by Nancy Houser

Created on: August 12, 2008

Albert Einstein once made a statment which said, "The most incomprehensible thing about the universe is that it is comprehensible." I wonder if he was referring to the fact that a total eclipse is actually seen by such a few people on Earth, mainly because the shadow of the eclipse covers such a tiny bit of our planet-a fact very people realize as they are all too busy searching for one. The word penumbra refers to a partial shadow (such as in an eclipse) that is located between an area of complete shadow and one of complete illumination. In Astronomy, the penumbra of an eclipse refers to an area of partial eclipse from behind the moon which allows us to see some part of the sun. Yet it must occur from where the dark umbra touches our planet, and only then will we be able to see the sun completely covered enough to witness a total eclipse.

Penumbral eclipses are only one of the three eclipse types-total and partial the remaining two. The total lunar eclipse is referred to as the best one to view which involves the Earth passing directly in front of a full moon-casting its gentle shadow on the Moon's surface. As the moon is always orbiting our planet, and the earth is always orbiting the sun while rotating on its axis-the umbra location is always moving while tracing out a path to follow. Yet when a penumbral eclipse is occuring, the Moon's area does not enter Earth's dark umbral shadow. This is the reason no distinct outline of Earth's shadow is shown by the Moon, yet will pass through the outer part of the shadow of our planet, dimming the Moon ever-so-much. A darkening can occur when the edge of the Moon passes nearest to the umbra, but approximatley 70% of the disk of the Moon needs to be inside the penumbra before it can be seen by the naked eye.

The next penumbral eclipses will occur next year in 2009.

* February 9, 2009: Easterm Europe, Asia, Australia, Pacific, Western North America
* July 7, 2009: Australia, Pacific, and Americas
* August 6, 2008: Americas, Europe, Africa, and Western Asia
* November 28, 2012: Europe, Eastern Africa, Asia, Australia, Pacific, North America

In March 14th of 2006, the penumbral eclipse was an extreme rarity as compared to most of them. The Moon had arrived two days earlier on the 12th at its furthest distance from the Earth-252,446 miles which allowed the moon to appear about 7% smaller than normal. This resulted in the Moon interacting with the shadow of the Earth, immersing in its small size within the penumbra-yet large

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