posted on Dec, 3 2010 @ 06:48 PM
In addition to the above-mentioned light pillar, also those Xenon-skylights came to mind. They don't necessarily create a continuos visible beam from
the ground up -depending on the atmospheric conditions- but become visible on clouds at higher altitudes. And as there are all variations of those,
stationary/strobe/pattern, i'd go for the latter, each flash being at a given spot of the skylights route on the sky. Seen those being used with
major events and have to say, seeing for the first time one of those, was a bit eerie.
Also, nice iridium satellite flare