Question 1

If the Moon's orbital plane was aligned with the celestial equator, when would eclipses occur?
A) every month
B) never
C) only at solstices
D) only at the equinoxes

Accepted Answer

The answer of If the Moon's orbital plane was aligned...

Question 2

What is apparent solar time?
A) the time between successive meridian crossings of a particular star
B) time measured relative to successive meridian crossings of the Sun
C) the period of time between successive solar eclipses at a given location on Earth
D) time measured relative to sunrise and sunset

Accepted Answer

Apparent solar time is based on the position of the Sun in the sky and is measured relative to successive meridian crossings of the Sun. It can be different from standard time as it takes into account the Earth's axial tilt and its elliptical orbit around the Sun.

Question 3

Suppose Earth orbited half as far from the Sun but that the size of the Moon and its orbit around Earth were the same as they are today. Which of the following statements would be true?
A) It would not be possible to experience a total solar eclipse from Earth.
B) It would not be possible to experience a partial solar eclipse from Earth.
C) A total solar eclipse would occur every month at some point on Earth.
D) Total solar eclipses would last twice as long.

Accepted Answer

If Earth orbited half as far from the Sun, the Sun would appear larger in the sky because it would be closer. Since the size of the Moon and its orbit around Earth would remain the same, the Moon would not be able to completely cover the Sun during an eclipse, making total solar eclipses impossible.

Question 4

Which event could occur about two weeks after a total lunar eclipse?
A) a total solar eclipse
B) another total lunar eclipse
C) a full Moon
D) a partial lunar eclipse

Accepted Answer

A total solar eclipse can occur about two weeks after a total lunar eclipse because the Earth, Moon, and Sun are aligned in such a way during a lunar eclipse that they can align again in the opposite order for a solar eclipse approximately two weeks later, when the Moon moves to the opposite side of the Earth.

Question 5

What is the term for the period of time it takes for the Moon to complete a cycle of the lunar phases that is approximately 29.5 days long?
A) sidereal period of the Moon
B) Saros cycle of the Moon
C) synodic period of the Moon
D) eclipse season of the Moon

Accepted Answer

The synodic period of the Moon refers to the time it takes for the Moon to complete one full cycle of its phases, from new Moon to new Moon again, which is approximately 29.5 days. This is due to the relative positions of the Earth, Moon, and Sun changing as they move in their orbits.

Question 6

Why does the Gregorian calendar use leap years?
A) because the tropical year is about 365.25 days long
B) because the sidereal year is longer than the tropical year
C) because Earth's axis is precessing
D) because Earth's rotation is slowing down

Accepted Answer

The Gregorian calendar uses leap years to align with the tropical year, which is approximately 365.25 days long. Adding an extra day every four years compensates for this quarter-day discrepancy, keeping the calendar in sync with the Earth's seasons.

Question 7

Why doesn't the Earth experience a solar eclipse every month?
A) Unpredictable weather patterns obscure the Moon.
B) The Moon always keeps its same side toward the Earth.
C) The Moon's orbit is not aligned with the Earth's orbit.
D) Sometimes the Moon is too far away.

Accepted Answer

The Moon's orbit is tilted about 5 degrees relative to the Earth's orbit around the Sun. As a result, the Moon does not line up with the Sun and Earth every month, causing a solar eclipse. Instead, it only lines up during certain times of the year, resulting in a limited number of solar eclipses per year.

Question 8

What is the sidereal period of the Moon?
A) the period of time between one full Moon and the next
B) the period of time for the Moon to orbit the Earth once with respect to the stars
C) the period of time between successive eclipses at a given location on Earth
D) the period of time from when the Moon rises until the Moon rises again the next night

Accepted Answer

The sidereal period of the Moon is the time it takes for the Moon to orbit the Earth once with respect to the stars. This is different from the synodic period, which is the period between one full Moon and the next, and takes into account the Earth's movement around the Sun.

Question 9

Which of the following describes a concept very similar to latitude?
A) right ascension
B) declination
C) magnitude
D) meridian

Accepted Answer

Declination is a measure in degrees of a celestial object's position above or below the celestial equator, much like latitude measures a location on Earth's surface above or below the equator.

