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The Elementary Characteristics of Solar & Lunar Eclipses

Solar and lunar eclipses are similar phenomena but are very different astronomical events. Both have to do with the relative positioning of the Earth, sun and the moon in relation to each other. Humans have always been fascinated by these events and have sought to explain them in accordance with their own understanding of science, astronomy and cultural references. Many ancient cultures saw them as portents of doom or signs of good luck. Many times people were simply terrified at these seemingly random and unexplainable events.

Total Solar Eclipse
- When the moon passes in front of the sun as observed from a fixed point on the Earth's surface, a solar eclipse occurs. The moon casts its shadow on the earth, blocking out much of the light and causing semi-darkness in the daytime. From the Earth, the eclipse begins with a small sliver of the sun being blocked and continues until the entire moon blocks out the total area of the sun. This is a total eclipse and lasts for approximately seven minutes. Total solar eclipses are rare events, likely to be a once-in-a-lifetime experience for observers.
Total Lunar Eclipse
- When the moon passes through the Earth's shadow, a total lunar eclipse occurs. The Earth casts a shadow from the sun called the umbra, and normally the moon does not pass through it because it orbits the Earth on an orbital plane about 5 percent above the Earth/sun plane. However, the moons orbital plane varies, and so at regular intervals it passes directly through the Earth's shadow. Total lunar eclipses can only with a full moon. From Earth, the Earth's shadow is seen at first as small crescent-shaped slice of darkness on the moon, gradually increasing until the entire moon is blocked.
Partial Solar Eclipse
- Partial solar eclipses are far more common than total eclipses. Partial solar eclipses occur when the moon is not quite on the right trajectory to completely block the sun from view, so only a portion of it is blocked. This may vary from a significant amount of the sun to just a tiny fraction. Partial lunar eclipses occur with much more frequency but are far less spectacular than total solar eclipses. They can be seen from many more points on Earth than total eclipses, which can only be seen in a narrow band of the Earth's surface.
Partial Lunar Eclipse
- The Earth's shadow or umbra is very dark but it also has a lighter shadow on the periphery of the umbra called the penumbra. This covers a much larger area than the darker umbra, so the moon's path travels through it far more frequently. When the moon passes through only some of the darker umbra and some of the lighter penumbra, this is known as a partial eclipse. When the moon passes only through the penumbra, the moon will darken but still be in view. This phenomenon is known as a penumbral eclipse.

Astronomy