1. Chapter 23
Sun-Earth-Moon
System

2. Key Terms
Rotation
– the spinning of
Earth on its axis (takes 24
hours )
Revolution – Earth’s
yearly orbit around the
sun.

3. Key Terms
Ellipse
– an elongated,
closed curve (Earth orbits
the Sun this way)

4. Solstices
Solstice
– the day when
the Sun is farthest north
or south of the equator.
Occurs twice yearly summer & winter (June
21/22 & Dec. 21/22)

5. Moon Rotation/Revolution
The
Moon’s rotation takes
27.3 days – the same
amount of time it takes to
revolve once around Earth.
Thus, we always see the
same side of the Moon!

6. Phases of the Moon
The
phases of the Moon
depend on the positions
of the Moon, Earth, and
the Sun.
There are 8 phases.

7. New Moon
Occurs
when the Moon is
between Earth and the Sun.
The lighted ½ faces the Sun,
the dark ½ faces Earth.
It’s in the sky but can’t be
seen.

8. Waxing Phases
Occur
after a new Moon, and
more of the lighted half of the
moon can be seen each night.
Waxing Crescent – can be
seen about 24 h after a new
moon as a thin slice.

9. Waxing
Crescent

10. 1 Quarter Phase
st
Can
be seen about 1 week
after a new moon.
Appears to about ½ of the
lighted side of the Moon.

12. Waxing Gibbous
Occurs
when more than ¼
of the Moon is visible.

14. Full Moon
Occurs
when all of the
Moon’s surface facing Earth
reflects light.
Remember, Earth is
between the Sun and Moon.

16. Waning Phases
Waning
occurs after a full
moon, and you see less of
its lighted half each night.
The lighted parts will be on
the left side of the Moon!

17. Waning Gibbous
Begins
just after a full
moon.
To me, you can see about
¾ of the lighted Moon.

19. Third-Quarter Phase
Occurs
when you can see
only ½ the lighted side.

21. Waning Crescent
Occurs
when you can see a
small lighted slice on the
left side.
Will occur just before
another new moon.

24.  Once
you can located the New and Full
moon on a diagram always move counter
clockwise from the NEW to the FULL
phase. If you go counter clockwise the
first set of phases are the WAXING
phases then after you reach the FULL
moon the set of phases are the waning
phases,