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Re: [Methane Hydrate Club] Trio of spacecraft analyze space weather

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  • mike
    Very interesting, David. ... From: David To: methanehydrateclub@yahoogroups.com Date: Fri, 20 Jun 2003 04:02:55 -0000 Subject:
    Message 1 of 2 , Jun 20, 2003
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      Very interesting, David.

      -----Original Message-----
      From: "David" <b1blancer1@...>
      To: methanehydrateclub@yahoogroups.com
      Date: Fri, 20 Jun 2003 04:02:55 -0000
      Subject: [Methane Hydrate Club] Trio of spacecraft analyze space weather

      > <html><body>
      >
      >
      > <tt>
      > Release:  03-66<BR>
      > <BR>
      > SPACECRAFT TRIO PEEKS AT SECRET RECIPE FOR STORMY SOLAR WEATHER<BR>
      > <BR>
      > A three-spacecraft collaboration recorded for the first time the<BR>
      > entire initiation process of a high-speed eruption of electrified
      > gas<BR>
      > from the Sun, providing clues about the Sun's secret recipe for
      > stormy<BR>
      > weather. The April 21, 2002 observation confirmed the predominant<BR>
      > scenario for how these eruptions, called Coronal Mass Ejections,
      > are<BR>
      > blasted from the Sun.<BR>
      > <BR>
      > The three spacecraft involved were NASA's Reuven Ramaty High Energy<BR>
      > Solar Spectroscopic Imager (RHESSI), which takes pictures of
      > flaring<BR>
      > regions using the Sun's high-energy X-rays and gamma rays; NASA's<BR>
      > Transition Region and Coronal Explorer (TRACE), which makes images<BR>
      > using ultraviolet light from the Sun; and the Solar and
      > Heliospheric<BR>
      > Observatory (SOHO) spacecraft, a collaboration between NASA and the
      > <BR>
      > European Space Agency.<BR>
      > <BR>
      > "This was the first time that we have been able to identify and
      > study<BR>
      > in detail the region on the Sun where the initiation and
      > acceleration<BR>
      > of a coronal mass ejection occurs," said Dr. Peter Gallagher,
      > research<BR>
      > scientist for RHESSI and SOHO at NASA's Goddard Space Flight Center,
      > <BR>
      > Greenbelt, Md., and lead author of two papers on this research.
      > "We<BR>
      > now have a better understanding of how the energy release above the<BR>
      > surface of the Sun relates to the ejection of material, perhaps<BR>
      > allowing some real-time forecasts." The results are being
      > presented<BR>
      > today during a meeting of the American Astronomical Society's Solar<BR>
      > Physics Division in a press conference at the Johns Hopkins
      > University<BR>
      > Applied Physics Laboratory, Laurel, Md.<BR>
      > <BR>
      > Coronal Mass Ejections (CME) are often associated with solar flares.
      > A<BR>
      > flare is a giant explosion in the solar atmosphere that spews<BR>
      > radiation and results in the heating of solar gas and the
      > acceleration<BR>
      > of particles to nearly the speed of light. Both events can be<BR>
      > initiated in a matter of seconds, making their joint observations<BR>
      > difficult to coordinate. <BR>
      > <BR>
      > The twisting and snapping of magnetic field lines on the Sun,
      > called<BR>
      > magnetic reconnection, seem to cause CMEs and solar flares. When
      > these<BR>
      > fields snap from the buildup of magnetic energy, plasma is heated
      > and<BR>
      > particles are accelerated, resulting in massive explosions and<BR>
      > emitting radiation ranging from radio waves to X-rays. <BR>
      > <BR>
      > Frequently, a CME and flare will burst from the same region of the
      > Sun<BR>
      > nearly simultaneously. Just like the debate over whether the
      > chicken<BR>
      > or the egg came first, solar researchers discuss whether flares
      > cause<BR>
      > CMEs or the reverse, or if they are more loosely associated. <BR>
      > <BR>
      > The April 21, 2002 observation confirmed the predominant scenario
      > for<BR>
      > high-speed CMEs (those moving at one million to 5 million miles per<BR>
      > hour or 1.6 million to 8 million km/hr.). This is where solar
      > magnetic<BR>
      > fields act like a lid, holding down a blob of gas (CME) that is
      > trying<BR>
      > to rise. Somehow, the magnetic lid opens, possibly as a result of<BR>
      > magnetic reconnection and the generation of a flare, and then the CME
      > <BR>
      > rises from the Sun, dragging the magnetic fields with it. Magnetic<BR>
      > reconnection continues to energize the associated flare for over 12
      > hours.<BR>
      > <BR>
      > All three spacecraft played vital roles in confirming that this was<BR>
      > the process. First, RHESSI saw a gradually increasing burst of
      > X-rays<BR>
      > announcing the start of the flare. TRACE observed the CME in the<BR>
      > extreme ultraviolet as it began to rise from the Sun. Several
      > minutes<BR>
      > later, RHESSI saw a burst of high energy X-rays under the erupting<BR>
      > CME, and TRACE saw a similar explosion of ultraviolet rays, both<BR>
      > indicating a large flare. SOHO then captured the CME as it continued
      > <BR>
      > moving away from the Sun.<BR>
      > <BR>
      > "Each of these spacecraft is quite complementary," said
      > Gallagher.<BR>
      > "It's only through their coordination in this observation that
      > we're<BR>
      > now able to understand the predominant scenario for these fast,
      > large<BR>
      > coronal mass ejections and the associated flares."<BR>
      > <BR>
      > The current results feed into the decades-old controversy over
      > whether<BR>
      > solar flares cause coronal mass ejections, or vice versa. While the<BR>
      > first signs of the flare occur before the CME liftoff, the bulk of
      > the<BR>
      > flare energy is released later, after the CME has already been<BR>
      > accelerated. The two phenomena are revealed to be merely different<BR>
      > aspects of the same event, according to the team. For images and more
      > <BR>
      > information, refer to:<BR>
      > <BR>
      > <a
      > href="http://www.gsfc.nasa.gov/topstory/2003/0617rhessicme.html">http:/
      > /www.gsfc.nasa.gov/topstory/2003/0617rhessicme.html</a><BR>
      > <BR>
      > </tt>
      >
      > <br>
      >
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