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Astro 103 Exam 1
Cerritos, not sure if this is all correct
228
Astronomy
Undergraduate 1
02/14/2017
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Term
Which unique quality distinguishes human beings from other living things?
 Definition

 

curiosity, the need to explore and understand our surroundings
Term
Astronomy
 Definition
has had important practical applications including the development of Newtonian mechanics, on which much of modern technology is based.
Term
The intellectual foundation of science is
 Definition
observation, logic, and skepticism.
Term
In science, if new observations disagree with a well-established theory then
 Definition
the observations must be discarded.
Term
The scientific method is a major force in science and has been developed to ensure that
 Definition

 

theories about physical phenomena agree with what we find in experiments and observations.
Term
According to the scientific method, a hypothesis that is proposed to explain a particular physical phenomenon is considered wrong if
 Definition
it is in conflict with the results of just one reliable and repeatable observation.
Term
The laws of physics developed in laboratories on Earth are generally assumed to be valid
 Definition
everywhere in the universe.
Term
Which of the following is not considered to be part of our solar system?
 Definition

 

the Orion Nebula
Term
New stars appear to be formed i
 Definition
nebulae.
Term
The lifetime of a typical star (like our Sun) appears to be
 Definition
a few billions of years.
Term
Heavy elements, such as those throughout Earth and within our bodies, appear to have been formed
 Definition
deep inside some now-vanished sta
Term
Astronomers sometimes announce they have discovered a new solar system beyond our own, or a new galaxy beyond our own. Which choice correctly describes the terms “solar system” and “galaxy”?
 Definition
A solar system consists of planets and other objects orbiting around a star, whereas a galaxy is a system consisting of an immense number of stars.
Term
In angular measurements used in astronomy, how many right angles are there in a full circle?
 Definition
four
Term
An arcsecond is a measure of
 Definition

 

angle.
Term
One arcsecond is equal to
 Definition

 

