Study Points• What is a mare?

• What causes craters, especially on the Moon?

• What is the Moon’s terminator?

• Explain why the Moon exhibits phases. Draw the Sun-Earth-Moon system showing the Moon’s orbit (not to scale), draw Moon in 8 different positions in its orbit and shade in Earth and Moon indicating which side is lit and which is dark. Use that drawing to explain what phase you will see for each of the Moon’s locations you drew.

• Knowing when New Moon occurs, predict about when First Quarter, Full, and Last Quarter Moons will occur. Know about how many days are in between the phases.

• Explain why the Sun, Moon and stars appear to rise in the east and set in the west. Explain why we have day and night using a sketch of Sun-Earth-Moon system to help.

• In one hour, the Moon, Sun, and stars move about how many degrees in the sky? (hint: how many degrees does the Earth rotate in 24 hours)?

• In one day, the Moon moves about how many degrees in the sky? (hint: about how many degrees does the Moon revolve in 30 days)?

• What direction does the Moon move from one night to the next? Explain?

• Explain why you always see the same face of the Moon.

Cycles of the Sky: Part 1Moon

Moon Terminology

http://www.astronomy.org/StarWatch/January/1-15-08-moon.jpg

• Terminator – line between light and dark*

• Craters – indents caused by meteoroids*

• Mare/Maria (mar-e-ah) – dark, lowland areas*

• Phases• Rotation (spin)• Revolution (orbit)

Moon Observation Projects:Moon Phases (starts today)Moon Craters (starts next Tue.)

Motion

• Everything is in motion

• Some motion is easy to see, some is not

Which direction does the Earth rotate (spin)?

Clockwise or Counterclockwise?

Motion

• Everything is in motion

• Some motion is easy to see, some is not

Which direction does the Earth rotate (spin)?

Clockwise or Counterclockwise?

Motion

• Everything is in motion

• Some motion is easy to see, some is not

Which direction does the Earth rotate (spin)?

Clockwise or Counterclockwise?

Which direction does the Earth revolve (orbit)?

Clockwise or Counterclockwise?

Motion

• Everything is in motion

• Some motion is easy to see, some is not

Which direction does the Earth rotate (spin)?

Clockwise or Counterclockwise?

Which direction does the Earth revolve (orbit)?

Clockwise or Counterclockwise?

Motion

• Everything is in motion

• Some motion is easy to see, some is not

• Earth rotates and revolves in the counterclockwise direction

Moon’s Motion

You decide to watch our moon for a few hours one night. Which way does it move in the sky?

1. Toward the east

2. Toward the west

(Show on Starry Night)

Moon’s Motion

You decide to watch our moon for a few hours one night. Which way does it move in the sky?

1. Toward the east

2. Toward the west

(Show on Starry Night)

• The Moon rises in the East and Sets in the West*

• Same motion as the Sun in our sky

Moon’s Motion: East to WestWhat is moving?

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Both

Moon’s Motion: East to WestWhat is moving?

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Both

Moon’s Motion: East to WestWhat is moving?

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Both

What is moving that predominantly causes the Moon to move east to west?

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Sun moves

Moon’s Motion: East to West*What is moving?

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Both

What is moving that predominantly causes the Moon to move east to west?*

1. Moon orbits (revolution)

2. Earth spins (rotation)

3. Sun moves

About how long does Earth take to spin (rotate) once?

1. ~1 hour

2. ~1 day

3. ~1 month

4. ~1 year

About how long does Earth take to spin (rotate) once?

1. ~1 hour

2. ~1 day

3. ~1 month

4. ~1 year

About how long does our Moon take to orbit (revolve) once around Earth?

1. ~1 hour

2. ~1 day

3. ~1 month

4. ~1 year

About how long does our Moon take to orbit (revolve) once around Earth?

1. ~1 hour

2. ~1 day

3. ~1 month

4. ~1 year

Which way does our Moon revolve (orbit)?

1. Same direction that Earth spins

2. Opposite direction that Earth spins

- View from space with Solar System Simulator http://sssim.com/en/index.html

- Draw it

You can try your own Solar System Simulator here: http://www.faustweb.net/

Which way does Moon revolve (orbit)?

1. Same direction that Earth spins = CCW

2. Opposite direction that Earth spins

- View from space with Solar System Simulator http://sssim.com/en/index.html

- Draw it

You can try your own Solar System Simulator here: http://www.faustweb.net/

If you watch Moon for a few hours, which motion dominates?

