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Are there 2 lunar eclipse a year?
Generally, yes; there are normally two lunar eclipses and two solar eclipses each year. Bot not always. Here in 2009, because the Moon, Earth and Sun aren't lining up quite …as precisely as they usually do, we have four partial or "penumbral" lunar eclipses this year, and two partial or annular solar eclipses. In a "penumbral" eclipse, the Moon only gets partly into the Earth's "penumbra" or outer shadow, and in many cases you can hardly see any darkening of the Moon. In a partial eclipse, the Moon gets completely into the outer shadow but only partly into the inner "umbra", the total shadow of Earth. Here's what's going on. The Sun is enormous, WAY bigger than the Earth. The Earth's shadow is a cone-shaped region that narrows down to a point. The inner cone or "umbra" is when the entire Sun is hidden behind the Earth, and the outer cone or "penumbra" is when part of the Sun is behind the Earth, and part of it is exposed. In a partial solar eclipse, Sun is being blocked by the Moon. It doesn't get dark, until about 75% of the sun is hidden, because the part of the Sun that isn't hidden is still very bright. A penumbral lunar eclipse is like a partial solar eclipse as seen from the Moon. In a penumbral lunar eclipse the entire Moon is is PART of the sunshine, but some fragment of the Sun is behind the Earth. (MORE)
