Full circle rainbow. And it's a double
EarthSky
Full circle rainbow was captured over Cottesloe Beach near Perth, Australia in 2013 by Colin Leonhardt of Birdseye View Photography. He was in a helicopter flying between a setting sun and a downpour. Used with permission. Order prints of this photo.
When sunlight and raindrops combine to make a rainbow, they can make a whole circle of light in the sky. But its a very rare sight. Sky conditions have to be just right for this, and even if they are, the bottom part of a full-circle rainbow is usually blocked by your horizon. Thats why we see rainbows not as circles, but as arcs across our sky.
When you see a rainbow, notice the height of the sun. It helps determine how much of an arc youll see. The lower the sun, the higher the top of the rainbow. If you could get up high enough, youd see that some rainbows continue below the horizon seen from closer to sea-level. Mountain climbers sometimes see more of a full-circle rainbow, though even a high mountain isnt high enough to show you the whole circle.
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