1/3600°
Term
One arcminute is equal to
 Definition
1/60
Term
The mean distance of Jupiter from the Sun, 778,300,000 km, can be written in shorthand notation as
 Definition
7.783 × 108 km
Term
0.0064 meter is
 Definition
6.4 mm
Term
The number five hundred thousand is written in powers-of-ten notation as
 Definition
5 × 105
Term
An astronomer is measuring the brightness of a star using infrared light of wavelength 7.8 μm. This corresponds to a wavelength of
 Definition
7.8 millionths of a meter
Term
An astronomer finds an object at a distance of 6.8 AU from Earth. Based on the distance, which of the following is this object most likely to be?
 Definition
a comet in our solar system
Term
If a radio message were sent toward the nearest star to the Sun and a reply were sent back immediately on receipt of the message by intelligent beings from a planet near that star, how long after transmission would we have to wait for a reply?
 Definition
8.6 years
Term
In 2004, an inhabitant of a planet orbiting a distant star observes the flash of the first nuclear explosion on Earth, which occurred in July 1945. Approximately how far away is his solar system from Earth?
 Definition
17.1 pc
Term
If an extraterrestrial being were to send a signal to Earth immediately to confirm the sighting in 2004 of a nuclear explosion on Earth in July 1945, and we were ready to receive such a message, when would we expect it? (Note to instructors: This question is linked to the previous question.)
 Definition
2063 A.D.
Term
The following distance units, arranged in size from smallest to largest, are
 Definition
km, AU, ly, pc
Term
How long does it take light to travel from the Sun to Earth? (There are 3.15 × 107 seconds in one year.)
 Definition
nine minutes
Term
We know the properties of hydrogen atoms well from studying them in laboratories on Earth. A fundamental idea in astronomy is that
 Definition
a hydrogen atom anywhere else in the universe is the same as it is here.
Term
The element helium was discovered (through spectroscopy) in the atmosphere of the Sun before it was discovered in trace amounts on Earth. This was possible because
 Definition
all helium atoms in the universe are believed to be fundamentally the same.
Term
The study of galaxies gives astronomers important clues about the
 Definition
creation of the universe.
Term
A scientist observes a new phenomenon that disagrees with the scientist's own explanation or hypothesis. Following the scientific method, the correct procedure is to
 Definition
accept the disagreement as part of the fundamental incomprehensibility of the universe.
Term
In applying the scientific method to the study of our natural surroundings, scientists are
 Definition
formulating hypotheses or models that describe the present observations of nature and that predict possible further tests for these models.
Term
The most important reason for exploring other planets is that
 Definition
it allows us to understand our own planet more thoroughly
Term
In our exploration of the solar system, we have sent spacecraft intended to land on or fly past
 Definition
meteorites.
Term
The lifetime of our Sun is estimated to be about
 Definition
12.5 billion years.
Term
The number of degrees in a full circle is
 Definition
360.
Term
The Moon's angular diameter in our sky is measured to be half of a degree. From this, we can find the
 Definition
diameter of the Moon in kilometers if we know the Moon's distance
Term
One astronomical unit, or one AU is defined as the
 Definition
mean distance between the Sun and Earth.
Term
In our exploration of the solar system, we have sent spacecraft intended to land on or fly past
 Definition
all planets from Mercury to Neptune as well as Pluto
Term
One light-year is the
 Definition
distance that light travels in one year
Term
An astronomer finds an object at a distance of 5.6 pc from Earth. Based on the distance, which of the following is this object most likely to be?
 Definition
a star in our Galaxy
Term
An astronomer discovers an object at a distance of 28 Mpc from Earth. Based on the distance, which of the following is this object most likely to be?
 Definition
a distant galaxy
Term
What is the distance between Earth and the nearest star? (Think carefully about your answer!) (Check the list of stars in the Appendix 4 of Universe, 10th ed.)
 Definition
1 AU
Term
Which of the following statements best represents the overall rationale for scientific investigation?
 Definition
Reality is comprehensible, and a limited number of fundamental principles govern the nature and behavior of the universe.
Term
An underlying theme of astronomy is that the
 Definition
entire universe is governed by a single set of fundamental physical laws
Term
