Optical phenomena

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A 22deg halo around the Moon in Atherton, California Moon 22 degree halo atherton ca.jpg
A 22° halo around the Moon in Atherton, California

Optical phenomena are any observable events that result from the interaction of light and matter.


All optical phenomena coincide with quantum phenomena. [1] Common optical phenomena are often due to the interaction of light from the sun or moon with the atmosphere, clouds, water, dust, and other particulates. One common example is the rainbow, when light from the sun is reflected and refracted by water droplets. Some phenomena, such as the green ray, are so rare they are sometimes thought to be mythical. [2] Others, such as Fata Morganas, are commonplace in favored locations.

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

A solar halo as seen from 41deg south latitude SunHaloOverGoldenBay4thFeb06.jpg
A solar halo as seen from 41° south latitude


Optical phenomena include those arising from the optical properties of the atmosphere; the rest of nature (other phenomena); of objects, whether natural or human-made (optical effects); and of our eyes (Entoptic phenomena). Also listed here are unexplained phenomena that could have an optical explanation and "optical illusions" for which optical explanations have been excluded.

There are many phenomena that result from either the particle or the wave nature of light. Some are quite subtle and observable only by precise measurement using scientific instruments. One famous observation is of the bending of light from a star by the Sun observed during a solar eclipse. This demonstrates that space is curved, as the theory of relativity predicts.

Atmospheric optical phenomena

A circumzenithal arc over Grand Forks, North Dakota Circumzenithalarc.jpg
A circumzenithal arc over Grand Forks, North Dakota
The Belt of Venus over Paranal Observatory atop Cerro Paranal in the Atacama Desert, northern Chile Belt of Venus over Paranal Observatory.jpg
The Belt of Venus over Paranal Observatory atop Cerro Paranal in the Atacama Desert, northern Chile

Other optical phenomena

Green flash appears above the solar disc for a second or so. One such occurrence was taken from Cerro Paranal. Double Green Flash.jpg
Green flash appears above the solar disc for a second or so. One such occurrence was taken from Cerro Paranal.

Optical effects

Entoptic phenomena

Optical illusions

Unexplained phenomena

Some phenomena are yet to be conclusively explained and may possibly be some form of optical phenomena. Some[ weasel words ] consider many of these "mysteries" to simply be local tourist attractions that are not worthy of thorough investigation. [4]

See also

Related Research Articles

<span class="mw-page-title-main">Optics</span> Branch of physics that studies light and its interaction with matter

Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.

<span class="mw-page-title-main">Refraction</span> Physical phenomenon relating to the direction of waves

In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed.

<span class="mw-page-title-main">Atmospheric duct</span>

In telecommunications, an atmospheric duct is a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals are guided or ducted, tend to follow the curvature of the Earth, and experience less attenuation in the ducts than they would if the ducts were not present. The duct acts as an atmospheric dielectric waveguide and limits the spread of the wavefront to only the horizontal dimension.

Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin lux, meaning "light", and generally implies radiance, gloss, or brilliance.

<span class="mw-page-title-main">Glory (optical phenomenon)</span>

A glory is an optical phenomenon, resembling an iconic saint's halo around the shadow of the observer's head, caused by sunlight or moonlight interacting with the tiny water droplets that comprise mist or clouds. The glory consists of one or more concentric, successively dimmer rings, each of which is red on the outside and bluish towards the centre. Due to its appearance, the phenomenon is sometimes mistaken for a circular rainbow, but the latter has a much larger diameter and is caused by different physical processes.

<span class="mw-page-title-main">Sun dog</span> Atmospheric optical phenomenon

A sun dog or mock sun, also called a parhelion in meteorology, is an atmospheric optical phenomenon that consists of a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun within a 22° halo.

Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.

<span class="mw-page-title-main">Halo (optical phenomenon)</span> Optical phenomenon of the sky

A halo is an optical phenomenon produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these appear near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo, light pillars, and sun dogs, but many others occur; some are fairly common while others are extremely rare.

<span class="mw-page-title-main">Min Min light</span>

Min Min is a light phenomenon that has often been reported in outback Australia.

<span class="mw-page-title-main">Atmospheric refraction</span>

Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light through air decreasing with increased density. Atmospheric refraction near the ground produces mirages. Such refraction can also raise or lower, or stretch or shorten, the images of distant objects without involving mirages. Turbulent air can make distant objects appear to twinkle or shimmer. The term also applies to the refraction of sound. Atmospheric refraction is considered in measuring the position of both celestial and terrestrial objects.

<span class="mw-page-title-main">Fata Morgana (mirage)</span> Optical phenomenon

A Fata Morgana is a complex form of superior mirage visible in a narrow band right above the horizon. The Italian term Fata Morgana translates the name of the Arthurian sorceress Morgan le Fay, due to a belief that these mirages, often seen in the Strait of Messina, were fairy castles in the air or false land conjured up by her witchcraft to lure sailors to their deaths.

