Astronomy Chapter 2

The Moon's angular width is A) 1/2 degree. B) 1/2 arcminute. C) 1/2 arcsecond. D) it changes, growing larger at the horizon.

A) 1/2 degree.

How many arcseconds are in one arcminute? A) 60 B) 360 C) 3600 D) 100 E) 10,000

A) 60

How does Earth's varying distance from the Sun affect our seasons? A) It doesn't. Earth's orbital distance plays no significant role in the seasons. B) It makes summer warmer in the Northern Hemisphere than in the Southern Hemisphere. C) It is responsible for the fact that the seasons are opposite in the Northern and Southern hemispheres. D) It causes the seasons to be more extreme than they would be if the Earth's distance from the Sun were always the same.

A) It doesn't. Earth's orbital distance plays no significant role in the seasons.

Polaris is 10 degrees above your horizon. Where are you? A) Latitude 10 degrees north B) Latitude 10 degrees south C) Latitude 80 degrees north D) Latitude 80 degrees south

A) Latitude 10 degrees north

Your friend tells you that last night, they saw Mars high in the sky at midnight. You conclude that A) Mars must be in retrograde. B) your friend must be mistaken: Mars can never be seen at midnight. C) Mars must be at its farthest distance from the Earth. D) Mars must be at its closest distance from the Sun.

A) Mars must be in retrograde.

By locating the north celestial pole (NCP) in the sky, how can you determine your latitude? A) The altitude of the NCP is the same as your latitude. B) The altitude of the NCP is your angular distance from the North Pole. C) The direction of the NCP is the same as your latitude. D) The direction of the NCP is the angular distance from the North Pole. E) The altitude of the NCP is the same as your distance from the North Pole.

A) The altitude of the NCP is the same as your latitude.

What conditions are required for a solar eclipse? A) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. B) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. C) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. D) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. E) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic.

A) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

If we have a new moon today, when will we have the next full moon? A) in about two weeks B) in about 1 week C) in about 1 month D) in about 6 months

A) in about two weeks

The number of official constellations is A) 56. B) 88. C) 123. D) 205.

B) 88.

Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? A) Due to Earth's tilt, the Northern Hemisphere is closer to the Sun than the Southern Hemisphere. B) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. C) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. D) It isn't; both hemispheres have the same seasons at the same time. Summer comes when Earth is nearest the Sun.

B) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.

What happens during the apparent retrograde motion of a planet? A) The planet rises in the west and sets in the east. This is an illusion completely due to Earth's motion. B) The planet appears to turn around in its eastward path through the stars and backs up for many nights traveling westwardly. C) The planet, under strong gravitational influences, travels backwards, westward in its orbit around the Sun. D) The planet's orbit decays and it retrogressively returns to its former orbit.

B) The planet appears to turn around in its eastward path through the stars and backs up for many nights traveling westwardly.

About how many stars are visible to the naked eye on a clear, dark night away from city lights? A) a few dozen B) approximately two thousand C) several million D) a few hundred billion

B) approximately two thousand

Earth's distance from the Sun varies during the year A) not at all. B) by 3%. C) by 10%. D) by 30%.

B) by 3%.

The Moon is nearly tidally locked to the Earth, which means the Moon's rotation period is almost the same as its orbital period. If you were camped at the equator of the Moon, you would experience (approximately) A) 14 hours of darkness followed by 14 hours of sunshine. B) sunshine all the time, except when the Earth blocks the Sun. C) (14 × 24) hours of darkness followed by (14 × 24) hours of sunshine. D) sunshine (day) all the time.

C) (14 × 24) hours of darkness followed by (14 × 24) hours of sunshine.

If Earth's rotation slowed down so that it completed exactly one rotation about its axis in 100 hours, what would be the typical time interval between sunrise and sunset? A) 24 hours B) 25 hours C) 50 hours D) 100 hours

C) 50 hours

During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space? A) Mars is moving around the Sun in the opposite direction from which Earth is moving around the Sun. B) Earth and Mars are getting closer together. C) Earth is catching up with and passing by Mars in their respective orbits. D) Earth and Mars are on opposite sides of the Sun.

C) Earth is catching up with and passing by Mars in their respective orbits.

