity. If it is moving at 90 m/s at one moment how fast is it moving 5 second later
Definition
140 m/s
Term
consider the 4 forces acting upon the train. What force is directed vertically upward?
Definition
the force of the rail on the train
Term
imagine the same force acting upon the two objects 1 & 2. Object 2 has twice the mass of object 1. In this case, the acceleration of object 2 will be ____ as that oject 1.
Definition
one half as much
Term
Imagine that a force of ____ newtons acts upon an object having a mass of ____ kilograms. For which case wil the resulting acceleration be highest?
Definition
10, 2
Term
According to Newotons 3rd law of motion, the force pushing you ahead as you dash of down a sidewalk is
Definition
the force of the sidewalk upon you
Term
suppose a force of 20 newtons us applied to an object having a mass of 4 kg. What is the acceleration?
Definition
5 meters per sec per sec
Term
Imagine an object moving in a circle at a constant speed. In this case, we can conclude that
Definition
there is a net force acting on the object perpendicular to its motion
Term
the weight of an object is defined as the _____. An appropriate unit for weight is the
Definition
Gravitational force acting upon the object, newton.
Term
Your mass on the moon would be ____ your mass on earth. Your weight on the moon would be ____ your weight on Earth.
Definition
The same as, 1/6th
Term
What quantities determine the gravitational force between two objects?
Definition
Masses, distance between their centers
Term
"weightlessnss" occurs for an object when it is
Definition
only subject to the gravitational force
Term
a pound of bread on the moon would contain____ as a pound of bread on the earth.
Definition
6 times as much bread.
Term
If the distance between two objects increases 3 times (with the masses remaining the same) the gravitational force between them will
Definition
decrease 9 times
Term
the gravitational force that the earth exerts upon the sun is ____ the force that the sun exerts upon the earth
Definition
equal to
Term
the acceleration a 10 kg object experiences when dropped is ____ the acceleration of a 1000 kg object.
Definition
the same as
Term
if the masses of two objects are each trippled (and all other conditions remain the same) the gravitational force between them will
Definition
increase 9 times
Term
which person experiences weightlessness
Definition
olympic diver who has just left the springboard
Term
approximatly what day of the year in lexington has the greatest number of hours of sunlight?
Definition
June 21
Term
approximatly what day of the year in Sydney, Austrailia has the fewest number of hours of sunlight?
Definition
june 21
Term
the earth is closest to the sun in early january of each year. What is the significance of this fact to the seasons on Earth?
Definition
this fact has very little relevance to seasons on earth
Term
the spring equinox in melbourne, Austrailia occurs on about what date?
Definition
september 21
Term
on about what day in lexington would the Sun rise furthest south of east?
Definition
December 21
Term
On about what day in Melbourne,Austrailia would be the SUn be highest in the sky at high noon?
Definition
December 21
Term
If the earths rotational axis were perpendicular to its orbit, then
Definition
polar regions on the earth would experience about 12 hours of sunlight per day on any day of the year but still colder than equatorial regions.
Term
Point barrow, Alaska is north of the arctic circle. About how many hours of sunlight does Point Barrow experience in late December.
Definition
none
Term
How do celestial objects move in the sky over 24 hours as seen from the Earths North Pole?
Definition
they trace out circles around the sky at constant angles above the horizon
Term
the cause of the seasons on Earth is
Definition
the 23.5 tilt of the earths axis relative to its orbit
Term
at the earths South Pole where will the sun be in late June?
Definition
about 23 degrees below the horizon
Term
shortly after the new moon, the phase of the moon is said to be
Definition
waxing crescent
Term
suppose the moon is new on about November 1. In this case, we expect the third quarter moon to be visible on about
Definition
november 21
Term
At any given momment,____ of the surface of the moon is illuminated. This illuminated part is of the moons surfaces faces the _____
Definition
One half, the sun
Term
What fraction of the illuminated surface of the moon faces the earth?
Definition
the answer is different depending on the phase of the moon
Term
What is the effect of the earths shadow upon the lunar phases?
Definition
no effect
Term
if the moon sets at sunset, what is the phase of the moon?
