About a Total Solar Eclipse

Eclipses are one of the magnificent phenomena which are observed with great enthusiasm all over the world. Both scientists and laymen wait anxiously for this natural show of light.

There are two different types of eclipses; solar eclipse and lunar eclipse. Basically it occurs when, for an observer in the Earth, one celestial body is hidden partially or completely by another celestial object. Thus, whatever eclipse occurs involves all the three key players namely the Sun, Moon and Earth. Since the position of the Sun is the same in both cases, the orbits of the Moon and the Earth are responsible for the two eclipses.

When the Earth obscures the Moon, it creates a lunar eclipse and when the Moon obscures the Sun it is a solar eclipse. Another major difference between these two types of eclipses is the time of occurrence. A solar eclipse occurs during the daytime whereas the lunar eclipse is a night-time phenomenon. Not only that, the solar eclipse is a new moon event while the lunar eclipse is a full moon event. Lunar eclipses are more frequent than the solar eclipses.

In the solar system all the planets revolve round the Sun. In the same way the Moon, which is the only natural satellite of the Earth, rotates around the Earth completing one revolution in 29.5 days. As in the case of the planets, the lunar orbit too is elliptical in shape and it is inclined 5 degrees to Earth’s orbit. So the chances for the Sun and the Moon to come in conjunction become rare. Another important condition for the occurrence of a solar eclipse is the new moon. Thus, during a solar eclipse when these three celestial bodies are in the same plane the solar rays are obscured partially or completely by the Moon. Hence, an observer on Earth can see only the outer part of the Sun which is called the corona, and causes a dark shadow to pass over the observer. But, the effect is not so prominent when the Moon only partially obscures the solar rays, and this makes the total solar eclipses unique.

The Moon’s shadow has two parts the dim outer shadow called penumbra and the dark inner shadow called the umbra. During a total solar eclipse, both these regions are visible on the Earth, while during partial solar eclipse the path of totality caused by the umbra misses the Earth allowing only the penumbra's shadow to hit the surface.

Since it is harmful to the eyes to look directly at a solar eclipse it is advisable to use a pinhole projection on white paper, welder's glass or special glasses that can be purchased for the event.

http://www.earthview.com/tutorial/causes.htm

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