Why is there a blue moon?
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Once in a Blue Moon ... is a common way of saying not very often, but what exactly is a Blue Moon?\n\nAccording to the popular definition, it is the second Full Moon to occur in a single calendar month.\n\nThe average interval between Full Moons is about 29.5 days, whilst the length of an average month is roughly 30.5 days. This makes it very unlikely that any given month will contain two Full Moons, though it does sometimes happen.\n\nOn average, there will be 41 months that have two Full Moons in every century, so you could say that once in a Blue Moon actually means once every two-and-a-half years.
647101
The Moon is 400 times smaller than the Sun, but 400 times closer.\n\nWe are very lucky
806918
Where does it appear blue? Never heard of that!
1088788
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.\n\nGo here for a detailed explanation and a cute little picture to show you! lol\n\nhttp://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html
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The blue moon is the second full moon in a calendar month.  Their frequency is irregular.  The last blue moon occurred on July 31, 2004.  The next one will occur on June 30, 2007.
773542
it's because they use the moon to navigate.  artificial light confuses them.
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Once in a Blue Moon\n\n"Blue moon" appears to have been a colloquial expression long before it developed its calendrical senses. According to the Oxford English Dictionary, the first reference to a blue moon comes from a proverb recorded in 1528:\n\n    If they say the moon is blue,\n    We must believe that it is true.\n\nSaying the moon was blue was equivalent to saying the moon was made of green (or cream) cheese; it indicated an obvious absurdity. In the 19th century, the phrase until a blue moon developed, meaning "never." The phrase, once in a blue moon today has come to mean "every now and then" or "rarely"—whether it gained that meaning through association with the lunar event remains uncertain.
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The moon has a side that always faces us! That's not always filled with light though. That's why we have phases of the moon.
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Depends on atmospheric conditions ,small water droplets form into ice crystals in the upper atmosphere. The moon reflects light into these droplets causing refraction of that light, givind a halo effect sometimes even a 'luna rainbow'
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A full moon is the phase when the entire circular shape of the moon is visible.\n\nA new moon is the phase when no part of the moon is visible due to the position of the earth.  It happens to block the light from the sun so the moon is not able to be seen.\n\nsilly fact- the term "blue moon" like "once in a blue moon" refers to the unusual event of having two new moons in a calendar month.
3229
the actual meaning? Well, once in a blue moon means that it happends very very rarely. but a blue moon supposedly is the second Full Moon to occur in a single calendar month. :)have a good one!
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There is one full moon in a lunar month. When thre is 2full moons in a calendar mont it is called a blue moon. Hence the saying once in a blue moon, not very often.
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It's because your mind sees the moon in proportion to landscape features when it is low.  It's kind of an optical illusion - it's not really bigger but your mind interprets it as bigger.
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it happens at the end of any month.because that time the moon is very near to earth.\nred color of moon : because of gasses that are in the atmosphere.
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Its an illusion.  Its because the moon is closer to objects to which you can compare it.
