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Final Exam
Troland
108
Astronomy
Undergraduate 2
12/10/2009

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Cards

Term
How many stars exist in the Solar System?
Definition
1
Term
Which object below is not a member of the Solar System?
Definition
Proxima Centauri
Term
The Solar is system is about .... as old as the universe itself?
Definition
1/3rd
Term
The nearest star to the planet Neptune is?
Definition
The Sun
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...? The object is a..?
Definition
the sun, 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 approx... the diameter of the 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 proportionately), 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 around the center of the Galaxy in a nearly circular 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 part of what large 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 system 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 (for example, a stellar explosion) that actually occurred about the time of the birth of Christ. If this event is observed in the present epoch (say, 2009), 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 is 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
South Pole
Term
The city of Melbourne, Australia has latitude of 38* south. Where in the skies of Melbourne would you find the south celestial pole?
Definition
38* above the south point of the horizon
Term
Where on Earth do both the north and south celestial poles lie on the horizon?
Definition
The equator
Term
Which object below was not a "wondering star" identified by ancient astronomers?
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 Scorpia 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.. degrees... in 24 hours as a result of the Earths rotation
Definition
360, westward
Term
The sun appears to move... degrees... in 24 hours as a result of the earths orbital motion
Definition
1, eastward
Term
Constellations of the zodiac (of astrological importance) are different from other constellations in the sky that zodiac constellations
Definition
lie along the ecliptic
Term
The dates of the year associated with the sun signs of astrology are different now from what they were in 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 rises higher above 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. This information was used by ancient astronomers to infer
Definition
that the earth 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 had been mistaken about the distance between alexandria and seyene. In particular, suppose he mistakingly thought the two cities were twice as far as part as they actually are. in this case, his estimate of the diameter of the earth would have been
Definition
two times larger than 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
Approximately how often does the planet jupiter exhibit retrograde motion?
Definition
once per year
Term
In 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 neighbor 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... model, while Copernicus's model is a...model
Definition
Geocentric, heliocentric
Term
What was the significance of Galileo's 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 the tycho brahe to the copernican revolution?
Definition
he measured the positions of the planets relative to the background stars.
Term
which scientists 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
Instruments that allowed for very accurate measurements of the positions of planets relative to the background stars
Term
What is the significance of Kepler's discovery regarding the shapes of planetary orbits?
Definition
they are not circles nor 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 kepler's 1st law, one focus of a planets orbit 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
what is the significance of kepler's second law of planetary motion ("equal areas" law)
Definition
a given planet (earth) 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 third law of planetary motion? (p2=a3)
Definition
planets closer to the sun (mercury) take less time to orbit the sun than planets further from the sun( earth)
Term
According to keplers 3rd law (p2=a3), which planet has the longest period?
Definition
Jupiter
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 acceleration of the vehicle?
Definition
accelerator, brake and steering wheel
Term
suppose an object is falling downward under the acceleration of the earths gravity. If it is moving at 90 m/s at one moment, how fast is it moving 5 seconds later? ( neglect air resistance)
Definition
140 m/s
Term
consider the 4 forces acting upon a train. what force is directed vertically upward?
Definition
the force of the rail on the train
Term
imagine the same force acting upon two objects, 1 and 2. Object 2 has twice the mass of object 1. in this case, the acceleration of object 2 will be.. as that of object 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 will the resulting acceleration be highest?
Definition
10, 2
Term
according to newtons 3rd law of motion, the force pushing you ahead as you dash off down a sidewalk is
Definition
the force of the sidewalk upon you
Term
Suppose a force of 20 newtons is applied to a object having a mass of 4 kilograms. what is the acceleration?
Definition
5 meters per sec per sec
Term
Imagine an object moving in a circle at constant speed ( planet in a hypothetical circular orbit about the sun) 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
"weightlessness" 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 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 kilogram object experiences when dropped is... the acceleration of a 1000 kilogram object
Definition
the same as
Term
if the masses of two objects are each tripled (and all other conditions remain the same) the gravitational force between them will
Definition
increase 9 times
Term
which person experiences weightlessness?
Definition
olympic driver who has just left the spring board
Term
approximately what day of the year in lexington has the greatest number of hours of sunlight?
Definition
june 21
Term
approximately what day of the year in Sidney, Australia has the fewest number of hours of sunlight?
Definition
June 21
Term
the earth is closest to the sun in early january each year. what is the significance of this fact to seasons on earth.
Definition
this fact has very little relevance to seasons on the earth
Term
the spring equinox in Melbourne, Australia 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 say in Melbourne, Australia wold the sun be highest in the sky at high noon?
Definition
December 21
Term
If the earths rotational axis were perpendicular to its orbit ( no tilt) then...
Definition
Polar regions on the Earth would experience about 12 hours of sunlight per day on any day of the year but still be 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 Earth's north pole?
Definition
They trace out circles around the sky at constant angles above the horizon
Term
The cause of the season on earth is..
Definition
The 23 1/2 degree tilt of the Earth's 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 moment... of the surface of the moon is illuminated. This illuminated part of the Moons surface 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 upon the phase of the moon
Term
What is the effect of the earths shadow upon lunar phases?
Definition
The shadow has no effect upon phases of the moon
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 phases 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. This 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 earth?
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 cycle 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. ( the side facing away from the earth?)
Definition
2 weeks
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