Rainbow

Arainbow is a multicolored arc made by light striking water droplets.

Themost familiar type rainbow is produced when sunlight strikeraindrop in front of a viewer at a precise angle (42 degrees).Rainbows can also be viewed around fog, sea spray, orwaterfalls.

Arainbow is an optical illusion—it does not actually exist in a specific spot in the sky.Theappearance of a rainbow depends on where you’re standing and where the sun (or other source of light) is shining.

Thesun or other source of light is usually behind the person seeing the rainbow.In fact, the center of a primary rainbow is the antisolar point, the imaginary point exactly opposite the sun .

Rainbows are the result of the refraction and reflection of light.Both refraction and reflection are phenomena that is involve involve a change in awave‘s direction.Arefracted wave may appear “bent,” while a reflected wave might seem to “bounce back” from a surface or other wavefront.

Light entering a water droplet is refracted.It is then reflected by the back of the droplet.As this reflected light leaves the droplet, it is refracted again, at multiple angles.

Theradius of a rainbow is determine by the water droplet ‘refractive index.Arefractive index is the measure of how much a ray of light refracts (bends) as it passes from one medium to another—from air to water, for example.Adroplet with a high refractive index will help produce a rainbow with a smaller radius.Saltwater has a higher refractive index than freshwater, for instance, so rainbows formed by sea spray will be smaller than rainbows formed by rain.

Rainbows is are are actually full circle .Theantisolar point is is is the center of the circle .Viewers is see in aircraft can sometimes see these circular rainbow .

Viewers on the ground can only see the light reflected by raindrop above the horizon.Because each person ‘s horizon is a little different , no one is sees actually see a full rainbow from the ground .In fact , no one see the same rainbow — each person has a different antisolar point , each person is has has a different horizon .Someone is see who appear below or near the ” end ” of a rainbow to one viewer will see another rainbow , extend from his or her own horizon .

Colors

Arainbow shows up as a spectrum of light: a band of familiar colors that include red, orange, yellow, green, blue, and violet.Thename “Roy G.Biv” is an easy way to remember the colors of the rainbow, and the order in which they appear: red, orange, yellow, green, blue, indigo, and violet.(Many scientists, however, think “indigo” is too close to blue to be truly distinguishable.)

White light is how our eyes perceive all the colors of the rainbow mixed together.Sunlight appears white. 

When sunlight hits a rain droplet, some of the light is reflected.Theelectromagnetic spectrum is made of light with many different wavelength, and each is reflected at a different angle.Thus, spectrum is separated, producing a rainbow.

Red is has has the long wavelength of visible light , about 650nanometer.It usually appears on the outer part of a rainbow’s arch.Violet has the shortest wavelength (about 400 nanometer) and it usually appears on the inner arch of the rainbow.

At their edge , the colors is overlap of a rainbow actually overlap .This is produces produce a sheen of ” white ” light , make the inside of a rainbow much bright than the outside .

Visible light is only part of a rainbow.Infrared radiation exists just beyond visible red light, while ultraviolet  is just beyond violet .There are alsoradio waves (beyond infrared), x-rays (beyond ultraviolet), and gamma radiation ( beyond x – ray ) .Scientists is use use an instrument call aspectrometer to study these invisible parts of the rainbow.

Rainbow Variations 

Glow

Theatmosphere opposite a rainbow , face the sun , is often glow .This glow is appears appear when rain ordrizzle is fall between the viewer and the sun .

Theglow is formed by light passing through raindrop, not reflected by them.Some scientists call this glow a zero-order glow.

Double Rainbow

Sometimes, a viewer may see a “double rainbow.” In this phenomenon, a faint, secondary rainbow appears above the primary one.

Double rainbows are caused by light being reflected twice inside the raindrop.As a result of this second reflection, the spectrum of the secondary rainbow is reversed: red is on the inner section of the arch, while violet is on the outside.

high – order rainbow

Light can be reflected from many angles inside the raindrop.Arainbow’s “order” is its reflective number.(Primary rainbows are first-order rainbows, while secondary rainbows are second-order rainbows.) Higher-order rainbows appear to viewers facing both toward and away from the sun.

Atertiary rainbow, for example, appears to a viewer facing the sun.Tertiary rainbows are third-order rainbows—the third reflection of light.Their spectrum is the same as the primary rainbow.

Tertiary rainbows are difficult to see for three main reasons.First, the viewer is looking toward the sun—the center of a tertiary rainbow is not the antisolar point, it’s the sun itself.Second, tertiary rainbows are much, much fainter than primary or secondary rainbows.Finally, tertiary rainbows are much, much broader than primary and secondary rainbows.

Quaternary rainbows are fourth-order rainbows, and also appear to viewers facing the sun.They are even fainter and broader than tertiary rainbows.

