GREENVILLE, N.C. (WNCT) — Did you know that every rainbow is shaped like a complete circle and that no two people have ever seen the same rainbow, even those standing right next to one another? Both surprising facts are true because rainbows are just another optical illusion that takes place in our earth’s atmosphere.
Like most optical illusions that occur in weather, a rainbow formation has a lot to do with sunlight, which appears clear but it is made up of all colors of the visible spectrum. The way sunlight interacts with water droplets is what creates that band of vibrant colors we see in a rainbow.
First, picture a water droplet or raindrop. As light enters one side of the water droplet, it is refracted, and bends. This is because water is denser than air, causing the light to slow down as it travels.
Once the traveling light reaches the opposite side of the water drop, it is reflected through the droplet and the light exits the drop in the same direction that it came in. Once this traveling light transitions from water back into air, it is refracted once again.
With that being said, different colors of the visible spectrum travel at different speeds. Red travels the fastest, so it is seen at the top of the rainbow. Blue travels the slowest, so it is seen at the bottom of the rainbow.
When looking for a rainbow, a person must be standing in between the sun and a rain cloud. There needs to be few to no clouds present around the sun, and the sun must also be lower in the sky. In fact, the closer the sun is to the horizon, the more arc a rainbow will possess.
The longest ever recorded rainbow lasted for eight hours and 58 minutes in the mountains of Taiwan in 2017. Next time you find yourself caught in a rainstorm, don’t forget to look for that rainbow.