A rainbow is an optical illusion
Similar to a mirage, a rainbow forms when light bends, creating an effect that is visible but cannot be touched or approached. For rainbows, light is reflected and refracted through water droplets, dividing white light into the seven colors of the spectrum.
Rainbows can exist at night
When the light from the moon spreads through the water droplets, the result is called the moon bow. Since moonlight is weaker than sunlight, the bow itself may appear white, but a camera with a long exposure can capture the full color.
Loved watching rainbows, look here
Morning and evening after a storm are the best times to catch a glimpse of a rainbow. When the sun is low in the sky (about 42 degrees to be precise), light passes through the water droplets at the right angle, forming a rainbow above the horizon. When the sun is much higher (e.g. 1 p.m.) or a low point in the sky, the angle of the light casts a rainbow below the horizon, where it is more likely to be blocked by trees or buildings, or not visible at all. Rainbows appear in the sky opposite the sun, so make sure you have your back to the sun so that you have the best chance of seeing the rainbow.
A rainbow can be a complete circle
Consider the horizon again: this line cuts the entire circle of the rainbow in half. There is no horizon (such as from the view from an airplane or when skydiving) and the entire circumference of the rainbow can be seen.
Remember the colors of the rainbow with this abbreviation
Please allow us to introduce you to Roy G. Biv. Remember the name, and you'll recite the colors of the spectrum (and the rainbow colors from top to bottom) in order: red, orange, yellow, green, blue, indigo, purple. Because the second darker rainbow in a double rainbow is a reflection of the first rainbow, the colors are reversed.
Aristotle was obsessed with rainbows
The Greek scholar Aristotle was one of the first thinkers to seriously consider how and why rainbows were formed—he devoted much of the third volume of Meteorology to this subject. Although some of his theories were wrong (he assumed that the rainbow consisted of only three colors), he correctly deduced that white light split into spectral colors to form a rainbow.