February 18, 2009--Light pillars scrape the night sky over Victor, Idaho, on January 26. Typically seen in polar regions, the vertical columns of light have been appearing along with frigid temperatures at lower latitudes this winter.
Light pillars appear when artificial light (shown in diagram above) or natural light bounces off the facets of flat ice crystals wafting relatively close to the ground.
When the light source is close to the ground, the light pillar appears above the floating crystals. When the light comes from the sun or moon, the light pillar can appear beneath them, too, as the light refracts through the crystals.
—Photograph by Bradly J. Boner/Jackson Hole News & Guide; diagram by Les Cowley/Atmospheric Optics
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很美丽，继Aurora和Noctilucent Cloud之后，我最想看的天文景象~
希望有生之年可以有机会涉足这些地方~
-Shin- '09
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