A double rainbow in Oz

November 7, 2014 • 1:42 pm

Well, from near Perth, Australia. The reason you can see the whole thing is that it’s taken from the air. As Science News explains:

A full double rainbow, captured from a helicopter flying over Cottesloe Beach in Western Australia, frames a golf course near Perth. A downpour reflects light from the setting sun back toward photographer Colin Leonhardt, creating two concentric rings of color that appear to encircle the course.

. . . All rainbows are round, but seeing a full circle requires a viewing area with plenty of droplets in all directions; that’s tough for people on the ground. When the observer flies through a water-laden sky, however, a complete rainbow emerges.

The second, dimmer rainbow appears when light bounces off the inside of raindrops twice before coming back. Because most of the light leaks out after just one reflection, secondary rainbows are usually much fainter than primary ones.

scivis_3

23 thoughts on “A double rainbow in Oz

    1. I have both Internet Explorer and Firefox all I did was to right click and select ‘set as background’.

      1. I am quite aware of how to set a desktop picture, thanks 😛

        What I meant was, the largest version of the picture is 860 x 555 pixels. My desktop is 1920 x 1200. Sure it can be resized, but what comes out lacks sharpness. A higher resolution picture would therefore be nicer for this use.

  1. As Phil P explains, there are higher order rainbows as well, each fainter than the last, caused by successive partial internal reflections inside spherical raindrops. Don’t think anyone has ever seen them in nature, but they can be produced in “the lab”, or your garage. Older readers may remember the Amateur Scientist feature in Scientific American. It once showed how to do this. The 3rd and 4th order bows are seen looking towards the light source, and off to the side.
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    ROY G BIV

  2. Pilots are actually rather familiar with this phenomenon. It’s either called the “glory” or the “pilot’s halo.” The latter, because, when it appears over a cloud, the plane’s shadow is projected to the exact center of the rainbow.

    Wikipedia has an article on the subject:

    https://en.wikipedia.org/wiki/Glory_(optical_phenomenon)

    It’s worth noting that the glory is an indication of lots of moisture present. In low temperatures, that means conditions may be ripe for icing; a wise pilot will steer clear of clouds in icing conditions when a glory is visible. (Air traffic control can vector you around the clouds or to the nearest airport to wait for conditions to clear. This assumes, of course, that your plane lacks suitable de-icing equipment, as most general aviation craft do.)

    b&

    1. Yeah, I was going to point out that they’re relatively common as seen from aircraft in general. I’ve seen at least a half-dozen from my flights out to various rigs, and I spend most of those with my nose in a book, a Sudokou, or just plain snoring my head off.
      In space, no one can hear you scream. But at 105dB no one can hear you snore. Well, not normally.

        1. 105dB ambient noise in the passenger cabin. Double hearing protection for everyone. Foam ear plugs inside the ears and “ear muff” type foam-filled ones outside.

    2. According to the internets, glories are a different phenomenon than rainbows, and this picture is actually a rainbow. One hint is its large size; due to their formation, glories are smaller.

      The difference is that rainbows (as well as sun dogs) are the product of refraction and reflection, while glories (as well as iridescent clouds) are caused by diffraction.

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