At least two lunar rainbows, including a stunning double rainbow, appeared in the US sky as the super blue moon rose.
An extremely rare lunar rainbow lit up the night sky above the United States shortly before the super blue moon rose. Also known as a nighttime rainbow, the phenomenon is created similarly to a regular rainbow but is different in that it occurs when moonlight, rather than sunlight, reflects and refracts through raindrops. But they are much rarer because they can only be seen on the night of a full moon, when Earth’s natural satellite is at its brightest in the night sky, according to Live Science.
Moonlight is so faint compared to sunlight that rainbows usually appear white because the color receptors in the human eye don’t work well in low light to distinguish the spectrum of colors, according to the Met Office. However, the moon has been unusually bright in the past few days leading up to the super blue moon, making this rainbow appear more colorful.
Astrophotographer Aaron Watson spotted a double moonbow over Paonia, Colorado, around 2 a.m. on August 18, according to Spaceweather.com. “The rainbow was so bright that it was visible to the naked eye and lasted for a few minutes before slowly fading away,” Watson said. A moonbow was also spotted that same night over Keuka Lake in New York. It wasn’t as bright as the one in Colorado, but it still had a lot of color when captured on camera.
Although the moon will be less bright over the next few nights, experts say lunar rainbows can still occur during rainy weather, as long as the moonlight is refracted through the raindrops. Additionally, the phenomenon is only visible when the moon is behind the observer. The colors of the rainbow may be more visible in photos because cameras can pick up subtle colors that the human eye misses.