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The Earth's sky is blue because the air molecules (largely nitrogen\nand oxygen) are much smaller than the wavelength of light. When light\nencounters particles much smaller than its wavelength, the scattered\nintensity is inversely proportional to the 4'th power of the\nwavelength. This is called "Rayleigh scattering," and it means that\nhalf the wavelength is scattered with 2**4 = 16 times more intensity.\nThat's why the sky appears blue: the blue light is scattered some 16\ntimes more strongly than the red light. Rayleigh scattering is also\nthe reason why the setting Sun appears red: the blue light has been\nscattered away from the direct sunlight.\n\nThus, if the atmosphere of another planet is composed of a transparent\ngas or gases whose molecules are much smaller than the wavelength of\nlight, we would, in general, also expect the sky on that planet to\nhave a blue color.\n\nIf you want another color of the sky, you need bigger particles in the\nair. You need something bigger than molecules in the air---dust.\n\nDust particles can be many times larger than air molecules but still\nsmall enough to not fall out to the ground. If the dust particles are\nmuch larger than the wavelength of light, the scattered light will be\nneutral in color (i.e., white or gray)---this also happens in clouds\nhere on Earth, which consist of water droplets. If the dust particles\nare of approximately the same size as the wavelength of light, the\nsituation gets complex, and all sorts of interesting scattering\nphenomena may happen. This happens here on Earth from time to time,\nparticularly in desert areas, where the sky may appear white, brown,\nor some other color. Dust is also responsible for the pinkish sky on\nMars, as seen in the photographs returned from the Viking landers.\n\nIf the atmosphere contains lots of dust, the direct light from the Sun\nor Moon may occasionally get some quite unusual color. Sometimes,\ngreen and blue moons have been reported. These phenomena are quite\nrare though---they happen only "once in a blue moon...." :) The dust\nresponsible for these unusual color phenomena is most often volcanic\nin origin. When El Chicon erupted in 1982, this caused unusually\nstrongly colored sunsets in equatorial areas for more than one year.\nThe much bigger volcanic explosion at Krakatoa, some 110 years ago,\ncaused green and blue moons worldwide for a few years.\n\nOne possible exception to the above discussion is if the clouds on the\nplanet are composed of a strongly colored chemical. This might occur\non Jupiter, where the clouds are thought to contain sulfur, phosphorus,\nand/or various organic chemicals.\n\nIt's also worth pointing out that the light of the planet's primary is\nquite insignificant. Our eyes are highly adaptable to the dominating\nillumination and perceive it as "white," within a quite wide range of\npossible colors. During daytime, we perceive the light from the Sun\n(6000 K) as white, and at night we perceive the light from our\nincandescent lamps (2800 K, like a late, cool M star) as white. Only\nif we put these two lights side-by-side, at comparable intensities,\nwill we perceive a clear color difference.\n\nIf the Sun was a hot star (say of spectral type B), it's likely we\nstill would perceive its light as "white" and the sky's color as blue
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The moon is orange in the fall, because it's celebrating Halloween! Just Kidding! Actually, the moon can have an orange color at any time of the year. As a matter of fact, just last month (December 1997) in Michigan, there were a few nights when the moon looked big and orange. \nThe reason for the orange color is due to the scattering of light by the atmosphere. When the moon is near the horizon, the moonlight has to pass through much more atmosphere than when the moon is directly overhead. By the time the moonlight reaches your eyes, the green, blue, and purple pieces of visible light have been scattered away by air molecules. You only see yellow, orange, or red. \n\nSometimes the moon appears orange even when it's directly overhead. This occurs when there's a lot of dust, smoke, or pollution in the atmosphere. The size of those particles will determine the type of color you will see. Sometimes the moon will look red, orange...even blue. \n\nIt seems like the moon appears in certain colors during certain times of the year. For instance, the Harvest moon during the fall appears very large and orange. There are two reasons for this: the moon's path across the sky, and the climate of earth. During certain times of the year, the moon will rise and set at different angles. Sometimes the moon stays really low in the sky and never reaches an overhead position. The earth's atmosphere also goes through certain changes at certain times of the year. In some months, the atmosphere has more dust particles than usual; in other months, the atmosphere contains a lot more cloud particles than usual. Extra particles in the atmosphere mean more scattering of light. \n\nIn the fall, many farmers are harvesting their crops. Lots of dust from the soil of the crops gets disturbed. The dust floats into the atmosphere. At the same time, the moon is lower in the sky during the fall season. So if there's more dust in the sky and the moon is closer to the horizon, then what color will the moon be? Orange! That's where "Harvest Moon" gets its name. \n\nPollution in the atmosphere can cause the same distortion of color. If you live in Los Angeles (which has a lot of pollution), for example, the moon will constantly appear in color. If the pollution is really thick, you might not be able to see the moon at all!