From: Paul Doherty (pauld@exploratorium.edu)
Date: Wed Apr 04 2001 - 09:42:10 PDT
Message-Id: <l0311070db6f0ff35e715@[192.174.2.173]> Date: Wed, 4 Apr 2001 09:42:10 -0700 From: Paul Doherty <pauld@exploratorium.edu> Subject: NASA press release on giant solar flare.
Hi Pinholers
Here's background info on the recent huge solar flare.
Paul D
X-Authentication-Warning: spinoza.public.hq.nasa.gov: majordom set sender
to owner-press-release using -f
Date: Tue, 3 Apr 2001 15:50:15 -0400 (EDT)
From: NASANews@hq.nasa.gov
Subject: SUN UNLEASHES RECORD SUPERFLARE,EARTH DODGES SOLAR BULLET
Sender: owner-press-release@lists.hq.nasa.gov
To: undisclosed-recipients:;
Dolores Beasley
Headquarters, Washington, DC April 3, 2001
(Phone: 202/358-1753)
Bill Steigerwald
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/286-5017)
RELEASE: 01-66
SUN UNLEASHES RECORD SUPERFLARE,
EARTH DODGES SOLAR BULLET
The Sun blasted one of its largest flares in 25 years
from the same region harboring the largest sunspot of the
current solar cycle Monday evening.
The region, designated active region 9393, has continued to
rotate with the Sun and is no longer in line with the Earth,
so most of the flare's energy was directed away from our
planet. However, radiation from the flare temporarily
disrupted radio communications, and flare-related events
generated a storm of high-velocity particles that, in greater
numbers and energies, can affect sensitive electronic
equipment in space.
"This explosion was estimated as an X-20 flare, and was as
strong as the record X-20 flare on August 16, 1989, " said Dr.
Paal Brekke, the European Space Agency Deputy Project
Scientist for the Solar and Heliospheric Observatory (SOHO),
one of a fleet of spacecraft monitoring solar activity and its
effects on the Earth. "It was more powerful that the famous
March 6, 1989 flare which was related to the disruption of the
power grids in Canada."
Monday's flare and the August 1989 flare are the most powerful
recorded since regular X-ray data became available in 1976.
Solar flares, among the solar system's mightiest eruptions,
are tremendous explosions in the atmosphere of the Sun capable
of releasing as much energy as a billion megatons of TNT.
Caused by the sudden release of magnetic energy, in just a few
seconds flares can accelerate solar particles to very high
velocities, almost to the speed of light, and heat solar
material to tens of millions of degrees.
The flare erupted at 4:51 p.m. EDT Monday, and produced an R4
radio blackout on the sunlit side of the Earth. An R4
blackout, rated by the NOAA SEC, is second to the most severe
R5 classification. The classification measures the disruption
in radio communications. X-ray and ultraviolet light from the
flare changed the structure of the Earth's electrically
charged upper atmosphere (ionosphere). This affected radio
communication frequencies that either pass through the
ionosphere to satellites or are reflected by it to traverse
the globe.
The explosion, near the Sun's northwest limb (the upper right
in SOHO images), was associated with an eruption of a cloud of
electrified gas, called a coronal mass ejection, or CME, into
space, but apparently not directed towards Earth.
"We are perhaps lucky that this event didn't occur over the
weekend, when the resulting CME would almost certainly have
been aimed towards Earth," said Brekke. "A smaller flare-
related CME event in March 1989 caused major power failures in
Canada, and subsequent smaller events have disrupted
communication and navigation satellites."
Solar ejections are often associated with flares and sometimes
occur shortly after the flare explosion. CMEs are clouds of
electrified, magnetic gas weighing billions of tons ejected
from the Sun and hurled into space with speeds ranging from 12
to 1,250 miles per second. Depending on the orientation of the
magnetic fields carried by the ejection cloud, Earth-directed
CMEs cause magnetic storms by interacting with the Earth's
magnetic field, distorting its shape and accelerating
electrically charged particles (electrons and atomic nuclei)
trapped within.
Severe solar weather is often heralded by dramatic auroral
displays, northern and southern lights, and magnetic storms
that occasionally affect satellites, radio communications and
power systems. The flare and solar ejection has also generated
a storm of high-velocity particles, and the number of
particles with ten million electron-volts of energy in the
space near Earth is now 10,000 times greater than normal. The
increase of particles at this energy level still poses no
appreciable hazard to air travelers, astronauts or satellites,
and the NOAA SEC rates this radiation storm as a moderate S2
to S3, on a scale that goes to S5.
The SOHO project is an international cooperative program
between NASA and the European Space Agency for the
International Solar Terrestrial Science Program.
For additional information and images regarding the flare,
space weather and the giant sunspot, see:
http://sohowww.nascom.nasa.gov/hotshots/X17/
http://www.spaceweather.com/
http://www.sel.noaa.gov/NOAAscales/index.html
http://www.noao.edu/outreach/press/pr01/img0101.html
-end-
* * *
NASA press releases and other information are available automatically
by sending an Internet electronic mail message to domo@hq.nasa.gov.
In the body of the message (not the subject line) users should type
the words "subscribe press-release" (no quotes). The system will
reply with a confirmation via E-mail of each subscription. A second
automatic message will include additional information on the service.
NASA releases also are available via CompuServe using the command
GO NASA. To unsubscribe from this mailing list, address an E-mail
message to domo@hq.nasa.gov, leave the subject blank, and type only
"unsubscribe press-release" (no quotes) in the body of the message.
Paul "But it is more complicated than that!" Doherty,
Senior Staff Scientist, The Exploratorium.
pauld@exploratorium.edu, www.exo.net/~pauld
This archive was generated by hypermail 2b29 : Tue Oct 16 2001 - 12:22:19 PDT