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[[Coadan:Rainbow 02.jpg|thumb|300px|Goal twoaie as aahoilshey echey 'sy logh]]
==Soilshaghey oaylleeagh==
Ta soilshey [[aascellaghey]] tra t'eh goll stiagh 'sy vineen. T'eh aahoilshaghey jeh cooyl y vineen, as eisht aascellaghey reesht tra t'eh goll magh ass y vineen. Er y fa dy vel soilshey tonn giare aascellaghey ny smoo na soilshey tonn liauyr, ta'n soilshey eddyrscarrey dys spectrum.<ref>{{enmyseddyrvoggyl
| kiangley = http://www.physicsclassroom.com/Class/refrn/u14l4b.cfm
| ennym = Rainbow Formation
| screeudeyr = Physics Classroom
}}</ref> Ta'n soilshey smoo jeean er uillin mysh 40–42°. T'eh uillin hene croghey er [[ayndagh aahoilshaghey]] y vineen. Ta ayndagh aahoilshaghey saailley ny smoo na fliaghey, as myr shen ta lieh-chrantessen sloo ec goal twoaie ayns spreie marrey na goal twoaie ayns fliaghey.
[[Coadan:Rainbow1.svg|right|300px|thumb|Ta soilshey bane rheynn ayns "daahghyn" (tonnyn-lhiuridyn) lesh goll stiagh 'sy vineen, er y fa dy vel soilshey "jiarg" (tonn liauyr) aascellaghey er uillin sloo na soilshey "gorrym" (tonn ghiare). Tra t'ad faagail y bineen, ta ny scellyn jiargey er gassey trooid uillin sloo na ny scellyn gorrym, as myr shen ta straih daaghyn ry-akin, jiarg dys gorrym as ny daaghyn elley eddyr oc.]]
|<!--[[File:Rainbow single reflection.svg|right|250px|thumb|Light rays enter a raindrop from one direction (typically a straight line from the Sun), reflect off the back of the raindrop, and fan out as they leave the raindrop. The light leaving the rainbow is spread over a wide angle, with a maximum intensity at 40.89–42°.]] ▼-->
Cha nel ynnyd er lheh ec goal twoaie 'sy speyr. Ta'n ynnyd baghtal echey croghey er ynnydyn ny greiney as y chronneyder. Ta dagh bineen aascellaghey as aahoilshaghey soilshey ny greiney 'syn aght cheddin, agh cha nel agh beggan jeh'n toilshey roshtyn sooill y chronneyder. She yn soilshey shen ta jannoo magh goal twoaie da'n chronneyder shen. Ta ynnyd goal twoaie 'sy speyr noi y ghrian cosoylit rish y chronneyder, as ta mean y ghoal twoaie erskyn scaa-doo kione y chronneyder, ec yn [[ynnyd noi-ghrianagh]]. Ta'n goal twoaie ry-akin mysh 40–42° jeh linney eddyr kione y chronneyder as scaa-doo y chione. Myr shen, my ta'n ghrian ny s'ardjey na 42°, ta'n goal twoaie fo oirr ny cruinney, as cha nel eh ry-akin mannagh vel y chronneyder fodder erskyn y thalloo.
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==Visibility==
At good visibility conditions (for example, a dark cloud behind the rainbow), the second arc can be seen, with inverse order of colours. At the background of the blue sky, the second arc is barely visible.
==Scientific explanation==
The light is first [[refraction|refracted]] entering the surface of the raindrop, [[reflection (physics)|reflected]] off the back of the drop, and again refracted as it leaves the drop. The overall effect is that the incoming light is reflected back over a wide range of [[angle]]s, with the most intense light at an angle of 40–42°. The angle is independent of the size of the drop, but does depend on its [[refractive index]]. Seawater has a higher refractive index than rain water, so the radius of a "rainbow" in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.<ref>{{cite web |author=Cowley, Les |url=http://www.atoptics.co.uk/rainbows/seabow.htm |title=Sea Water Rainbow |work=Atmospheric Optics |accessdate=2007-06-07}}</ref> The amount by which light is refracted depends upon its [[wavelength]], and hence its colour. Blue light (shorter wavelength) is refracted at a greater angle than red light, but due to the reflection of light rays from the back of the droplet, the blue light emerges from the droplet at a smaller angle to the original incident white light ray than the red light. You may then think it is strange that the pattern of colours in a rainbow has red on the outside of the arc and blue on the inside. However, when we examine this issue more closely, we realise that if the red light from one droplet is seen by an observer, then the blue light from that droplet will not be seen because it is on a different path from the red light: a path which is not incident with the observer's eyes. The blue light seen in this rainbow will therefore come from a ''different droplet'', which must be below that whose red light can be observed.
Contrary to popular belief, the light at the back of the raindrop does not undergo [[total internal reflection]], and some light does emerge from the back. However, light coming out the back of the raindrop does not create a rainbow between the observer and the Sun because spectra emitted from the back of the raindrop do not have a maximum of intensity, as the other visible rainbows do, and thus the colours blend together rather than forming a rainbow.<ref name="Zero order glow">Cowley, Les. [http://www.atoptics.co.uk/rainbows/ord0.htm "Zero order glow"] ''Atmospheric Optics.''</ref>
{| style="margin-left: auto; margin-right: auto;"
▲|[[File:Rainbow single reflection.svg|right|250px|thumb|Light rays enter a raindrop from one direction (typically a straight line from the Sun), reflect off the back of the raindrop, and fan out as they leave the raindrop. The light leaving the rainbow is spread over a wide angle, with a maximum intensity at 40.89–42°.]]
|[[File:Rainbow1.svg|right|250px|thumb|White light separates into different colours on entering the raindrop because red light is refracted by a lesser angle than blue light. On leaving the raindrop, the red rays have turned through a smaller angle than the blue rays, producing a rainbow.]]
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A rainbow does not actually exist at a particular location in the sky. Its apparent position depends on the observer's location and the position of the Sun. All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. This light is what constitutes the rainbow for that observer. The position of a rainbow in the sky is always in the opposite direction of the Sun with respect to the observer, and the interior is always slightly brighter than the exterior. The bow is centred on the shadow of the observer's head, or more exactly at the [[antisolar point]] (which is below the [[horizon]] during the daytime), appearing at an angle of 40–42° to the line between the observer's head and its shadow. As a result, if the Sun is higher than 42°, then the rainbow is below the horizon and usually cannot be seen as there are not usually sufficient raindrops between the horizon (that is: eye height) and the ground, to contribute. Exceptions occur when the observer is high above the ground, for example in an aeroplane (see above), on top of a mountain, or above a waterfall.
==Variations==
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