What is stellar parallax? A) It is the daily rise and set of the stars. B) It describes the fact that stars are actually moving relative to one another, even though to our eyes the stars appear fixed in the constellations. C) It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun. D) It is the change in the set of constellations that we see at different times of year in the evening sky.

C) It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun.

Which of the following conditions must exist for a solar eclipse to occur? A) The only condition is that the phase of the Moon must be new. B) The only condition is that the phase of the Moon must be full. C) Moon phase is new, and the Moon is passing through the Earth's orbital plane. D) Moon phase is full, and the Moon is passing through the Earth's orbital plane.

C) Moon phase is new, and the Moon is passing through the Earth's orbital plane.

Which of the following statements about the celestial sphere is not true? A) The Earth is placed at the center of the celestial sphere. B) When we look in the sky, the stars all appear to be located on the celestial sphere. C) The "celestial sphere" is another name for our universe. D) The celestial sphere does not exist physically.

C) The "celestial sphere" is another name for our universe.

The parallax angle of two stars is reported in a star catalog. Which star is farther? A) The one with the larger parallax angle B) You can't tell, since parallax angle has nothing to do with distance. C) The one with the smaller parallax angle

C) The one with the smaller parallax angle

What is a circumpolar star? A) a star that is close to the north celestial pole B) a star that is close to the south celestial pole C) a star that always remains above your horizon D) a star that makes a daily circle around the celestial sphere E) a star that is visible from the Arctic or Antarctic circles

C) a star that always remains above your horizon

When the Moon's phase is a first quarter moon, it rises A) just before sunset. B) just after sunset. C) around noon. D) close to sunrise.

C) around noon.

Lunar eclipses can occur only during a ________. A) new moon B) first quarter moon C) full moon D) third quarter moon

C) full moon

Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at ________. A) latitude 40 degrees north B) latitude 50 degrees south C) latitude 40 degrees south D) longitude 40 degrees

C) latitude 40 degrees south

If part of the full moon passes through Earth's umbra, we will see a(n) A) total lunar eclipse. B) penumbral lunar eclipse. C) partial lunar eclipse. D) partial solar eclipse. E) annular eclipse.

C) partial lunar eclipse.

If our year were twice as long (that is, if Earth took twice as many days to complete each orbit around the Sun), but Earth's rotation period and axis tilt were unchanged, then ________. A) stars would take twice as long to rise and set B) the cycle of precession would take 13,000 years instead of 26,000 years C) the four seasons would each be twice as long as they are now D) the Earth would not have seasons

C) the four seasons would each be twice as long as they are now

You experience night-time when A) the Moon blocks the Sun's light. B) the Earth revolves 90 degrees in its orbit. C) the side of the Earth you occupy is facing away from the Sun. D) the Earth's axis precesses.

C) the side of the Earth you occupy is facing away from the Sun.

What causes the apparent retrograde motion of the planets? A) As Earth passes another planet, its gravitational pull slows that planet and causes it to travel backwards for a short period. B) Planets, when further from the Sun, move more slowly than when nearer the Sun. It is during this slower period that they appear to move backwards, in retrograde. C) The other planets never really appear to move backward; the background stars shift due to Earth's revolution around the Sun. D) As Earth passes another planet, the planet appears to move backward with respect to the background stars. This is an apparent effect; the planet's true motion has not changed. E) Planets have slowed in their orbits since their formation, leading to retrograde motions.

D) As Earth passes another planet, the planet appears to move backward with respect to the background stars. This is an apparent effect; the planet's true motion has not changed.

Which of these (hypothetical) modifications would cause lunar eclipses to happen once per month? A) Make the Moon orbit the Earth twice as fast. B) Relocate the Moon to twice its current distance from the Earth. C) Change the Moon's orbital plane so it tilts the opposite way. D) Change the orbital plane of the Moon so it lies in the same plane as Earth's orbit around the Sun.

D) Change the orbital plane of the Moon so it lies in the same plane as Earth's orbit around the Sun.

Which of the following statements about lunar phases is true? A) The time between new moons is two weeks. B) Only one quarter of the first-quarter moon is illuminated by the Sun. C) The full moon sometimes rises around midnight. D) It is possible to have two full moons during January, but not during February. E) It is possible to have two full moons during November, but not during December.

D) It is possible to have two full moons during January, but not during February.

