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单词 Phase of Moon
释义

Phase of Moon

英语百科

Lunar phase

The phase and libration of the Moon for 2013 at hourly intervals, with music, titles and supplemental graphics.
Animation of the Moon as it cycles through its phases, as seen from the northern hemisphere.  The apparent wobbling of the Moon is known as libration. The apparent change in size is due to the eccentricity of the lunar orbit.
This video provides an illustration of how the Moon passes through its phases — a product of its orbit, which allows different parts of its surface to be illuminated by the Sun over the course of a month. The camera is locked to the Moon as the Earth rapidly rotates in the foreground.
A crescent moon above Earth's horizon is featured in this image photographed by an Expedition 24 crew member in 2010.

The lunar phase or phase of the moon is the shape of the illuminated (sunlit) portion of the Moon as seen by an observer on Earth. The lunar phases change cyclically as the Moon orbits the Earth, according to the changing positions of the Moon and Sun relative to the Earth. The Moon's rotation is tidally locked by the Earth's gravity, therefore the same lunar surface always faces Earth. This face is variously sunlit depending on the position of the Moon in its orbit. Therefore, the portion of this hemisphere that is visible to an observer on Earth can vary from about 100% (full moon) to 0% (new moon). The lunar terminator is the boundary between the illuminated and darkened hemispheres. Each of the four "intermediate" lunar phases (see below) is roughly seven days (~7.4 days) but this varies slightly due to the elliptical shape of the Moon's orbit. Aside from some craters near the lunar poles such as Shoemaker, all parts of the Moon see around 14.77 days of sunlight, followed by 14.77 days of "night". (The side of the Moon facing away from the Earth is sometimes called the "dark side", which is a misnomer. It receives just as much sunlight as the Earth-facing side − actually slightly more, since the Earth never obscures the Sun from it.)

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更新时间:2025/6/17 2:42:44