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magnetic field

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  • XK SAZ
    What makes the earth s magnetic field suddenly shift from south to north? Anything specific? It s as if a person standing with their face to the wind turns and
    Message 1 of 2 , Oct 24, 2003
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      What makes the earth's magnetic field suddenly shift from south to
      north? Anything specific?

      It's as if a person standing with their face to the wind turns and
      walks backwards so they won't get so much dust in their eyes.

      >
      >Message: 1
      > Date: Thu, 23 Oct 2003 04:08:52 -0000
      > From: "David" <b1blancer1@...>
      >Subject: Solar Activity Report for 10/22/03
      >
      >** Aurora Watch In Effect **
      >
      >Active conditions on both the solar and geomagnetic fronts continue
      >unabated. Although the solar wind speed has slowed down from
      >yesterday's high of around 770 km/sec, G-2 geomagnetic storm
      >conditions have been observed within the last 24 hours, and an aurora
      >watch remains in effect. The geomagnetic storms would've been even
      >stronger had the Interplanetary Magnetic Field rather suddenly shifted
      >to a north-pointing orientation. Active geomagnetic conditions should
      >continue over the next couple of days as a result of a chain of
      >CME's from sunspot region 484. There have been 13, count 'em, 13
      >significant flares from this sunspot region since the 19th, and
      >another one that is just now appearing over the eastern limb of the
      >solar disk. Region is the largest sunspot to be seen in years, and is
      >now bigger than the planet Jupiter. I've counted three partial halo
      >CME's, and a rather irregular full-halo CME that happened today. Look
      >for more flares from these two very active sunspot regions in the days
      >ahead.
      >
      >The current solar and geomagnetic conditions are :
      >
      >NOAA sunspot number : 117
      >SFI : 154
      >A index : 28
      >K index : 3
      >
      >Solar wind speed : 537.8 km/sec
      >Solar wind density : 4.5 protons/cc
      >Solar wind pressure : 2.2 nPa
      >
      >IMF : 10.5 nT
      >IMF Orientation : 9.3 nT North
      >
      >Conditions for the last 24 hours :
      >Space weather for the past 24 hours has been moderate. Geomagnetic
      >storms reaching the G2 level occurred. Radio blackouts reaching the R2
      >level occurred.
      >Forecast for the next 24 hours :
      >Space weather for the next 24 hours is expected to be minor.
      >Geomagnetic storms reaching the G1 level are expected. Radio blackouts
      >reaching the R1 level are expected.
      >
      >Solar activity forecast :
      >Solar activity is expected to be at moderate levels. Regions 484 and
      >486 are both capable of producing isolated major flares.
      >
      >Geomagnetic activity forecast :
      >The geomagnetic field is expected to be at predominantly active levels
      >through day one of the forecast period. The partial halo CME from
      >today is expected to arrive mid-day on the 24th of October and may
      >produce periods of major storming. Day three should see a return to
      >unsettled to active conditions.
      >
      >Recent significant solar flare activity :
      >23-Oct-2003 0241Z M2.4
      >22-Oct-2003 2204Z M2.1
      >22-Oct-2003 2007Z M9.9
      >22-Oct-2003 1601Z M1.2
      >22-Oct-2003 1511Z M1.4
      >22-Oct-2003 0956Z M1.7
      >22-Oct-2003 0844Z M1.7
      >22-Oct-2003 0351Z M3.7
      >21-Oct-2003 0827Z M1.0
      >20-Oct-2003 0722Z M1.9
      >19-Oct-2003 1926Z M1.0
      >19-Oct-2003 1650Z X1.1
      >19-Oct-2003 0626Z M1.9
      >
      >
      >
      >________________________________________________________________________
      >________________________________________________________________________
      >
      >
      >
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    • David
      ... I think you re getting the Earth s magnetic field confused with the Interplanetary Magnetic Field. Earth s magnetic field does indeed swap ends
      Message 2 of 2 , Oct 24, 2003
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        --- In methanehydrateclub@yahoogroups.com, XK SAZ <group@s...> wrote:
        > What makes the earth's magnetic field suddenly shift from south to
        > north? Anything specific?
        >
        > It's as if a person standing with their face to the wind turns and
        > walks backwards so they won't get so much dust in their eyes.
        >

        I think you're getting the Earth's magnetic field confused with the
        Interplanetary Magnetic Field. Earth's magnetic field does indeed
        swap ends occasionally, but it only happens every few hundred thousand
        years. Einstein said that how the Earth's magnetic field is generated
        is one of the greatest mysteries of modern physics. Nobody is certain
        of exactly how it works. It's presumed that it has something to do
        with motion of liquid iron in the Earth's outer core, but beyond that,
        not much else is known. The occasional polarity shifts are equally
        puzzling.

        The Interplanetary Magnetic Field (IMF) originates at the sun, is
        carried along by the solar wind. It shifts polarity frequently. A
        north-pointing IMF will reinforce Earth's magnetic field and tend to
        suppress geomagnetic activity. A south-pointing IMF has exactly the
        opposite effect.

        Believe it or not, the sun's magnetic field also reverses every 11
        years at the peak of the sunspot cycle.
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