Which of the following was not obtained by people of ancient civilizations from observations of the night sky?
 Definition
the relative distances of Sun, Moon, and stars from Earth
Term
Meaningful observations of the sky by ancient peoples
 Definition
were made in regions throughout the world.
Term
In modern astronomy, the constellations are
 Definition
88 regions of sky, covering the entire sky.
Term
Constellations are generally made up of stars that are
 Definition
merely located along more or less the same line of sight as viewed from Earth.
Term
If a star is described as being in the constellation Leo, a modern astronomer knows that it is
 Definition
somewhere in a particular region of sky having definite boundaries.
Term
Which of the following statements correctly describes the relationship between stars and constellations?
 Definition
Every star is located in a constellation.
Term
The constellation whose stars are used as pointers to the north celestial pole in the northern hemisphere is
 Definition
Ursa Minor, the Little Bear, containing the bright star Polaris
Term
The Summer Triangle, a group of three bright stars in the summer sky, consists of Deneb, Altair, and
 Definition
Vega.
Term
The nightly motion of objects across our the sky is caused by the
 Definition
rotation of Earth on its axis.
Term
A star rises at 8 P.M., moves across the sky (crossing high overhead), and then sets at
 Definition
8 A.M.
Term
The most readily observed east-to-west motion of objects in the night sky is caused by the
 Definition
rotation of Earth on its axis
Term
What basic pattern do stars seem to trace out in our sky if you watch (or photograph) stars near the north celestial pole for a period of several hours?
 Definition
circles, with the north celestial pole at the center
Term
Which way are you moving with respect to the stars during the rotation of Earth?
 Definition
eastward
Term
In late September, Andromeda appears high in the sky at midnight. Six months later Virgo appears high in the sky at midnight. Where is Andromeda at this time?
 Definition
It is high in the sky at noon and is thus not visible.
Term
Cygnus appears high in the sky at midnight in July. Andromeda appears high in the sky at midnight in September. (See Figure 2-5 of Universe, 10th ed.) Where is Andromeda at midnight in July?
 Definition
It has moved to the eastern horizon.
Term
Which of the following points remains fixed in the sky relative to an observer's horizon?
 Definition
north celestial pole
Term
Which of the following directions remains fixed in the sky relative to an observer's horizon?
 Definition
zenith
Term
How much of the overall sky is north of the celestial equator, that is, in the northern hemisphere?
 Definition
exactly one half
Term
The celestial equator is defined as the
 Definition
extension into space of Earth's equator.
Term
Which of the following lines or points is always directly over your head, no matter where on Earth you go?
 Definition
zenith
Term
The celestial coordinate system of declination and right ascension
 Definition
can be used to assign coordinates to any direction in the sky.
Term
If you view the sky from twenty degrees north of the equator, the north circumpolar stars (which do not rise and set) would be
 Definition
the stars within 20° of Polaris, the north star.
Term
You are standing at a position 45° north of the equator, and you view the stars rising above the horizon. They will move in a direction that makes a slant with the horizon. The direction of this slanted path is from the horizon to the
 Definition
southwest.
Term
The elevation angle between the northern horizon of a fixed observer and the north celestial pole is equal to
 Definition
the observer's latitude
Term
The celestial coordinates that together describe a star's position precisely and unambiguously are
 Definition
right ascension and declination.
Term
The declination angle between the north celestial pole and the celestial equator is
 Definition
90°.position north or south of the celestial equator along a great circle passing through the north and south celestial poles.
Term
The right ascension of a star is one coordinate of its position, measured along the
 Definition
celestial equator.
Term
At what approximate value of declination was the Sun on March 21 this year?
 Definition
At what approximate value of declination was the Sun on June 21 this year?
Term
At what approximate value of declination was the Sun on September 22 this year?
 Definition
0°
Term
At what approximate value of declination was the Sun on December 21 this year?
 Definition
–23.5°
Term
At what approximate value of right ascension was the Sun this year on March 21?
 Definition
0 hours
Term
At what approximate value of right ascension was the Sun this year on June 21?
 Definition

