Satgen515 Magnetic Moments  by GM4IHJ   (BID SGEN515)   1999-02-06

It has been common knowledge for centuries that the Earth is a magnet.
But only in the last century has it become clear that it is an electro
magnet, not a permanent bar magnet. While even more recently it has
been demonstrated that this electro magnet can over several decades
shift the position of its poles relative to the earths rotation poles,
and , over centuries and millenia it can even reverse its polarity.
Such that a north magnetic pole becomes a south pole , and vice versa.

Fortunately complete changes of polarity are relatively rare events,
and, up to now even the drift of the magnetic pole position with
respect to the rotation axis pole, has been slow. But this comfortable
state of affairs may now be changing. In the last year the north
magnetic pole has moved 20 kms towards the rotation pole, ie the
biggest shift anyone has seen in more than 70 years of monitoring.
Whilst at the same time the field strength has dropped 1% in ten years
- enough to disappear completly in 1000 years.

Does this actually mean we may see a complete reversal in the new
millenia which is just about to start ? It is to be hoped not. The
field protects us from both cosmic radiation and solar storms, and its
absence for decades or centuries ie as has occured with previous flips
at the start of reversals, would spell very serious problems for life
on earth. http://physicsweb.org  refers.

One clue in our favour may be that the recent move of the magnetic
pole towards the rotation pole is the opposite of what has been the
pattern in previous reversals. Equally noteworthy the decline into a
reversal is usually slow, followed by a build up in the reverse
direction which is quite fast. So even if a reversal is being
signalled, at least we may be in the slow part of the cycle.

But it has to be asked whether we need to pay more attention to what
is going on. Scottish skies have featured 10 radio auroral events in
this month of January 1999 just past - which may be telling us
something. Producing data from far beyond Scotland the signals of the
RS12/13 downlink on 29.458 MHz cw morse have featured auroral tones
sometimes from mid morning to midnight during this same month of
January . With some auroras being traceable by radio from 1000z to
2100z m then, being followed by a superb visual display until after
midnight.

So while IHJs experimental asperations might lean towards welcoming a
reversal in our time - where would the South Atlantic Anomaly finish
up, what would happen to the Van Allen Radiation Belts, would'nt it be
nice to receive sats at IHJ without the distortion of the signals 
passage through the auroral oval ? Common sense and old age, suggest
that the accompanying need to protect onesself against the 50 rad/year
radiation dosage that lack of protection from cosmic radiation would
bring , plus a sizzling of the type that geosats sometimes get in
solar storms becoming an earth surface event, will win out and prayers
will be said that any reversal should " not be in our time " hi.