Is a full rainbow a semi circle or a full circle??
411880
Actually is an Arch... then SEMI.
160214
They also occur as a circle, if you're in a plane (i was in a microlight) above mist/cloud it's the most spectacular sight, I looked down and there was a circular rainbow. It has to do with the fact that you're viewing it from one point, all the rainbow is relative to you.
91814
These are refered to as sun dogs.  The light is being refracted by ice crystals in the upper atmoshere and that is what give them the rainbow effect. They would be positioned at 45 degrees on either side of the sun (like you saw). You know it is going to be very cold weather when you see sun dogs.
655891
It doesn't matter if the rainbow appears around the sun or on the ground after a rainshower. The two rainbows are called primary and secondary bows. There are two because the sunlight is relected off the inside of a water droplet twice instead of once; once would result in only one rainbow. This all depends on the angle in which the sunlight enters the water droplet.\nThe secondary bow is fainter and  the colors are reversed.
775308
Def. not a rainbow \n\nbut I am both Red, White and Blue.  Anything wrong with that?
388125
A rainbow occurs when sunlight passes through sheets of falling rain which act as a prism to separate the light into it's full spectrum of colors. A double rainbow occurs when there are multiple sheets of rain that are perhaps angled slightly differently. One sheet of rain bends the light into one rainbow, the other sheet of rain bends the light in a slightly different path to create a second prismatic display. \n\nBasically, it is like haveing one light source (the sun) and two separate prisms set next to each other, but at slightly different angle giving you two separate spectra or rainbows.\n\nDouble rainbows are very cool indeed. I saw one last summer!
765835
Wow, not enough information to calculate. We would need the following information:\n\nYour position in latitude and longitude\nTime of day to the minute\nThe position of the clouds that are raining\n\nThen, let's state a few facts...\n\n1) Rainbows do not have a position, they are an optical illusion. The refraction/reflection can be inches away or thousands of feet. You would not necessarily know the distance by looking.\n\n2) You can only see a rainbow when the light source is behind you.\n\n3) There is no base of a rainbow because they do not exist, remember they are an optical illusion. You can see where the rainbow appears to be cut off by the ground, but there is no base. In fact if you were in the right position you could see a full circle rainbow.\n\n4) There is no location to move on a rainbow, but if you did move, yes it would look like the rainbow moved too. In fact there is no way to could be in a rainbow. HOWEVER, that does not mean a friend could not move to a position and appear to be in the rainbow, however your friend would not see the rainbow.\n\n5) Seeing dual rainbows (one at 42 degrees and the next at 50 degrees) is not uncommon. Seeing a triple or quadruple is much more unusual.\n\nSO there you go, so rainbow facts.
920214
It's called a lunar halo.  It is caused by refraction of light by water droplets in the atmosphere, in much the same way that a rainbow is caused, and there is a solar halo, as well, at times.  if you see it again, place your closed fist at arm's length at one side of the halo and see how many fists it takes to get across to the other side.  It should be two, plus about two fingers worth, 22.5 degrees diameter (same for the solar halo).  At times the solar halo is broken into two very bright spots 11 degrees or so either side of the sun:  these are popularly called "sun dogs".  If thin ice crystal clouds are the cause there is usually no coloration associated with the halo.
359455
A rainbow is produced when white light is split by differaction into light of different colours as it passes through raindrops. The colours that are produced are called spectrum. the colours in the spectrum are usually said to be red,orange,yellow,green,indigo and violet.
33383
A rainbow will never be a straight line.  They are not fixed in location.  A really small segment of a really big rainbow might look straight, but it is just curved to an inperceptably small extent.\n\nthe rainbow appears in a place that is ~41 degrees from the shadow cast by your head in the sunlight.  All of the places that fit this description will arch around in a circle.  However, there must be a lot of distant, small droplets for the full circel to be seen.  This can happen in the air, or if you're on the edge of a mountain with the sun right behind you, but usually more than half of all such points are in the direction of the ground, and there's no raindrops in the earth that can reflect a rainbow back to you.\n\nIf you've ever seen a fine-mist sprinkler on a sunny day, you might have seen the full circle.  But usually, you only see a small section of the total possible rainbow.
557311
hmmmm, my bubles have all the colors of the rainbow.\njust need to look closely. a beauty, those colors are slowly flowing over the surface of the bubble, ....then i pop the bubble, muahahahaha.
