rainbow: Quick Facts

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Last updated

Nov. 12, 2026

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Photos and Videos

wind bending palm trees

$Diagram showing sunlight entering a water droplet, refracting, reflecting inside it, and emerging as separated red-to-violet light. Rays reaching an observer at about 42 degrees for red and 40 degrees for violet form a rainbow opposite the sun.$

A colored-pencil drawing of a rainbow on a white background.

Know how rainbows are formed

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Topics

What causes a rainbow?secondary rainbow primary rainbow Why are rainbows curved?supernumerary rainbow Atmosphere Aurora Airglow Chemical equator double refraction Snell’s law mirage refractive index Halo Aureole Cellini’s halo

Key People

Roger Bacon

Roger Bacon

English philosopher and educational reformer

Torbern Bergman, detail of an oil painting by Per Krafft; in the Royal Swedish Academy of Sciences, Stockholm

Torbern Olof Bergman

Swedish chemist and naturalist

rain. Child in the rain, wearing a rain coat, under a yellow umbrella. April Showers weather climate rain storm water drops

April Showers to March’s Lions and Lambs