Parhelia, pronounced as /pɑːˈhiːliə/, is a weather phenomenon that creates a halo or a bright spot around the sun. The word is derived from the Greek "parēlion," which means "beside the sun." It is spelled with a "p," "a," "r," "h," "e," "l," "i," and "a." Each letter corresponds to a specific sound in the word's pronunciation, with the /h/ being silent. This spelling is important to ensure that the word is understood and communicated correctly in scientific and atmospheric contexts.
Parhelia, also known as sundogs or mock suns, are atmospheric optical phenomena that manifest as bright, colored spots of light appearing on either side of the sun. Derived from the Greek words "para" meaning "beside" and "helios" meaning "sun," parhelia refers to these bright, halo-like spots that form at an angle of about 22 degrees from the sun.
The occurrence of parhelia is primarily caused by the refraction, dispersion, and reflection of sunlight by ice crystals present in the atmosphere. These ice crystals are typically found in high-altitude cirrus clouds or in cold, polar regions. When sunlight passes through these ice crystals, it gets bent, split, and redirected, resulting in the formation of parhelia.
Parhelia often appear as two (or occasionally more) bright spots, sometimes displaying colors ranging from red, orange, and yellow closest to the sun, transitioning to green, blue, and violet farther away. These spots are typically located on the sunward side of the halo, appearing along a horizontal circle at the same altitude as the sun.
The formation of parhelia is not restricted to specific times or locations, as they can occur anywhere sunlight interacts with ice crystals in the atmosphere. Although parhelia are breathtaking and visually striking, they are essentially optical illusions resulting from the complex interplay of light and ice crystals. Studying and understanding the various atmospheric conditions that give rise to parhelia can provide valuable insights into the physics of light and the behavior of ice crystals in the atmosphere.
A mock sun appearing as a bright light near the real sun.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "Parhelia" is derived from two Greek terms. "Para" means "beside" or "parallel", and "helios" means "sun". Parhelia refers to the atmospheric optical phenomenon commonly known as "sun dogs" or "mock suns". These are bright spots, often accompanied by a halo, that appear on either side of the Sun. The term "Parhelia" was coined by combining these Greek roots, highlighting the parallel nature of the phenomenon with the position of the Sun.