A false sunrise is any of several

atmospheric An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

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 center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

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 a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...

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 be deceivingly similar to a 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 Tangent arcs are a type of halo, an atmospheric optical phenomenon, which appears above and below the observed Sun or Moon, tangent to the 22° halo. To produce these arcs, rod-shaped hexagonal ice crystals need to have their long axis aligned ...

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 ice exhibiting atomic ordering on various length scales and include hexagonal columns, hexagonal plates, dendritic crystals, and diamond dust. Formation The hugely symmetric shapes are due to depositional growth, na ...

suspended in the atmosphere, often in the form of

cirrus Cirrus may refer to: Science *Cirrus (biology), any of various thin, thread-like structures on the body of an animal *Cirrus (botany), a tendril *Infrared cirrus, in astronomy, filamentary structures seen in infrared light *Cirrus cloud, a type ...

cirrostratus cloud Cirrostratus is a high-level, very thin, generally uniform ''stratiform'' genus-type of cloud. It is made out of ice-crystals, which are pieces of frozen water. It is difficult to detect and it can make halos. These are made when the cloud takes t ...

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'', meanin ...

, specifically the

Novaya Zemlya effect The Novaya Zemlya effect is a polar mirage caused by high refraction of sunlight between atmospheric thermal layers. The effect gives the impression that the sun is rising earlier than it actually should, and depending on the meteorological sit ...

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

Novaya Zemlya Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) 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, ...

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 roundnesse" two weeks before its predicted return after the

polar night The polar night is a phenomenon where the nighttime lasts for more than 24 hours that occurs in the northernmost and southernmost regions of Earth. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnig ...

. The account, written by officer

Gerrit de Veer Gerrit de Veer (–) was a Dutch officer on Willem Barentsz' second and third voyages of 1595 and 1596 respectively, in search of the Northeast passage. De Veer kept a diary of the voyages and in 1597, was the first person to observe and reco ...

, was met with general scepticism 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 direction in ...

References

Atmospheric optical phenomena {{optics-stub

See also

References