What inherent geometric property of ice dictates the $22^ ext{o}$ minimum deviation angle for the halo?
Answer
Hexagonal symmetry
The consistency and predictability of the $22^ ext{o}$ halo are direct consequences of the fundamental molecular structure of ice. Ice molecules naturally organize themselves into a hexagonal lattice as they crystallize in the atmosphere, forming six-sided plates. If these crystals were randomly shaped, light would scatter chaotically. However, the inherent hexagonal symmetry ensures that when light enters one side face of a crystal and exits another side face oriented at a $60^ ext{o}$ angle relative to the first, the resultant minimum deviation angle is consistently $22^ ext{o}$, creating the defined ring.
#Videos
What is a lunar halo? - YouTube
Related Questions
What optical phenomenon causes the luminous ring known as a lunar halo?What precise minimum angle reflects light refraction by common hexagonal ice crystals in a lunar halo?Which specific types of high-level clouds produce the ice crystals necessary for a lunar halo?Approximately how many times the Moon's diameter must be stacked to span the $22^ ext{o}$ circle outward to the ring?What inherent geometric property of ice dictates the $22^ ext{o}$ minimum deviation angle for the halo?In mid-latitude areas, what weather condition often follows the appearance of a high-level lunar halo?For the $22^ ext{o}$ halo to form, what specific angle must the exit face be relative to the entry face of the hexagonal ice crystal?What observation suggests turbulence within the high cloud layer when viewing a lunar halo?Besides the $22^ ext{o}$ halo, what other, larger halo is sometimes produced by moonlight interacting with ice crystals?What angular span, measured by a fully stretched hand at arm's length, can help an observer estimate the $22^ ext{o}$ halo?