Definition
New
Term
imagine that you observe a third quarter moon this evening in Lexington. What phase of the moon would be observed at the same time in Santiago, Chile?
Definition
third quarter
Term
the sea of showers is a prominent dark region on the surface of the Moon. The region always faces the Earth, regardless of the position of the Moon in its orbit about the Earth. Why does the Sea of Showers always face the Eart?
Definition
The moon rotates on its axis in the same time it revolves around the Earth
Term
Imagine living on the Moon. How long would a full cycles of phases of the Earth take to complete?
Definition
about a month
Term
about how long is the sun above the horizon as seen on the far side of the Moon
Definition
2 weeks
Term
Does some hemisphere of the moon always face the earth as the moon orbits the earth?
Definition
yes
Term
So does the moon rotate on its axis at all?
Definition
yes, to keep the same face pointed at Earth, moon must rotate exactly once with every orbit (once in 29.5 days)... this effect is called Synchronous Rotation
Term
the concequence of synchronous rotation
Definition
earth remains motionless in the lunar sky
Term
How long is one day on the moon?
Definition
1 month
Term
Is the far side of the moon always dark?
Definition
no it is completely dark only at a full moon
Term
umbra
Definition
where the sunlight is completely blocked
Term
penumbra
Definition
where the sunlight is partially blocked
Term
solar eclipse
Definition
earth is in the shadow of the moon. the shadow of the moon sweeps across the earth, and the sunlight is blocked.
Term
lunar eclipse
Definition
moon falls into the earths shadow. The moon sweeps through the shadow of the earth.
Term
Coincidences between the moon and the sun
Definition
the sun is 400 times bigger then the moon and also 400 times farther away.
the moon is barely large enough in the sky to completely cover the sun during a total solar eclipse
Term
when a observer can only see a partial solar eclipse they are..
Definition
in the moons penumbra
Term
At what lunar phase is the far side of the moon fully illuminated by the sun?
Definition
New Moon
Term
What phase of the moon is required for a solar eclipse?
Definition
New Moon
Term
What properties of the sun & moon lead to unusually spectacular eclipses of the sun?
Definition
the sun and the moon appear the same size in the sky
Term
Why is a totally eclipsed moon not completely dark?
Definition
earths atmosphere bends(refracts) sunlight into its umbra, so umbra is not completely dark
Term
From where on earth is a total lunar eclipse visible?
Definition
anywhere on the hemisphere facing the moon!
Term
why do we not have eclipses every month?
Definition
moons orbit tilted 5 degrees to earths so proper alighnment does not usually occur.
Term
Sun
Definition
gaseous, diameter is 100xearth, is 99.8% of the mass of the solar system
Term
planets
Definition
much smaller than the sun, less massive than the sun, mostly solid & liquid composition (colder)
Term
Jupiter
Definition
Largest Planet, sun has 10x diameter, sun has 1000x mass
Term
Smaller Objects in the solar system
Definition
satellites and asteroids
Term
saturn
Definition
titan(has a atmosphere)
Term
comet
Definition
is an icy nucleus (dirty iceball), tail faces away from the sun
Term
asteroids & meteroids
Definition
asteroid:range in size of rocks to boulders
meteroids:out in space
meteorite: after its hit earth
Term
Which object is not in the solar system?
Definition
several stars
Term
when a small piece of space debris hits earth it is a
Definition
meteorite
Term
what is not true about the planets
Definition
they are evenly spaced
Term
motions of the solar system
Definition
motions of satellites exhibit many regularities, not required by laws of physics
Term
how are motions of the planets similar?
Definition
revolution
-they all orbit in the same direction
-they orbit in nearly the same plane
-nearly circular orbits
Term
most planets have roation_____ nearly____ to their orbits
Definition
axes, perpendicular
Term
mass
Definition
a measure of resistance of an object being put into motion
Term
units of mass
Definition
gram & kilogram
Term
volume
Definition
a measure of space occupied by an object
Term
units of volume
Definition
cubic centimeters
Term
what is a large object with a small mass?
