From: LARRY KLAES (ljk4_at_msn.com)
Date: Thu Oct 30 2003 - 05:38:29 PST
----- Original Message -----
From: Cary Oler
Sent: Thursday, October 30, 2003 8:04 AM
To: sun-earth_at_SkyandTelescope.com
Subject: AstroAlert: Historic Solar and Auroral Activity - with More to Come!
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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
(very hard to get on right now)
(due to overwhelming traffic)
30 October 2003
HISTORIC SOLAR AND AURORAL ACTIVITY - WITH MORE TO COME !
Active Region 486 continues to amaze and impress. At 20:49 UTC on
29 October, this active region blew out another exceptionally energetic solar
flare. Although x-rays were not quite as energetic as the 28 October flare,
they were nonetheless remarkable and will undoubtably provide scientists with
a plethora of new questions and answers concerning these incredibly energetic
events.
Only 21 minutes after the peak x-ray flux was observed from this flare,
another blast of energetic protons swept past the Earth, reinvigorating the
already intense space radiation storm (which reached category S4 levels on 29
October). This space radiation storm has become the second most energetic
event this solar cycle. This latest enhancement to the radiation storm was
not as intense as the 28/29 October event, but is still creating quite a mess
with space-based instruments that are sensitive to energetic protons. For
example, when protons strike light-sensitive cameras, they produce flashes or
streaks of light that can confuse star-tracking algorithms or simply become
an annoying nuisance on other visual images taken from space. These effects
are predicted to continue through at least the next 24 to 48 hours, with a
healthy chance for additional strong injections of energetic protons from
future major solar flares during the next week.
Region 486 is a remarkable sight to behold. The sight was even more
impressive for residents of San Diego, where smoke from the fires there
allowed residents to see the two enormous sunspot complexes (Region 486 and
developing Region 488) without the aid of special protective filters. We
don't recommend people look at the sun under any circumstances without
suitable solar filters to protect the eyes. Nevertheless, we did receive a
few reports from California of the spectacular sight through the dense smoke.
Region 486 is now the largest sunspot complex of the solar cycle. It is
BIG! It now covers a surface area of over 7.8 BILLION square kilometers (or
slightly over 3 BILLION square miles)! And it's still growing larger!
Although this is difficult to place into perspective, it may help to
understand that you could map the entire surfaces of the 4 inner planets
(Mercury, Venus, Earth and Mars) together with the giant gas planet Neptune,
all within the area encompassed by sunspot complex 486 - with room to spare.
Analysis of the most recent X10 solar flare suggests that the coronal
mass ejection associated with it could strike the Earth near 18:00 UTC on 30
October (this is equivalent to the early afternoon hours of Thursday, 30
October for North Americans). If it's late, it should still arrive before
darkness falls over North America on Thursday. As a result, observers across
North America are encouraged to watch the skies for another impressive
auroral display on Thursday night, commencing as soon as it gets dark and
ending at dawn. It is unlikely that North America will get an opportunity to
observe activity on Friday night, unless Region 486 or 488 produce another
major solar flare with a similarly high velocity coronal mass ejection.
The activity should be similar to what was observed on 29 October.
Auroras across North America were observed into the extreme southern
United States (sightings as far south as Arizona and similarly located
latitudes) during the initial hours of the disturbance. Europe will be best
positioned to observe effects perhaps similar to what North America observed
on 29 October (where activity was observed into the far south). If the
disturbance does not arrive much later than predicted, southern regions of
Australia may also be greeted by a pre-dawn aurora.
This is significant activity. Events as powerful as what we have
observed are only typically observed a few times each solar cycle
(roughly 11 years). Also, events this strong are almost always accompanied by
strong aurora. If you have never seen aurora before and discover you might be
under the clouds when the event occurs, you might do well to consider taking
a drive to a clear location - regardless of the distance.
Don't forget your camera and a steady tripod. These auroral displays are producing
producing spectacular photographic material by many people.
Region 486 is expected to continue producing major solar flares. If
these events occur within the next 48 to 72 hours, there is a good chance the
associated coronal mass ejections will continue to be directed heavily
Earthward. Beyond that time frame, the region will begin pointing
increasingly west of the Earth and the associated CME's will begin striking
the Earth less directly, with less impressive consequences.
So enjoy the show(s) while they last!
** End of the AstroAlert Bulletin **
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