What are they?
by Jack Smits
(Richmond Hill, Ontario)
Mysterious Truhin light pillars
MYSTERY PILLARS: "The air
was very cold and filled with small ice crystals on Dec. 28th when we saw these strange pillars of light," reports Aigar Truhin of Sigulda, Latvia. Many people have seen light pillars. They appear during winter when city lights shine upward into the icy air. Reflections from plate-shaped crystals spread the light into a vertical column: examples.
Truhin's pillars, however, are not the ordinary kind. Even two leading experts in atmospheric optics can't quite figure them out: "These pillars are mysterious," say Les Cowley and Marko Riikonen. "They have unexplained curved tops and even curved arcs coming from their base. Arcs in rare displays like these could be from column crystals to give parts of tangent arcs, others could be the enigmatic Moilanan arc or even the recently discovered reflected Parry arc. We do not know !"
Richmond HillBarry's Response
- You have me with this one, Jack. I might need to consult another expert myself.
Parry arcs take the form of light coloured circles surrounding a source of light. They appear in ice crystal atmospheres 22 degrees from the light; this angle is set by the hexagonal structure of the ice crystal.
Moilanan arcs give the "v" shape resembling the cone shape at the top of the columns in your photo. They are often associated with the Parry arcs, appear at 22 degrees as well, and sometimes at half of that angle. If these do not quite match with the image, there could be either additional distortions to the image (compare with the problems meteorologists handle with weather radar
at times) or a previously undocumented phenomenon as you suggest.Search
this site for more information now.