Definition
beach ball
Term
what is a small object with a large mass
Definition
steel ball
Term
density
Definition
a measure of amount of mass contained in a unit volume
Term
Joviah vs. Terrestrial planets
Definition
inner and outer planets are quite different in properties
Term
inner(terrestrial) planets
Definition
mercury, venus,earth, and mars
Term
outer(joviah) planets
Definition
jupiter, saturn, uranus, and neptune
Term
how are inner and outer planets compare in diameter, mass, avg density, and rotation period.
Definition
diameter=outer is bigger
mass=joviah is bigger
avg. density=inner is bigger
rotation period=inner is longer
Term
when a lunar eclipse is seen on the earth, what is the phase of the earth as seen on the moon?
Definition
new earth, solar eclipse
Term
when the earth views a solar eclipse what is the phase of the earth as seen from the moon?
Definition
full moon, total eclipse of the sun.
Term
geological processes
Definition
change solid surfaces of planets and satellites over time
Term
4 main types of geological processes
Definition
1.volcanism
2.erosion
3.impact cratering
4.tectonics
Term
volcanism
Definition
outflow of molten material onto the surface
Term
tectonics
Definition
large scale movement or deformation of the outer layers
Term
erosion
Definition
wearing away or buidling up of surface by wind, water, and glaciers.
Term
what characteristic of the motions of planets is not required by the basic laws of physics?
Definition
planets all orbit the sun in the same direction
Term
how would you calculate the average density of a planet?
Definition
mass/volume
Term
what planet has the lowest average density?
Definition
saturn
Term
during a total lunar eclipse observed on earth..
Definition
an eclipse of the sun is viewed on the moon
Term
which solar system object is much affected by erosion?
Definition
earth and mars
Term
which solar system object is little affected by erosion?
Definition
the moon and mercury
Term
geological age of a solid surface
Definition
on a planet or satellite, the geological age may vary significantly with location ex) on earth
Term
estimated geological age
Definition
radiosotopic dating of rocks
Term
crater counting on a surface
Definition
assume impacts have occurred throughout history of the solar system. Approx. age can be determined by number of craters.
Term
which regions of the moon are younger and older
Definition
lunar seas: younger
lunar highlands:older
Term
what object in a solar system has a geologically old surface?
Definition
the moon & mercury
Term
what object in the solar system has a geologically young surface?
Definition
earth (very few craters)
Term
what part of the earths surface is geologically youngest?
Definition
the big island of Hawaii
Term
what part of the moons surface is geologically oldest
Definition
the heavily cratered lunar highlands
Term
what planet or satellite has a solid, very geologically young surface?
Definition
the earth
Term
why is the surface of the earth so geologically young compared to that of the moon & mercury?
Definition
volcanically active, erosion, and tectonics
Term
internal heat in planets and satellites
Definition
does not come from the sun, but from 3 other sources.
Term
3 sources of internal heat
Definition
accretion
differentiation
radioactive decay
Term
accretion
Definition
planets and satellites formed by the falling together of smaller object:generates heat
Term
differentiation
Definition
shortly after formation, denser, materials, settled towards center:generates heat
Term
radioactive decay
Definition
generates heat
Term
because of three heating processes, planets, and satellites were very hot right after formation
Definition
with time heat flows out of planets and satellites and they cool off.
Term
which process has not contributed to the internal heat of the earth?
Definition
solar radiation falling on earth
Term
what solar system object below is likely to have cooled of soonest?
Definition
the moon
Term
which solar system object is least likely to have active volcanism at present?
Definition
the moon
Term
how do we know about earths interior?
Definition
not so much from drilling into earth but by the study of seismic waves.
Term
what does the study of seismic waves reveals
Definition
how densities vary in the interior
whether regions in the interior are solid or liquid
Term
the core of planets and satellites
Definition
the highest density
Term
the mantle
Definition
the lower density
Term
crust:
Definition
lowest density
Term
lithosphere
Definition
outermost rigid, different from mantle.. as an object cools the lithosphere thickens.
Term
where in the earth are seismic waves created?
