[GreenKeys] FWD: Largest Explosion in history

[Don Robert House]

The largest explosion ever recorded in our Solar System!

----- Original Message -----
From: "ARRL Web site" >
Sent: Friday, November 07, 2003 6:52 PM
Subject: ARLP045 Propagation de K7RA

>  To all radio amateurs
>
>  SB PROP ARL ARLP045
>  ARLP045 Propagation de K7RA
>
>  The opening line to last week's propagation bulletin read, ''Solar
>  excitement continued this week''.  Last week's events caused
>  excitement, but this week was positively historic.  The largest
>  explosion ever recorded in our solar system occurred Tuesday,
>  November 4 when an X28 class flare exploded from sunspot 486.  See
>  data for this on
>  http://sohowww.nascom.nasa.gov/hotshots/2003_11_04/, from the Solar
>  and Heliospheric Observatory.
>
>  The flare erupted as the giant sunspot 486 was about to rotate from
>  the visible disk.  This means the blast wasn't aimed at earth, but
>  was in a great position for taking images.  The eruption saturated
>  X-ray detectors on NOAA's GOES (Geostationary Operational
>  Environmental Satellites, see http://goes.gsfc.nasa.gov/ ), and was
>  so strong that the X28 measurement had to be estimated, as did the
>  solar flux for November 4.  The solar flux for that day (taken from
>  the daily 2000 UTC reading) was measured at the observatory in
>  British Columbia at 560.9, which is way off the scale.  It was
>  adjusted downward to an estimated 168 by NOAA's Space Environment
>  Center.
>
>  The flare saturated observing satellites for about 13 minutes during
>  the peak of the event, according to Christopher Balch of NOAA SEC,
>  who spoke with Tomas Hood, NW7US (Tomas' web site is
>  http://prop.hfradio.org/ ).  The measurements stopped at X17.4.  The
>  level of the flare was estimated by analyzing data from HESSI, the
>  High Energy Solar Spectroscopic Imager (see
>  http://hessi.ssl.berkeley.edu/ ).  An explanation of the X classes
>  for rating solar flares is at
>  http://spaceweather.com/glossary/flareclasses.html.  Also, see
>  http://hesperia.gsfc.nasa.gov/sftheory/flare.htm.  The last time a
>  huge flare saturated X-ray detectors was in April, 2001, and that
>  one was X-20, the biggest recorded at that time.  Keep in mind that
>  there aren't any accurate records of flare intensity before about 30
>  years ago.
>
>  Roger Bonuchi, WB9JXE of Plainfield, Illinois wrote to say that his
>  astronomy calendar for November 5 noted that on that day in 2001
>  there was a ''huge red aurora visible for hours over North
>  America''.  Looking back to our bulletin that covered that time at
>  http://www.arrl.org/w1aw/prop/2001-arlp046.html we see that indeed
>  there was a large geomagnetic storm.  The bulletin reported that
>  frightened Midwest residents, unfamiliar with aurora borealis,
>  called 9-1-1 to report a ''nuclear death cloud''.  Roger also said
>  he picked up the N9RET CW beacon, which runs 2 watts on 28.2335 MHz.
>  He found it odd that N9RET is about 25-30 miles from him and he was
>  copying it for the first time at around S6.  He called Tim Lanners,
>  N9RET who told him he rarely gets reports from Illinois.  Tim is in
>  Broadview, Illinois in the Chicagoland area.
>
>  This bulletin is running late past deadline on Friday, so it is time
>  to end it.  Today the solar disk is completely blank with no visible
>  spots.  Mark Downing, WM7D of Reno, reported another notable event.
>  He wrote that 298.3 was a new solar flux high for cycle 23.  The
>  previous high was 282.6 set on September 26, 2001.  The Japan
>  International DX Phone Contest is this weekend, as well as the
>  Worked All Europe DX RTTY Contest.  We can hope for lower
>  geomagnetic activity, and the planetary A index for Saturday through
>  Wednesday, November 12 is predicted at 15, 15, 20, 30 and 35.
>  Sunspot numbers and solar flux are way down, and the predicted solar
>  flux for the same days is 90, 90, 95, 100 and 115.
>
>  For more information about propagation and an explanation of the
>  numbers used in this bulletin see the Propagation page on the ARRL
>  Web site at http://www.arrl.org/tis/info/propagation.html.
>
>  Sunspot numbers for October 30 through November 5 were 293, 266,
>  277, 174, 76, 79 and 32, with a mean of 171. 10.7 cm flux was 271.4,
>  248.9, 210.4, 190.4, 166.9, 168 and 114, with a mean of 195.7.
>  Estimated planetary A indices were 162, 93, 21, 18, 10, 31 and 9,
>  with a mean of 49.1.
>  NNNN
>  /EX