Today’s Wonder of the Day was inspired by Aiden. Aiden Wonders, “how rare is a moonbow” Thanks for WONDERing with us, Aiden!
When you awake in the morning and look out the window, what do you hope to see? If you're like most kids, you probably hope to see the Sun shining down, warming the air around you so you can play outside and enjoy the sunshine.
Some mornings, though, you're greeted by clouds and rain. While the rain might prevent you from playing outside, there's a chance that'll you get to see a beautiful natural phenomenon if the Sun comes out after the rain. What are we talking about? A rainbow, of course!
A brilliant rainbow is like a reward for making it through the rain. As the sunlight shines through the water droplets still floating in the air, the droplets act like prisms, scattering the sunlight in a visible spectrum we see as the rainbow.
When the Sun goes down, so does the chance of seeing a rainbow, right? Maybe not! Although they're rare, rainbows produced by moonlight — known as lunar rainbows or moonbows — do occur from time to time.
Just like the rays of the Sun can create a rainbow during the day, reflected light from the Moon can create a moonbow if the conditions are just right. One of the main reasons moonbows are so rare is that moonlight isn't very bright. To see a moonbow, a bright full Moon is usually necessary.
In addition, the sky must be very dark and the Moon must be very low in the sky (less than 42º above the horizon). Finally, a source of water droplets, such as rain or the mist from a waterfall, must be present in the opposite direction of the Moon. Given all of these necessary conditions, it's no surprise that moonbows aren't very common.
If you're lucky enough to see a moonbow, you'll notice that it probably doesn't look exactly like a rainbow. Instead, a moonbow often looks white to the human eye, because the dim light from the Moon produces colors that usually aren't bright enough to be detected by the color receptors in the eye. Colors can be seen, however, if you use a camera and a long exposure time.
Although moonbows are rare, they do tend to happen more frequently in certain locations. These locations usually have waterfalls that generate layers of mist in the air. The moonbows created near waterfalls are often called spray moonbows. If you hope to get a glimpse of a spray moonbow, some of the best locations include Yosemite National Park in California, Cumberland Falls State Resort Park in Kentucky, Victoria Falls between Zambia and Zimbabwe in Africa, Waimea in Hawaii, and Plitvice Lakes in Croatia.