You will be able to… •Describe the movements of Earth known as rotation and revolution. •Explain how the moon goes through phases. •Explain how eclipses occur. 22.2 The Earth-Moon-Sun System
You will be able to… •Describe the movements of Earth known as rotation and
revolution.
•Explain how the moon goes through phases.
•Explain how eclipses occur.
22.2 The Earth-Moon-Sun System
Motions of Earth
22.2 The Earth–Moon–Sun System
The two main motions of Earth are
rotation and revolution.
22.2 Motions of Earth
Rotation • Rotation is the turning, or spinning, of a body on its
axis.
• Earth’s axis is the imaginary line that passes thru
the center and connects the north and south pole.
• 1 complete rotation of Earth equals 1 Day = 24 hrs.
22.2 Motions of Earth
Revolution • The movement of one object around another
in space is called revolution.
• It takes Earth 365.25 days to make one
complete orbit or revolution around the sun.
http://www.youtube.
com/watch?v=8bAfi
G7hTvM&feature=r
elated
Seasons
• As earth revolves around the sun, we experience different seasons. – Seasons are caused by the
23.5° tilt of Earth’s axis.
• During the summer in the Northern Hemisphere, the north pole is tilted towards the sun.
• During the winter in the N. Hemisphere, the north pole is tilted away from the sun.
• Earth is closer to the sun during our winter
and farther away during our summer.
22.2 Lunar Cycle
• Lunar phases are a result of the motion of the
moon and the sunlight that is reflected from its
surface.
•The gradual change in the appearance of
the moon is known as the lunar cycle.
Phases of the Moon
• New moon – when the moon is between earth and the sun
Phases of the Moon
• Full moon – When earth is between the moon and the sun.
Phases of the Moon
• Crescent – More darkness than
light on the moon.
Phases of the Moon
• Quarter (Half) – When half the moon
is dark and half is light.
Phases of the Moon
• Gibbous – When more of the
moon is light than dark.
Adding to the Phases of the Moon
• Waxing – when the
size of the visible
portion of the moon
increases.
• Waning – The portion
of the moon visible
from earth decreases.
22.2 Two Types of Eclipses
Solar eclipses occur when the moon moves
in a line directly between Earth and the sun,
casting a shadow on Earth.
• S = Sun
• o = moon
Solar Eclipse • Tip: Lasts no longer than 7 ½ minutes.
• 2 to 5 per year.
• Solar eclipse can only been seen by
people along the shadows path
• http://csep10.phys.utk.edu/astr161/lect/time/eclipse_anim.html
• http://csep10.phys.utk.edu/astr161/lect/time/eclips94.mpg
• Lunar eclipses occur when the moon passes
through Earth’s shadow.
During a new-moon or full-moon phase,
the moon’s orbit must cross the plane of
the ecliptic for an eclipse to take place.
Can occur at most 3 times a year
Lunar eclipse can be seen by everyone on the
dark (night) side of earth.
Lunar Eclipse • Lasts no longer than 3 hours and 40 minutes.
• During a total lunar eclipse, the moon doesn't simply fade to
black. In fact, it often takes on a reddish hue, ranging from
peach to crimson. This has to do with the way the atmosphere
scatters sunlight.