A Little Knowledge
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A little knowledge Why are Eclipses so rare? When themoon in its journey around the earth passes directly between the earth and the sun,it casts its shadow on the surface of the earth, and an eclipse of the sun takes place. An eclipses of the sun occurs on ly when themoon is new, for then the moon is n that side of the earth facing toward the sun. Then why isn?t there an eclipse of the sun every there?s a new moon? The reason is that thepath of the moon around the earthdoesnot lie directly in line with the orbit of the earth about the sun. In its 29-day trip around the earth,the moon passes sometimes above and sometimes below the path of the earth. An eclipse of the sun can be total, annular,or partial. If the moon hides the sun completely, the eclipse is total. But the monn is not always the same distance form the earth. Often,it is too far from the earth to hide the sun completely. Then,when an eclipse takes place, the moon is seen as a dark disk,which covers the whole sun except a narrow ring around its edge. This thincircel of light is called?the annulus?,meaning,?ring. This is an annular eclipse. An eclipse is partial whenever only part of the disk of the moon comes between the sun and the earth. An eclipse of the moon occurs ony when the moon is full, for then it is at the opposite side of the earth from the sun. When the moon comes directly behind the earth, as seen for the sea, it passes gradually into the great shadow-cone cast by the earth and disappears from view. A total eclipse of the moon then occurs. Insome years,no eclipses of the moon occur. In other years, theremust be at least two solar eclipses, and there maybe as many as five. At anyone plac eonthe earth?s surface, a total solar eclipse will be visible only once in about 360 years.
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