From: LARRY KLAES (ljk4_at_msn.com)
Date: Thu Sep 08 2005 - 13:35:30 UTC
>From: Cary Oler <oler_at_solar.spacew.com>
>To: sun-earth_at_SkyandTelescope.com
>Subject: AstroAlert: Intense Solar Flare Prompts Warnings
>Date: Wed, 7 Sep 2005 23:23:21 +0000 (GMT)
>
>=================================================================
>This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
>=================================================================
>
>A s t r o A l e r t
>
>07 September 2005
>
>Solar Terrestrial Dispatch
>www.spacew.com
>
>
>INTENSE SOLAR FLARE PROMPTS WARNINGS
>
> A very strong class X17.1 solar flare exploded on the Sun at 17:40
>UTC
>(1:40 pm EDT). This is a significant event. Very few solar flares ever
>reach
>the X-class rating, and far fewer ever exceed an X10 level. Only a few
>solar
>flares each solar cycle (a 10-year period) exceed an X10 rating. An X17
>solar
>flare is 17 times more intense in x-rays than a class X1.0 (which is, by
>itself, a very energetic event). This particular event was strong enough to
>saturate one of the x-ray sensors on the GOES spacecraft and very nearly
>saturated both sensors. This intense solar flare was visible in white-light
>by observers at Holloman solar observatory in New Mexico.
>
> This event was associated with intense radio emissions and a strong
>high-velocity coronal mass ejection that was ejected well to the southeast
>of
>the Earth. Despite the poor location of this event, there is a chance the
>extreme western flanking edge of the associated shock wave may reach the
>Earth sometime on 9 September. Prior to that time, energetic protons from
>the
>solar flare may begin reaching the Earth and result in an increase in the
>radiation environment in the near-Earth space environment. Although no
>significant geomagnetic or auroral storming is expected this time,
>additional
>possible major solar flares from this region during the next two weeks
>could
>easily provide the impetus for very strong space weather storms.
>
> The sunspot complex responsible for this event is an old "friend," by
>the name of Region 10798, which was responsible for producing periods of
>severe geomagnetic storming last month. It's longevity is impressive, as
>most
>sunspot groups do not survive this long. As it came into view, NOAA
>assigned
>a new number to this region. It will hereafter be known as Region 10808
>(nick
>named Region 808).
>
> The fact that this region has produced such a powerful flare suggests
>that it contains a complex magnetic topology. It is just now coming into
>view
>around the eastern limb of the Sun and is still too close to the limb to
>discern any significant detail. We expect additional major flares and
>possibly additional significant major flares of X10 or greater intensities,
>during the next week.
>
> Region 808 will gradually rotate across the solar disk during the
>next
>two weeks. During that time, if it retains its volatility, it may produce
>some serious effects at the Earth. The health of spacecraft may be
>compromised if additional extreme events are observed. Power grids may
>suffer
>from induced currents caused by intense geomagnetic storms. Radio
>communications may suffer from strong scintillation and absorption. And
>large
>regions of the Earth may be able to spot periods of auroral activity
>("northern lights"). Region 808 will be best positioned to inflict strong
>impacts on the Earth in approximately another 4 to 5 days, with maximal
>effects possible from roughly 11 September through 18 September. Spacecraft
>will remain vulnerable to potential strong space radiation storms through
>to
>about 23 September.
>
> It is perhaps produnt to note that these strong solar flares pose no
>known significant health threat to humans on the Earth. There is a greater
>threat to human health for astronauts on the International Space Station,
>but
>even they are relatively well protected in the heavily shielded regions of
>the space station. The combined effects of the Earth's magnetic field and
>the
>ionosphere protect human activities on Earth. However, some sensitive
>industries on the ground can be adversely effected, including electrical
>power generation facilities, ionospheric radio communications, satellite
>communications, cellular phone networks, sensitive fabrication industries,
>and others. During the next two weeks, these industries may see an increase
>in anomalous incidents that may be attributed to space weather effects.
>
>
>** End of AstroAlert **
>==================================================================
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