Question 10

If the Sun were twice as large but remained at its current distance from Earth, which of the following changes would allow people on Earth to still experience a total solar eclipse?
A) Double the size of the Moon and double the size of its orbit around Earth.
B) Keep the Moon at its current size but double the size of its orbit around Earth.
C) Keep the Moon at its current size but halve the size of its orbit around Earth.
D) Halve the size of the Moon and keep the size of its orbit around Earth the same.

Accepted Answer

Doubling the Sun's size while keeping the Moon at its current size and halving its orbit around Earth would make the Moon appear larger in the sky, compensating for the increased size of the Sun and allowing for a total solar eclipse.

Question 11

Why is the Moon's synodic period longer than its sidereal period?
A) because most months have more than 27 days
B) because the Sun moves faster than the Moon
C) because Earth has moved along its orbit during a sidereal period
D) because one complete orbit of the Moon around Earth takes longer than the cycle of lunar phases

Accepted Answer

The Moon's synodic period is longer than its sidereal period because as the Moon completes one orbit around Earth (a sidereal month), Earth has moved in its orbit around the Sun. This means the Moon has to travel a bit further to reach the same phase as seen from Earth, thus extending the synodic period (the time between similar phases, e.g., full moon to full moon) compared to the sidereal period (the time it takes to complete one orbit relative to the stars).

Question 12

The star delta Cephei has a declination of about +58.5 degrees. Which observer will see it above their horizon for the longest fraction of one night?
A) an observer in Valdivia, Chile, at a latitude of 39° S
B) an observer in Windhoek, Namibia, at a latitude of 22.5° S
C) an observer in Zacatecas, Mexico, at a latitude of 22.5° N
D) an observer in Edmonton, Canada, at a latitude of 53.5° N

Accepted Answer

The higher the latitude of the observer, the longer any given star will appear above the horizon. Therefore, the observer in Edmonton, Canada, at a latitude of 53.5° N will see the star delta Cephei above their horizon for the longest fraction of one night.

Question 13

Why is it possible to view a total solar eclipse from Earth?
A) because the Sun and the Moon have nearly the same diameter
B) because the Sun and the Moon have nearly the same angular diameter when viewed from Earth
C) because the Sun and the Moon are at nearly the same distance from Earth
D) because the Moon orbits Earth in the same plane that Earth orbits the Sun

Accepted Answer

The Sun and the Moon appear to be nearly the same size in the sky because they have nearly the same angular diameter when viewed from Earth. This allows the Moon to completely cover the Sun during a total solar eclipse.

Question 14

Which of the following measures time relative to the stars?
A) solar day
B) sidereal day
C) tropical year
D) synodic month

Accepted Answer

The sidereal day measures time relative to the stars. It is the time it takes for the Earth to rotate once relative to a fixed point in the sky, which is a distant star. The solar day, on the other hand, measures time relative to the Sun, while the tropical year and synodic month are based on the position of the Sun and Moon relative to the Earth.

Question 15

How much does the RA coordinate of the Sun change in 2 months?
A) 0 hours, it does not change
B) about 2 hours
C) about 4 hours
D) about 24 hours

Accepted Answer

The Sun appears to move eastward along the ecliptic relative to the stars, completing a circuit of 360 degrees in about one year. Therefore, in two months, it would move approximately 1/6 of its annual path, which is about 60 degrees. Since the celestial equator is divided into 24 hours of right ascension (RA), corresponding to 360 degrees, 60 degrees equates to about 4 hours of RA.

Question 16

During a total lunar eclipse, where is the Moon?
A) in the solar umbra
B) in the Earth's umbra
C) between the Earth and the Sun
D) at its greatest distance from the Earth

Accepted Answer

During a total lunar eclipse, the Moon passes through the Earth's umbra, which is the darkest part of the Earth's shadow. This causes the Moon to appear reddish in color and is often referred to as a "blood moon".

