Eclipse PDF
Document Details
Uploaded by SublimeMimosa
University of Karachi
Tags
Summary
This document provides a detailed explanation of eclipses, including solar and lunar eclipses. It defines eclipses as the partial or complete obscuring of one celestial object by another. It also explains the different types of eclipses and the conditions under which they occur.
Full Transcript
Eclipse Eclipse Eclipse is complete or partial obscuring of a celestial body by another. An eclipse occurs when three celestial objects become aligned. There are two types of eclipse: 1. Solar Eclipse 2. Lunar Eclipse Lunar Eclipse...
Eclipse Eclipse Eclipse is complete or partial obscuring of a celestial body by another. An eclipse occurs when three celestial objects become aligned. There are two types of eclipse: 1. Solar Eclipse 2. Lunar Eclipse Lunar Eclipse lunar eclipse occurs when the Moon entering the shadow of Earth, opposite the Sun, so that Earth’s shadow sweeps over the Moon’s surface. An eclipse of the Moon can be seen under similar conditions at all places on Earth where the Moon is above the horizon. Lunar eclipses occur only at full moon and do not occur every month because the plane of the Moon’s orbit is inclined to that of Earth’s orbit around the Sun (the ecliptic) by about 5°. Therefore, at most new and full moons, Earth, the Sun, and the Moon are not in a straight line. Solar Eclipse An eclipse of the Sun takes place when the Moon comes between Earth and the Sun so that the Moon’s shadow sweeps over the face of Earth. This shadow consists of two parts: the umbra, a cone into which no direct sunlight penetrates; and the penumbra, which is reached by light from only a part of the Sun’s disk. To an observer within the umbra, the Sun’s disk appears completely covered by the disk of the Moon; such an eclipse is called total. To an observer within the penumbra, the Moon’s disk appears projected against the Sun’s disk so as to overlap it partly; the eclipse is then called partial for that observer. Annular eclipse When the Sun is nearest to Earth and the Moon is at its greatest distance, the apparent disk of the Moon is smaller than that of the Sun. If an eclipse of the Sun occurs at this time, the Moon’s disk passing over the Sun’s disk cannot cover it completely but will leave the rim of the Sun visible all around it. Such an eclipse is said to be annular eclipse. Total and annular eclipses are called central.
