THE SUN, EARTH, & MOONPhases of the Moon

Something to Think About!

■ Rotation:

– When an object rotates, it spins on its axis

■ The Earth makes one complete rotation on its axis every 24 hours

■ The Moon makes one complete rotation in approximately 28 days

■ Revolution:

– When an object Revolves, it moves around another object

■ The Earth revolves around the Sun

■ The Moon revolves around the Earth

The Sun, Earth, and Moon

■ The Sun is the center of the solar system

■ The Earth rotates on its axis every 24 hours

– Cause of day and night on Earth

■ The Earth has one moon

– The moon makes one complete revolution around the Earth every

28 days

All About The Moon

■ The Moon is:

– Earth’s only natural satellite

– Approximately 384,400 km [238,855 miles] away from the Earth

■ Is the orbit of the Moon around the Earth perfectly circular?

– No, the orbit of the moon is not a perfect circle.

■ When the moon is at the closest point [perigee] the moon is 225,804 miles away

from the earth

■ When the moon is at the most distant point [apogee] the moon is 251,968 miles

away from Earth

Man on the Moon

July 30, 1971

Apollo 15 astronaut Jim

Irwin on the Moon with the

first Lunar Roving Vehicle.

Jim Irwin was the 8th man

to walk on the Moon

Moon Light

■ The Moon is not a star and does not give off light

– The Moon reflects light from the Sun

■ The Moon is rotating on its axis and revolving around the Earth

– The position of the Moon changes during the 29 and ½ day lunar

cycle

The Lunar Cycle

■ As the Moon revolves around

the Earth:

– The shape of the Moon

appears to change

■ Do you think that the shape of

the moon actually changes?

– Study the images of the

lunar cycle before you

answer

More About the Lunar Cycle

■ Only the side of the moon facing the

sun can reflect sunlight.

■ During much of the lunar cycle we

can only see a portion of the sunlit

moon

■ What do you think we see during a

‘new moon’?

■ What do we see when the moon is a

crescent?

The outside images are what

we see when we look up at

the moon from Earth

The portion of the moon

facing the sun reflects

sunlight

Views of the Moon from Earth

■ Green lines represent

portions of the Moon we

cannot see from Earth

■ White areas of the Moon

are what we see from

the Earth

A Waxing Moon

■ When the Moon is said to be ‘Waxing’

– The sunlit part of the Moon at any time before a full Moon

– The sunlit part of the Moon we see is getting larger

A Waning Moon

■ When the Moon is said to be ‘Waning’

– The sunlit part of the Moon at any time after a full Moon

– The sunlit part of the Moon we see is getting smaller

The New Moon

■ During a new moon, we do

not see the moon in the sky

– The dark side of the

moon is facing the

Earth

– The other side of the

moon is very bright

and facing the sun

■ Can you find the new moon

in the picture to the right?

The Waxing Crescent Moon

■ When we see the ‘waxing

crescent moon’ a thin sliver or

crescent of the moon is

visible.

– When we are able to see

a bit more of the moon,

we say the moon is

waxing.

■ Can you find the waxing

crescent moon in the picture

to the right?

The Quarter Moon

■ About one-week after the

new moon, the moon has

completed about one-

quarter of its orbit around

the Earth.

– We are able to see

one-half of the bright

side of the moon.

Actually, that is a

quarter of the moon.

■ Can you find the waxing

quarter moon in the image

on the right?

The Waxing Gibbous Moon

■ As the moon continues to orbit the Earth, we are able to see more of the bright portion of the moon.

– The gibbous moon is nearly a full moon

– We call it a waxing moon because we can see more of the moon from Earth.

■ Can you find the waxing gibbous moon in the image on the right?

The Full Moon

■ When the moon is full, we

are able to see the half of

the moon illuminated by

the sun.

– The Sun, Earth and

Moon are nearly in a

straight line.

■ What other time during the

moon’s orbit are the Sun,

Earth, and Moon nearly in a

straight line?

The Waning Gibbous Moon

■ The waning gibbous moon

is nearly a full moon but

we are seeing less of the

moon.

– We say the moon is

waning and we call the

moon a gibbous moon

because it is nearly full

■ Can you find the waning

gibbous moon in the image

to the right?

The Last Quarter

■ The portion of the moon

lit by the sun is growing

smaller.

– The left half of the

moon is illuminated

by the sun

■ Can you find the last

quarter of the moon in

the image on the right?

The Waning Crescent Moon

■ As the moon appears to be smaller and smaller in the sky, it is called the waning crescent.

– The waning crescent moon will continue to appear smaller and smaller with each day.

■ Can you find the waning crescent moon in the image on the right?

The Moon from the Earth

Something to Think About!

■ How is the Waxing Crescent Moon different from the Waning Crescent

Moon?

■ If you looked into the night sky during the New Moon, would you

expect the stars to be more or less visible in the night sky?