Full Rainbow: Reasons You See Arches Instead Of Full Circles

Rainbows are a beautiful phenomenon seen in the sky that mesmerizes its spectators with their beautiful and vibrant colors.

Often after a gloomy storm passes by, we can spot a colorful rainbow painting a portion of the sky. This atmospheric wonder is a result of the intricate interplay of the sun's visible light falling on the atmospheric water droplets in a series of scientific ways.

For the creation of a rainbow, several factors like the angle of the sun, the vantage point of the viewer, presence of water droplet in the atmosphere, and the angle at which the white light passes into a water droplet and the same light exits from it play an important role. The basic scientific principles underlying the rainbow formation are that of reflection and refraction of the light from different angles. In the presence of atmospheric moisture and sunlight shining, the light hits a water droplet at a certain angle. Since the density of water is heavier than air, the light bends or refracts while entering the water droplet. Thereafter, white light gets reflected from the droplet and while exiting from water to the air it again gets refracted. At this time, the hues present in the visible spectrum of the white light bounce out of the droplet according to the speed of their wavelengths. As a result, we see a series of colors in the form of a rainbow.

Want to find out more astonishing reasons for the occurrence of a full rainbow? Read on to know more.

You can also take a look at amazing information about the big bang and wind facts.

Full Rainbow From Space

While most of us have seen a semi-circular rainbow but did you know that a full rainbow circle has also been spotted in several locations.

While a rainbow forms in a full circle we only get to see rainbow arches as the horizon and the earth's surface blocks its view from the ground level. It occurs as the earth's surface lowers the concentration and number of water droplets from the line of sight of the observer in the ground. Another factor is the antisolar point that restricts the view of the circular rainbow. The point right opposite to the sun shining, where you can see the shadow of your head is called the antisolar point. The center of the rainbow lies at this position, so the nearer the sun is towards the horizon, the higher is the antisolar point and the bigger is the rainbow that you can clearly see. But when the sun is high up in the sky, the antisolar point comes downwards and the rainbow becomes smaller, allowing you to see only a portion of the arch through the naked eye.

Interestingly, many people have spotted a circular full rainbow from a plane over the years. Right after a storm, the sky with misty clouds and the sun's position lying above 42 degrees makes up an ideal condition for circular rainbows. As the vantage point of the observer is high above the earth's surface, this rare sight can be an experience of a lifetime for its observers. This circular interlocking band of colors seen from a plane is referred to as glory.

Full Rainbow Colors

The seven primary colors that a human eye can see from a rainbow are VIBGYOR or violet, indigo, blue, green, yellow, orange, and red.

A rainbow emitting these colors is a result of the same principles of refraction and reflection that we discussed earlier. The water droplet acts as a prism for the white light, separating the colors and causing each colored light to reflect out of the droplet at its own wavelength speed and angle. While the common colors we see in a typical rainbow are in the order of the red light (having longest wavelength) at the outer ring and violet (shortest wavelength) at the inner edge. In places where multiple rainbows form, the colored light rays may get reversed with violet at the outer and red at the inner edge.

When the light hitting on liquid water or ice crystals creates a double reflection from the water or ice surface, which results in the formation of double rainbows. In these reflection rainbows, the colors of the primary bow occur in the usual order, the reflected rainbow has its colors reversed, with blue light in the outer rim and red light in the inner rim. A secondary rainbow or reflection rainbow is also much fainter than the primary rainbow. Since the reflection rainbows depend on how many times light gets reflected from the water droplets, it can also cause triple or quaternary rainbows if reflection happens thrice or four times.

Another rare sighting is the supernumerary rainbow found inside the inner band of the primary rainbows. Here light reflecting out of water droplets less than 0.03 in (1 mm) in size forms thin pastel-colored bands beneath the inner color arcs of the primary rainbow. This faded secondary rainbow inside the primary rainbow is known as the supernumerary rainbow.

Full Circle Rainbow Meaning

While most of us have either seen a rainbow arch or a half-circle rainbow, a handful of the lucky ones have got the chance of seeing a rainbow that is shaped as a whole circle.

A full circle rainbow or circular rainbow can only be seen from a very high altitude where the horizon or the earth's surface doesn't block its view from the vantage point of the spectators. Although a rare sighting, full circle rainbows can be seen from a plane when the sun's position is at the opposite side of the rainbow. It can best be seen during afternoons or dusk when the sun is about to set on the west and on its opposite side, a circular rainbow can be seen high up in the sky.

What is a full circle rainbow called?

A full circle rainbow is also known as a circular rainbow or a glory.

All rainbows are formed as circles, but their circular view gets obstructed when it hits the earth's surface or at the horizon of their spectators. Consequently giving it a bow or arch shape.

Often we see a glowing band of light around the sun that is called the sun's halo. Another optical phenomenon called glow is found on the side of the sun, which exhibits a beam of colors but isn't a rainbow. This happens when it drizzles in between the sun and the observer where the raindrops do not reflect the light forming rainbows, instead, the light just passes in between the droplets.

Did you know?

A lunar rainbow or moonbow is a glowing arc of light formed from reflected moonlight. Lunar rainbows occur in the lunar months with a full moon shining. As moonlight is diffused sunlight, the lunar rainbows appear as a faint arc around the edge of the moon, encircling it.

Twinned rainbow is another example of rare rainbows where two rainbows are formed from the same base. Unlike a double rainbow, the pattern of colors in the twinned rainbows appear in their original order with red at the outer rim and blue at the inner edge. When two rain showers occur one after another after a small gap, the different shapes and sizes of water droplets from clouds after each shower make up a twinned rainbow.

At sunrise or sunset, as the sun's light has to travel the maximum across the atmosphere, the blue light gets scattered while the red light doesn't because of its longest wavelength. This gives rise to a red rainbow or monochrome rainbow in the sky.

Fog bows are extremely faint rainbows that appear when light exits out of a fog. It can be found at a higher altitude, with cold and cloudy weather, or can also occur above a fog formed by sea spray above the water surface.

Reflected rainbows are a type of secondary rainbows that are formed directly above the surface of a water body. As the water acts as a mirror reflecting the secondary rainbows, they are less fainter than other kinds of secondary rainbows.

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