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blue Moon
blue Moon(blue Sun) The occasional appearance of the Moon or Sun when partly obscured by large particles in the atmosphere, as in dust storms, or following forest fires or great volcanic explosions. When the Moon or Sun is viewed through dust or smoke trails it usually appears to be very white, but when the suspended particles are predominantly of one size it sometimes appears blue, at other times green or orange. The phenomenon is attributed to diffraction, although no full explanation seems to be known. The smaller the particles, the more the colour of the Sun or Moon tends to the blue end of the spectrum. The phenomenon is believed to be more common in China than elsewhere. (In the neighbourhood of the 1883 Krakatoa volcanic explosion the Sun was seen as an azure blue sphere.)
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Cite this article
MICHAEL ALLABY. "blue Moon." A Dictionary of Ecology. 2004. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "blue Moon." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O14-blueMoon.html MICHAEL ALLABY. "blue Moon." A Dictionary of Ecology. 2004. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-blueMoon.html |
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blue Moon
blue Moon (blue Sun) Occasional appearance of the Moon or Sun when partly obscured by large particles in the atmosphere, as in dust storms, or following forest fires or great volcanic explosions. When the Moon or Sun is viewed through dust or smoke trails it usually appears to be very white, but when the suspended particles are predominantly of one size it sometimes appears blue, at other times green or orange. The phenomenon is attributed to diffraction, although no full explanation seems to be known. The smaller the particles, the more the colour of the Sun or Moon tends to the blue end of the spectrum. The phenomenon is believed to be more common in China than elsewhere. (In the neighbourhood of the 1883 Krakatoa volcanic explosion the Sun was seen as an azure blue sphere.)
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "blue Moon." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "blue Moon." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O13-blueMoon.html AILSA ALLABY and MICHAEL ALLABY. "blue Moon." A Dictionary of Earth Sciences. 1999. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-blueMoon.html |
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blue Moon
blue Moon
1. A phenomenon caused by high-altitude dust in the Earth's atmosphere, which scatters red light preferentially, making the Moon appear blue (see Mie Scattering). Blue Moons were seen in 1883 after the eruption of the volcano Krakatoa, and in 1950 because of forest fires in Canada. The phenomenon is rare, hence the expression ‘once in a blue Moon’. 2. In modern US usage, the second full Moon in a calendar month. This occurs every 2–3 years on average. |
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Cite this article
"blue Moon." A Dictionary of Astronomy. 1997. Encyclopedia.com. 30 May. 2012 <http://www.encyclopedia.com>. "blue Moon." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 30, 2012). http://www.encyclopedia.com/doc/1O80-blueMoon.html "blue Moon." A Dictionary of Astronomy. 1997. Retrieved May 30, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-blueMoon.html |
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