Magnetic Field

Prior to July, 1995 ZetaTalk stated that the Earth's Magnetic Field was appearing to weaken as it was diffused and confused by the 12th Planet's approach. On March 14, 1999, a NASA expert confirmed that.

Question #1-D (the Answer Man)
Answer from David P. Stern - NASA/GSFC Code 695
Updated March 14, 1999

QUESTION: (Earth's magnetic field weakening--leading to a pole shift?)

I am just a tax paying citizen, interested in astromony all of my life. I am very interested in the physics of our earth which I believe is related to astronomy as it is our home and a part of this solar system. My question is: Is the earths magnetic field weakening, heading to zero point? With this, is the base pulse frequency of the earth speeding up causing the magnetic fields to fluctuate so that it interferes with the pilots navigational equipment, so that the navigational charts have to be redrawn periodically and the air strips renumbered? Are the magnetic poles fluctuating? My experience is that they are. I have a quality, liquid filled compass secured to my desk. It has been very still now for the past month but the six weeks or so prior to that, there were consistant fluctuations in its direction, up to as much as 2 1/2 degrees, always to the west. My understanding is: I have seen photographs of the sun taken from satellites, showing the sun going through major activity. Repolarizing itself? Causing the earth to repolarize itself? Going through a natural cycle as it has many times in the past with pole shifts? On a scale from 1 to 10, with 1 being the weakest and 10 the strongest, 2,000 years ago it was a 10, today it is a 1. Is it heading for a zero point when a pole shift will occur? The closer it gets to the zero point, the more fluctuations will occur?

Are the change in the magnetic frequencies causing at times a confusion in migratory animals? Causing cells to mutate, changing the DNA pattern within the cell? Causing certain strains of bacteria such as staph infections to become resistant to our antibiotics and causing new viruses to appear that we have never seen before, being able to survive in a new magnetic frequency? I believe these are very facinating times in which we live. The science of all of this intrigues me to no end. I have some taped interviews of scientists and geologists relating to this subject and I read all that I can get my hands on, on the subject also. Your straightforward comments and answers will be most welcomed to help me to understand more, what is taking place. Thank you so very much.

Michael

REPLY:

Dear Michael,

A question on reversals appears in a list of questions and answers, at
http://www-spof.gsfc.nasa.gov/Education/FAQ.html
and two more are due to be posted there soon. Also, if you look up "Exploration of the Earth's Magnetosphere" you will see that the reason the Earth has a magnetic field is not any polarization, but electric currents flowing in the Earth's core. You will also find there a great deal of material on the Sun's magnetic field and its relation to sunspots and their cycle.

Now to your questions. Is the Earth's field getting weaker? Yes and no. That field is often viewed as being a two-pole ("dipole") structure similar to that of a small bar-magnet at the center of the Earth, inclined by about 11 degrees to the rotation axis of the Earth, so that the magnetic poles are not the same as the geographic ones. But the actual situation is more complicated, and magnetic charts note the fact by mapping deviations between magnetic north and the direction to the magnetic pole, which fit no simple pattern. Why? Because the magnetic field is actually more complicated, and it contains additional fields, of more complex nature. All this originates in the Earth's core, about half the radius of the Earth. If we could go to the surface of the core, all the complicated parts would be much bigger. But they weaken more rapidly with distance, so at the surface of the Earth they are already quite weak, while the "dipole" part stands out more (in addition of actually being the biggest chunk of the field).

Are you still with me? The magnetic field of the Earth changes all the time, and yes, magnetic charts have to be redrawn from time to time (this was first found in 1641, by an Englishman named Gellibrand). And yes, in the century and a half since the first careful mapping of the Earth's field, the dipole has become weaker by about 8% (the rate may have speeded up in 1970). If you draw a straight line through the points, you will find that perhaps 1200 years from now, the line goes through zero. Extending straight lines too far beyond the present, however, is risky business, as noted by no less a scientific authority than Mark Twain. In Life on the Mississippi Twain noted that the Mississippi river was getting progressively shorter (mainly by floods - and by people - creating shortcuts through bends in the river) and he wrote:

"Now, if I wanted to be one of those scientific people, and "let on" to prove what had occured in the remote past by what had occured in a given time in the recent past, or what will occur in the far future by what has occured in late years, what an opportunity is here! Please observe: In the space of one hundred and seventy six years the lower Mississippi has shortened itself two hundred and forty-two miles. That is an average over a mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the lower Oolitic Silurian Period, just a million years ago next November, the lower Mississippi was upward of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing rod. And by the same token any person can see that seven hundred and forty years from now the lower Mississippi will be only a mile and three quarters long, and Cairo and New Orleans will have joined their streets together, and will be plodding comfortably along under a single mayor... There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment in fact."

It is not impossible that the magnetic field will go through zero 1200 years from now, but (judging by the past record of reversals) not likely. In any case, the field is not going away: when one uses observations on the surface to reconstruct fields at the core, one finds that while the dipole field is getting weaker, the complicated parts are getting stronger, and the total magnetic energy does not change, within our observational accuracy. That's why I wrote "yes and no." I don't know about migrating animals (they may have magnetic organs, sort of built-in compasses), but there seem to exist no magnetic effects on DNA, resistance to antibiotics and so on; those changes seem more related to chemistry. Finally, be cautious with compass readings in your house. Houses do contain electric currents and machinery, and these may affect the readings of a magnetic compass. On NASA's satellites the magnetic sensor usually sits at the end of a long boom, to keep it away from interfering electric currents in the satellite's circuits. Keep up your interest in science!

David