Aurora season is now fully underway around the Arctic circle. With the end of
northern summer approaching, dancing green lights are beaming through the
deepening polar twilight on a regular basis. Unlike lower latitudes, the Arctic
does not require a full-fledged geomagnetic storm for aurora sightings. Check
the latest images on the front page of http://spaceweather.com
Meanwhile, another polar phenomenon is on the wane: noctilucent clouds (NLCs).
Data from NASA’s AIM spacecraft suggest that the northern summer season for NLCs
ended on or about August 26th. The “noctilucent daisy” shown on
http://spaceweather.com will probably remain blank until November, when NLC
activity shifts to the southern hemisphere. NLCs are a summertime phenomenon
and they switch back and forth between the hemispheres accordingly. Stay tuned
for more electric blue … in a few months.