be three bright Suns lined up neatly
on the horizon, then you’ve
probably witnessed the
phenomenon knows as sundogs. This rare
phenomenon occurs when hexagonal ice
crystals in the air align to refract sunlight into
your eye at a precise angle. This forms a halo of
light around the Sun, with two bright patches on
either side of it called parhelia, or sundogs.
Even rarer are jumping sundogs, which occur
when lightning discharge in a thundercloud
temporarily changes the electric fi eld above it.
This adjusts the orientation of the ice crystals so
that they refract the sunlight differently, making
the sundogs move around as if they’re jumping.
As they need ice crystals to form, sundogs
usually only appear during cold weather and
when the Sun is low in the sky. However, they
have sometimes been spotted from several
different locations around the world. It’s not just
the Sun either, as light from the Moon can
generate Moon halos and moondogs in much the
same way.
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