 

6 hours
Term
At what approximate value of right ascension was the Sun this year on September 22?
 Definition
12 hours
Term
At what approximate value of right ascension was the Sun this year on December 21?
 Definition

 

18 hours
Term
The difference in declination angles between the north and south celestial poles is
 Definition
180°.
Term
The declination of Polaris, the north pole star, when viewed from a location 35° north of the equator, is
 Definition
90°.
Term
Where must you stand on Earth to have the celestial equator along your horizon?
 Definition
either pole
Term
Where must you stand on Earth to have the celestial equator pass through your zenith?
 Definition
the equator
Term
The apparent path of the Sun across our sky, day by day, throughout the year, is known as the
 Definition
ecliptic.
Term
The ecliptic is defined as the
 Definition
line traced in our sky by the Sun over one year against the background stars.
Term
The ecliptic crosses the celestial equator at
 Definition
two points, known as equinoxes.
Term
If the daytime sky were not bright, in which direction would we see the Sun move along the ecliptic over the course of a year, relative to the background stars?
 Definition
toward the northwest
Term
What is the primary cause of Earth's seasons?
 Definition

 

Earth's rotation axis tilts with respect to the plane of its orbit around the Sun.
Term
Summertime in the northern hemisphere is when
 Definition
sunlight falls most obliquely on this region of Earth.
Term
It is warmer in summer than winter because
 Definition
the Sun is higher in the sky and the days are longer
Term
When the Sun is at one of the equinoxes,
 Definition
day and night are of equal length only for people on the equator
Term
The autumnal equinox is that time of the year when the
 Definition
Sun crosses the equatorial plane, moving south.
Term
At the summer solstice in the northern hemisphere, the Sun
 Definition
reaches its highest angle above the southern horizon for the whole year.
Term
In winter in the southern hemisphere, the Sun will rise on the
 Definition
northeastern horizon.
Term
Astronomers living north of the Arctic Circle around the time of summer solstice will enjoy which of the following?
 Definition
24 hours of sunlight
Term
If the Sun passes through your zenith sometime during the year, then you must be
 Definition
anywhere within 23.5° of the equator
Term
From the North Pole,
 Definition
only half the celestial sphere can be seen on every clear night
Term
If you were at the South Pole for a full year, what would be the highest angle the Sun would reach above your horizon (at midday, of course)?
 Definition
23.5°
Term
The zodiac is a
 Definition
band of sky extending 8° on either side of the ecliptic.
Term
Precession is
 Definition
a very slow conical motion of Earth's axis of rotation.
Term
The slow coning pattern of the spin axis of Earth's precession will move the end of this axis in a complete circle in a period of
 Definition
1 year.
Term
Earlier in this chapter we discussed some ancient buildings that were constructed so that they were aligned to the rising of the Sun at vernal equinox or some other important astronomical date. How does the precession of the equinoxes affect these alignments in a building, say, 2000 years old?
 Definition
The alignments of such a building should still be perfect.
Term
In one year, the apparent path of the Sun through the background of the stars passes through
 Definition
the 12 zodiac constellations plus the constellation Ophiuchus.
Term
An observer's celestial meridian is the
 Definition
arc joining the north and south celestial poles through the observer's zenith.
Term
A solar day is the time it takes Earth to rotate around its axis between two consecutive solar positions (i.e., high noon to high noon or sunset to sunset). A sidereal day is the time it takes Earth to rotate around its axis between two consecutive positions of a distant star (i.e., Vega on the eastern horizon to Vega again on the eastern horizon). Which is longer?
 Definition
A solar day is always longer
Term
A major theme of Ancient Greek philosophy was that stars and planets in the sky
 Definition
ollowed patterns that could be described logically
Term
The word planet is derived from a Greek term meaning
 Definition
wanderer.
Term
When observing planetary motions from Earth, the phrase “retrograde motion” refers to
 Definition
a slow westward motion of the planet from night to night against the background stars.
Term
An apparent westward motion of a planet from night to night compared to the background stars (as viewed from Earth) is referred to as
 Definition
retrograde motion.
Term
The motions of the planets against the background stars in our sky can best be described as
 Definition
regular patterns, with general eastward motion interrupted by periods of westward motion.
Term
If Mars is moving retrograde it will rise above which horizon?
 Definition


west

     
Term
Ptolemy's model for the solar system was
 Definition
Earth-centered, with epicyclic planetary orbits.
Term
The primary purpose of describing planetary orbits in terms of epicycles and deferents was to account for the
 Definition
pattern of direct and retrograde motion of a planet as it moved slowly against the background of stars.
Term
The deferent in the Greek planetary model is the
 Definition
circle along which each planet's epicycle center moves.
Term
Which of the following most closely expresses the principle of Occam's razor as it applies to theoretical explanations of physical phenomena?
 Definition
The theory requiring the fewest assumptions is the most likely explanation.
Term
If you were observing Earth's motion from another planet, would you observe occasional retrograde motion?
 Definition
Yes, from any of the planets.
Term
The geocentric model for the solar system became unsatisfactory to astronomers compared with the heliocentric model early in the sixteenth century. Each of the following is part of the explanation for this except one. Which is the exception?
 Definition
Observations by spacecraft proved that all planets orbited the Sun.
Term
Copernicus lived
 Definition
after Ptolemy but before Kepler.
Term
Nicolaus Copernicus was the first person to
 Definition
develop a mathematical model for a Sun-centered solar system.
Term
Copernicus'ss nationality was
 Definition
Polish
Term
When Venus is at inferior conjunction,
 Definition
it is at its smallest distance from Earth.
Term
A planet is observed (through a telescope) to have a crescent shape whenever it is close to
 Definition
inferior conjunction.
Term
How will the illuminated side of Mars appear to us when it is at opposition?
 Definition
a full circle
Term
When a planet is seen at opposition, it is always near its
 Definition
closest point to Earth.
Term

