eclipse

eclipse In astronomy, partial or total obscuration of the light from one celestial body as it passes through the shadow cast by another body. Eclipses are transitory; the most familiar are lunar and solar eclipses. Within any given year, a maximum of seven eclipses can occur, either four solar and three lunar or five solar and two lunar. A solar eclipse occurs when the Moon passes between the Earth and the Sun, blocking the Sun's light from the part of the Earth on which the Moon's shadow falls. It can only happen at new Moon. The maximum duration of a total solar eclipse is 7min 8sec. A lunar eclipse occurs when the Earth intervenes between the Sun and the Moon, blocking the Sun's light from the Moon. It can only happen at full Moon. The longest duration of a lunar eclipse is 1hr 42min. Because the Earth and Moon shine only by the reflected light of the Sun, each casts a shadow into space in the direction away from the Sun. The shadow consists of a region of total darkness (umbra) and partial darkness (penumbra).