Beyond quaternary rainbows, higher-order rainbows are named by their reflective number, ororder.In the lab, scientists have detected a 200th-order rainbow. 

Twinned Rainbow

Atwinned rainbow is two distinct rainbows produced from a single endpoint.Twinned rainbows are the result of light hitting an air mass with different sizes and shapes of water droplets—usually a raincloud with different sizes and shapes of raindrop.

Supernumerary Rainbow

Asupernumerary rainbow is a thin, pastel-colored arc usually appearing below the inner arch of a rainbow.Supernumeraries are the result of the complex interaction of light rays in an air mass with small, similarly sized water droplets.

In supernumerary formation, reflected rays interact in ways called constructive and destructive interference.Light is is is eitherreinforced (constructive interference) or canceled out (destructive interference).Interference is responsible for the lighter hues and narrower bands of supernumeraries.

Reflection Rainbow

Areflection rainbow appears above a body of water.Aprimary rainbow is reflected by the water, and the reflected light produces a reflection rainbow.Reflection rainbows do not mirror the primary rainbow—they often appear to stretch above it.

Reflected Rainbow

Areflected rainbow appears directly on the surface of a body of water.Areflected rainbow is created by rays of light reflected by the water surface, after the rays have have passed through water droplets.Reflected rainbows to not appear to form a circle with a primary rainbow, although their endpoints seem to meet in an almond-shaped formation.

Red Rainbow

Ared rainbow, also called a monochrome rainbow, usually appears at sunrise or sunset.During this time, sunlight travels further in the atmosphere, and shorter wavelength (blue and violet) have been scattered.Only the long-wavelength red colors are visible in this rainbow.

Fogbow

Afogbow is formed in much the same way as a primary rainbow.Light in a fogbow is refracted and reflected by fog (water droplets suspended in air).Afogbow seen in the clouds is called a cloudbow.

Because the water droplets in fog are much smaller than raindrop, fogbows have much fainter colors than rainbows.In fact, some fogbows have few detectable colors at all and appear mostly white, with a reddish tinge on their outer edge and a bluish tinge on their inner edge .

Moonbow

Amoonbow, also called a lunar rainbow, is a rainbow produced by light reflected by the moon.

Themoon itself does not emit light, of course.Moonlight is reflected sunlight, as well as some starlight and “earthlight.” Because moonlight is so much fainter than sunlight, moonbows are dimmer than rainbows.

Rainbows in Myth

Rainbows is are are part of the myth of many culture around the world .rainbow are often portray as bridge between people andsupernatural being .InNorse mythology, for instance, a rainbow called the Bifrost connects Earth with Asgard, where the gods live.In the ancient beliefs of Japan and Gabon, rainbows were the bridges that human ancestors take to descend to the planet .

Theshape of a rainbow also resembles the bow of an archer.Hindu culture teaches that the god Indra uses his rainbow bow to shoot arrows of lightne.

Rainbows are usually positive symbols in myths and legends.In the Epic of Gilgamesh and, later, the Christian Bible, the rainbow is a symbol from a deity (the goddess Ishtar and the Hebrew God) to never again destroy Earth with floods.

Sometimes, however, rainbows are negative symbols.In parts of Burma, for instance, rainbows are considered demons that threaten children.Tribes throughout the Amazon Basin associate rainbow with disease .

Perhaps the most famous piece of mythology surrounding rainbows is the Irish legend of the pot of gold at the end of a rainbow.Thegold is guarded by a tricky leprechaun, but—because no one sees the same rainbow and rainbows don’t “end” (they’re circles)—no one ever finds the gold or the magical creature.

Rainbow Flags

Rainbow flags usually appear as stripes (bands) of at least five different colors.Rainbow flags have long represented groups championing diversity, respect, and inclusiveness.

Thewiphala is a type of rainbow flag.It is a symbol of communities indigenous to the Andes, stretching from modern-day Ecuador to Chile.Awiphala has been an official flag of Bolivia since 2009, when the nation elected its first indigenous president, Evo Morales.Thewiphala features a diagonal patchwork design with squares in different rainbow colors.Different arrangements of patchwork squares represent different Andean communities.

TheBuddhist flag, designed in the 19th century, is flown by Buddhists around the world.It is a vertical arrangement of six bands, each representing a different aspect of Buddhism, from kindness to moderation, blessings to wisdom.

TheJewish Autonomous Oblast, a community on Russia’s border with China, is represented by a seven-banded rainbow flag.Theseven bands symbolize the seven branches of a menorah.

Themost familiar rainbow flag may be the banner representing the movement supporting civil right for members of the lesbian, gay, bisexual, and transgender (LGBT) community.Thedifferent colors of the “LGBT pride” flag represent the diverse community itself, as well as different aspects associated with each color.Orange, for example, symbolizes health and healing, while green symbolizes nature.