Atmospheric optical phenomena, especially rainbows, are fascinating. Various texts and the scientific literature
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have done well in explaining the rainbow in terms of geometric optics. The phenomenon of the double rainbow is shown to be one collective optical pattern not always seen or recognized as such. In particular, knowledgeable observers have aptly described the dark zone between the primary and the secondary rainbows as an optical interferometric condition. The effect of the interference is clearly visible in the photograph. However, the destructive interference in the dark zone is not complete; witness the mountain image in the background.
The Week in Physics" is likely a reference to the regular updates or summaries of new physics research, such as those found in publications like Physics Today from AIP Publishing or on news aggregators like Phys.org.