Transcript moon phases

Earth Moon
and Sun
Ch. 12
I. Motion of the Earth and Moon
• The Earth, Moon and all other
bodies in the solar system are
in constant motion. All objects
can have 2 types of motion:
1. Rotation: spinning on its axis
– Causes day and night
– Earth: 24 hour period of rotation
– Moon: 28 day period of rotation
2. Revolution: traveling around
another body (like planets around
the sun or moons around their
planets)
–Objects in our solar system travel in
elliptical orbits (or paths) around
other objects
–Earth: 365 1/4 day period of
revolution
–Moon 28 day period of revolution
3. Objects in our solar system
typically revolve in paths called
orbits.
4. Most orbits in our solar system
are shaped like an elongated
circle, this shape is called an
ellipse
How to draw an ellipse:
How to draw an ellipse:
II. Gravity and Motion
1. Gravity is the force that attracts all
objects toward each other
– Universal Law of Gravitation: Newton
realized that all objects ( even the moon
and planets) have to follow the law all
through the universe
A. Gravity depends on mass and
distance
• Gravity and Mass: a bigger mass
has more gravity
• Weight: the force of gravity on an
object is the object’s weight
• Gravity and Distance: the force of
gravity decreases rapidly as distance
increases
B. We do not feel the effect of
Universal Gravitation because the
Earth is so massive and we are so
close to it. The Earth’s gravity “wins”
over all other gravitational forces on
Earth.
2. Orbital motion: the motion of bodies in
orbit is caused by a combination of two
factors:
gravity: pulling downward
inertia: moving in a straight line
III. Phases and Eclipses
• The revolution of the Earth
around the sun and the Moon
around the Earth causes moon
phases and eclipses
1. Moon Phases: the different shapes of
the moon as you see from Earth
all bodies in our solar system are lighted
on the side that faces the sun and dark
on the side that faces away
The phase of the moon you see depends
on the fraction of the lighted side that you
can see.
FIVE MAIN SHAPES
QUARTER
NEW
CRESCENT
FULL
GIBBOUS
Five Main Moon Shapes
• New: none of the lighted half is visible
• Crescent: any amount between new and
quarter
• Quarter: half of the lighted half is visible
• Gibbous: any amount more than a quarter and
less than full
• Full: all of the lighted half is visible
1st QTR
Waxing
Gibbous
Waxing
Crescent
Dusk
New Moon
Midnight
Earth
Noon
Full Moon
Dawn
Waning Gibbous
Waning Crescent
3rd QTR
SU
NLI
GH
T
Waxing and Waning
• The moon gets “light from the right”
• Waxing: the moon is getting “bigger” or
more of the lighted area is visible each
night. The right side is lit up.
• Waning: the moon is getting “smaller” or
less of the lighted area is visible each
night. The left side is lit up.
Moon Phases
•
•
•
•
•
•
•
•
1. new moon
2. waxing crescent
3. first quarter
4. waxing gibbous
5. full moon
6. waning gibbous
7. 3rd (or last) quarter
8. waning crescent
Phases of the Moon
2. Eclipses: an eclipse occurs
when the shadow of one body
falls on another
Lunar Eclipse: When the shadow
of the Earth falls on the Moon.
Lunar Eclipse
• The shadow darkens
the Moon and turns it
red because of light
bending through the
atmosphere (just like
a sunset)
• About 2-3 per year
• Last up to 4 hours
Solar Eclipse: When the shadow
of the Moon falls on the Earth.
Solar Eclipse
• Occurs every 1 to 2
years
• Last from 2-10
minutes
• Can only be seen in a
narrow path of totality
Future Total Solar Eclipses
Our Moon: The far side
The near side
Size
About ¼
the Earth’s
diameter
Features:
Craters
Can you see the rays?
Maria
Does this photo show
us a limb or terminator
line?
Name this phase!
Full Moon
What time does this phase rise and set?
Craters
Name these
features.
Maria
Name
these
features.
Does this image show us the near
side or far side of the moon?
Far Side
How can you tell?
Is this line the limb or
terminator?
Limb
Terminator
Is this line the limb
or terminator?
Name this phase!
First Quarter
Name this phase!
Waxing Crescent
Does this image show the near side or the
far side of the moon?
Near Side
Name this phase!
Waning
Gibbous
Name this
phase!
Third Quarter
From what direction does
the moon rise?
The East
Name this phase!
Waxing Gibbous
Name this phase!
Waning Crescent
What might be happening in this image?
Lunar Eclipse
Is this line the limb or
the terminator?
Limb
Name this phase!
Look closely!
Waxing Gibbous
True or False:
The Far Side and the
Dark Side of the moon
are the same thing.
False!
Name this phase!
Full Moon
Name this phase!
New Moon
Does the moon rise or set in the west?
It sets in the west.
Name this phase!
Waning Gibbous
Name this
phase!
Waning Crescent
Name this phase!
Waning Gibbous