Deck 2: Discovering the Universe for Yourself

Question 1

Which of the following statements about lunar phases is true?

A) The time between new moons is two weeks.
B) The time from one new moon to the next new moon is the same as the time from first-quarter moon to third-quarter moon.
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.

Answer 1

D

Question 2

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.

Answer 2

B

Question 3

When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the

A) new Earth phase.
B) first-quarter Earth phase.
C) crescent Earth phase.
D) third-quarter Earth phase.
E) full Earth phase.

Answer 3

D

Question 4

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

Question 5

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.

Question 6

If the Moon is setting at noon, the phase of the Moon must be

A) full.
B) first quarter.
C) third quarter.
D) waning crescent.
E) waxing crescent.

Question 7

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.

Question 8

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.

Question 9

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.

Question 10

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 summer solstice.
D) The Southern Hemisphere receives the most direct sunlight on the summer solstice.
E) Both A and C are true.

Question 11

If the Moon is rising at midnight, the phase of the Moon must be

A) full.
B) first quarter.
C) third quarter.
D) waning crescent.
E) waxing crescent.

Question 12

Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?

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

Question 13

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.

Question 14

Orion is visible on winter evenings but not summer evenings because of

A) interference from the full moon.
B) the tilt of Earth's axis.
C) the location of Earth in its orbit.
D) the precession of Earth's axis.
E) baseball on television.

Question 15

How many arcseconds are in one degree?

A) 60
B) 360
C) 3,600
D) 100
E) 10,000

Question 16

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

Question 17

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.

Question 18

When we look into the band of light in our sky that we call the Milky Way, can we see distant galaxies? Why or why not?

A) Yes, they appear as small, fuzzy patches on the other side of our galaxy.
B) Yes, there are many other galaxies that we see inside the Milky Way.
C) No, because the stars, gas, and dust of the Milky Way block us from seeing them.
D) No, because there are only galaxies above and below the plane of the Milky Way.

Question 19

Which of the following is not a phase of the Moon?

A) first-quarter moon
B) third-quarter moon
C) half moon
D) new moon
E) full moon

Question 20

If it is midnight in New York, it is

A) daytime in Sydney, Australia.
B) midnight in Sydney, Australia.
C) midnight in Los Angeles.
D) midday in Rio de Janeiro, Brazil.
E) midnight everywhere.

Question 21

When are eclipse seasons?

A) in the spring and fall
B) in the summer and winter
C) when the nodes of the Moon's orbit are nearly aligned with the Sun
D) when Earth, the Sun, and the Moon are exactly aligned for an eclipse
E) during an eclipse

Question 22

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.
E) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic.

Question 23

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.

Question 24

Which of the following never goes in retrograde motion?

A) the Sun
B) Venus
C) Mars
D) Jupiter
E) Saturn

Question 25

What happens during the apparent retrograde motion of a planet?

A) The planet rises in the west and sets in the east.
B) The planet appears to move eastward with respect to the stars over a period of many nights.
C) The planet moves backward through the sky.
D) The planet moves backward in its orbit around the Sun.
E) The planet moves through constellations that are not part of the zodiac.

Question 26

If the Moon rises around 3 A.M., its phase must be

A) full.
B) first quarter.
C) third quarter.
D) waning crescent.
E) waxing crescent.

Question 27

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 observed parallax as an argument in favor of an Earth-centered universe.

Question 28

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.

Question 29

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

Question 30

Which of the following statements about the Moon is true?

A) The Moon goes through a cycle of phases because it always has the same side facing Earth.
B) If you see a full Moon from North America, someone in South America would see 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.

Question 31

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.

Question 32

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
E) getting away from streetlights

Question 33

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

Question 34

In which direction does a quarter moon rise?

A) north
B) south
C) east
D) west
E) The Moon becomes a quarter moon only after it has risen and changed phase.

Question 35

If the Moon is relatively far from Earth, so that its umbra does not reach Earth, someone directly behind the umbra will see

A) a penumbral lunar eclipse.
B) a partial lunar eclipse.
C) a partial solar eclipse.
D) an annular eclipse.
E) no eclipse.

Question 36

What causes the apparent retrograde motion of the planets?

A) As Earth passes another planet, its gravitational pull slows down the other planet so that it appears to be traveling backward.
B) When planets are farther from the Sun, they move slower than when they are nearer the Sun; it is during this slower period that they appear to move backwards.
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 other planet appears to move backward with respect to the background stars, but the planet's motion does not really change.
E) Apparent retrograde motion is an illusion created by turbulence in Earth's atmosphere.

Question 37

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.

Question 38

At approximately what time would a first quarter moon rise?

A) 6 A.M.
B) 9 A.M.
C) noon
D) 6 P.M.
E) midnight

Question 39

The precession of the Moon's nodes means that

A) there is a lunar eclipse every 6 months.
B) there is a solar eclipse every 6 months.
C) the eclipse seasons occur less than 6 months apart.
D) the vernal equinox will be in Aquarius in a few hundred years.
E) there are never two solar eclipses in the same year.

Question 40

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.

Question 41

The Milky Way can be seen only from the Northern Hemisphere.

