Optical phenomenon

An optical phenomenon is any observable event which results from the interaction of light and matter . See also list of optical topics and optics

Common optical phenomena are often due to the interaction of light from the sun or moon with the atmosphere, clouds, water, ordust and other particulates. One common example would be the rainbow , when light fromthe sun is reflected off water droplets in rain as it falls to the ground. Others, such as the green ray , are so rare that many consider them to be mythical. Some, such as instances of fata Morgana , are commonplace only in certain locations.

Other phenomena are simply interesting aspects of optics , or optical effects. Thecolors generated by a prism are often shown in classrooms for instance.

A list of optical phenomena

Entopic phenomena include optical phenomena arising from the structures of the eye .

Some optical illusions can be explained as observations ofunusual optical phenomena.

Atmospheric optical phenomena

• Afterglow
• Airglow
• Alexander's band ,the dark region between the two bows of a double rainbow.
• Alpenglow
• anticrepuscular rays
• Auroral light (northern and southern lights, aurora borealis andaurora australis)
• crepuscular rays
• Elves [1]
• Glories (also known as Brocken'sSpecter or Specter of the Brocken)
• the Green ray
• Halos , of Sun or Moon, including sun dogs
• Rainbows
• Sprites [2]

Other optical phenomena

• Zodiacal light
• Gegenschein
• Sylvanshine
• Iridescence

Optical effects

• Asterism , star gems such as star sapphire or star ruby .
• Aventurescence , also called the Schiller effect, spangled gems such as aventurinequartz and sunstone .
• The Camera obscura
• Caustics
• Chatoyancy , cat's eye gems such as chrysoberyl cat's eye or aquamarine cat's eye
• Chromaticpolarization
• cathodoluminescence
• Diffraction , the apparent bending and spreading of light waves when they meet an obstruction.
• dispersion
• Double refraction
• The Double-slit experiment
• electroluminescence
• fluorescence , also called luminescence or photoluminescence .
• phosphorescence
• metamerism as of alexandrite
• pleochroism gems or crystals which seem many-colored
• Rayleigh scattering (Why the sky is blue, sunsets arered, clouds are white, and associated phenomena)
• Synchrotron radiation
• The separation of light into colors by a prism
• triboluminescence
• The Zeeman effect
• Thomson Scattering
• Total internal reflection
• The Umov effect
• Polarized light -related phenomena such as double refraction , or Haidinger's brush
• The ability of light to travel through space or through a vacuum.

Entopic phenomena

• Diffraction of light through the eye lashes
• Floaters
• Haidinger's brush
• Monocular diplopia (or polyplopia ) from reflections at boundaries between the various ocular media

Optical illusions

• The unusually large size and rich color of the Moon as it rises and sets

There are many phenomena which result from either the particle or the wave nature of light. Some are quite subtle andobservable only by precise measurement using scientific instruments. One famous observation was of the bending of light from astar by the Sun during a solar eclipse. This demonstrated that space is curved. See Theory ofrelativity .

Observations of some phenomena such as the photoelectriceffect , the flow of electric current in a material or through a vacuum (as in a photocell) when the material is exposed tolight, led to advances in science, as they could not be easily explained by existing theory.

Unexplained phenomena

Some phenomena are still unexplained, and they could very possibly be some kind of optical phenomena. Many of the "mysteries"are just local tourist attractions not worthy to be investigated.

• Marfa lights
• Hessdalen lights
• Min Min lights

Further reading

• Thomas D. Rossing and Christopher J. Chiaverina, Light Science: Physics and the Visual Arts, Springer, New York,1999, hardback, ISBN0-387-98827-0
• Robert Greenler, Rainbows, Halos, and Glories, Elton-Wolf Publishing, 1999, hardback, ISBN 0-897-16926-3
• Polarized Light in Nature, G. P. Können, Translated by G. A. Beerling, Cambridge University Press, 1985,hardcover, ISBN 0-521-25862-6
• Abenteuer im Erdschatten (German).