 

When Jupiter is at opposition, it rises at
Definition
sunset.
Term
When observed at greatest eastern elongation (see Figure 4-6 of Universe, 10th ed.), Venus is about 45° from the Sun. How long after sunset does Venus set on the western horizon?
 Definition
about 3 hours
Term
Where and when would Jupiter be seen from Earth when it is at opposition?
 Definition
high in the south at midnight
Term
The synodic period of a planet is the time between
 Definition
successive alignments of Sun, planet, and Earth (e.g., time between successive oppositions).
Term
Which one of the following statements about Copernicus'ss system of planetary motion is correct?
 Definition
It used uniform circular motion.
Term
The reason why Copernicus's heliocentric theory eventually came to be regarded as preferable to the geocentric theory of Ptolemy is that the heliocentric theory
 Definition

 

accounted for the same observed motions of the planets as the geocentric theory but did so in a much simpler way.
Term
Tycho Brahe
 Definition
made accurate measurements of planetary positions, which Kepler later used to find the shapes of planetary orbits.
Term
Kepler's laws describe the
 Definition
motions of the planets around the Sun.
Term
Kepler's first law states that the orbit of a planet about the Sun is a(n)
 Definition
ellipse with the Sun at one focus.
Term
If an object's orbit around the Sun has an eccentricity of 0.1, then the orbit is
 Definition
almost circular.
Term
Kepler's second law states that a planet moves fastest when it
 Definition
is closest to the Sun.
Term
How many moons of Jupiter were seen by Galileo?
 Definition
4
Term
Which one of the following relationships represents Newton's most important contribution to physics?
 Definition
the relationship between force and motion
Term
What was the most important contribution of Newton to the development of astronomy?
 Definition
He showed that astronomical phenomena can be explained using only basic physics and mathematics.
Term
To specify an object's velocity completely, we need to specify
 Definition
its speed and direction of travel.
Term
I have a massive purple object in my laboratory. If I were to take it to the Moon, which of its characteristics will be guaranteed to change?
 Definition
weight
Term
The strength of gravity on Mars is about 40% of that on Earth. If you were to visit Mars, what would happen to your mass and weight compared to when you were on Earth?
 Definition
Your mass would be the same but your weight would be less.
Term
Compared with your mass on Earth, your mass out in space among the stars would be
 Definition
the same.
Term
According to Newton's laws, a force must be acting whenever
 Definition
an object is moving with some speed.
Term
Newton, in his second law of motion, stated that any body of mass m acted on by a force F
 Definition
will be given an acceleration a, of size a = F/m.
Term
Two spaceships that have different masses but rocket engines of identical force are at rest in space. If they fire their rockets at the same time, which ship will speed up fastest?
 Definition
The one with the lower mass will speed up fastest.
Term
A horse is dragging a loaded sled across a field. Which of the following pairs of forces is an action–reaction pair as described by Newton's third law?
 Definition
the force of the horse on the sled and the force of the sled on the horse
Term
The action and reaction forces referred to in Newton's third law of motion
 Definition
act on the same body
Term
Which one of the following statements describes the Newtonian understanding of the mechanics of the solar system?
 Definition
The natural motion of the planets is motion in a straight line. They are prevented from straight line motion by the gravitational force of the Sun.
Term
A body moves through space with a certain speed. How many forces are needed to make this object move in a circle?
 Definition
only one, toward the center of the circle
Term
Newton stated that a constant force continuously applied to a body in space would give it a
 Definition
constant acceleration.
Term
Imagine a 10-kilogram rock speeding through empty space at 200 meters per second, so far away from other objects that there is no gravitational force (or any other outside forces) exerted on the rock. What is the rock's subsequent motion?
