Geography, SS1, Week 5
Topic: Eclipse, Dawn and Twilight
Eclipse
Eclipse is formed when the three bodies- sun, earth and the moon are in straight line during movement f the earth. The moon revolves round the earth once in every twenty seven days (a month), the earth and the moon travel together, making a complete movement around the sun once in a year. During this movement, there will be a time when these three bodies (earth, sun and moon) will be in straight line resulting in the formation of an Eclipse.
Types of Eclipse
There are two types of eclipse. These are:
(1) Eclipse of the moon(lunar eclipse): Eclipse of the moon occurs when earth comes between the moon and the sun
Sun Earth Moon
(2) Eclipse of the sun (solar eclipse): Eclipse of the sun occurs when the moon comes between the sun and the earth, thereby, causing a partial or total darkness of the earth
Sun Moon Earth
Dawn and Twilight
Dawn refers to the brief period between sunrise and full day light. Twilight refers to the brief period between sunset and complete darkness.
Dawn and twilight occur because the earth receives diffused or reflected light from the sun while it is still below the horizon. In case of the twilight, there is little or no twilight at the equator because the sun rises or sets rapidly. The sun rises almost vertically from the horizon at the equator.
Twilight occurs longer at higher latitudes because the sun sets more slowly. The sun rises and set at a low level. Therefore, there are periods of twilight than full day light at the Arctic Circle.
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