989426
between 10am -2pm the sun is high in the sky. with a high hummity it is posible to see a rainbow all the way  around the sun
270700
much to many people's belief's 7 basic colors aren't based on the rainbow colors. in fact some of the colors on the rainbow is actually a mix of primary colors that are really secondary or tetiary. not primary [basic]. so... here we go...\n\n\n7 basic colors are:\n\n1- a cool yellow a.k.a Hansa Yellow Medium—a lemony, slight bias to blue-green;\n\n2- a warm yellow a.k.a New Gamboge— a golden, slight bias to red-orange;\n\n3- a cool blue a.k.a Phthalo Blue (GS)—an icy, slight bias to blue-green;\n\n4- a warm blue a.k.a French Ultramarine— a purplish blue, slight bias to violet;\n\n5-  a cool red a.k.a Quinacridone Rose—a rosy, slight bias to red-violet;\n\n6- a warm red a.k.a Pyrrol Orange—a tomatoey red, slight bias to red-orange;\n\nok..only six [6] are listed here. to get the 7th color,all u need to do is... well here's where the magic is....\n\na] Use a warm and a cool of each primary hue (a warm red and a cool red; a warm yellow and a cool yellow; a warm blue and a cool blue) to mix bright, high-inten sity secondary called a Mixed Primary Hue. The secret is in using the right split primary colors and not crossing over the lines into another section!\n\n++TIPS++\n\nTo mix the oranges, mix the red and yellow within the lines to the left of the circle. First mix orange, and then add more yellow for yellow-or ange and more red for red-orange. \nTo mix the greens, mix the blue and yellow within the lines to the right of the circle. First mix green, and then add more yellow for yellow-green and more blue for blue-green. \nTo mix the purples or violets, mix the pink or rose with the blue within the lines at the bottom of the circle. First mix purple , and then add more blue for blue-violet and red for red-violet. \n\nNow here's the rule that makes this work: 'When mixing two colors on the wheel to achieve high- intensity color, don't cross over the line-stay in each section. Just imagine, no more muddy colors!\n\nCrossing over the lines and mixing the colors on either side of the line causes the mixtures to become less intense and slightly grayer. Cross two lines and even more graying occurs. This graying is called neutralizing. It is the result of a slight touch of that third color being added to the mix. To mix earth colors, you simply cross over the lines or add a warm neutral to your mixtures.\n\nOK ...\n\nNow for the much awaited 7th basic color....\n\nThat's where Quinacridone Burnt Orange—the seventh color of our essential 7 basics-enters the scene… it's a versatile warm neutral.\n\n\nhehe. quite interesting. hmm. [^_^]
147785
It is a second rainbow caused by the way light reflects inside of raindrops.  They will appear between 50 and 53 degrees above the horizon and the colors are inverted.  There is also a band of darker sky between the two, this is called an Alexander's band.
329385
A rainbow is created when white light from the sun enters droplets of water in the sky and is refracted. The light is refracted when entering spherical droplets, then it is reflected inside them and refracted again upon leaving. This bends the light, as you would see in a lens.  The red end of the spectrum bends less than the blue, which is why they separate when they come out of the drop.\nWikipedia has a page about rainbows, with some diagrams which may help you understand.\nhttp://en.wikipedia.org/wiki/Rainbow
43821
When light and water meet in the sky on a summer's day, for a few moments, a rainbow will appear. Such a beautiful sight! This phenomena of the atmosphere appears during or immediately following local showers, when the sun is shining and the air contains raindrops. A rainbow can best be seen with polarized sunglasses. We cannot follow the arc of a rainbow down below the horizon, because we cannot see those droplets in the air below the horizon. But the higher we are above the ground, the more of the rainbow circle we would see. That is why, from an airplane in flight, a rainbow will appear as a complete circle with the shadow of the aitplane in the center.\n\nThe bow is divided into bands displaying the different colors of the spectrum and is formed by the refraction and reflection of the sun's rays in drops of rain. Reflection is simply the return of light waves from the raindrop's surface. Light which appears to be white, is really made up of a mixture of red, orange, yellow, green, blue, and violet light
318480
Yes it is rainbow. Here is the Russian spelling of it: "радуга"