 Definition
The rock will continue to move in a straight line at 200 meters per second
Term
Earth exerts a force on you as you stand on its surface. What is the size of the force exerted on Earth by you, when compared to the above force?
 Definition
the same
Term
The law of gravitation expounded by Newton for the force F between two objects of masses M and m with separation (between centers) of R is given, with G being a constant, by
 Definition
F = GMm/R2
Term
Suppose that a planet of 10 times the mass of Earth were orbiting the Sun at the same distance as Earth (1 AU). The gravitational force on this planet due to the Sun would be
 Definition
10 times that on Earth due to the Sun
Term
Suppose that an object is discovered moving around the Sun once every 120 years. Which of the following paths is a possible orbit for this object?
 Definition
ellipse
Term
Which of the following conic sections can be considered to be a closed path in which an object could move in a stable long-term orbit around the Sun?
 Definition
ellipse
Term
A hyperbola is
 Definition
an open curve of infinite length.
Term
Imagine a cannonball shot straight upward. At its highest point it stops, momentarily, before falling back to earth. At this highest point, what forms of energy does it possess?
 Definition
he energy is entirely gravitational potential energy.
Term
Consider a spacecraft in a circular orbit. Suppose a rocket thruster is fired, increasing the speed of the spacecraft. What will be its subsequent orbit? (See Figure 4-22, Universe, 10th ed.)
 Definition
The eccentricity of the orbit will increase, but the semimajor axis will stay the same.
Term
The period in Kepler's third law, P2 = a3, is measured in
 Definition
sidereal years
Term
In the years after Newton published his laws of motion, it was found that the observed positions of the planet Uranus did not match the predictions of Newton's theory. The reason for this turned out to be the
 Definition
perturbing effect of Neptune, which at that time had not yet been discovered.
Term
Who predicted the existence of the planet Neptune before it was discovered observationally?
 Definition
Adams and Leverrier
Term
The Moon produces tidal disturbances on the oceans of Earth. In general, there are
 Definition
one high tide and one low tide per month.
Term
The gravitational pull of the Sun on the Moon is stronger than the gravitational pull of Earth on the Moon. Which of these is more important in raising tides on the Moon?
 Definition
Earth is more important in raising tides on the Moon because the difference between the near-side and far-side forces caused by Earth is greater than the difference between the near-side and far-side forces caused by the Moon.
Term
uppose we are having an exceptionally strong tide (a spring tide) right now. Approximately how long do we have to wait until we experience an exceptionally weak tide (neap tide)?
 Definition
one week
Term
The water on the side of Earth that faces away from the Moon experience
 Definition
a high tide because the Moon in effect pulls the solid Earth out from under the water on the far side
Term
Sometimes high tides are lower than at other times. What name is given to the lowest high tides?
 Definition
neap tides
Term
What are spring tides?
 Definition
high tides that are significantly higher than the average high tide
Term
When do neap tides occur?
 Definition

 

whenever Earth-Moon line makes a 90° angle to Earth-Sun line
Term
If you were going to send a spacecraft to circle the Moon and photograph the entire far side (the side not visible from Earth), during which lunar phase (as seen from Earth) would you do the photography?
 Definition
new moon
Term
How much of the total surface of the Moon is illuminated by the Sun when it is at crescent phase?
 Definition
half
Term
Why do we see different phases of the Moon?
 Definition
The motion of the Moon in its orbit around Earth causes us to see different amounts of Earth's shadow falling on the Moon.
Term
What is the one major difference between the Sun and the Moon in our sky?
 Definition
The Sun emits light while the Moon merely reflects it.
Term
Where in the northern hemisphere can you see the true astronomical new moon?
 Definition

