Cloud PointField Guide

Optical phenomenon — diffraction

Glory

Rainbow rings around your own shadow

Written by Laurence WayneEntry No. 20Uncommon

Glory: Rainbow rings around your own shadow
Plate XXPhotograph by formulanone from Huntsville, United States, CC BY-SA 2.0.

A glory is a set of shimmering, rainbow-coloured rings centred precisely on the shadow of your own head — most often seen from an aircraft, ringing the plane's shadow on the clouds below, or from a mountain looking down onto fog with the sun behind you. It forms when sunlight is scattered almost straight back toward you by small, uniform cloud droplets. Remarkably, each person sees only their own glory.

Worth knowing

  • A glory is always centred on the shadow of your own head, so in a group on a mountainside everyone sees their own rings and no one else's — historically this haloed shadow on the fog was known as the 'Brocken spectre'.
Note

Still unsure it's the same cloud? Our app, Cloud Point— on iOS and Android — reads a photo and returns the likely type with altitude, useful when a formation is fading faster than you can look it up.

Test yourselfThree levels

Choose a difficulty

Where do you see the coloured rings of a glory?

  1. aCentred on the shadow of your own head (or an aircraft) on cloud or fog
  2. bAround the sun itself
  3. cDirectly overhead at night
  4. dAlong the horizon at sunset
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AnswerCentred on the shadow of your own head (or an aircraft) on cloud or fog

A glory appears as concentric coloured rings centred exactly on the shadow of your head, cast onto a cloud or fog bank opposite the sun.

What creates a glory?

  1. aSunlight reflecting off ice crystals
  2. bSunlight scattered almost straight back toward you by small cloud droplets, interfering to form rings
  3. cRain refracting light into an arc
  4. dHeat shimmering off the ground
Show answer

AnswerSunlight scattered almost straight back toward you by small cloud droplets, interfering to form rings

Small, uniform cloud droplets scatter sunlight back toward its source. The backscattered light waves interfere to produce the concentric coloured rings centred on the point opposite the sun.

Two hikers stand side by side above a fog bank and both see a glory. What is true?

  1. aThey both see the same glory in the same place
  2. bEach sees only their own glory, centred on their own head's shadow
  3. cOnly the taller hiker can see one
  4. dThe glory appears halfway between them
Show answer

AnswerEach sees only their own glory, centred on their own head's shadow

A glory is locked to the point directly opposite the sun, which is unique to each observer's line of sight. So each person sees their own rings centred on their own shadow, and cannot see anyone else's.

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