1. Moon’s motion due Earth’s spin (rotation)

2. Moon’s motion due to its own orbit around Earth (revolution)

(Draw it)

If you watch Moon for a few hours, which motion dominates?

1. Moon’s motion due Earth’s spin (rotation)

2. Moon’s motion due to its own orbit around Earth (revolution)

(Draw it)

If you note Moon’s position from one hour to the next, predict if it will move

1. East to west

2. West to east

If you note Moon’s position from one night to the next (same time), predict if it will move

1. East to west

2. West to east

Starry Night for both

If you note Moon’s position from one hour to the next, predict if it will move

1. East to west*

2. West to east

If you note Moon’s position from one night to the next (same time), predict if it will move

1. East to west

2. West to east

Starry Night for both

If you note Moon’s position from one hour to the next, predict if it will move

1. East to west*

2. West to east

If you note Moon’s position from one night to the next (same time), predict if it will move

1. East to west

2. West to east*

Starry Night for both

Moon’s Motion Conclusion*

• Minute to minute (or hour to hour) the Sun, Moon, stars appear to rise in east and set in west due to Earth’s spin (rotation).*

• Day to day, Moon moves west to east due to Moon’s orbit (revolution) around Earth*

How much do the Moon, Sun, and stars move in our sky in an hour?

How much do the Moon, Sun, and stars move in our sky in an hour?

First answer: How many degrees do they move in a day?

How much do the Moon, Sun, and stars move in our sky in an hour?

First answer: How many degrees do they move in a day?

About 360 degrees around Earth in one day as Earth revolves

How much do the Moon, Sun, and stars move in our sky in an hour?

First answer: How many degrees do they move in a day?

About 360 degrees around Earth in one day as Earth revolves

= 360 degrees / 24 hours = 15 degrees per hour across our sky*

How much does the Moon move each day?

How much does the Moon move each day?

How many degrees does the Moon move as it revolves (orbits) around Earth?

How much does the Moon move each day?

How many degrees does the Moon move as it revolves (orbits) around Earth?

360 degrees

How much does the Moon move each day?

How many degrees does the Moon move as it revolves (orbits) around Earth?

360 degrees

How long does the Moon take to revolve around Earth?

How much does the Moon move each day?

How many degrees does the Moon move as it revolves (orbits) around Earth?

360 degrees

How long does the Moon take to revolve around Earth?

about 30 days

How much does the Moon move each day?

How many degrees does the Moon move as it revolves (orbits) around Earth?

360 degrees

How long does the Moon take to revolve around Earth?

about 30 days

So…each day the Moon moves:

About 12 degrees per day (~10 deg/day)*

How much does the Moon move each day? How many degrees does the Moon move as it revolves (orbits) around Earth?

360 degreesHow long does the Moon take to revolve around Earth?

about 30 daysSo…each day the Moon moves:About 12 degrees per day (~10 deg/day)*

Moon rises later each day; about 50 minutes later each day

Now compare the Moon’s movement to the Earth’s movement in 1 day.

Which motion dominates?How much does the Earth move each day?

How many degrees does the Earth move as it revolves (orbits) around the Sun?

Now compare the Moon’s movement to the Earth’s movement in 1 day

How much does the Earth move each day?

How many degrees does the Earth move as it revolves (orbits) around the Sun?

360 degrees

Now compare the Moon’s movement to the Earth’s movement in 1 day

How much does the Earth move each day?

How many degrees does the Earth move as it revolves (orbits) around the Sun?

= 360 degrees/365 days ~= 1 deg/day

Now compare the Moon’s movement to the Earth’s movement in 1 day

How much does the Earth move each day?

How many degrees does the Earth move as it revolves (orbits) around the Sun?

Earth moves about 1 degree/day

And

The Moon moves about 10 degrees/day

Which motion dominates?

Now compare the Moon’s movement to the Earth’s movement in 1 day

How much does the Earth move each day? How many degrees does the Earth move as it revolves (orbits) around the Sun?

Earth moves about 1 degree/dayAndThe Moon moves about 10 degrees/dayWhich motion dominates?The Moon (10 deg/day > 1 deg/day)*This is the reason the Moon appears to move

backward in the sky from one day to the next (& rises later each day).*

Moon’s Motion Conclusion*

• Minute to minute (or hour to hour) the Sun, Moon, stars appear to rise in east and set in west due to Earth’s spin (rotation).*

• Day to day, Moon moves west to east due to Moon’s orbit (revolution) around Earth*

8 Moon Phases*

What we see from Earth…New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to New Moon?

