Sometimes it looks like the Sun is being viewed through a large lens [
http://www.opticalr…]. In the above case, however, there are actually millions of lenses: ice crystals [
http://www.sundog.c…]. As water freezes in the upper atmosphere [
http://csep10.phys.…], small, flat, six-sided, ice crystals might be formed. As these crystals [
http://www.its.calt…] flutter to the ground, each crystal [
http://cst-www.nrl.…] can act like a miniature lens, refracting sunlight into our view. The above image [
http://www.vydor.ne…] was taken near sunset last month near Nashville, Tennessee [
http://www.state.tn…], USA [
http://www.cia.gov/…]. Dramatically visible [
http://hyperphysics…] behind neighborhood houses and trees and above the cloud deck is the 22 degree halo [
http://hyperphysics…] created by sunlight refracting [
http://www.sundog.c…] off of atmospheric ice crystals.
Explanation
Sometimes it looks like the Sun is being viewed through a large lens [
http://www.opticalr…]. In the above case, however, there are actually millions of lenses: ice crystals [
http://www.sundog.c…]. As water freezes in the upper atmosphere [
http://csep10.phys.…], small, flat, six-sided, ice crystals might be formed. As these crystals [
http://www.its.calt…] flutter to the ground, each crystal [
http://cst-www.nrl.…] can act like a miniature lens, refracting sunlight into our view. The above image [
http://www.vydor.ne…] was taken near sunset last month near Nashville, Tennessee [
http://www.state.tn…], USA [
http://www.cia.gov/…]. Dramatically visible [
http://hyperphysics…] behind neighborhood houses and trees and above the cloud deck is the 22 degree halo [
http://hyperphysics…] created by sunlight refracting [
http://www.sundog.c…] off of atmospheric ice crystals.
Explanation