 

the Moon is not visible at new moon
Term
At what approximate time will the new moon rise?
 Definition
sunrise
Term
Which way will the “horns,” or sharp ends of the crescent, of the Moon point in the sky when the Moon is above the western horizon at sunset, at a phase 3 days after new moon? (Hint: Think about what causes the crescent phase of the Moon; Figure 3-2 of Universe, 10th ed., may help.)
 Definition
away from the Sun, eastward
Term
Which of the following phases of the Moon is most easily seen during the daytime (mid-morning or mid-afternoon, not near sunrise or sunset)?
 Definition
quarter
Term
How much of the total surface of the Moon is illuminated by the Sun when it is at quarter phase?
 Definition
one half
Term
When the Moon is in its gibbous phase, the positions of Moon, Earth, and Sun are such that the
 Definition
Moon is farther from the Sun than is Earth.
Term

 

The gibbous phase of the Moon occurs when the Moon passes
Definition
from first quarter to full moon.
Term
A full moon always occurs
 Definition
when the Moon is farther from the Sun than is Earth.
Term
The Moon would not go through phases if
 Definition

 

it took one year to go around Earth.
Term
Which one of the following affects the rate at which the Moon goes through its phases?
 Definition
the rotation period of Earth about its axis
Term

 

If the Moon is now in its waxing crescent phase, two weeks from now it will be
Definition

 

waxing gibbous.
Term
You are standing in the middle of the far side of the Moon.  Which one of the following statements about what you can and cannot see would be true?
 Definition
You could never see Earth from that location.
Term
When viewed from a point directly above the plane of the planetary system, the Moon would appear to rotate on its axis
 Definition
not at all, since on Earth we always see the same face.
Term
If astronauts landed on the Moon near the center of the visible surface at full moon, how many Earth days would pass before the astronauts would experience darkness on the Moon?
 Definition
one week
Term
The term “synodic month” refers to the
 Definition
time over which the Moon completes one orbit around Earth, relative to the stars.
Term
The Moon moves eastward in its orbit.  It always keeps the same face toward Earth.  This means that it
 Definition
does not rotate
Term

 

Eclipses of the Moon can occur only
Definition
in the spring and fall, when the Sun is on the ecliptic plane.
Term
During a solar eclipse, the
 Definition

 

Moon comes between Earth and the Sun.
Term
Which of the following conditions holds for relative distances during a solar eclipse?
 Definition
The Moon is closer to the Sun than is Earth.
Term
In a period of 1 month, the Moon moves across the sky
 Definition
along a plane that is neither the ecliptic plane nor the celestial equator, nor is it parallel to the horizon.
Term
The Moon's location in our sky
 Definition

 

is confined to a band of sky around the ecliptic, the zodiac.
Term
A lunar eclipse does not occur at every full moon because
 Definition
the plane of the Moon's orbit is at an angle to the plane of Earth's orbit.
Term
You travel to an exotic place to observe a total solar eclipse in December and someone on this trip tells you that the next eclipse to occur on Earth will be a lunar eclipse in March. Is this likely to be true?

 Definition
no
Term
During a total lunar eclipse, the Moon is
 Definition
barely visible because of light passing through Earth's atmosphere.
Term
When in total lunar eclipse, the Moon shows a reddish color because
 Definition

 

the red part of the solar spectrum, predominantly, is deflected onto the Moon by Earth's atmosphere.
Term
Which of the following factors makes it far more likely that a person will have seen a total lunar eclipse than a total solar eclipse?
 Definition
A total lunar eclipse can be seen by people on most of the nighttime side of Earth, while a specific total solar eclipse can be seen only by people within a narrow strip of Earth's surface.
Term
A person standing in the Moon's penumbra will see a
 Definition

 

partial solar eclipse.
Term
What is the maximum time of totality for any total solar eclipse observed from Earth's surface?
 Definition
about 7.5 minutes
Term
Which of the following parameters will dictate whether a particular solar eclipse appears as a total or an annular eclipse to an observer on the centerline of the Moon's shadow?
 Definition
the distance of the Moon from Earth at the time of eclipse
Term
During the particular solar eclipse, when the Moon and Sun are precisely in line, the eclipse can be either total (Sun completely covered) or annular (Sun not quite covered) when viewed from the eclipse centerline because
 Definition

