A false sunrise is any of several

atmospheric An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere ...

optical phenomena Optical phenomena are any observable events that result from the interaction of light and matter. All optics, optical phenomena coincide with Quantum mechanics, quantum phenomena. Common optical phenomena are often due to the interaction of ligh ...

in which the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

appears to have risen, but is actually still some distance below the horizon. A number of different atmospheric conditions can be responsible for this effect, all of which divert the

sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

in such a way as to allow it to reach the observer's eye, thereby giving the impression that the light comes directly from the Sun itself. The spread of light can sometimes resemble that of the true sun. Several atmospheric phenomena that may alternatively be called a "false sunrise" are: * Simple reflection of the sunlight off the bottom of the clouds. * A type of ice crystal halo, such as an upper tangent arc or, more commonly, an upper sun pillar (similar to a subsun, but extending above the sun instead of below it). Like all halos, these phenomena are caused by the reflection and/or refraction of sunlight by

ice crystals Ice crystals are solid water (known as ice) in crystal structure, symmetrical shapes including hexagonal crystal family, hexagonal columns, hexagonal plates, and dendrite (crystal), dendritic crystals. Ice crystals are responsible for various at ...

suspended in the atmosphere, often in the form of cirrus or

cirrostratus cloud Cirrostratus () is a high-altitude, very thin, and generally uniform stratiform genus-type of cloud. It is composed of ice crystals, which are particles of frozen water. Cirrostratus is difficult to see and can produce halos. These optical ...

s. The temperature on the ground is irrelevant to their occurrence, meaning that halos can be seen throughout the year and in all climates. * A type of

mirage A mirage is a naturally-occurring optical phenomenon in which light rays bend via refraction to produce a displaced image of distant objects or the sky. The word comes to English via the French ''(se) mirer'', from the Latin ''mirari'', mean ...

, specifically the Novaya Zemlya effect. Restricted mainly to the polar regions, this phenomenon was named after its first observation on

Novaya Zemlya Novaya Zemlya (, also , ; , ; ), also spelled , is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, considered the extreme points of Europe ...

during the third polar expedition led by

Willem Barentsz Willem Barentsz (; – 20 June 1597), anglicized as William Barents or Barentz, was a Dutch Republic, Dutch navigator, cartographer, and Arctic explorer. Barentsz went on three expeditions to the far north in search for a Northern Sea Route, N ...

in 1596/97, when the Sun was seen above the horizon "in his full roundness" two weeks before its predicted return after the

polar night Polar night is a phenomenon that occurs in the polar regions of Earth, northernmost and southernmost regions of Earth when the Sun remains below the horizon for more than 24 hours. This only occurs inside the polar circles. The opposite phen ...

. The account, written by officer Gerrit de Veer, was met with general skepticism for centuries, and not until modern times was the effect proven to be genuine.Siebren van der Werf, ''Het Nova Zembla verschijnsel. Geschiedenis van een luchtspiegeling'' ("The Novaya Zemlya phenomenon. History of a mirage"), 2011; . The term "false sunrise" should not be confused with "false dawn", which is a term sometimes used to refer to the

zodiacal light The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direct ...

References

Atmospheric optical phenomena {{optics-stub

See also

References