Don't worry. It is usually smog in cities and frost or water vapour in the country side. Or, it can just be a natural occurrance in the eyes when you look at bright objects. A third possibility is that you are just tired. If you are still unsure, go see a doctor.
A rainbow appears as a circle when viewed from an airplane because the observer is seeing the full circular arc of the rainbow due to their high altitude. The shape of a rainbow is actually a full circle, but when viewed from the ground, the bottom half is usually blocked by the horizon. So, from higher altitudes, the full circle can be seen.
Actually it is circular but usually the sun needs to be quite low in the sky for the angle of the sunbeams hitting the raindrops to be suitable to create a rainbow visible from the ground. But, when that happens, a part of the rainbow is cut-off by the horizon and so it appears semicircular. Full circles are rare but have been seen/photographed.
A rainbow appears in the sky when sunlight is refracted, reflected, and dispersed in water droplets, usually after a rain shower. The light bends as it enters the droplet, reflects off the inner surface, and then refracts again as it exits, splitting the light into its component colors. This creates a circular arc of colors, which we perceive as a rainbow, typically appearing when the observer is positioned between the sun and the rain.
Usually people think that there is gold at the end of the rainbow. (It's a myth.)
Usually circular.
Usually people think that there is gold at the end of the rainbow. (It's a myth.)
A rainbow forms a circular arc in the sky, with its center located at the antisolar point, which is the point directly opposite to the sun. However, when viewed from the ground, only a portion of the arc is usually visible to the observer due to the horizon.
Unicorns may live at the end of a rainbow if they choose but that's usually leprechauns.
around the eyes and lips
They are usually called the bases.
A gasket may or may not be circular, and it is usually flat on both sides. An O ring is always circular, and circular in girth as well.
A butterfly generally represents someone who is transgendered or transexual. A rainbow usually stands for gay pride.