The Glory: A Spectacular Display of Atmospheric Optics |…

What is a Glory?

A glory is an optical phenomenon that appears as a colored circular halo, often with a central shadow or black spot, surrounding the shadow of the observer on clouds. This effect is most commonly observed when looking down from high altitudes at low-hanging cloud formations.

The term 'Brocken' refers to Mount Watzmann in Germany, where this phenomenon was first described by Johann Wilhelm Ritter in 1824.

How a Glory Forms

A glory forms due to the backward scattering of light from water droplets or ice crystals in clouds. When sunlight enters these droplets, it is refracted (bent), reflected internally, and then exits the droplet in a particular direction, creating a circular pattern around the observer's shadow.

The central black spot corresponds to the exact position where the observer’s shadow falls on the cloud, acting as a focal point for the scattered light.

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Governing Principles

The formation of a glory is governed by Snell's Law and the principles of internal reflection. When light enters a water droplet at an angle greater than the critical angle, it undergoes total internal reflection within the droplet before exiting in another direction.

The colors observed in a glory are due to the dispersion of light into its constituent wavelengths, similar to how a prism splits white light.

Real-World Examples and Applications

Glories have been observed in various natural settings, such as rainbows over waterfalls or during rain showers. They are also significant for atmospheric scientists studying cloud microphysics and the distribution of aerosols.

In meteorology, understanding glories can help in predicting weather patterns and identifying specific types of clouds.

Frequently asked questions

What conditions must be met to observe a glory?

To see a glory, the observer must be standing on high ground with their back to the sun, looking at low-hanging clouds. The angle of sunlight and the size of water droplets in the cloud are crucial for the phenomenon to occur.

Can glories form in other types of weather conditions besides rain?

Yes, glories can also be observed during snowstorms or when looking at fog. Ice crystals in clouds and ice wedges on the ground can create similar effects.

How does a glory differ from a rainbow?

A glory is a circular halo around the observer's shadow, while a rainbow forms an arc in the sky. Glories are caused by backward scattering within individual droplets or crystals, whereas rainbows result from refraction and reflection at the interface between air and water.

Why do glories appear to be colored?

The colors in a glory arise due to the dispersion of light into its different wavelengths as it is internally reflected within the droplets. This dispersion effect is similar to how a prism separates white light into a spectrum.

Try it live

Everything above runs in your browser — open Glory Brocken Spectre Simulator and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

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