Consider three circles that may be imaginatively "drawn" across the night sky (note that we see only parts of each circle at any time): the Milky Way; the ecliptic; and the celestial equator. Which statement about these circles is true? A) The celestial equator is unique, since it traces the path of an object, namely, the Sun. B) The ecliptic circle is unique as it traces a broad band of stars. C) The Milky Way and the ecliptic are the only two circles that are tilted relative to each other. D) Only the ecliptic circle passes through all the zodiacal constellations. E) All three circles cross at the same two points: the equinoxes.

D) Only the ecliptic circle passes through all the zodiacal constellations.

Tonight, your telescope shows you RXJ1800, a galaxy, very near in the sky to the bright star Vega. What can you conclude from this observation? A) RXJ1800 and Vega will drift apart from each other on the sky, over a matter of nights. B) Vega and RXJ1800 must be very close to each other, less than a few light-years. C) Vega orbits the center of mass of RXJ1800. D) RXJ1800 and Vega will set in the west, at very similar times.

D) RXJ1800 and Vega will set in the west, at very similar times.

What is represented by the figure-eight analemma? A) a positional map of Earth's wandering north celestial pole projected into the sky over the course of the next 10,000 years B) the time-lapse photograph of a planet (e.g., Mars) as it undergoes retrograde motion C) an eight-fold intermediate analytical theorem (lemma) pertaining to all astronomical motions D) a composite snapshot of the Sun taken from the same location at the same time of day over one year

D) a composite snapshot of the Sun taken from the same location at the same time of day over one year

As Earth goes around the Sun each year, Earth's rotation axis in the North points A) tipped toward the Sun, 23-1/2 degrees. B) in a direction that traces a cone of radius 23-1/2 degrees, crossing through Polaris and Vega. C) tipped toward the galactic center, 23-1/2 degrees. D) in the direction of the celestial pole, near Polaris, throughout the year.

D) in the direction of the celestial pole, near Polaris, throughout the year.

We describe a location on Earth's surface by stating its ________. A) altitude and direction (or azimuth) B) meridian and longitude C) latitude and direction D) latitude and longitude

D) latitude and longitude

The phenomenon where Earth's rotation axis slowly makes a circle in the celestial sphere over 26,000 years is called A) spin-coupling. B) osculation. C) contortion. D) precession.

D) precession.

If you see Polaris directly overhead at midnight, you must be at A) the equator. B) the South Pole. C) the Tropic of Cancer. D) the North Pole.

D) the North Pole.

Which of the following statements is true? A) Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes. B) Both the Northern and Southern hemispheres receive the same amount of sunlight on the solstices. C) The Northern Hemisphere receives the most direct sunlight on the June solstice. D) The Southern Hemisphere receives the most direct sunlight on the June solstice. E) Both A and C are true.

E) Both A and C are true.

Which of the following statements about constellations is false? A) There are only 88 official constellations. B) Some constellations can be seen from both the Northern and Southern hemispheres. C) Some constellations can be seen in both the winter and summer. D) It is possible to see all the constellations from Earth's equator. E) Most constellations will be unrecognizable hundreds of years from now.

E) Most constellations will be unrecognizable hundreds of years from now.

Ancient people who knew the saros cycle could A) completely predict every lunar eclipse. B) completely predict every solar eclipse. C) predict what type of eclipse would occur. D) predict when they'd see the next total solar eclipse in their area. E) predict when an eclipse would happen, but not necessarily what type and where it would be visible.

E) predict when an eclipse would happen, but not necessarily what type and where it would be visible.

How many arcseconds are in one degree? A) 60 B) 360 C) 3,600 D) 100 E) 10,000

C) 3,600

How many arcminutes are in one degree? A) 60 B) 360 C) 3600 D) 100 E) 10,000

A) 60

During a lunar eclipse the Moon's phase must be A) full. B) new. C) 1st quarter. D) 3rd quarter.

A) full.

What makes the North Star, Polaris, special? A) It is the brightest star in the sky. B) It is the star straight overhead. C) It appears very near the north celestial pole. D) It is the star directly on your northern horizon. E) It can be used to determine your longitude on Earth.

C) It appears very near the north celestial pole.

You are standing on Earth's equator. In which direction is Polaris, the North star? A) The answer depends on what time of day (or night) it is. B) The answer depends on whether it is winter or summer. C) It is on the northern horizon. D) It is directly overhead.

C) It is on the northern horizon.

