Thursday, May 24, 2012
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Makhzan-e-Urdu Adab
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Join Date: May 2010
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Lunar Eclipse
A lunar eclipse can be defined as an eclipse which occurs when the moon passes behind the earth in such a way that the Earth doesn't let the sun's rays strike the moon.
It looks like this,
This eclipse depends on the alignment of the sun,earth and moon in such a way that earth comes in the middle.Lunar eclipse can be observed when the moon is on the opposite side of the earth from the sun and it passes through the earth's shadow.There are stages of moon's passage as it passes through the layers of earth's shadow.The shadow is composed of two cone-shaped components,one inside the other.
The outer or penumbral shadow is a zone where some portion of the sun's rays are blocked.When the moon is in the penumbra,a partial solar eclipse can be observed by an observer on the moon.The core of earth's shadow is called the umbra and this region is devoid of direct sunlight.When the moon is in the umbra,the observers on the moon would see a total solar eclipse.
~*Lunar eclipse happens atleast once a year and maximum number is thrice a year.
~*During this eclipse,speed of moon is about one kilometer per second and it remains for about one hundred minutes.
~*The colour of the eclipsed lunar disk depends upon the types of particles which are present in the earth's atmosphere at the time of eclipse.Color and deepness of shadow is also affected by the type of eclipse,local weather and atmospheric conditions as well as geographic location of the observer.
Types of Lunar Eclipses
There are three types of lunar eclipses;
Partial Lunar Eclipse:
It occurs when a portion of the moon passes through the earth's umbral shadow.It can be observed even with the unaided eye.
Penumbral Lunar Eclipse:
It occurs when the moon passes through the earth's penumbral shadow.It can not be observed easily.During this eclipse,the moon's light becomes dim but it doesnot happen to be dark because the penumbral shadow is not dark enough to black out the sun's rays.
Total Lunar Eclipse:
It occurs when the entire moon passes through the earth's umbral shadow.During this eclipse,the moon's colour may change to a dull copper tone due to reflected earth light.
(Below is a view of events for each of the three different types of lunar eclipses. The light gray represents the penumbral shadow, while the darker gray represents the umbral shadow.)
Lunar Eclipse occurs only at about the times of full moon while solar eclipse never occurs on full moon days. Explain why?
It is important point that eclipses occur only during a new moon or full moon.The reason is that it is the only time when sun,earth and moon's alignment is in such a way that it blocks the sunlight whether totally or partially,either by the earth or by the moon.
A lunar eclipse occurs when the moon passes through the earth's shadow.It is possible only when the moon is on the opposite side of the earth from the sun and it happens usually when there is full moon.
A solar eclipse can be observed when the moon passes in front of the sun casting its shadow upon the surface of the earth.It is possible only when the moon is on the same side of the earth where the sun is and it happens when there is a new moon.
Solar Eclipse
Solar eclipses and lunar eclipses go together in pairs. A solar eclipse always occurs within interval of two weeks after or two weeks before a total lunar eclipse.
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Last edited by marwatone; Saturday, May 26, 2012 at 12:22 AM.
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