In each phase of the Moon, how much of the Moon is
lit up by the Sun?
Half the Moon is always
lit by the Sun
Except . . .
When the Earth’s shadow hits the Moon we have a …….
Lunar Eclipse
Eclipses
Solar Eclipse—the moon moves in a line
directly between the Earth and sun
Lunar Eclipse---the moon moves into the
Earth’s shadow
Eclipses
• A solar eclipse can only happen at new Moon,
when the lunar disk passes directly between us
and the Sun.
• A lunar eclipse occurs during full Moon, when
our satellite passes through Earth's shadow.
• These alignments don't occur at every new and
full Moon because the lunar orbit is tipped about
5° to Earth's orbital plane — only occasionally
do the Sun, Earth, and Moon line up exactly
enough for an eclipse to occur.
http://sunearthday.gsfc.nasa.gov/2008eclipse/mec
hanics.php
Lunar Eclipse
• When Earth blocks most of the sunlight from
illuminating the Moons surface for several
hours when in the full moon phase
Remember that when the shadow falls on Earth it is a SOLAR
ECLIPSE (always at NEW Moon) & when the shadow falls on the
Moon it is a LUNAR ECLIPSE (always at FULL Moon).
Lunar Eclipses
Lunar Eclipses
• Why is the Moon Red During a Total Lunar Eclipse?
During a total lunar eclipse, the Earth blocks the Sun's light from
reaching the Moon. Astronauts on the Moon would then see the
Earth completely eclipse the Sun. (They would see a bright red ring
around the Earth as they watched all the sunrises and sunsets
happening simultaneousely around the world!) While the Moon
remains completely within Earth's umbral shadow, indirect sunlight
still manages to reach and illuminate it. However, this sunlight must
first pass deep through the Earth's atmosphere which filters out most
of the blue colored light. The remaining light is a deep red or orange
in color and is much dimmer than pure white sunlight. Earth's
atmosphere also bends or refracts some of this light so that a small
fraction of it can reach and illuminate the Moon.
Blood Moon
• What is a lunar tetrad? Astronomers are
talking about the lunar tetrad of 2014-2015.
What is a tetrad? It’s four successive total
lunar eclipses, with no partial lunar eclipses in
between, each of which is separated from the
other by six lunar months (six full moons).
Current media is referring these as Blood
moons - the term originally was used for
Lunar eclipses that occur during passover.
When the Moon’s shadow hits the Earth, we have a ….
Solar Eclipse
Solar Eclipses
Solar Eclipse
Annular Eclipse
Partial Eclipse
Total Eclipse
Which positions cause which eclipses
Moon
full
• When the ______
is in the _____
phase and is
Earth and the ____
Sun
directly in line with the _____
, you get
a ______
eclipse?
lunar
new
Moon
• When the ______
is in the _____
phase and is
Earth and the ____
Sun , you get
directly in line with the _____
solar
a ______
eclipse?
Important Moon dates (North America)
and Eclipses
• 2015:
Autumn Equinox: September 23
Harvest Moon: September 28
Hunter’s (Blood) Moon: October 27
Eclipses
• Total Solar March 20 –not visible here
• Partial lunar April 4
• Total Lunar September 28 (maybe visible here)
• August 21 2017 next visible Total Solar eclipse here
Eclipses lab
• Follow the directions on the lab sheet. We
will need to have lights off again to see our
eclipses.