Has Polaris always been the "North Star", also known as the "Pole Star"? A) Yes, because stars position change little over many centuries. B) No, because it is a young star which formed only a few hundred years ago. C) No, because the Earth's axis slowly changes the direction it points. D) No, because the Milky Way blocked our line of site to it for a long time.

C) No, because the Earth's axis slowly changes the direction it points.

Which of the following statements about the Moon is true? A) The Moon goes through its cycle of four phases in a month (30 or 31 days). B) If you see a full moon from North America, someone in South America will be seeing a new moon. C) The Moon's distance from Earth varies during its orbit. D) The Moon is visible only at night. E) The side of the Moon facing away from Earth is in perpetual darkness.

C) The Moon's distance from Earth varies during its orbit.

Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? A) The Northern Hemisphere is "on top" of Earth and therefore receives more sunlight. B) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. C) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. D) It isn't: both hemispheres have the same seasons at the same time. E) The Northern Hemisphere is closer to the Sun than the Southern Hemisphere.

C) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.

Why were ancient peoples unable to detect stellar parallax? A) They did not look for it. B) They could not see distant stars. C) They did not have the ability to measure very small angles. D) They did not observe for long enough periods of time. E) They did detect it, but they rejected the observations.

C) They did not have the ability to measure very small angles.

We see two stars separated by one degree on the celestial sphere. What can we infer about these stars? A) They are very close together in space. B) They have similar luminosities. C) They rise and set at about the same time. D) They were born about the same time.

C) They rise and set at about the same time.

At midnight, on a clear and moonless night, the number of stars that are distinctly visible to the eye is in the range B) 20,000-50,000. C) 200,000-500,000. D) 2 million-5 million.

A) 2000-5000.

What do astronomers mean by a constellation? A) A constellation is a region in the sky as seen from Earth. B) A constellation is a group of stars related through an ancient story. C) A constellation is any random grouping of stars in the sky. D) A constellation is a group of stars that are all located in about the same place in space.

A) A constellation is a region in the sky as seen from Earth.

Each choice below describes how a few astronomical phenomena are related to time periods. Which list is entirely correct? (Careful: some lists are partially correct.) A) Earth's rotation defines a day. The cycle of the Moon's phases takes about a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years. B) Earth's rotation defines a day. The cycle of the Moon's phases takes about a week. Earth's orbit defines a year. Earth's cycle of axis precession defines a month. C) Earth's rotation defines a day. The Sun's rotation defines a week. The Moon's rotation defines a month. Earth's orbit defines a year. D) Earth's rotation defines a day. The saros cycle of eclipses defines a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years.

A) Earth's rotation defines a day. The cycle of the Moon's phases takes about a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years.

If you are located in the Northern Hemisphere, how can you learn how far you are from the North Pole? A) The altitude of the north celestial pole equals your latitude. B) The altitude of the celestial equator equals your latitude. C) The altitude of the north celestial pole equals your longitude. D) The longitude of the north celestial pole is circumpolar, and therefore crosses your zenith at the meridian.

A) The altitude of the north celestial pole equals your latitude.

If the Moon is 3rd quarter phase, what shape does it have in the sky? A) a quarter circle B) a full circle C) a half circle D) nothing (It is impossible to view a 3rd quarter moon.)

C) a half circle

What is the celestial sphere? A) The celestial sphere is a representation of how the entire sky looks as seen from Earth. B) The celestial sphere is a model that shows the true locations in space of the Sun and a few thousand of the nearest stars. C) The celestial sphere is a model of how the stars are arranged in the sky relative to our Sun, which is in the middle of the sphere. D) It represents a belief in an Earth-centered universe, and hence is no longer considered to have any use.

A) The celestial sphere is a representation of how the entire sky looks as seen from Earth.

If Earth's rotation axis was tilted by 45 degrees instead of 23.5 degrees, what are some of the implications, and why? A) The seasons would be more extreme, because the Sun's rays would be more direct in summer, and less direct in winter. B) The seasons would be more extreme, because the surface of the Earth would be closer to the Sun in the summer, and farther from the Sun in the winter. C) The seasons would be less extreme, because the Sun's rays would be less direct in summer, and more direct in winter. D) The seasons would be less extreme, because the surface of the Earth would be farther from the Sun in the summer, and closer to the Sun in the winter.

