From: LARRY KLAES (ljk4_at_msn.com)
Date: Sat May 31 2003 - 09:34:27 PDT
----- Original Message -----
From: Cary Oler
Sent: Friday, May 30, 2003 10:28 PM
To: sun-earth_at_SkyandTelescope.com
Subject: AstroAlert: Bad Luck for North American Aurora Observers
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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
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A s t r o A l e r t
Sun-Earth Alert
Solar Terrestrial Dispatch
http://www.spacew.com
Supporting Imagery and Movies are available at:
http://www.spacew.com/astroalert.html
30 May 2003
BAD LUCK FOR NORTH AMERICAN AURORA OBSERVERS
Sometimes (lots of times) things don't go quite according to plan when
you're hunting for the elusive "Northern Lights." The fact that the
occurrence of auroral activity is predictable at all is a testament to our
scientific knowledge and expertise of the Sun and the processes that couple
solar disturbances with the Earth's magnetosphere.
As most North American aurora observers can attest, the anticipated
display of the northern lights on 29 and 30 May were foiled by circumstances
beyond anyones control.
Just as the Sun began setting over the eastern fringes of North America,
the disturbance that had been broiling furiously began to decay. By the time
it was dark enough to observe anything, very few people were able to spot the
northern lights. Some travelled great distances to see the phenomena, only to
be disappointed. Dedicated observers in eastern Canada were treated to a few
relatively brief periods of moderately strong activity during the evening
hours last night, but such luck didn't hold out for most. Unfortunately, this
is one of the quirks of hunting aurorae. They can be frustratingly elusive at
times.
Prospects were much rosier for Europeans. Numerous reports of moderate
to strong auroral activity were received from the United Kingdom, the
Netherlands and even Germany. Had the solar disturbance arrived 6 to 9 hours
later than it did, observers across North America and down to the central
United States might have been priviledged to observe activity as well.
The last coronal mass ejection to impact the Earth arrived around 12:25
pm EDT (16:25 UTC) on 30 May and did not contain sufficient "punch" to
rejuvinate auroral storming. Although there remains a chance some middle
latitude regions may spot periods of low to moderately strong auroral
substorming over the next 12 to 18 hours as the magnetosphere stabilizes, the
chances for observing activity from most middle latitude regions have
vanished.
Active sunspot complex Region 10365, which was responsible for the
flurry of recent space storm activity, is still capable of producing
energetic major solar flare activity. However, it has rotated into a less
favorable position for throwing coronal mass ejections Earthward. Ironically,
although it is in a less favorable position for ejecting mass Earthward, it
IS in almost an ideal position (at least, statistically speaking) for
accelerating high energy protons toward the Earth should a major proton flare
occur. As a result, operators of satellites and other vulnerable technology
in space are as concerned now as they were several days ago. Energetic proton
bombardments can permanently decrease the ability of solar arrays to generate
electricity - thereby shortening spacecraft lifetimes. Energetic protons can
also produce occasional anomalies such as phantom commands or single event
upsets (SEUs). As far as the satellite industry is concerned, we are not yet
out of the woods.
** End of the AstroAlert Bulletin **
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