April 7, 2016. Culpeper, Virginia. Photo: Janet Furlong.
We were totally wowed by the beauty and coolness of the rainbow pics posted by our Facebook friends. All I can say is – scroll down and enjoy!
FAQ: What gives rainbows their curved shape?
FAQ: Can you ever see the whole circle of a rainbow?
Eliot Herman caught this shot in September, 2015. He wrote to EarthSky: “This one is my fav ground-hugging rainbow, right out my front door … my daughters made this one into my luggage tags … September 14 was as the local TV weather stated the end of our annual monsoon season. A final last thunder storm and as the day was ending it cleared and the low angle sun lit up this ground hugging rainbow on the adjacent hillside.”
Eliot Herman in Tucson sent in this one, too. He said: “I also love it when it is lightning and rainbow at the same time. Monsoon season is a couple of months off, and then it is a few months of great lightning and rainbows, all in my backyard.”
Richard Hasbrouck in Truchas, New Mexico caught this glorious double rainbow at sunset.
A rainbow in a wave shaped cloud, Big Island of Hawai’i. Photo: Imaginscape Photography
After the rain in Normandy, France via our friend Jean Marie Delaporte.
Nevada, after heavy monsoon rain. Photo credit: RN Misha
Double rainbow. Steinkjer, Norway. Photo: Bjørn Sørhøy
Double rainbow from Hilda Gerlock in Fort Simpson, Northwest Territories of Canada.
The colors in rainbows are due to what’s called the prism effect. The specific angle is called the rainbow angle, first described by Descartes in the year 1637. Sunlight that shines into a raindrop leaves that raindrop at an angle of 138 degrees from the path that the light traveled before it entered the drop.
Double rainbow viewed from San Diego in 2011 by Jim Grant.
Manila, Philippines. Photo Credit: Jv Noriega
“Finding the end of the rainbow” by Louise Richards-Green in Australia
You can see a small complete circular rainbow in the spray from a garden hose if you get the angle just right. Photo via Katherine Keyes Millett in Salem, Massachusetts.
Photo credit: Lee Capps
Sometimes people say they see full-circle rainbows from airplane windows, with the shadow of the airplane inside the circle. But those aren’t true rainbows. Instead, those are called glories. Read about glories here.
Niagra Falls, Ontario. Photo credit: Anthony J. Amado
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Normandy, France. Photo credit: Mohamed Laaïfat
Overlooking Dublin Bay, Sandymount, Ireland. Photo credit: Elaine Amy May McFeeters
Late afternoon in Semporna, Sabah, Malaysia. Photo credit: Shahzan Ibrahim
Grand Canyon. Photo credit: Anne McLellan Swan
Niagra Falls. Photo credit: Bob Lennartz
Photo credit: Jean Marie Delaporte
A rainbow is caused by sunlight hitting water droplets in the air. You typically see a rainbow in the sky opposite the sun after or during a rain shower. When light enters a raindrop, it’s refracted, or bent.
Then the light is reflected from the drop in such a way that the white light breaks into its separate wavelengths and you see a spectrum of colors.
If the light left the water droplet at 180 degrees, it’d head straight back toward the sun. With a rainbow angle of 138 degrees, the light is traveling in a direction somewhat, but not directly, back toward the sun. That direction of travel by the light explains why you always see rainbows when the sun is behind you.
The sunlight emerges from many raindrops at once. The combined effect is a mosaic of light, spread out in an arc in the sky.
But that’s not the end of the story. When sky conditions and your vantage point are perfect, the rain and sun work together in this way to create a complete ring of light – a circle rainbow. You’ll never see this from Earth’s surface because your horizon gets in the way.
The early Greeks had a more fanciful – but very beautiful – explanation for rainbows. They believed that Iris, the Greek goddess of the rainbow, could fly at the speed of the wind from one end of the Earth to the other. As she flew, she left an arc of colors trailing in her wake.
“From my home in Alberta, Canada” by Heather McRae Lapp
Photo: Peri Melodi Yanmaz in Datça, Turkey.
Bottom line: Rainbow photos from around the world from EarthSky friends. Thanks, everyone!