A) The seasons would be more extreme, because the Sun's rays would be more direct in summer, and less direct in winter.

If the Earth's rotation axis were tilted by 45 degrees instead of 23.5 degrees, what are some of the implications, and why? A) The seasons would be more extreme, because the Sun's rays would be more direct in summer, and less direct in winter. B) The seasons would be less extreme, because the Sun's rays would be less direct in summer, and more direct in winter. C) The seasons would be less extreme, because the surface of the Earth would be farther from the Sun in the summer, and closer to the Sun in the winter. D) The seasons would be more extreme, because the surface of the Earth would be closer to the Sun in the summer, and farther from the Sun in the winter.

A) The seasons would be more extreme, because the Sun's rays would be more direct in summer, and less direct in winter.

Which of the following best describes why we have seasons on Earth? A) The tilt of Earth's axis causes different portions of the Earth to receive more direct sunlight and more hours of sunlight at different times of year. B) Earth's elliptical orbit means we are closer to the Sun and therefore receive more intense sunlight at some times of year than at others. C) The tilt of Earth's axis causes the northern hemisphere to be closer to the Sun than the southern hemisphere in summer, and vice versa in winter. D) The varying speed of Earth in its orbit around the Sun gives us summer when we are moving fastest and winter when we are moving slowest.

A) The tilt of Earth's axis causes different portions of the Earth to receive more direct sunlight and more hours of sunlight at different times of year.

You observe a full moon rising at sunset. What will you see 6 hours later? A) a full moon on or near your meridian B) a waning gibbous moon C) a first quarter moon D) a third quarter moon

A) a full moon on or near your meridian

When we look toward the constellation Sagitarius, we are looking A) at the galaxy's central bulge. B) toward Polaris, the "Pole Star." C) toward the Winter Triangle. D) out towards the outer Milky Way.

A) at the galaxy's central bulge.

We can't detect stellar parallax with naked-eye observations. Which of the following would make parallax easier to observe? A) increasing the size of Earth's orbit B) speeding up Earth's orbital motion C) slowing down Earth's orbital motion D) speeding up the precession of Earth's axis

A) increasing the size of Earth's orbit

In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because ________. A) our evening view of space depends on where Earth is located in its orbit around the Sun B) during some times of year, some constellations drop below the southern horizon C) some constellations are circumpolar D) on any particular night, we can only see stars that are directly opposite (180 degrees away from) the Sun in the sky

A) our evening view of space depends on where Earth is located in its orbit around the Sun

The Sun A) seems to move around the celestial sphere daily to the East. B) is a fixed point on the celestial sphere at its distance from Earth. C) circles around the celestial equator once each year. D) is the fixed point at the north celestial pole.

A) seems to move around the celestial sphere daily to the East.

Which of the following never goes in retrograde motion? A) the Sun B) Venus C) Mars D) Jupiter E) Saturn

A) the Sun

The ecliptic crosses the celestial equator on the celestial sphere at points called A) the equinoxes. B) the solstices. C) the nodes. D) aphelion and perihelion.

A) the equinoxes.

What is the ecliptic? A) the path the Sun appears to trace around the celestial sphere each year B) the Sun's daily path from east to west in our sky C) the path traced by the Moon's shadow on Earth during a solar eclipse D) a half-circle extending from your horizon due north, through your zenith, to your horizon due south

A) the path the Sun appears to trace around the celestial sphere each year

Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours? A) to the right of Polaris; that is, 90 degrees counterclockwise from its current position B) to the left of Polaris; that is, 90 degrees clockwise from its current position C) directly above Polaris D) still in the same place, below Polaris

A) to the right of Polaris; that is, 90 degrees counterclockwise from its current position

The Milky Way shows itself as a blurry circle of light in the sky because A) we are looking along the plane of our galaxy that is filled with stars. When we look in other directions, we see fewer stars because we are looking through (at a steep angle to) the plane of our galaxy. We actually see only a small fraction of the stars of the Milky Way Galaxy. B) the Sun is at the center of the Milky Way Galaxy. The galaxy is a flat disk of stars appearing as a blurry band or ring of stars and dust in the sky, all seen at great distances. C) it is a ring-like structure of stars and dust located hundreds of thousands of light-years from Earth. It is blurry because it is so far away. D) the spinning Earth blurs the stars above its equator onto this faint circle of blurry starlight and dust.