 

the Moon's distance from Earth varies from eclipse to eclipse.
Term
An observer can see a total solar eclipse from within a narrow band along Earth's surface.  This band
 Definition

 

can begin almost anywhere on Earth's surface.
Term
What is the cause of an annular eclipse?
 Definition
The Moon's position in its orbit is near apogee, its farthest point from Earth.
Term
The saros is the period of time between
 Definition
successive solar eclipses in a series of similar eclipses at about the same latitude on Earth.
Term
How does the duration of a total solar eclipse compare with the duration of a total lunar eclipse?

 Definition
The lunar eclipse is always longer
Term

 

The Greek astronomer who first measured the radius of Earth reasonably accurately was
Definition

 

Eratosthenes.
Term
Eratosthenes measured the radius of Earth by
 Definition
noting the different angles of the Sun at midday on the same day of the year at different positions on Earth.
Term

 
In about 280 B.C., Aristarchus devised a method of estimating the relative distance of the Sun and the Moon from Earth by
Definition
measuring the angle between the Sun and Moon when the Moon is at first or third quarter.
Term
How did the ancient Greek astronomer Aristarchus of Samos determine that the Moon's diameter was about 1/3 that of Earth?
 Definition

 

by measuring the time it takes the Moon to move through Earth's shadow during a lunar eclipse
Term

 
One of the most significant achievements of the ancient Greeks was the
Definition
precision with which they measured the distances of Sun and Moon from Earth.
Term
At the ancient Egyptian city of Syene the Sun was directly overhead only at summer solstice.  Thus, Syene must have been very close to the
 Definition
Tropic of Cancer.
Term
You face the Moon from a position in the northern hemisphere and observe that the right half is illuminated and the left half is dark.  What phase are you observing?
 Definition

 

first quarter
Term
What is the phase of the Moon when it rises at midnight?  You may want to sketch a diagram to work this out.  Earth rotates toward the east, and the Moon's motion around Earth is also eastward.
 Definition

 

third quarter
Term
When will the first quarter moon rise, approximately? (You may want to examine Figure 3-2 of Universe, 10th ed., and think about where you would need to stand on Earth to see the first quarter moon rising.)
 Definition
noon
Term
At what approximate time does a full moon rise?
 Definition

 

sunset
Term
A full moon is always at its highest in our sky at
 Definition

 

midnight.
Term
A full moon will be on the horizon at
 Definition

 

sunrise or sunset.
Term
When does the third quarter moon rise? (You may want to examine Figure 3-2 of Universe, 10th ed., and think about where you would need to stand on Earth to see the third quarter moon rising.)
 Definition
close to midnight
Term

 
The Moon is visible in the sky in the daytime from most places on Earth
Definition
about half the time, or for two weeks in every month.
Term
Suppose the moon orbited Earth with the same period it has now but in the opposite direction. Which one of the following would not change?
 Definition

 

the length of a sidereal month
Term

 

If an observer on Earth sees the Moon to be full, than at the same time an observer on the Moon would see Earth to be at what phase?
Definition

 

new
Term

 

If an observer on Earth sees the Moon to be at first quarter, then at the same time, an observer on the Moon would observe Earth to be at what phase?
Definition

 

third quarter
Term
If the Moon is now in its waxing crescent phase, a week ago it was
 Definition
waning crescent.
Term

 
In its orbit around Earth, the Moon
Definition
always keeps the same side toward Earth.
Term
To observers on Earth, the Moon shows
 Definition
only one side to Earth at all times.
Term

 

If you were standing on the Moon in darkness on the opposite side from Earth at a particular time, which of the following conditions would be true?
Definition
You would never see Earth from that position.
Term
The term “sidereal month” refers to the
 Definition
time over which the Moon completes one orbit around Earth, relative to the stars.
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