Phases of the Moon

1. Earth’s moon orbits the earth in a little less than a month.

2. It orbits the earth in a counter clockwise direction when viewed from the North pole

3. The orbit is an elliptical pattern and therefore the distance between the Earth and moon changes

-perigee is when the moon is closest to us-Apogee is when the moon is the farthest

Phases of the Moon

• The Moon orbits Earth at an average distance of 382,400 km.

• The lunar month is the 29.53 days

• During the lunar month, the Moon goes through all its phases.

• The phases we see result from the angle the Moon makes with the Sun as viewed from Earth..

Phases of the Moon

• The Universe: The Phases of the Moon

Phases of the Moon

Lunar phases are a result of the motion of the moon and the sunlight that is reflected from its surface.

Lunar phases are a result of the motion of the moon and the sunlight that is reflected from its surface.

WAXING CRESCENT1ST QUARTERWAXING GIBBOUS

FULL MOON: WHEN THE MOON IS ON THE

OPPOSITE SIDE OF THE EARTH SO THAT IT REFLECTS SUNLIGHT BACK TO EARTH

WANING GIBBOUS3RD QUARTERWANING CRESCENTNEW MOON

WHEN THE MOON IS BETWEEN THE EARTH AND THE SUN

http://www.moonconnection.com/moon_phases.phtml

The Universe: The Phases of the Moon

In each phase of the Moon, how much of the Moon is lit up by the Sun? Half the Moon is always

lit by the Sun

Except . . .

When the Earth’s shadow hits the Moon we have a …….

Lunar Eclipse

When the full Moon is rising in the East, what is the Sun always doing?

The Sun is always setting in the West.

Therefore the Sun and Moon are exactly ________ degrees apart…try a human animation if you are having difficulty visualizing this.

The only exception is …

180

…if there is a lunar eclipse, with the Moon crossing the line of nodes.

How are the motions and positions of Earth and the Sun connected to what

happens on Earth?• Earth’s rotation on its axis determines the

length of the day.

• Earth’s orbit around the Sun determines the length of the year.

• The tilt of Earth’s rotational axis with respect to the plane of Earth’s orbit causes the seasons.

The changing phases of the Moon originally inspired the concept of the month

Watch Movie at:http://antwrp.gsfc.nasa.gov/apod/image/9911/lunation_ajc.gif

Moon Phase Names• New Moon• Waxing Crescent• First Quarter• Waxing Gibbous• Full Moon • Waning Gibbous• Third Quarter• Waning Crescent

The Causes of Moon Phases

• Think to yourself about the answer to this question:

What causes the phases of the Moon?

Take out a piece of paper and quickly write out a brief answer.

How long does it take to complete the full cycle of Moon Phases?

A. About a dayB. About a weekC. About a monthD. About a yearE. None of the above

Check your answer with your partner!

Solar Period vs. Sidereal Period of the Moon

Synodic (Solar) vs. Sidereal Periodof

the Moon

Synodic Period is 29.53 days, Moon rotates to the orange line, more than 360 degrees; back to the same phase (new moon) as leftmost image.

Sidereal Period is 27.32 days, Moon rotates to the purple line (which should be parallel to the leftmost red dotted line), 360 degrees; not back to New Moon - same phase as leftmost image

Ask a neighbor

Let’s Watch some Moon Phase Animations!

Pay attention to where the Moon, Sun and Earth are located and how the Moon appears from Earth at each of these positions.

Look at how much of the Moon is illuminated when at each position.

Look at which side of the Moon is illuminated when at each position.

Animation

ZOOM IN

Prepare for Human Animation! Get volunteers! Look at tidal locking.

Discuss plane of Moon’s orbit and angle.

http://www.sumanasinc.com/webcontent/animations/content/moonphase.html

What is a monthly cycle

& what is a daily cycle?

Label the daily times and how

the Moon phases are

broken up over time. Name the phases of the Moon that are shown.

Discuss rising and setting.

Although the Moon is always

½ lit by the Sun, we see

different amounts of the lit portion from

Earth depending on

where the Moon is

located in its month-long

orbit.

Lecture Tutorials: Causing Moon Phases

• Work with a partner!• Read the instructions and questions carefully.• Discuss the concepts and your answers with one

another. Take time to understand it now!!!!• Come to a consensus answer you both agree on.• If you get stuck or are not sure of your answer, ask

another group.• If you get really stuck or don’t understand what the

Lecture Tutorial is asking, ask one of us for help.

During the full Moon phase, how much of the moon’s surface is being illuminated by sunlight?

1. None

2. Less than half

3. Half

4. More than half

5. All

During the full Moon phase, how much of the moon’s surface is being illuminated by sunlight?

1. None

2. Less than half

3. Half

4. More than half

5. All

When the moon appears to completely cover the Sun (a solar eclipse) the moon must be at which phase?

1. Full

2. New

3. First quarter

4. Last quarter

5. At no particular phase

1) How many phases shown in the picture will the Moon go through in one day?

2) How long does it take the Moon to complete one orbit? How many of the phases will the Moon have gone through in this time?

3) How long does it take the Earth to complete one rotation? How far will the Moon have moved?

4) How much of the Moons total surface is illuminated when it is in the New Phase? Full Phase?

5) How much of the illuminated surface of the Moon is visible from Earth when it is in the First Quarter Phase, Full Phase?

6) What time is it when the Waxing Gibbous Phase is highest in the sky, Rising? Setting? What phase will it be in one week later….see next slide for answer. SKIP RED PORTION.

Could you tell time by the phase of the moon?

Ask your elbow partner if you think you could? How could you?

At what time would the first quarter moon rise?

See if you can figure it out and share with someone.

E w

What quarter are we in if the sun is coming up and the moon is

overhead?

Ew

What time is it if the full moon is directly overhead?

See if anyone close by has the same answer?

Ew

What time would it be when the new moon would set behind the horizon?

A. 9:00 am

B. 12 noon

C.3 pm

D.Never, there is no moon when we have a new moon

Ew

What is a blue moon?

There are in fact two definitions for a blue moon.

1. a blue moon is the second full moon in a calendar month. For a blue moon to occur, the first of the full moons must appear at or

near the beginning of the month so that the second will fall within the same month (the average span between two moons is

29.5 days).2. states that the blue moon is the third full moon in a season that

has four full moons.

What phase is our Moon in right now?

Discuss light fills in from the right-ish side.

http://www.clarkplanetarium.org/pages/nightSky

http://meteorshowersonline.com/lyrids.html

http://yasirlioneljordan.blogspot.com/2011/04/moon-phases-2011-february.html

Lunar Calendar

Lecture Tutorials: Predicting Moon Phases

• Work with a partner!• Read the instructions and questions carefully.• Discuss the concepts and your answers with one

another. Take time to understand it now!!!!• Come to a consensus answer you both agree on.• If you get stuck or are not sure of your answer, ask

another group.• If you get really stuck or don’t understand what the

Lecture Tutorial is asking, ask one of us for help.

A Moon Phase is highest in the sky at 9 pm today. What phase will the Moon have in three weeks after today?

A few more resources you might enjoy!

Animations:

more complex demo. http://jove.geol.niu.edu/faculty/stoddard/JAVA/moonphase.html

http://home.hiwaay.net/~krcool/Astro/moon/moonphase/Gives information on the different moon phases and the times of day when they are visible.