Fact is the more humans learn about geology, the more we
learn we don't know.



"Roger (K8RI)" wrote in message
...
| On Wed, 25 Oct 2006 17:46:22 -0500, "Jim Macklin"
| wrote:
|
| Or it just does like the AC current in the power grid and
| switch to the other side of the power curve. The actual
| material doesn't have to move, the energy to flip over
| billions of tons of spinning matter isn't there. But as
an
| A/C generator, it is just a question of electrons.
|
| A while back Scientific American devoted a lot of space to
this. There
| was also a program on it at least a year ago.
|
| Apparently the core is not a uniform spinning mass. There
are
| convection currents up and down as well as the circulating
currents we
| normally think of. Depending on the orientation, the flow
across the
| top may be N,S, E, W, or some where in between. It
appears the
| reversals are not a singular event, but may happen in
stages and at
| different times through out the overall reversal. I don't
think they
| are even sure of how these events may even interact...if
they do.
|
| I've not seen any information on the total time expected
for a
| complete reversal to happen. Indications (some isolated
events that
| appear to be reversals) are that we are starting into or
could be well
| into a change. Does it take 10 years, 100 years, or a 1000
years once
| its started? I don't think any one knows enough to even
make a guess
| except for those based on core samples which are again
going to be
| local. OTOH I believe they are pretty well documented
along the mid
| Atlantic ridge which is probably the best accessible
global record
| that spans many millions of years. There they have done
surveys using
| magnetometers to get some pretty detailed maps along with
a number of
| core samples. http://www.geomag.bgs.ac.uk/reversals.html
|
| A comparable surface feature is the mid African rift
valley where the
| rift and active volcanoes can be seen. That is one wide
valley, but
| the eastern walls are virtually straight up. I've never
seen the
| western side..
|
| Now stop and think... The New Madrid fault lies atop a
"failed rift"
|
http://earthquake.usgs.gov/regional/...php#february_7
| between St Louis and Memphis. What if it decided to start
opening
| again? Even a major quake along that fault would be
something to
| behold. They figure if it lets go like it did back in
1812 there
| would be substantial damage clear up into lower Michigan
and it'd
| shake the skyscrapers in NY and NJ. These have not been
single events
| but a series of large events over several months.
|
|
|
|
|
|
| "Ross Richardson" wrote in message
| ...
| | Jim Macklin wrote:
| | The Earth is rotating and orbiting within a strong
| magnetic
| | field of the Sun, [not to mention the whole
Universe].
| |
| | The magnetic pole is not located on the axis and as a
| result
| | the variation wanders. It appears that the Earth's
| magnetic
| | field is electromagnetic and AC.
| |
| | The Earth doesn't physically flip over, the phase
angle
| | flips.
| |
| |
| |
| | "Ross Richardson" wrote in
message
| | ...
| | | Larry Dighera wrote:
| | | On Wed, 25 Oct 2006 06:17:38 -0500, "Jim Macklin"
| | | wrote in
| | | :
| | |
| | |
| | | BFD, All those radios are called Aids to
navigation
| for
| | a
| | | reason, they are conveniences.
| | |
| | |
| | | Were you aware of the design flaw in GPS as
| implemented?
| | I just
| | | thought it might be a good idea to provide the
| | information to those
| | | weren't.
| | |
| | | Of course, this issue makes no mention of solar
mass
| | ejections, that
| | | can potentially knock out any satellite.
| | |
| | | It appears that we are (finally?) seeing some
| | technological innovation
| | | tickling down to the GA fleet, but I'm becoming
| uneasy
| | with the
| | | apparent lack of robustness engineered in these
| early
| | systems.
| | |
| | |
| | | CAL found Paris with just a compass and a chart.
| | |
| | | Yes. It was an Earth Inductor Compass*. I've
never
| | seen one of those
| | | in any aircraft in which I've flown, let alone
| piloted.
| | |
| | |
| | | *
| http://oldbeacon.com/beacon/earth_inductor_compass.htm
| | |
| | |
| | | Did anybody see NOVA on PBS last night. The earth
is
| | overdue for a pole
| | | reversal. According to the program, we are already
| seeing
| | issues towards
| | | that. Interesting program.
| | |
| | | --
| | |
| | | Regards, Ross
| | | C-172F 180HP
| | | KSWI
| |
| |
| | What this program stated and I had read it elsewhere,
is
| the magnetic
| | core within the earth had flipped every 200K to 700K
| years. Geologist
| | know how to figure this out from core samples. They
said
| the last one
| | was over 700K years ago. The north magnetic pole (as we
| know it) flips
| | to the south pole.
| |
| | --
| |
| | Regards, Ross
| | C-172F 180HP
| | KSWI
|
| Roger Halstead (K8RI & ARRL life member)
| (N833R, S# CD-2 Worlds oldest Debonair)
| www.rogerhalstead.com