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Imagine that you were standing outside in
the middle of the day, and all of a sudden
it got dark, the stars came out, the temperature
dropped, and night animals started to call.
A few minutes later, the sun came out again
and everything was back to normal.
What happened?
You just saw a solar eclipse.
Ancient cultures were often frightened by
eclipses.
They did not understand why the sun became
dark.
Eclipses were seen as bad omens or predictions
of bad luck or disaster, but today we know
that eclipses are caused by the normal movement
of the sun and the moon.
There are actually three types of solar eclipses.
First, there is the most widely known type
of eclipse, a total solar eclipse.
A total solar eclipse occurs when the sun,
moon, and Earth align in the perfect position,
causing the shadow of the moon to fall on
a small area of the Earth's surface.
For people within the umbra, or darkest part
of the moon's shadow, the light of the sun
appears to vanish completely and the sky becomes
as dark as night.
The second type of solar eclipse is a partial
eclipse.
A partial eclipse occurs when the sun, moon,
and Earth are not perfectly aligned so that
the penubmra, or lighter outer portion of
the moon's shadow, falls on the earth.
In a partial eclipse, part of the sun's
surface appears to have a shadow on it.
The third type of solar eclipse is an annular
eclipse.
During an annular eclipse, the moon is at
its farthest distance from Earth, making the
shadow that falls on the Earth's surface smaller
than usual.
Because the moon appears smaller, the shadow
cannot block all of the sun, and the eclipse
will appear like a dark disk in front of the
sun.
Solar eclipses can only occur during a new
moon, as it is the only phase in the lunar
cycle when the moon is aligned correctly between
the earth and the sun.
Eclipses do not happen every time there is
a new moon, however, because the moon's orbit
is tilted compared to the earth's, and so
they only align sometimes instead of every
month.
Solar eclipses are actually fairly regular
astronomical events: between two and five
solar eclipses occur each year, but total
solar eclipses only happen about every year
and a half.
Because the area from which a total eclipse
can be seen is so small, however, the chances
of an individual eclipse being visible from
where you are is very small.
A total solar eclipse in your area might be
a once-in-a-lifetime event!
It is important to remember that looking directly
at the sun can hurt your eyes or even cause
blindness, so you should avoid looking at
the sun during an eclipse unless you have
special eye protection or filters to block
out the harmful light.
If you don't have these filters you can still
observe the eclipse by making a pinhole camera
using materials from around your home.
Find out when the next solar eclipse will
be visible from your area so that you can
prepare to observe this exciting astronomical
event.