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to New Moon?

~28 days

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to Full Moon?

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to Full Moon?

~14 days

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to First Quarter?

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

8 Moon Phases*

How many days from

New Moon to First Quarter?

~7 days

Also ~7 days between:

• First Quarter to Full Moon

• Full Moon to Last Quarter

• Last Quarter to New Moon

New

Waxing Crescent

First Quarter

Waxing Gibbous

Full

Waning Gibbous

Last Quarter

Waning Crescent

Moon Phases***

Orerry with light

What we see from Earth & space…

Moon Phases Demonstration

• Lamp in front of the room acts as the Sun

• Each student holds a Moon

• Try to see phases of the Moon as seen from Earth

Moon Phases* – Notice the Sun Location Changed*

Orerry with light

Sun

Moon Phases Observation• 10 points

• From Jan. 23 to Mar. 5 to complete

• Record phases and location of the Moon over 4 separate dates. Observe 4 different phases of the Moon. There are 8 phases of the Moon over ~28 days.

• Class website has more details in Moon Phases observation file.

– Helpful website: https://www.timeanddate.com/moon/usa/minneapolis

• Turn in the Moon Phases Observation sheet or submit on D2L or take a picture of it and email it to Raquel.

Does the Moon rotate?

Does the Moon rotate?

• Yes, its rotation keeps the same side of the Moon always facing Earth*

= Tidal Locking*

• Tidal Locking video demo: https://en.wikipedia.org/wiki/Tidal_locking

• Moon’s libration

• http://antwrp.gsfc.nasa.gov/apod/ap040829.html

Earth’s Moon

Moon Phases Survey

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

Moon Phases SurveyTop viewNot to scaleFive positions of Moon

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

1. Which position of Moon has the GREATEST amount of sunlight illuminating the Moon’s surface?a. Ab. Bc. Cd. De. They all have the same amount of sunlight illuminating the surface.

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

2. Which position of Moon has the LEAST amount of sunlight illuminating the Moon’s surface?a. Ab. Bc. Cd. De. They all have the same amount of sunlight illuminating the surface.

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

3. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

4. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

5. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Moon images from http://www.cstarsoas.org.nz/index.php?mod=art&id_pag=52

6. In the moon phase pictures on the right, what causes Moon to change its appearance this way?

a. As Moon orbits Earth, Earth’s shadow covers Moon.

b. Clouds block part of Moon from our view.

c. As Moon orbits Earth, we see different views of Moon’s sunlit side.

Moon Survey Answers

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

1. Which position of Moon has the GREATEST amount of sunlight illuminating the Moon’s surface?a. Ab. Bc. Cd. De. They all have the same amount of sunlight illuminating the surface.

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

2. Which position of Moon has the LEAST amount of sunlight illuminating the Moon’s surface?a. Ab. Bc. Cd. De. They all have the same amount of sunlight illuminating the surface.

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

3. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

4. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Sun

Earth

Sunlight

NOT TO SCALE

Moon’s Orbit

A

B

C

D

E

5. The arrow on the right points to one phase of the Moon. Which position in the drawing below corresponds to that phase?

Moon images from http://www.cstarsoas.org.nz/index.php?mod=art&id_pag=52

6. In the moon phase pictures on the right, what causes Moon to change its appearance this way?a. As Moon orbits Earth, Earth’s shadow covers Moon.b. Clouds block part of Moon from our view.c. As Moon orbits Earth, we see different views of

Moon’s sunlit side.

Homework• Continue flashcards of STUDY POINTS• Complete D2L Quizzes 1 &2 (#2 is new today) • Lab – arrive this week with the necessary materials

– If you missed Lab Tuesday, come talk with me.• Observations

– Earth-Sun Scale Model Start Jan. 16; Due Jan. 28 (10 points) Make scaled model & take picture

– Sunset – Part 1 Start Jan. 21; Due Feb. 18 (10 points)Take 1st picture of sunset (~4pm) at a place you can return for part 2

– Star Gazing (SG) Start Jan. 21; Due May 12 (20 points) Go star gazing & write report

– NEW: Moon Phases Start Jan. 23; Due Mar. 5 (10 points) Observe 4 phases & record in table

– Info about Planetarium Field Trip on Feb. 4: Bus from college at 8:15am and returns by 10:30am.

For additional learning or if you missed the lecture, watch this: Crash Course in Astronomy #4