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Earth's Magnetic Field Weakening

by Raven
Tags: earth, field, magnetic, weakening
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Raven
#1
Nov19-03, 07:21 PM
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I was watching a NOVA episode that talked about how there are clear signs that Earth's Magnetic Field is weakening at a fairly rapid rate -- a found it very interesting. According to the scientists interviewed, it's undeniably weakening but no one has an explanation. At its current rate of dissipation, the Earth's magnetic field will be absent in a thousand years.

One theory, however, suggests that the Earth is preparing to shift poles (north becomes south and south becomes north). In the past this has happened fairly frequently (approximately once every 200,000 years). The thing is, it hasn't happened in the past 780,000 years and seems we are a bit overdue.

Any opinions on whether you believe the Earth's magnetic field may be getting ready to flip?
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chemical
#2
Nov24-03, 04:12 AM
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i read about that somewhere else. it is due to swap in the next couple of 1000's of years (i think), and it would be interesting to see a compass point the other way!
Phobos
#3
Nov24-03, 08:59 AM
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All the talk I hear about it from scientists pertains to a flip. I have not heard predictions (from scientists) about it disappearing altogether.

chroot
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Nov24-03, 09:37 AM
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Earth's Magnetic Field Weakening

Originally posted by Phobos
All the talk I hear about it from scientists pertains to a flip. I have not heard predictions (from scientists) about it disappearing altogether.
A flip has to involve a disappearance of the field first. The field dissipates to zero, and then rebuilds. When the field comes back, it can come back either in the same polarity as before, or with opposite polarity.

- Warren
ranyart
#5
Nov24-03, 05:34 PM
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There is evidence that the Earths magnetic field undergoes regular reversals, "Flips".

Good link with projected data:http://www.psc.edu/science/Glatzmaier/glatzmaier.html
Raven
#6
Nov24-03, 06:57 PM
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Originally posted by chroot
A flip has to involve a disappearance of the field first. The field dissipates to zero, and then rebuilds. When the field comes back, it can come back either in the same polarity as before, or with opposite polarity.

- Warren
I'm no expert of course, but according to the NOVA documentary on this subject, the scientists do not expect a complete disappearance of the magnetic field if it intends to flip. They only predict a drop of strenght to as low as 10-20% of what it is today. That in itself seems scary enough. Also they predict this drop to occur during the next 1000 years, but they do not have any idea when the actually flip will occur.

The earth could remain in the 10-20% strength level for another 1000 years which has occurred in the past. It is also said that during this time the magnectic field will not have a designated north or south pole. In fact a compass would be completely useless since polarities of north and south will appear in various parts of the earth. The danger of having a magnetic field so low in strenght is that the solar winds will be able to penetrate the earth's atmosphere with greater intensity and greater radiation. The good thing about it will be that aurora lights will be seen almost all over the world.
Kerrie
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Nov24-03, 09:00 PM
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isn't there a point in the hudson bay that used to be where the north pole once was?
Nommos Prime (Dogon)
#8
Nov24-03, 10:30 PM
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Mars' magnetic field recently reactivated (according to Viking data). This was confirmed by more recent observations from later US probes.
Comets/asteroids and massive solar storms have the ability to strip away or reverse planetary magnetic fields. The Russians and James McCanney have done some good work on this subject.
LURCH
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Nov25-03, 02:42 PM
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There is also a thread about this in the "Earth" Sciences Forum (in "Other Sciences"). Polar inversions are a natural behavior of dynamos, so it is suspected that the Earth's magnetic field is created by a large dynamo in the core.

I have also heard it suggested that polar inversion accounts for the starnge alignment (or missalignment) of neptune's magnetic poles. We may actually be observing them in mid-flip. This of course is not the only proposed explanation, and makes no account for the alignment of the axial poles.
Raven
#10
Nov25-03, 03:03 PM
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Originally posted by Kerrie
isn't there a point in the hudson bay that used to be where the north pole once was?
I am not familiar with that. I have heard, however, that there are areas near the north and south pole today in which a compass would be confused and spin or point in the wrong direction (not north). Some of this has to do with the difference between True North and Magnetic North. But scientists have also discovered anomalies in the southern area of the earth in which north magnetic polarities occur and areas in the north where south magnetic polarities occur. It is suggested that as the Earth's magnetic field weakens, more of these anomalies will occur until the final polar shift completes.

