Optical phenomenon

An optical phenomenon is any observable event such as a rainbow which results from the interaction of light and matter. Some optical phenomena are commonplace such as the sky is blue or sunsets are red, others such as the green ray are so rare as to seem mythic. Some are commonplace in certain locations such as instances of fata Morgana. Optical phenomena illuminate and are explained by principles of optics.

Others include:

• Afterglow
• Airglow
• Alexander's Band, the dark region between the two bows of a double rainbow.
• Alpenglow
• Asterism, star gems such as star sapphire or star ruby.
• The unusually large size and rich color of the Moon as it rises and sets
• The Camera Obscura
• Chromatic polarization
• Diffraction, the apparent bending and spreading of light waves when they meet an obstruction.
• The Double-slit experiment
• Gegenschein
• Glories
• Halos, of Sun or Moon
• Sun Dogs
• Rayleigh scattering (Why the sky is blue, sunsets are red, Clouds are white, and associated phenomena )
• Synchrotron radiation
• The separation of light into colors by a prism
• The Zeeman effect
• Thomson scattering
• Total internal reflection
• The Umov effect
• Zodiacal light
• Polarized light related phenomena such as double refraction, or Haidinger's brush
• Light can travel through space or through a vacuum.

There are many phenomena which result from either particle or wave nature of light. Some are quite subtle and observable only by precise measurement using scientific instruments. One famous observation was of the bending of light from a star by the sun during a solar eclipse. This demonstrated that light had mass or did it show that space is curved...see Theory of relativity.

Observations of some phenomena such as the photoelectric effect, the flow of electric current in a material or through a vacuum (as in a photocell) when the material is exposed to light, were productive of scientific advancement as they could not be easily explained by current theory.

Further Reading

• Thomas D. Rossing and Christopher J. Chiaverina, Light Science: Physics and the Visual Arts, Springer, New York, 1999, hardback, ISBN: 0-387-98827-0
• Robert Greenler, Rainbows, Halos, and Glories, Elton-Wolf Publishing, 1999, hardback, ISBN: 0897169263.
• Polarized Light in Nature, G. P. Können, Translated by G. A. Beerling, Cambridge University Press, 1985, hardcover, ISBN:0-521-25862-6