"Exploring the Phenomenon Behind the Moon's Mysterious Halo"
A halo around the moon is caused by the refraction of moonlight through hexagonal ice crystals in high-altitude cirrus clouds, resulting in a 22-degree ring of light. This optical phenomenon is consistent worldwide and can also occur around the sun and on other planets. Folklore suggests that a moon halo predicts bad weather, which has some scientific basis as cirrus clouds can form before storm systems. Similar atmospheric phenomena include sun dogs and coronas, which involve sunlight interacting with ice crystals and water droplets, respectively.