Question 17

A total solar eclipse occurred in Brandon, Manitoba, on Feb. 26, 1979. At what other date was there (or will there be) the same eclipse visible at this location?
A) March of 1979
B) August of 1979
C) January of 2000
D) March of 2033

Accepted Answer

Eclipses, including solar eclipses, recur in cycles. The most notable cycle is the Saros cycle, which is approximately 18 years, 11 days, and 8 hours. This means that a similar eclipse will occur after this period. Given the date of the eclipse in February 1979, adding roughly 18 years brings us to 1997, and another cycle brings us close to 2015. Therefore, the next similar eclipse in Brandon, Manitoba, would not be until after these dates, making March of 2033 the correct choice based on the options provided.

Question 18

Do the constellations visible in the sky at a particular time of night (say, 9 p.m.) follow a seasonal pattern?
A) No; the same constellations are visible at 9 p.m. on any clear night of the year.
B) No; as the year progresses, the constellations visible at 9 p.m. are the same but their shapes change.
C) Yes; at 9 p.m. on a clear winter night, ALL of the constellations you can see are different from the ones that appear at the same time on a summer night.
D) Yes; at 9 p.m. on a summer night, MOST of the constellations you can see are different from those you can see on a winter night. Some constellations are visible all year long.

Accepted Answer

The constellations visible in the sky at a particular time of night do follow a seasonal pattern due to Earth's orbit around the Sun, changing the night sky view throughout the year. However, some constellations near the celestial poles are visible all year long in their respective hemispheres.

Question 19

The second is defined as a fixed interval of time, with no reference to astronomical timescales. If the Earth's period of rotation doubled, but its period of revolution stayed the same, what would happen?
A) There would half as many seconds in the day.
B) There would be twice as many seconds in the day.
C) There would be half as many seconds in the year.
D) There would be twice as many seconds in the year.

Accepted Answer

The definition of a second is independent of Earth's rotation or revolution periods. If the Earth's rotation period doubled, days would be longer, but the definition of a second wouldn't change, leading to twice as many seconds in a day to account for the longer duration of each day.

Question 20

For an observer at the North Pole, what is the angular distance between a star at a declination of +30° and the zenith?
A) 30°
B) 60°
C) 90°
D) 150°

Accepted Answer

The zenith at the North Pole directly corresponds to the celestial pole, which is at a declination of +90°. The angular distance from any point on the celestial sphere is the difference in their declinations. Therefore, the angular distance from +90° (North Pole zenith) to +30° (star's declination) is 60°.

Quiz 2: Users Guide to the Sky: Patterns and Cycles

If the Moon's orbital plane was aligned with the celestial equator, when would eclipses occur?

What is apparent solar time?

Suppose Earth orbited half as far from the Sun but that the size of the Moon and its orbit around Earth were the same as they are today. Which of the following statements would be true?

Which event could occur about two weeks after a total lunar eclipse?

What is the term for the period of time it takes for the Moon to complete a cycle of the lunar phases that is approximately 29.5 days long?

Why does the Gregorian calendar use leap years?

Why doesn't the Earth experience a solar eclipse every month?

What is the sidereal period of the Moon?

Which of the following describes a concept very similar to latitude?

If the Sun were twice as large but remained at its current distance from Earth, which of the following changes would allow people on Earth to still experience a total solar eclipse?

Why is the Moon's synodic period longer than its sidereal period?

The star delta Cephei has a declination of about +58.5 degrees. Which observer will see it above their horizon for the longest fraction of one night?

Why is it possible to view a total solar eclipse from Earth?

Which of the following measures time relative to the stars?

How much does the RA coordinate of the Sun change in 2 months?

During a total lunar eclipse, where is the Moon?

A total solar eclipse occurred in Brandon, Manitoba, on Feb. 26, 1979. At what other date was there (or will there be) the same eclipse visible at this location?

Do the constellations visible in the sky at a particular time of night (say, 9 p.m.) follow a seasonal pattern?

The second is defined as a fixed interval of time, with no reference to astronomical timescales. If the Earth's period of rotation doubled, but its period of revolution stayed the same, what would happen?

For an observer at the North Pole, what is the angular distance between a star at a declination of +30° and the zenith?