Question 42

Cognitive Dissonance? You are talking to a friend who insists that the seasons are caused by a varying Earth-Sun distance over the course of a year. What other fact does your friend likely know that completely contradicts this view of how the seasons are caused? Can you think of other examples of two beliefs that many people feel are both true but which completely contradict each other? How does science view this situation?

Question 43

A solar eclipse occurs only when the Moon is new.

Question 44

It is possible to see the full moon rising just before sunrise.

Question 45

In South Africa, it's usually quite warm around the time of the winter solstice and quite cool around the time of the summer solstice.

Question 46

The Moon and the Sun are approximately the same angular size.

Question 47

At midnight it is sometimes possible to observe the crescent moon on the meridian.

Question 48

You can find the tilt of Earth's axis by measuring the angle between your horizon and the North Star.

Question 49

If you lived on the Moon, you'd see full Earth when we see new moon.

Question 50

It is possible to view the Moon in first-quarter phase the day after a total lunar eclipse.

Question 51

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
The Big Dipper will look different 100,000 years from now than it does today.

Question 52

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
Polaris will no longer be the North Star 1,000 years from now.

Question 53

Scientific Reasoning: The scientific method requires that we put any hypothesis about how the universe works to the test by conducting observations of the natural world. Consider the Greek reaction to the idea of a heliocentric (Sun-centered) solar system. Why did most Greeks reject this hypothesis in favor of the geocentric (Earth-centered) model? Do you think that the Greeks were following a scientific form of reasoning to reach this conclusion? Does the fact that the Greeks reached the wrong conclusion affect your answer?

Question 54

A lunar eclipse occurs only when the Moon is new.

Question 55

It is possible to see the third-quarter moon near the western horizon at sunrise.

Question 56

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
The Moon rises in the east and sets in the west.

Question 57

The Sidereal Day: Using your wristwatch and observations of the night sky over the course of a few weeks, how can you demonstrate to a friend that 24 hours cannot be the true rotation period of the Earth (often called the sidereal day)? What assumptions do you make in this argument?

Question 58

The seasons on Earth are caused by its elliptical orbit around the Sun.

Question 59

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
In the year A.D. 15,000, Vega will be a better north star than Polaris.

Question 60

Models in Science: Models play a central role in astronomy and science in general. Two models used extensively in this chapter are the celestial sphere and the heliocentric (Sun-centered) model for the solar system. Astronomers clearly believe that the celestial sphere model is false and the heliocentric model is true. Given this, why do you think astronomers persist in using the celestial sphere model to describe the night sky?

Question 61

Consider the following statement, and explain whether or not it is sensible: Although all the known stars appear to rise in the east and set in the west, we might someday discover a star that will appear to rise in the west and set in the east.

Question 62

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
The stars of Orion's belt rise in the east and set in the west.

Question 63

Suppose you lived on the Moon near the center of the face that we see from Earth. During the phase of new moon, what phase would you see for Earth? Would it be day or night at your home?

Question 64

Consider the following statement, and explain whether or not it is sensible: When I looked into the dark fissure of the Milky Way with my binoculars, I saw what must have been a cluster of distant galaxies.

Question 65

Suppose the distance to the Moon were twice its actual value. Could we still have solar eclipses? If so, what type(s)?

Question 66

What would you see if you were on the near side of the Moon during a lunar eclipse?

Question 67

Why does the Milky Way appear as a band of light in the sky?

Question 68

What would you see if you were on the near side of the Moon during a solar eclipse?

Question 69

Consider the following statement, and explain whether or not it is sensible: Last night I saw Jupiter in the constellation Ursa Major.

Question 70

Suppose you lived on the Moon near the center of the face that we see from Earth. At what phase of the Moon would you see sunset? What phase of Earth would you see at this time?

Question 71

The choices below are for the following questions. For each question, choose the letter for the real motion that is responsible for the apparent motion as seen from Earth.
A. Earth rotates once each day.
B. Earth revolves around the Sun once each year.
C. The direction of Earth's axis in space precesses with a period of 26,000 years.
D. Stars appear to move randomly in the local solar neighborhood.
E. The universe is expanding.
A million years from now, Alpha Centauri will no longer be the nearest star system to our own.

Question 72

Consider the following statement, and explain whether or not it is sensible: My sign is Ursa Major because the Sun was in Ursa Major when I was born.

Question 73

Suppose you lived on the Moon near the center of the face that we see from Earth. At what phase of the Moon would you see sunrise? What phase of Earth would you see at this time?

Question 74

Why is the Moon not completely invisible (it appears as a very deep red color) to the naked eye during a total lunar eclipse?

Question 75

At what altitude and in what direction in your sky does the north or south celestial pole appear?

Question 76

Consider the following statement, and explain whether or not it is sensible: If you lived on the Moon, you'd see full Earth when we see new moon.

Question 77

Answer each of the following questions for our local sky.
A. Where is the north celestial pole in our sky?
B. Is Polaris a circumpolar star in our sky? Explain.
C. Describe the meridian in our sky.
D. Describe the celestial equator in our sky.

Question 78

Suppose you lived on the Moon near the center of the face that we see from Earth. During the phase of full moon, what phase would you see for Earth? Would it be day or night at your home?

Question 79

Consider the following statement, and explain whether or not it is sensible: If you had a very fast spaceship, you could travel to the celestial sphere in about 100 years.

Question 80

If Earth's axis had no tilt, would we still have seasons? Why or why not?