Who are moon dogs? - briefly
Moon dogs, also known as paraselene or mock moons, are optical phenomena that occur when the moon's light is refracted by ice crystals in the Earth's atmosphere. These appear as bright spots on either side of the moon, often resembling a pair of glowing eyes.
Who are moon dogs? - in detail
Moon dogs, also known as mock moons or parhelia, are a fascinating atmospheric phenomenon that occurs when the sun or moon is obscured by thin, high-altitude cirrus clouds containing ice crystals. These crystals refract and reflect light in such a way that they create bright spots of light on either side of the celestial body. The term "moon dogs" specifically refers to this phenomenon when it occurs around the moon, while "sun dogs" pertains to the same effect around the sun.
The scientific explanation behind moon dogs lies in the optical properties of ice crystals. When sunlight or moonlight passes through these hexagonal-shaped crystals, they act as tiny prisms that bend and disperse the light. The refracted light then exits the crystal at a specific angle, typically 22 degrees from the original source of light, creating the bright spots known as parhelia.
Moon dogs are often seen as two luminous points or patches of light flanking the moon. However, they can also appear as elongated streaks extending outwards from the moon, depending on the orientation and shape of the ice crystals in the clouds. The intensity and color of moon dogs can vary based on several factors, including the size and alignment of the ice crystals and the clarity of the atmosphere.
This optical phenomenon is not exclusive to the night sky; it can also be observed during daytime as sun dogs. Both phenomena are relatively common and can be seen from various locations around the world, provided there are suitable atmospheric conditions. While moon dogs and sun dogs share similar characteristics, they differ in their visibility and prominence due to the differences in light intensity between the sun and the moon.
Moon dogs hold significance not only in scientific study but also in cultural and mythological contexts. Throughout history, various civilizations have attributed different meanings to these celestial apparitions. Some cultures viewed them as omens or signs of change, while others incorporated them into their folklore and storytelling traditions.
In summary, moon dogs are a captivating natural phenomenon that results from the interplay of light, ice crystals, and atmospheric conditions. Their appearance offers a glimpse into the complex processes that shape our skies and continues to inspire wonder and curiosity among observers worldwide.