its a wonder of god bro.....

What causes the rainbow? The rainbow is caused by light from the sun (or moon) interacting with raindrops falling from the air. These raindrops are mostly round. A ray of light entering such a droplet is bent (refracted) and decomposed into all possible colors (wavelengths) which the white light consists of. The ray then reflects internally in the droplet, and emerges roughly into the direction it came from when it entered the drop. Since the rays of the different colors all exit at slightly different directions, you see a color band in the sky. Why is the rainbow colored? The colors are produced by a phenomenon called dispersion. Dispersion causes white light, which consists of all possible colors (better: wavelengths or frequencies) to break up into all components when the light travels from one medium (e.g. air) to another (e.g. water). The different colors of light have all slightly different directions, so if you look in a certain direction in the sky from which mostly some particular colored light comes, you see that color. Why is the rainbow round? The rainbow appears round for two reasons. First, because the raindrops in which it is visible, are mostly round. Falling raindrops do not have the typical teardrop shape, but are more or less round. Second, the light from the sun is being refracted ("bent") by the droplets over a certain angle. This angle is so big that the rainbow appears opposite the sun. Since this angle is constant for all orientations of raindrops with respect to you and the sun, the rainbow is a circular bow, centered on the point opposite the sun (where the shadow of your head is). It is usually only seen above the horizon since you are usually on the ground and there is no rain falling below you. In some circumstances, when the rainfall is very dense, you can see the rainbow in front of the ground, below the horizon. Did I saw two rainbows? There are infinitely many rainbows, with different radii. You probably saw the secondary rainbow, which lies just outside the first bow. The secondary bow has a radius of about 51 degrees. The tertiary and higher-order bows are never seen since they are too faint and some are in a bright part of the sky (near the sun). You will note that the colors of the secondary bow are reversed from the primary bow.