Question 1

Which way will the "horns," or the sharp ends of the crescent Moon,point in the sky when the Moon is on the western horizon at sunset three days later than new Moon?

Accepted Answer

A)   toward the Sun, westward
B)   The Moon is not crescent-shaped three days after new Moon.
C)   at right angles to the Sun direction, northward
D)   away from the Sun, eastward

Question 2

Which of the following statements about eclipses in the Sun-Earth-Moon system is NOT correct?

Accepted Answer

A)   A total eclipse of the Sun occurs only at full Moon.
B)   A total eclipse of the Moon occurs only at full Moon.
C)   Eclipses of the Moon and the Sun do not occur at quarter Moon phases.
D)   A total eclipse of the Sun occurs only at new Moon.

Question 3

If the direction of Earth's rotation about its axis were reversed but the direction of its revolution around the Sun remained the same,the sidereal day would be:

Accepted Answer

A)   4 minutes shorter than a solar day, as it is now.
B)   4 minutes longer than a solar day.
C)   the same length as a solar day.
D)   8 minutes shorter than a solar day.

Question 4

For a particular observer in the northern hemisphere,a given star in the sky will reach its highest point when it passes through the:

Accepted Answer

A)   celestial equator.
B)   zodiac.
C)   ecliptic plane.
D)   region of the sky due south.

Question 5

The diameter of the hydrogen atom,0.000,000,000,11 m,can be written in shorthand notation as:

Accepted Answer

A)   1.1 × 10-⁸ m.
B)   1.1 × 10-¹⁰ m.
C)   1.1 × 10-⁹ m.
D)   1.1 × 10-¹¹ m.

Question 6

Polaris is the name for the bright star almost directly in line with the north polar axis of Earth.What is the name of the bright star almost directly in line with the south polar axis of Earth?

Accepted Answer

A)   Fomalhaut
B)   Canopus
C)   Alpha Centauri
D)   There is no bright star almost directly in line with Earth's south polar axis.

Question 7

A solar eclipse occurs on Earth when:

Accepted Answer

A)   the Moon casts a shadow on Earth.
B)   Earth casts a shadow on the Moon.
C)   the Sun passes in front of the Moon.
D)   the Moon passes behind the Sun.

Question 8

The "Land of the Midnight Sun" is so-named because:

Accepted Answer

A)   the Sun is above the horizon for a full 24 hours at a certain time of the year.
B)   the Sun passes overhead at least once during the year within this region.
C)   twilight is bright and lasts all night through the summer months because the Sun never gets far below the horizon from these locations.
D)   the full Moon is always up whenever the Sun sets, maintaining light skies throughout the summer months.

Question 9

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:

Accepted Answer

A)   northwest.
B)   northeast.
C)   southwest.
D)   southeast.

Question 10

If Earth did not have a large Moon:

Accepted Answer

A)   precession would not occur, and the tilt of Earth's axis would remain constant.
B)   the tilt of Earth's axis would change relatively rapidly.
C)   Earth's axis would be perpendicular to the ecliptic.
D)   Earth's axis would lie in the plane of the ecliptic.

Question 11

The longest duration of a total lunar eclipse (i.e.,how long the Moon is within the umbra) is 107 minutes.If it takes the Moon 57 minutes to move a distance equal to its own diameter against the background stars,how wide is Earth's umbra at the closest distance of the Moon's orbit?

Accepted Answer

A)   about the same as the Moon's diameter
B)   a little less than twice the Moon's diameter
C)   a little less than three times the Moon's diameter
D)   It is not possible to calculate the answer from this information.

Question 12

There is about a 5° angle between the orbit of the Moon and:

Accepted Answer

A)   the plane of the Sun's equator.
B)   Earths' spin axis.
C)   the plane of Earth's equator.
D)   the plane of the ecliptic, or Earth's orbit.

Question 13

If you were on Mars,which of the following bodies would never be seen as a crescent?

Accepted Answer

A)   Jupiter
B)   Earth's Moon
C)   Venus
D)   Earth

Question 14

When is the Sun on the celestial equator and the ecliptic at the same time?

Accepted Answer

A)   never
B)   always
C)   only at the equinoxes
D)   only during a solar eclipse

Question 15

Which of the following conditions holds for relative distances during a solar eclipse?

