A rainbow can form a circle, but the view from the ground usually shows only an arc. An elevated viewpoint can reveal more of it when suitable sunlit droplets are present below the observer. Height alone is not enough.
A Zhihu Daily answer credited to Huanghe Bianer discusses this familiar puzzle. ThreadEast checked its broad geometry and double-rainbow explanation against the Met Office.
Three useful details to keep in a photo-reading note:
- 1.
Viewpoint: record the visible horizon, light direction and crop. A missing part of the image does not prove what existed outside the frame.
- 2.
Colours: the spectrum is continuous. Seven familiar names are a convention, not seven sharply separated physical bands.
- 3.
The second bow: the fainter secondary lies outside the primary and reverses its colour order. The Met Office explains it through two internal reflections in a water droplet.
These checks help assess a description. They do not authenticate a photograph, its location or its date. Follow the original image credit before attributing a sighting.
ThreadEast first observed the listing November 8 and recorded it again November 13 at 02:50 China Standard Time. No publication date was displayed in the answer. We did not authenticate its photographs, reproduce diagrams or validate every numerical angle.
Source-reviewed brief and practical checklist:
Original Q&A:
https://daily.zhihu.com/story/9793804
Met Office explanation:
https://www.metoffice.gov.uk/weather/learn-about/weather/optical-effects/rainbows