Eclipses:
Shadow and Light
Which of the Following is True?
1. An eclipse of the sun occurs when an
invisible dragon eats the sun.
2. During eclipses, poisons drop from the
sky
3. An eclipse is a sign that the world is
coming to an end.
4. None of thee above.
Answer
None of thee above.
People from cultures all over the world
created these and other stories to explain
the mysterious disappearance of the sun
and moon from the sky.
Solar Eclipse
A solar eclipse occurs when the Moon
comes directly between Earth and the
Sun.
The key word is directly, because the
moon orbits the Earth every month, and
every month the moon casts a shadow.
Solar Eclipses
During a solar eclipse, the darkest part of
the Moon’s shadow cone, called the
“umbra” is often only 250 kilometers in
diameter.
As the earth spins, different parts of it fall
within the umbra.
People who happen to be in the umbra
can see a total blocking of the Sun, or a
total solar eclipse.
Outside the Umbra
The moon blocks only part of the Sun and
creates a partial Solar Eclipse.
A shadow is cast, but it isn’t as dark as the
umbra. This lighter part of the shadow
cone is called the “preumbria.”
Lunar Eclipse
In a Lunar Eclipse, Earth comes directly
between the Sun and Moon - placing the
Moon in Earth’s shadow.
When the entire full moon falls within the
center of Earth’s umbra, we have a total
lunar eclipse.
Everyone on the night side of the Moon
can see the eclipse!
More on Lunar Eclipses
Depending on how much dust and how
many clouds are in Earth’s atmosphere,
the moon will appear dark brown, red,
orange, or yellow.
Partial Lunar Eclipse
A partial lunar eclipse occurs when only
part of the Moon passes through the
Earth’s umbra.
A penumrial lunar eclipse occurs when the
moon passes through only the lighter part
of Earth’s shadow cone.
Neither of these eclipses is as colorful as a
lunar eclipse.
Safe Way to View a Solar Eclipse
NEVER look through a telescope or
binoculars, or any optical aide or device
that magnifies an image, at the Sun or a
Solar Eclipse; this would cause
PERMANENT BLINDNESS INSTANTLY !
Safety!
NO filtering device, sunglasses,
photographic film or negatives, or
darkened or "smoked" glass or plastic, is
safe for looking at the Sun or a Solar
Eclipse, unless it is SPECIFICALLY
DESIGNED FOR SOLAR ECLIPSE
OBSERVING and UNDAMAGED (i.e.
includes no pinholes or holes of any size) !
Safety!
To safely view a Solar Eclipse, prepare a box
as shown, with a pinhole (perhaps in aluminum
foil covering a larger hole in the box) at one end
and a white sheet of paper at the other end,
inside.
Standing, with your back to the Sun and your
head inside the box, allow the Sun's light to
shine through the pinhole and observe a small
image of the Solar Eclipse on the white sheet of
paper.
Alternatives
If you cannot find a box, you can also use two
pieces of cardboard.
Place a pinhole in one piece of cardboard.
Standing with your back to the Sun, allow the
light from the eclipse to shine through the
pinhole and project onto the second piece of
cardboard, where you will see a small image of
the solar eclipse.
Again, NEVER look through the pinhole at the
Sun or a Solar Eclipse; this could cause MAJOR
EYE DAMAGE and POSSIBLE BLINDNESS !
Safety tips found at:
andrewcarnegie.tripod.com/solflyer2.htm