Fun_People Archive
7 Jun
Major X-Class WHITE-LIGHT Solar Flare Alert - 06 June

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From: Peter Langston <psl>
Date: Wed,  7 Jun 100 12:39:30 -0700
To: Fun_People
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Subject: Major X-Class WHITE-LIGHT Solar Flare Alert - 06 June

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                             A s t r o  A l e r t
                               Sun-Earth Alert

                          Solar Terrestrial Dispatch

                                 06 June 2000

               * Major X-Class WHITE-LIGHT Solar Flare Alert *
                     * Stereo Movie of X-Class Flare *

             Detailed images, movies and resources available at:

(We apologize for the delay in posting this. It has taken a while to
assemble the resources together after performing all the post-flare analyses
that are required.)

     Active sunspot region number 9026 produced a flurry of very energetic
solar activity on 06 June. Two X-class flares occurred between 13:10 and
17:00 UTC (9:10 am and 1:00 pm EDT) on 06 June. The largest X-class flare
was an enormous X2.3 x-ray event. In the light of hydrogen, the flaring
region covered an area so large you could fit roughly 30 times the entire
surface area of the Earth within it.

     Today's most powerful X2 solar flare was a rare WHITE-LIGHT flare.
A white-light flare is a brightening of the visible photospheric surface
of the Sun. Anyone observing the Sun with a simple telescope equipped with
a filter that cuts down the brightness of the Sun to safe levels could have
observed this event. It occurred at 16:06 UTC and lasted a couple of minutes
just as x-rays were increasing to X-class levels. Images and even a movie
of this event were captured by Antonio Sanchez-Ibarra at the University of
Sonora (Estacion de Observacion Solar [EOS]) using a CCD video camera at
the continuum. A movie of this event is available at: We congratulate the group there
at EOS for a job well done in capturing this event!

     An enormous coronal mass ejection, part of which is headed toward the
Earth, was observed in conjunction with today's major flare activity. Images
and movies of the progress of the halo coronal mass ejection are available
at the URLs: and: or: The velocity of the
coronal mass ejection was clocked to near 1,200 kilometers per second (4.3
million kilometers per hour or 2.7 million miles per hour) by measuring
the radio emissions created by the supersonic shockwave of the disturbance
as it travelled outward through the inner part of the solar corona.

     This Earth-directed disturbance is expected to slam into the Earth's
magnetosphere sometime during the mid-to-late UTC hours of 08 June
(mid-morning to late afternoon, Eastern Daylight Time on 08 June). The
disturbance may hit the Earth with a velocity near or in excess of 2.8
million kilometers per hour (or 1.8 million miles per hour), or about twice
the normal velocity of the solar wind.

     There is a chance the pressure of the solar wind against the
magnetosphere might be strong enough to push the boundary of the
magnetosphere inside the orbit of geosynchronous satellites. The passage
of satellites into the harsher domain of the magnetosheath (which is a more
turbulent region that separates the quiet inner shell of the magnetosphere
from the solar wind) can caused some satellites to begin pointing
incorrectly at the Earth. Historically, some satellites have lost control
completely and have begun tumbling when they have crossed the magnetopause
boundary.  Exposure to the more direct effects of the solar wind can also
degrade the life-span of solar arrays and other exposed surfaces. Increases
in radiation levels in space resulting from the disturbed conditions
produced by the disturbance may also result in single event upsets on
spacecraft electronics caused by surface charging anomalies. And increased
atmospheric drag caused by the ballooning of the Earth's atmosphere during
increased periods of geomagnetic and auroral activity can lower the orbital
altitudes of orbiting spacecraft. All of these effects may play a role in
the upcoming events.

     Auroral activity is expected to increase to storm levels on 08 and 09
June. Whether activity will become strong enough to observe from many middle
or low latitude locations won't be known for certain until after the
disturbance begins passing the Earth when spacecraft will be able to
directly sample the characteristics of the solar wind. But forecasters have
a hunch the disturbance could be moderately large, perhaps in the G2 to G4
category range for geomagnetic storms (on a scale from G1 [minor] to G5

     Region 9026 does not appear to have changed very significantly
following today's major solar flare. We'll know more tommorrow, but
for now it still appears to be a potentially very volatile sunspot group.
Additional major M and X class flares are possible. And even another
white-light flare may be observed.

     Among the various movies and images describing this event is one which
stands apart from the rest. The Solar Terrestrial Dispatch, in collaboration
with the Kanzelhohe Solar Observatory and the National Solar Observatory
at Sacramento Peak, New Mexico, has produced an experimental stereoscopic
movie spanning 30 minutes (or 13 frames) of the major flare observed today
(a small portion of the overall event). This is, to our knowledge, the
first ever near-realtime stereoscopic movie of a major X-class solar flare
in the light of hydrogen. Those who are interested can find it at:  To see the 13 frames in stereo,
look THROUGH your monitor, forcing your eyes to focus beyond the plane of
your monitor's screen until the two solar images merge into a single stereo
view of the Sun. Tilt your head very slightly left or right, or move your
head toward or away from the monitor until the images merge into a single
coherent view of the Sun. Then (without changing focus), have your movie
viewing software begin playing the movie in a loop. It's aesthetically
rather cool and scientifically potentially valuable to produce these types
of movies.

** End of AstroAlert **

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