Question 1

Predicting an eclipse is easy because all you have to do is keep track of where the Moon crosses the ecliptic.

Accepted Answer

True

Question 2

What is a new moon?
A) The lunar phase in which the first-quarter moon approaches full moon
B) The lunar phase in which Earth's shadow is cast on the Moon
C) The lunar phase in which the Moon's shadow is cast on Earth
D) The lunar phase in which sunlight illuminates only the far side of the Moon
E) The lunar phase in which sunlight illuminates the Earth facing side of the Moon

Accepted Answer

A new moon occurs when the Moon is positioned between the Earth and the Sun, causing the side of the Moon that faces Earth to be in shadow, while the far side is illuminated by the Sun.

Question 3

As the illuminated part of the Moon grows larger from new to full, it is said to "wane".

Accepted Answer

The illuminated part of the Moon does not "wane" as it grows larger from new to full. It is said to "wax" during this period. "Wane" is used to describe the decreasing illumination of the Moon from full to new.

Question 4

A "larger" Moon on the horizon is an optical illusion.

Accepted Answer

The Moon appears larger on the horizon due to an optical illusion called the moon illusion, where our brain perceives the Moon to be larger when it is closer to the horizon compared to when it is higher in the sky. However, this is just an illusion and the size of the Moon remains constant throughout its orbit.

Question 5

The geometry of a solar eclipse is the same as that of a lunar eclipse.

Accepted Answer

The geometry of a solar eclipse is different from that of a lunar eclipse. In a solar eclipse, the moon is between the sun and the earth, blocking the sun's light from reaching the earth. In a lunar eclipse, the earth is between the sun and the moon, casting a shadow on the moon.

Question 6

What are the two parts of a shadow during an eclipse?
A) total and partial
B) apogee and perigee
C) sidereal and synodic
D) waxing and waning
E) umbra and penumbra

Accepted Answer

During an eclipse, there are two parts to a shadow - the umbra (the darker central shadow) and the penumbra (the lighter outer shadow).

Question 7

The Moon has a dark side that is never lit by the Sun.

Accepted Answer

The Moon actually does not have a permanent dark side. Instead, it has a far side that is always facing away from Earth, but it does receive sunlight.

Question 8

Any location on the Moon is sunlit for three weeks and is in darkness for one week as the Moon rotates.

Accepted Answer

Any location on the Moon experiences about two weeks of sunlight followed by two weeks of darkness due to the Moon's rotational period being about 27.3 days.

Question 9

Since the Moon is about 0.5 degrees in angular diameter, about how far does it move in 24 hours across the background of the constellations?
A) 0.5 degrees
B) 1.0 degree
C) 2 degrees
D) 9 degrees
E) 13 degrees

Accepted Answer

The answer of Since the Moon is about 0.5 degrees...

Question 10

In most months, there are no eclipses.

Accepted Answer

Eclipses are rare phenomena that occur only a few times a year. Therefore, in most months, there are no eclipses.

Question 11

There is one side of the Moon that can never be seen directly by observers on Earth.

Accepted Answer

This is because the Moon is tidally locked with Earth, meaning that it takes the same amount of time to complete one rotation on its axis as it does to revolve around Earth. As a result, one side of the Moon always faces Earth while the other side remains permanently hidden from view. This hidden side is commonly referred to as the "far side" of the Moon.

Question 12

When the full Moon passes through Earth's shadow, the eclipse is visible from anywhere on Earth's dark side.

Accepted Answer

During a lunar eclipse, the Earth passes between the Sun and the Moon, causing the Moon to pass through the Earth's shadow. This means that as long as an observer is on the side of the Earth facing away from the Sun during the eclipse, they will be able to see the eclipse. Therefore, it is visible from anywhere on Earth's dark side.

Question 13

What is the length of time half of the Moon stays in sunlight per full rotation?
A) 29.53 days
B) 27.3 days
C) two weeks
D) one month
E) two months

Accepted Answer

The answer of What is the length of time half...

Question 14

The angular diameters of the Moon and Sun vary slightly because the orbits of the Moon and Earth are slightly elliptical.

Accepted Answer

The distance between the Moon and Earth and the distance between the Sun and Earth change as the two bodies revolve around each other, causing a slight variation in their angular diameters.

Question 15

When the Moon is totally eclipsed, the Moon is illuminated by some sunlight reflected by Earth's atmosphere.

Accepted Answer

The answer of When the Moon is totally eclipsed, the...

Question 16

To see a solar eclipse, you have to be in Earth's shadow.

Accepted Answer

To see a solar eclipse, you have to be in the moon's shadow, not Earth's shadow.

Question 17

What does a waning crescent moon mean?
A) The changing Moon between full moon and third quarter
B) The changing Moon between third quarter and new moon
C) The changing Moon between first quarter and full moon
D) The changing Moon between new moon and first quarter
E) The changing Moon between first and third quarters

Accepted Answer

A waning crescent moon occurs in the period between the third quarter and new moon phases. This is when the visible illuminated portion of the moon decreases in size each night until it becomes a new moon.

Question 18

What produces the lunar phases?
A) The rotation of the Moon
B) The revolution of the Moon
C) The changing direction of sunlight
D) Earth's tilted axis relative to the Moon
E) The changing direction of Earth to the Moon

Accepted Answer

The answer of What produces the lunar phases?
A) The rotation...

Question 19

The Moon moves slowly against the background of the constellations.

Accepted Answer

The answer of The Moon moves slowly against the background...

Question 20

Our calendar divides the year into 30-day periods in recognition of the synodic cycle of the Moon.

Accepted Answer

A synodic cycle of the Moon is the time it takes for the Moon to return to the same phase (e.g. full moon to full moon). This cycle is roughly 29.5 days, which is why our calendar divides the year into 30-day periods.

Quiz 3: Moon Phases and Eclipses