Accepted Answer

A)   The Moon is closer to the Sun than Earth is.
B)   Earth is closer to the Sun than the Moon is.
C)   The Moon and Earth are at the same distance from the Sun.
D)   Because the condition for a solar eclipse is independent of the relative distances of Earth and the Moon from the Sun, either the Moon or Earth can be closest to the Sun.

Question 16

Right ascension of a star is a measure of:

Accepted Answer

A)   the time of its rising in the eastern sky.
B)   its position above the observer's horizon, measured from the horizon.
C)   its position north or south of the celestial equator, along a great circle passing through the north and south celestial poles.
D)   the great circle joining north and south celestial poles upon which it is located, the position of which is measured along the celestial equator.

Question 17

If you follow a line through the "pointer stars" (the two stars in the bowl of the Big Dipper farthest from the handle) away from the open end of the dipper,the first moderately bright star you come to is:

Accepted Answer

A)   Polaris, the North Star.
B)   Spica, in Virgo.
C)   Arcturus, in Boötes.
D)   Vega, in Lyra.

Question 18

By what approximate factor,in powers-of-ten notation,is a human being (height about 2 m) larger than the nucleus of a hydrogen atom,or proton (diameter about 10-¹⁵ m) ?

Accepted Answer

A)   2 × 10¹³
B)   2 × 10³⁰
C)   2 × 10-¹⁵
D)   2 × 10¹⁵

Question 19

From the East Coast of the United States,you are observing a star rising above the horizon.At the same instant,your friend on the West Coast finds that this star:

Accepted Answer

A)   is just rising.
B)   is just setting.
C)   rose a few hours earlier.
D)   has not yet risen.

Question 20

The reason leap years have an extra day is to account for the fact that:

Accepted Answer

A)   Earth's rotation period is slowly increasing because of tidal effects.
B)   the year is not exactly equal to an integral number of days.
C)   the day is not exactly 24 hours because of Earth's periodically varying rotation period.
D)   the length of the year varies with a period of 4 years because of precession.

Exam 1: Discovering the Night Sky

If you were on Mars,which of the following bodies would never be seen as a crescent?

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Polaris is the name for the bright star almost directly in line with the north polar axis of Earth.What is the name of the bright star almost directly in line with the south polar axis of Earth?

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Right ascension of a star is a measure of:

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For a particular observer in the northern hemisphere,a given star in the sky will reach its highest point when it passes through the:

Correct AnswerverifiedShow Answer

By what approximate factor,in powers-of-ten notation,is a human being (height about 2 m) larger than the nucleus of a hydrogen atom,or proton (diameter about 10-¹⁵ m) ?

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If Earth did not have a large Moon:

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A solar eclipse occurs on Earth when:

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The "Land of the Midnight Sun" is so-named because:

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Which way will the "horns," or the sharp ends of the crescent Moon,point in the sky when the Moon is on the western horizon at sunset three days later than new Moon?

Correct AnswerverifiedShow Answer

The diameter of the hydrogen atom,0.000,000,000,11 m,can be written in shorthand notation as:

Correct AnswerverifiedShow Answer

The reason leap years have an extra day is to account for the fact that:

Correct AnswerverifiedShow Answer

Which of the following statements about eclipses in the Sun-Earth-Moon system is NOT correct?

Correct AnswerverifiedShow Answer

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:

Correct AnswerverifiedShow Answer

Which of the following conditions holds for relative distances during a solar eclipse?

Correct AnswerverifiedShow Answer

There is about a 5° angle between the orbit of the Moon and:

Correct AnswerverifiedShow Answer

If you follow a line through the "pointer stars" (the two stars in the bowl of the Big Dipper farthest from the handle) away from the open end of the dipper,the first moderately bright star you come to is:

Correct AnswerverifiedShow Answer

When is the Sun on the celestial equator and the ecliptic at the same time?

Correct AnswerverifiedShow Answer

If the direction of Earth's rotation about its axis were reversed but the direction of its revolution around the Sun remained the same,the sidereal day would be:

Correct AnswerverifiedShow Answer

From the East Coast of the United States,you are observing a star rising above the horizon.At the same instant,your friend on the West Coast finds that this star:

Correct AnswerverifiedShow Answer

The longest duration of a total lunar eclipse (i.e.,how long the Moon is within the umbra) is 107 minutes.If it takes the Moon 57 minutes to move a distance equal to its own diameter against the background stars,how wide is Earth's umbra at the closest distance of the Moon's orbit?

Correct AnswerverifiedShow Answer

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