PROJECT:-ECLIPSE STUDENT NAME:-JASPREET KAUR PREET KAUR TEACHER NAME:-AMARJEET SINGH
DEFINATION OF ECLIPSE
Eclipse, in astronomy, the obscuring of one celestial body by another, particularly that of the sun or a planetary satellite. Two kinds of eclipses involve the earth: those of the moon, or lunar eclipses; and those of the sun, or solar eclipses .
LUNAR ECLIPSE
. A lunar eclipse occurs when the earth is between the sun and the moon and its shadow darkens the moon
The earth, lit by the sun, casts a long, conical shadow in space. At any point within that cone the light of the sun is wholly obscured. Surrounding the shadow cone, also called the umbra, is an area of partial shadow called the penumbra. The approximate mean length of the umbra is 1,379,200 km (857,000 mi); at a distance of 384,600 km (239,000 mi), the mean distance of the moon from the earth, it has a diameter of about 9170 km (about 5700 mi).
Total lunar eclipse
A total lunar eclipse occurs when the moon passes completely into the umbra. If it moves directly through the center, it is obscured for about 2 hours. If it does not pass through the center, the period of totality is less and may last for only an instant if the moon travels through the very edge of the umbra.
Partial lunar eclipse
A partial lunar eclipse occurs when only a part of the moon enters the umbra and is obscured. The extent of a partial eclipse can range from near totality, when most of the moon is obscured, to a slight or minor eclipse, when only a small portion of the earth’s shadow is seen on the passing moon. Historically, the view of the earth’s circular shadow advancing across the face of the moon was the first indication of the shape of the earth.
SOLAR ECLIPSE
A solar eclipse occurs when the moon is between the sun and the earth and its shadow moves across the face of the earth.
Total solar eclipses
). Total solar eclipses occur when the moon’s umbra reaches the earth. The diameter of the umbra is never greater than 268.7 km (167 mi) where it touches the surface of the earth, so that the area in which a total solar eclipse is visible is never wider than that and is usually considerably narrower. The width of the penumbra shadow, or the area of partial eclipse on the surface of the earth, is about 4828 km (about 3000 mi). At certain times when the moon passes between the earth and the sun, its shadow does not reach the earth. At such times an annular eclipse occurs in which an annulus or bright ring of the solar disk appears around the black disk of the moon.
FREQUENCY OF ECLIPSES
If the earth’s orbit, or the ecliptic, were in the same plane as the moon’s orbit, two total eclipses would occur during each lunar month, a lunar eclipse at the time of each full moon, and a solar eclipse at the time of each new moon. The two orbits, however, are inclined, and, as a result, eclipses occur only when the moon or the sun is within a few degrees of the two points, called the nodes, where the orbits intersect.