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Sun-Earth Day Presents: Eclipse, In a Different Light



How Long Will Totality Last?
The amount of time that the sun will appear to completely cover the moon (totality) lessens as you move outward from the center line of the eclipse path. But by how much? This activity will teach you how to find the answer!


Relative Size and Distance
Of all the planets in our solar system, we are the only one that has a moon that “appears” to be the same size as the sun. Of course, this is just an illusion. The moon is many, many times smaller than the sun. But, the sun is also many, many times farther away from the Earth. Using the tables provided in this activity, can you convince yourself that the moon and sun are, in fact almost identical in apparent size in the sky?


What is the moon's orbital period?
The moon moves in an orbit around the Earth about once every month. But the moon actually has two different orbital periods depending on the location of the observer. So, let's first understand what we mean when we say: "The moon goes around the Earth".


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Amateur Astronomers


Eclipse Fact

During totality, the horizon is illuminated in a narrow band of light, because an observer is seeing distant localities not under the direct umbra of the Moon's shadow.

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