The images were taken by designer Aigar Truhins with a standard digital camera in Sigulda, Latvia, last month.
The air was quite cold and indeed filled with small ice crystals, just the type known to create light pillars and moon halos.
pillars only appear in winter when city lights shine upward into the
icy air. Reflections from plate shaped crystals spread the light into a
They only happen when the crystals are oriented
mostly horizontally, and that happens when they are falling in calm
air, like a leaf falling.
The reason why the dramatic pillars fan
out at the top is currently unknown but could be a natural behaviour of
the light itself. Even laser lights spread out over long distances.
this case, there could be some wind higher up and it is calmer lower
down, and the 'fan out' of the light pillars happens near the boundary
between calm and stirred up air.
The crystals near the boundary
would tend to be close to horizontal but as you get higher into the
wind, their orientations are more dispersed, so the reflections would
be more spread out form the vertical line.
The differences in
colour responds to the source of the light. Mercury vapour lights are
somewhat blueish or red, while high pressure sodium lights appear
reddish or yellowish.