The Earth-Moon-Sun
System
Rotation vs. Revolution
• Rotation – the spinning of a
body on its axis
• Revolution – the motion of
a body along a path around
some point in space
Precession
• The slight movement of
Earth’s axis over a period
of 26,000 years
Seasons
• Caused because Earth’s axis is
tilted 23.5 degrees
• Summer – N. Hemisphere is
farthest from sun
• Winter – N. Hemisphere is
closest to sun
Moon Shine
•The moon does
not make it’s
own light. It
reflects
sunlight.
Waxing & Waning
• Waxing – Light side gets larger
• Waning – Light side gets smaller
New Moon
First Quarter Full Moon
Third Quarter New Moon
Eclipses
• Lunar: The shadow from Earth
blocks the light from the sun. Lunar
= Moon goes dark.
• Solar: The shadow from the Moon
blocks the light from the sun. Solar =
Sun goes dark.
Umbra & Penumbra
• The Moon & Earth cast 2
shadows. The darkest is the
Umbra. The lighter is the
Penumbra.
The Origin of the Moon
• It is widely
believed that the
moon was
formed when a
Mars sized
object smashed
into the early
Earth.
The Lunar Surface
• Craters – round
depressions in the surface
of the moon – most were
produced by the impact of
rapidly moving debris
•Highlands – densely
pitted, light-colored
areas that cover most
of the lunar surface
• Maria – dark, smooth
surfaces – originated
when asteroids punctured
the lunar surface, letting
magma bleed out
• Lunar Regolith – a soil-like
layer of gray debris covering
the surface of the moon –
made up of rocks, glass
beads, and fine lunar dust