Ancient peoples thought that the sun and moon disappeared during eclipses, / but they don't really. // An eclipse happens when three celestial objects line up, / such as the moon,/ Earth,/ and Sun. // Eclipses can be seen without a telescope. // For this reason, / the recording of eclipses goes back to ancient times. // During a solar eclipse, / the moon passes between the sun and Earth. // The shadow of the moon sweeps over Earth. // The umbra, / or inner part of the moon's shadow, / blocks all sunlight on Earth. // The sun is completely covered to observers on Earth who are within the umbra. // This kind of eclipse is a total solar eclipse. // Because the umbra is very narrow when it intersects Earth,/ the total solar eclipse can only be viewed from with the zone of totality. // This is why a total solar eclipse can be seen for less than eight minutes at any one place on Earth. // There is usually a total solar eclipse visible somewhere on Earth every 1.5years. //

Excerpted from Eclipses © Literacy New York. All Rights Reserved.