Originally posted by Nommos Prime
Mars' magnetic field recently reactivated (according to Viking data). This was confirmed by more recent observations from later US probes.
Comets/asteroids and massive solar storms have the ability to strip away or reverse planetary magnetic fields. The Russians and James McCanney have done some good work on this subject.
Wow. I find really fascinating. I would like to hear more about it and will probably research it on my own. Any sites that you know of that shares this info?
Nommos Prime (Dogon)
#11
Nov25-03, 09:25 PM
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Woops, posted the same stuff twice, and can't work out how to delete it.
Nommos Prime (Dogon)
#12
Nov25-03, 09:34 PM
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All my Viking data is unfortunately in paper form, and I can’t locate it on the Internet yet (not surprising). But I’ll start from NASA’s latest admission, in August 1997. Here goes;

From the “Martian Magnetic Field Missions”;
http://denali.gsfc.nasa.gov/terr_mag/mars_missions.html

Here’s the Press Release from NASA (woops, better bury this one someone thought!);
http://www.qadas.com/qadas/nasa/nasa-hm/1004.html

Because then they claimed they were “localised”;
http://mgs-mager.gsfc.nasa.gov/press...-56_field.html

It then became “crustal”, rather than of “dynamo” origin;
http://solid_earth.ou.edu/readings/mars_mag_field.html

http://mgs-mager.gsfc.nasa.gov/publi...over_black.jpg

The next bits from;
http://isaac.exploratorium.edu/~paul...ofplanets.html

“Mars does not have a strong dipole magnetic field and so does not have auroras circling its poles. However at one time it had a strong magnetic field which was recorded in molten volcanic rocks creating stripes like those due to continental drift on earth.
Red and Blue stripes on Mars record an ancient Martian magnetic field which changed its polarity.”

Here’s a nice little paper called “Paleomagnetic Pole Positions And Reversals Of Mars” by J. Arkani-Hamed.
http://www.lpi.usra.edu/meetings/lpsc2001/pdf/1478.pdf

Martian Magnetic Anomalies;
http://www.geophys.washington.edu/Pe...mars/mars.html

http://www.planetary.org/html/news/a...ln-091897.html
Here’s the NASA stuff (even they concur – although its mostly typical pseudo-scientific “double-speak”);
http://denali.gsfc.nasa.gov/terr_mag/onldoc.html

Here’s a nice quote from NASA, in the below website;
“Second, the Martian magnetic field may have reversed direction less frequently, which would have given more time for any one field direction to imprint itself in the steadily moving crust, resulting in wider bands.”
http://science.nasa.gov/newhome/head...t29apr99_1.htm

and an oldie from ’78;
http://adsabs.harvard.edu/cgi-bin/np...pm..conf...84R

That’s the saga from 97.

Other froot-loops like myself and some Russians have been doing some fringe work on the reactivation of Mars’ magnetic field. I don’t have a website, and I’m sure how many of you understand the Russian way of things (eg. they refer to space as the “vacuum medium”). For an idea on how comets/asteroids effect magnetic fields, have a suss at McCanney’s site;
http://www.jmccanneyscience.com/

If anybody wants a summary of the Viking data, drop me a line.
russ_watters
#13
Nov26-03, 03:13 PM
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Originally posted by Kerrie
isn't there a point in the hudson bay that used to be where the north pole once was?
Probably. It moves pretty fast. http://www.geolab.nrcan.gc.ca/geomag/northpole_e.shtml
CrazyEYe
#14
Mar7-06, 05:30 AM
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This Video might be intresting because I saw the Nova video also and this is from it (I watched it in school)

http://www.pbs.org/wgbh/nova/magnetic/reversals.html

it's on the left side click on the picture (sorry if this is spam I don't think it is.)

this talk about the entire world changing poles is making my stomach weird fealing lol.

i'm hoping I get to live after the Magnetic poles switch that will be so cool.(i'm 15 so i'm not sure :S)
ZaUS22
#15
Apr3-10, 03:06 PM
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I read that by studying lava samples it was determined the Earth’s magnetic field has reversed about 18,000 times in 20 million years--I wonder what will happen to us if it were to occur in our lifetime
Chronos
#16
Apr4-10, 01:17 AM
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The last flip occured about 780,000 years ago. I doubt we are in any immediate peril. See http://news.nationalgeographic.com/n...ield_flip.html
Vanadium 50
#17
Apr4-10, 05:48 AM
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Quote Quote by ZaUS22 View Post
I read that by studying lava samples it was determined the Earth’s magnetic field has reversed about 18,000 times in 20 million years
Where did you read that? This sounds very, very high. That's every 1100 years.
jixon
#18
Apr9-10, 11:50 PM
P: 3
Not to worry; the super volcano under Yellowstone will blow, removing the need to worry about compasses not working or excess RADiation from the Sun.


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