A) we are looking along the plane of our galaxy that is filled with stars. When we look in other directions, we see fewer stars because we are looking through (at a steep angle to) the plane of our galaxy. We actually see only a small fraction of the stars of the Milky Way Galaxy.

Which of the following statements about the celestial equator is true at all latitudes? A) It lies along the band of light we call the Milky Way. B) It represents an extension of Earth's equator onto the celestial sphere. C) It cuts the dome of your local sky exactly in half. D) It extends from your horizon due east, through your zenith, to your horizon due west. E) It extends from your horizon due north, through your zenith, to your horizon due south.

B) It represents an extension of Earth's equator onto the celestial sphere.

What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane? A) Solar eclipses would be much rarer. B) Solar eclipses would be much more frequent. C) Total solar eclipses would last much longer. D) Both A and C E) Both B and C

B) Solar eclipses would be much more frequent.

Which of the following statements does not use the term angular size or angular distance correctly? A) The angular distance between those two houses in the distance is 30 degrees. B) The angular distance between those two bright stars in the sky is about 2 meters. C) The angular size of the Sun is about the same as that of the Moon. D) You can use your outstretched hand against the sky to estimate angular sizes and angular distances.

B) The angular distance between those two bright stars in the sky is about 2 meters.

If Earth rotated once every 48 hours, and everything else was the same, which of the following statements would not be true? A) There would still be summer and winter in the temperature zones. B) The length of the year would be longer. C) The daytime temperatures would be higher on average. D) High tide would happen less frequently. E) The length of a day would be longer.

B) The length of the year would be longer.

What conditions are required for a lunar eclipse? A) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. B) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. C) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. D) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic.

B) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

Which of the following statements about circumpolar stars is true at all latitudes? A) They are the stars close to the north celestial pole. B) They always remain above your horizon. C) They make relatively small circles, traveling clockwise around the north celestial pole. D) Like all other stars, they rise in the east and set in the west. E) You cannot see them from the Southern Hemisphere.

B) They always remain above your horizon.

RXJ1800, a galaxy, lies very near in the sky to the bright star Vega. What is the best explanation for them appearing close together? A) Their random motions have caused RXJ1800 and Vega to drift to within a few light-years of each other. B) They coincidentally lie along the same line of sight. C) Vega orbits the center of mass of RXJ1800. D) Vega must have recently formed in RXJ1800 and been ejected.

B) They coincidentally lie along the same line of sight.

The Greeks rejected the notion that the Earth orbits the Sun. Why? A) They could not measure how big the Earth was. B) They could not measure a change in stars' positions on the sky. C) They were not as smart as we are. D) They believed that the Sun is a God.

B) They could not measure a change in stars' positions on the sky.

Today the Sun is in the middle of the constellation Virgo. Therefore, tomorrow the Sun will be in the constellation A) Libra. B) Virgo. C) Leo. D) Sagittarius.

B) Virgo.

Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight? A) Your friend will see a gibbous moon. B) Your friend will also see a crescent moon. C) Your friend will see a first quarter moon. D) Your friend won't see the Moon tonight, because it is up only in the morning.

B) Your friend will also see a crescent moon.

While the historical definition of a constellation is "a pattern or figure of stars in the sky," the modern definition used by astronomers is A) a group of stars in the sky that are all very close to each other. B) a specifically named and bordered region of the celestial sphere. C) any grouping of very bright stars in our galaxy, often hosting a star cluster. D) no definition. Astronomers no longer use the term constellation, just numerical coordinates.

B) a specifically named and bordered region of the celestial sphere.

You are standing on Earth's equator. Which way is Polaris, the North star? A) 30 degrees up, due West B) on the northern horizon C) directly overhead D) The answer depends on whether it's winter or summer. E) The answer depends on what time of day (or night) it is.

B) on the northern horizon

What is the saros cycle? A) the 26,000-year cycle of the Earth's precession B) the roughly 18-year cycle over which the pattern of eclipses repeats C) the roughly one-month cycle of lunar phases in the sky D) the annual cycle of the seasons

B) the roughly 18-year cycle over which the pattern of eclipses repeats

The point directly over your head is called ________. A) the meridian B) the zenith C) the north celestial pole D) the North Star

B) the zenith

The stars stay in "fixed" positions on the celestial sphere because A) the stars on the sphere are all chosen to be approximately the same distance from Earth. B) while they actually move through space, they are too far away for their motion to be seen. C) the sphere to which they are attached moves with them through space. D) they are all expanding away, so they have no transverse (sideways) motions.