<span class="mw-page-title-main">Ray (optics)</span> Idealized model of light

In optics a ray is an idealized geometrical model of light, obtained by choosing a curve that is perpendicular to the wavefronts of the actual light, and that points in the direction of energy flow. Rays are used to model the propagation of light through an optical system, by dividing the real light field up into discrete rays that can be computationally propagated through the system by the techniques of ray tracing. This allows even very complex optical systems to be analyzed mathematically or simulated by computer. Ray tracing uses approximate solutions to Maxwell's equations that are valid as long as the light waves propagate through and around objects whose dimensions are much greater than the light's wavelength. Ray optics or geometrical optics does not describe phenomena such as diffraction, which require wave optics theory. Some wave phenomena such as interference can be modeled in limited circumstances by adding phase to the ray model.

<span class="mw-page-title-main">Rainbow</span> Meteorological phenomenon

A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the Sun.

<span class="mw-page-title-main">Circumhorizontal arc</span> Optical phenomenon

A circumhorizontal arc is an optical phenomenon that belongs to the family of ice halos formed by the refraction of sunlight or moonlight in plate-shaped ice crystals suspended in the atmosphere, typically in cirrus or cirrostratus clouds. In its full form, the arc has the appearance of a large, brightly spectrum-coloured band running parallel to the horizon, located far below the Sun or Moon. The distance between the arc and the Sun or Moon is twice as far as the common 22-degree halo. Often, when the halo-forming cloud is small or patchy, only fragments of the arc are seen. As with all halos, it can be caused by the Sun as well as the Moon.

<span class="mw-page-title-main">Circumzenithal arc</span> Optical phenomenon arising from refraction of sunlight through ice crystals

The circumzenithal arc, also called the circumzenith arc (CZA), upside-down rainbow, and the Bravais arc, is an optical phenomenon similar in appearance to a rainbow, but belonging to the family of halos arising from refraction of sunlight through ice crystals, generally in cirrus or cirrostratus clouds, rather than from raindrops. The arc is located at a considerable distance above the observed Sun and at most forms a quarter of a circle centered on the zenith. It has been called "a smile in the sky", its first impression being that of an upside-down rainbow. The CZA is one of the brightest and most colorful members of the halo family. Its colors, ranging from violet on top to red at the bottom, are purer than those of a rainbow because there is much less overlap in their formation.

Light scattering by particles is the process by which small particles scatter light causing optical phenomena such as the blue color of the sky, and halos.

<span class="mw-page-title-main">Cloud iridescence</span> Optical phenomenon

Cloud iridescence or irisation is a colorful optical phenomenon that occurs in a cloud and appears in the general proximity of the Sun or Moon. The colors resemble those seen in soap bubbles and oil on a water surface. It is a type of photometeor. This fairly common phenomenon is most often observed in altocumulus, cirrocumulus, lenticular, and cirrus clouds. They sometimes appear as bands parallel to the edge of the clouds. Iridescence is also seen in the much rarer polar stratospheric clouds, also called nacreous clouds.

<span class="mw-page-title-main">Atmospheric optics</span> Study of the optical characteristics of the atmosphere or products of atmospheric processes

Atmospheric optics is "the study of the optical characteristics of the atmosphere or products of atmospheric processes .... [including] temporal and spatial resolutions beyond those discernible with the naked eye". Meteorological optics is "that part of atmospheric optics concerned with the study of patterns observable with the naked eye". Nevertheless, the two terms are sometimes used interchangeably.

In atmospheric optics, a photometeor is a bright object or other optical phenomenon appearing in the Earth's atmosphere when sunlight or moonlight creates a reflection, refraction, diffraction or interference under particular circumstances. The most common examples include halos, rainbows, fogbows, cloud iridescences, glories, Bishop's rings, coronas, crepuscular rays, sun dogs, light pillars, mirages, scintillations, and green flashes.

Atmospheric optics ray tracing codes - this article list codes for light scattering using ray-tracing technique to study atmospheric optics phenomena such as rainbows and halos. Such particles can be large raindrops or hexagonal ice crystals. Such codes are one of many approaches to calculations of light scattering by particles.


  1. Lahiri, Avijit (2016). "Electromagnetic Theory and Optics". Basic Optics: Principles and Concepts. Elsevier. pp. 1–140. doi:10.1016/B978-0-12-805357-7.00001-0. ISBN   978-0-12-805357-7.
  2. "Green Rays". mintaka.sdsu.edu.
  3. "Belt of Venus over Cerro Paranal". Picture of the Week. ESO. Retrieved 14 August 2013.
  4. "Welcome to Phenomenon! Your guide through the mysterious and unexplained". www.stateoftheart.nl.
  5. Philip Mantle. "The Hessdalen Lights". Archived from the original on 4 April 2005. Retrieved 14 October 2017.
  6. "UQ scientist unlocks secret of Min Min lights".
  7. "Big Thicket National Preserve Virtual Field Trip". Archived from the original on 4 March 2005.
  8. Gagliardi, Jason (17 November 2002). "Behind the Secret of the Naga's Fire". Archived from the original on January 19, 2007 via www.time.com.


Ozerov, Ruslan P.; Vorobyev, Anatoli A. (2007). "Wave Optics and Quantum–Optical Phenomena". Physics for Chemists. pp. 361–422. doi:10.1016/B978-044452830-8/50008-8. ISBN   978-0-444-52830-8.

Further reading