Definition
very close to the surface
Term
what region of the earths interior is densest?
Definition
the inner core
Term
the lithosphere of the earth consists of...
Definition
the crust and the upper mantle only
Term
results of plate tectonics
Definition
mountain chains, many landforms.
Term
colliding plates
Definition
build mountains, convergent plate boundaries.
Term
diverging plates build
Definition
mid-ocean ridges (mid-atlantic ridge) volcanic process
Term
what plate tectonics process is ocurring along the western coast of s. america?
Definition
two plates coming together (converging)
Term
what plate tectonics process is occuring along the mid-atlantic ridge?
Definition
two plates are moving apart (diverging)
Term
what process causes plates of the earths lithosphere to slowly move?
Definition
motions of the material in the earths mantle.
Term
changes in earth from plate tectonics
Definition
arr. of continents has changed dramatically (pangea)
Term
volcanism on earth
Definition
caused by plate tectonics, volcanic mountains, volcanic plains.
Term
erosion on earth
Definition
erosion occurs vigorously from wind, water, and glaciers.wears away surface
Term
impact cratering on earth
Definition
the vast majority of craters have been erased by tectonics & erosion (150 known on earth)
Term
the moon
Definition
two types of terrain
highlands and lowlands(seas)
Term
which type of terrain is older?
Definition
the highlands because they are heavily cratered
Term
how are the earth and the moon alike?
Definition
they both have highlands and lowlands
Term
how re the earth and the moon different?
Definition
moons surface is older
moon has no long mountain chains
moon has no continents fitting together
moons surface has not been affected by plate tectonics
Term
Moon impact cratering
Definition
craters of all sizes... craters upon craters.
Term
What geographical process on Earth is very closely related to plate tectonics?
Definition
volcanism
Term
What part of the earths surface is most similar to the lunar seas?
Definition
the ocean floors
Term
what evidence exists on the moon for the existence of plate tectonics
Definition
no evidence at all
Term
the moon & volcanism
Definition
there is no sign of volcanic mountains on the moon, lunar seas are volcanic plains
Term
only sign of tectonics on the moon
Definition
slight wrinkle ridges
Term
erosion on the moon
Definition
very slow due to micrometeorite bombardment
Term
impact cratering on the moon
Definition
is very extensive
Term
what did the Apollo mission find out about water
Definition
there was no water in any of the soil or rocks brought back
Term
what did the rocks from the lunar seas contain?
Definition
Basalt, or volcanic rock very similar to the rocks found in earths volcanic regions
Term
what did the mission find out about rocks from the highlands
Definition
they were almost as old as the moon, so the highlands were geographically very old
Term
how did the surface of the moon come to look as it does today?
Definition
the surface was heavily cratered, and asteroid strikes the surface.. and the imbrium basis is formed. This period of intense volcanism began 3.8 billion years ago.
Term
the "wrinkle ridges" seen on some areas of the lunar seas are evidence for what geological process?
Definition
tectonics
Term
erosion occurs very slowly on the lunar surface owing to
Definition
micrometeorite bombardment
Term
basalts are a type of _______ rock found in the lunar ______
Definition
volcanic;seas
Term
surface of mars
Definition
thin C02 atmosphere
a few water ice clouds
liquid h20 is not stable on the surface
Term
how are the earth and mars alike and different?
Definition
they both have regions of high and low elevation
diff: mars has no mountains or continents
no plate tectonics
Term
where are the lowlands mostly located on Mars
Definition
in the northern hemisphere
Term
impact cratering on mars
Definition
craters are in the Southern Hemisphere nearly as plentiful as in the lunar highlands
Term
volcanism on mars
Definition
northern plains of mars. enormous shield volcanoes on Tharsis Bulge. Olympus Mons. Lowlands are volcanic plains
Term
Tectonics
Definition
extensive long ago, in a vertical motion. Created Mariner Valley: ancient fault associated with the formation of the Tharsis bulge.
Term
erosion on mars
Definition
wind erosion,eroded craters
Ancient water erosion: channels
-when h20 was present and the climate was warmer
light wind erosion is still present
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