B) while they actually move through space, they are too far away for their motion to be seen.

Which of the following correctly describes the meridian in your local sky? A) a half-circle extending from your horizon due east, through your zenith, to your horizon due west B) a half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west C) a half-circle extending from your horizon due north, through your zenith, to your horizon due south D) the point directly over your head

C) a half-circle extending from your horizon due north, through your zenith, to your horizon due south

The celestial sphere is A) the central spherical region of the Milky Way Galaxy, dense with stars. B) a spherical galaxy, centered on the Sun. C) a useful illusion used to map the stars and other objects in the sky. D) the star-sphere discovered by the Greeks and other ancient civilizations which shows the physical location in space of the nearby stars. E) the orb of the Sun; a normal star.

C) a useful illusion used to map the stars and other objects in the sky.

Stars in the local sky that never cross below the horizon during the year are called ________. A) bright B) seasonal C) circumpolar D) celestial

C) circumpolar

In which direction on the horizon does a crescent moon rise? A) north B) south C) east D) west E) The Moon can become a crescent moon only after it has risen and changed its phase.

C) east

If the Moon is setting at 6 A.M., the phase of the Moon must be A) first quarter. B) third quarter. C) full. D) new. E) waning crescent.

C) full.

When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting ________. A) brighter B) dimmer C) higher in the sky D) lower in the sky

C) higher in the sky

The celestial equator A) is another name for the ecliptic. B) defines the path of the Sun through the stars, and it also defines the plane of the solar system. C) is a projection into space of Earth's equator onto the celestial sphere. D) is the technical name of the Sun's equator.

C) is a projection into space of Earth's equator onto the celestial sphere.

During the time that a planet is in its period of apparent retrograde motion, ________. A) the planet moves backwards (clockwise as viewed from above Earth's north pole) in its orbit of the Sun B) the planet appears to rise in the west and set in the east, rather than the usual rising in the east and setting in the west C) over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars D) the planet is getting closer to the Sun in its orbit

C) over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars

The constellation Orion, located on the celestial equator, is visible on winter evenings but not on summer evenings because of A) blockage by the full moon. B) the tilt of Earth's rotation axis. C) the location of Earth in its orbit around the Sun. D) the precession of Earth's rotation axis.

C) the location of Earth in its orbit around the Sun.

In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse? A) Earth must lie completely within the Moon's umbra. B) Earth must lie completely within the Moon's penumbra. C) Earth must be near aphelion in its orbit of the Sun. D) The Moon's umbra must touch the area where you are located. E) The Moon's penumbra must touch the area where you are located.

D) The Moon's umbra must touch the area where you are located.

Which of the following statements about parallax is not true? A) You can demonstrate parallax simply by holding up a finger and looking at it alternately from your left and right eyes. B) The existence of stellar parallax is direct proof that Earth orbits the Sun. C) Measurement of stellar parallax allows us to determine distances to nearby stars. D) The technique of stellar parallax was used by Hubble to determine that the Andromeda Galaxy (M 31) is about 2 million light-years away. E) Ancient astronomers were unable to measure parallax and used the absence of any changes in the stars' separations as an argument in favor of an Earth-centered universe.

D) The technique of stellar parallax was used by Hubble to determine that the Andromeda Galaxy (M 31) is about 2 million light-years away.

Which of the following statements about stellar parallax is true? A) We observe all stars to exhibit at least a slight amount of parallax. B) Stellar parallax was first observed by ancient Greek astronomers. C) The amount of parallax we see depends on how fast a star is moving relative to us. D) It takes at least 10 years of observation to measure a stars parallax. E) The closer a star is to us, the more parallax it exhibits.

E) The closer a star is to us, the more parallax it exhibits.

At approximately what time would a full moon be on your meridian? A) 6 A.M. B) 9 A.M. C) noon D) 6 P.M. E) midnight

E) midnight

If the Moon is setting at noon, then it rose at A) 6 A.M. B) 9 A.M. C) noon. D) 6 P.M. E) midnight.

E) midnight.