SETI bioastro: Fw: AstroAlert: Solar Flare Energies & A Mid-Latitude Aurora Warning

New Message Reply Date view Thread view Subject view Author view Attachment view

Date: Mon Dec 31 2001 - 11:57:02 PST

----- Original Message -----
From: Cary Oler
Sent: Monday, December 31, 2001 1:07 PM
Subject: AstroAlert: Solar Flare Energies & A Mid-Latitude Aurora Warning

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

                          Solar Terrestrial Dispatch

                               30 December 2001



     A middle latitude auroral activity warning has been issued for the
middle latitude regions. A fairly strong interplanetary disturbance impacted
the Earth's magnetosphere around 20:10 UTC on 30 December (3:10 pm EST) and
has the potential to intensify levels of auroral activity to sporadic minor
storm levels. Activity may be observed despite the near-full phase of the
moon. The source of this disturbance is uncertain, but may be a manifestation
of the large and high velocity coronal mass ejection that was observed
following the major class X3 solar flare of 28 December from behind the east
limb of the Sun.

     Observers interested in watching for auroral activity are encouraged to
pay attention to conditions watch the skies tonight. Regularly updated
current conditions and discussions of activity are available at:

     Anyone who observes activity are encouraged to report observations to
the Global Auroral Activity Observation Network, available at:

     Observations reported to the network are automatically and immediately
disseminated (within 1 or 2 minutes) to observers world-wide via e-mail,
digital SMS (, and on the web at: They are also used by space weather
forecasters and professionals engaged in research.


     The last AstroAlert compared the energy of the 28 December major solar
flare with a system of measuring flare intensities in the integrated light of
x-rays. This has been a bit hard for many people to put into perspective. We
would like to help clarify things by relating the energy released by the
flare in a more 'down-to-Earth' way.

     Before we elaborate, please note that the entire energy released by the
solar flare of 28 December can only be very roughly estimated. There are
whole host of parameters that must be taken into consideration - heating by
various mechanisms, mass motions and many other parameters that can only
crudely be estimated at the present time. Therefore, take the following
numbers with a grain of salt. The values presented below are only intended to
help illustrate the energy that is released by a solar flare in terms that we
can comprehend. The actual value of this particular event may differ
substantially. But as you will see, the numbers are so large, it really
doesn't matter.

     Let us suppose the energy released by the solar flare of 28 December
was somewhere near 4 x 10^24 Joules (which should be somewhat reasonable).

     In order to produce that much energy release at one time, you would need
to explode around 73,000,000,000 (that's 73 BILLION) Hiroshima sized nuclear

     The largest Earthquake we are aware of was a magnitude 9.5 earthquake in
Chile in 1960. If the energy of the solar flare of 28 December was released
in the form of an earthquake, it would have produced an unfathomable
earthquake measured on the Richter scale as a magnitude 13.2 event.

     Now, to help put this into perspective, a magnitude 13.2 earthquake is
around 5,000 TIMES more powerful than a magnitude 9.5 earthquake. Imagine the
damage an earthquake only TWICE as large as the Chilean event would have
produced. An earthquake 5,000 times more powerful is truly hard to imagine.

     The entire energy demands of the U.S. could be satisfied for more than
40,000 years if the energy released by the 28 December solar flare could have
been utilized.

     It would take the combined energy released by approximately 4 BILLION
hurricanes to match the energy released by the solar flare.

     You could place around 400 BILLION space shuttles into orbit if you had
the energy of the 28 December solar flare.

     Again, these are VERY rough estimates that could be significantly in
error and are based on incomplete and unconfirmed models of solar flare
energy release. Nevertheless, they bring into perspective the awe and true
power of major solar flares.

** End of the AstroAlert Bulletin **
AstroAlert is a free service of SKY & TELESCOPE magazine, 49 Bay
State Rd., Cambridge, MA 02138, U.S.A. This e-mail was sent to
AstroAlert subscribers. If you feel you received it in error, or
to unsubscribe from AstroAlert, please see our unsubscribe form
at or send
a plain-text e-mail to with the following
line (and nothing else) in the body of the message:
unsubscribe sun-earth
replacing "" with your actual e-mail address.

New Message Reply Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.2 : Mon Dec 31 2001 - 12:04:33 PST