The term "sun dog" refers to a bright spot in the sky caused by the refraction of sunlight through ice crystals. Its spelling can be understood using the International Phonetic Alphabet (IPA) as /sʌn dɔɡ/. The "u" in "sun" is pronounced with a short vowel sound, while the "o" in "dog" has an open-mid back rounded vowel sound. The letters "g" and "o" together make the sound of a hard "g" and a long "o" sound, respectively. Overall, the IPA helps to accurately convey the pronunciation of "sun dog."
A sun dog, also known as a parhelion, is a natural optical phenomenon that occurs when sunlight interacts with ice crystals in the atmosphere. It is characterized by the appearance of one or sometimes two bright spots, or halos, on either side of the Sun, usually at the same horizontal elevation. These bright spots, known as mock suns, are often colored and share similar characteristics with the Sun, appearing as bright and circular disks.
Sun dogs are typically seen in cold regions and at high altitudes, such as in polar regions or mountainous areas. They are formed when sunlight passes through hexagonal ice crystals suspended in the atmosphere and is refracted, or bent, to create a halo of light around the Sun. The hexagonal shape of the ice crystals is important for the formation of sun dogs, as it determines the angle at which light is bent.
The colors observed in sun dogs are caused by the dispersion of sunlight as it passes through the ice crystals. This dispersion causes the different colors of light to separate, resulting in a range of hues, with red typically appearing closer to the Sun and blue further away.
Sun dogs are considered a type of atmospheric optical phenomenon and are often accompanied by other atmospheric phenomena, such as halos, arcs, or other types of atmospheric refraction. They are a captivating and beautiful sight, creating a unique and surreal display in the sky, and have fascinated observers for centuries.
The word "sun dog" is derived from the Old Norse term "sundǫ́gr", which means "sun dog". In Old Norse, "sund" refers to "sun", while "ǫ́gr" means "dog". This name was likely given due to the observation that these atmospheric phenomena often appear as bright spots of light or small patches of rainbow-like colors close to the sun, almost as if the sun had "dogs" accompanying it.