Why is a rainbow shaped like a semicircle? This is the explanation

Who doesn't like seeing rainbows? Everyone will be amazed by this natural phenomenon. Nothing other than because the color is very beautiful.

So, Tafansa friends, on July 21, 2017, a crane operator in Russia recorded a natural phenomenon, namely a rainbow in the shape of a complete circle. This natural phenomenon was recorded from the top of the Lakhta Centre, a skyscraper with a height of 1,515 feet or around 460 meters in St. Petersburg. St. Petersburg. Suddenly, the video caused a stir among the wider community. Not only Russian media but even foreign media also reported on this rare natural phenomenon. Wow, as the author knows, a rainbow is only half a circle; the other half is in your eyes. Yes, you, friend Tafansa.

If we study science, this is not an extraordinary event because the true shape of a rainbow is a complete circle. How come? Why do we see only half a circle? Come on, look carefully at the explanation in this article.

Before going into the explanation, Tafansa's friends need to know that the condition for people to be able to see a rainbow is that there is the sun behind them and raindrops in front of them. That's why rainbows always appear in the western sky when they occur in the morning and appear in the eastern sky when they happen in the afternoon.

The process of creating a rainbow

Do you know how a rainbow occurs? If Tafansa's friends don't know yet, repeat the lessons from elementary school. Rainbows are the result of the refraction of white light as it passes through a medium. In this case, it is water droplets. Sunlight that passes through these water droplets will be refracted into seven different colors, namely red, orange, yellow, green, blue, indigo, and purple.

Based on the refractive index of each color, the positions of the colors in a rainbow are always sequential. For example, red has the smallest refractive index, so red will be refracted with the smallest refractive angle. Purple has the largest refractive index, which will be refracted with the largest refractive angle.

Well, quoted from the Kumparan page, Prof. Hendra Gunawan, professor at the Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, said that the rainbow undergoes refraction twice namely sunlight is refracted in water and then refracted in the eyes. Just found out, right?

One Whole Circle Rainbow

So, as explained above, rainbows are formed due to the refraction of sunlight passing through raindrops. And this habituation makes the sunlight reflected by the water become bent. Because there are many water droplets that reflect sunlight, the sunlight will continue to bend.

The sunlight that continues to bend is what makes the rainbow become circular. So, the actual rainbow is circular.

According to Prof.'s explanation. Hendra Gunawan is a collection of dots reflecting sunlight, which then becomes a circular rainbow. He described it as being like a cone, where the top of the cone is where our eyes are, and the base of the circle is the rainbow that we see.

When will we be able to see a complete rainbow? Tafansa friends, does anyone know? We can see a complete circular rainbow when we are at a certain height, for example, on top of a tall building, on a mountain top, or when we are on a plane.

Why Do We See Half Circles?

Well, Tafansa friends, in general, we see rainbows in the shape of a semicircle. This is due to the limitations of the human eye, which can only see rainbows from a viewing angle of 42°. Meanwhile, different rainbows outside that viewpoint will not be visible to the eye. As a result, the visible rainbow is semicircular and seems to end on the ground.

Apart from the limited visibility of the human eye, another reason why we cannot see the rainbow in its entirety is because the earth's surface limits the number of raindrops in our line of sight.

Interesting Rainbow Facts

As an additional insight, here are some interesting facts about rainbows:

Rainbows can appear at night.

Rainbows don't always rely on sunlight. Moonlight can be refracted into beautiful colors, too. This phenomenon is called a moonbow. This is because the rainbow produced is from moonlight.

Your right and left eyes see different rainbows.

When you see a rainbow, try to close the other eye; then, the rainbow you see will be different from the other eye.

There are more than a million colors in the rainbow.

Tafansa friends, another surprising fact is that the colors of the rainbow are not just seven colors as we see. There are more than a million colors in this natural phenomenon. The seven colors seen are only the primary colors that the human eye can see.

You can't touch the rainbow.

As with the mirage phenomenon, a rainbow can never be touched or achieved. There will still be a distance between the eye and the rainbow itself. The closer we get, the more the rainbow will also move.

Rainbows never occur during the day.

Tafansa friends need to know that rainbows only occur in the morning, afternoon, or evening. Rainbows hardly occur during the day. That's because the occurrence of a rainbow really depends on the position of the sun. As in the discussion above, the viewing angle formed is 42° to be able to see the rainbow. And that happens when the sun is about to rise and set.

Rainbows only occur on Earth.

Advice from the author: never make plans to move planets, deh. Because only on this planet can we see God's truly beautiful creation. Why? Because on other planets, it doesn't rain like on Earth. Still want to move planets?

Video source: https://youtu.be/odgqgmmdiXw