Barnes and the Earth's magnetic field

Organization: Jet Propulsion Laboratory
From: tjt@Jpl.Nasa.Gov (Tim Thompson)
Message-ID: <26l3eq$kmc@elroy.jpl.nasa.gov>
Reply-To: tjt@Jpl.Nasa.Gov
Newsgroups: talk.origins

Here is a copy of the post I put up when the question of the Barnes
version of the history of the Earth's magnetic field came up last
February. Hope this tells you what you want to know.

==================================================================

   In his report on the CalTech "Evolution and Creation" seminar,
Wayne Broughton mentioned Thomas Barnes' study claiming that analysis
of the earth's magnetic field proves that the earth cannot be over
10,000 years old. I have studied Barnes' claim, and I feel qualified
to talk about it.

   Barnes published his study in the monograph "The Origin and Destiny
of the Earth's Magnetic Field", published in 1974(?) by the Creation
Research Society. No doubt there is a more recent "updated" edition,
but I have not seen one. Everything I say is based on the first
edition.

   Thomas Barnes is emeritus professor of physics and planetary
science, University of Texas at El Paso. He has a B.A. in physics
from Hardin-Simmons College (now University), in Abilene, Texas,
and an M.A. in physics from Brown University. His doctorate is
an honorary degree, conferred by Hardin-Simmons University. He's
an old timer, as I recall his B.A. dates from the early 30's. He
is the author of a college textbook on electricity and magnetism.
I cannot recall the title, but I have seen it, and it looks like
any other ordinary upper division type E&M text, lots of Maxwell's
equations, nothing peculiar that I saw. This would lead on to
believe that he should know what he's talking about.

   A brief outline of Barnes's claim goes like this:

      1. Only the dipole component of the Earth's magnetic field is
         generated in the core. All other components are either
         ionospheric, telluric currents, or magnetic rocks.

      2. Cowling's Theorem specifically prohibits the dynamo
         maintenance of the Earth's magnetic field.

      3. The dipole component of the Earth's magnetic field is
         generated by circular currents in the core.

      4. The dipole component is decaying along an exponential

      5. The extrapolated exponential shows unacceptably high field
         strengths upwards of 10,000 years ago.

   Barnes never produces a satisfactory explanation of the first claim.
In his terminology, it's obvious that evolution scientists are confusing
"signal" (the dipole component), and "noise" (everything else). Personally,
I find it hard to believe that exploration geophysicists would overlook
a field of magnetic rocks big enough to affect the quadropole moment
of the earth's magnetic field. Also, the spherical harmonic expression
of the earth's magnetic field, as produced by Gauss himself, clearly
seperates field sources above and below the earth's surface. That means
the ionospheric components are eliminated right from the start (they
have been shown to average out over long time periods anyway). Likewise,
telluric currents should average out over long time periods. And, of
course, rocks don't move much faster than the continents they ride on.

   Cowling's theorem (Monthly Notices of the Royal Astronomical Society,
vol. 94, pp 39-48, 1934), by Thomas G. Cowling, proves that dynamo
generation will not support an axially symmetric field, nor one that
is similar, in the mathematical sense. Indeed, this would apply to a
pure dipole. Since the Earth's field is neither dipolar, nor similar,
Barnes must make claim number 1, in order to make any sense at all.
Barnes glosses over his first claim as if it were almost trivial, and
spends a great deal of time on Cowling's theorem. He is quite
ostentatious, in fact, and proud of his adherence to hard mathematics,
unlike the sloppy evolution scientists.

   The whole thing is a setup. If he can't prove that ONLY the dipole
component is generated in the core, then his reliance on Cowling's
theorem is irrelevant. Neither proof, nor evidence are offered. In fact
this weakness destroys the entire concept at once. All the rest of the
work hinges on the acceptance of "dipole only" in the core.

   The fun part is where he talks about exponential decay of the field.
Barnes fits an exponential function via least-squares, on a CDC 6600,
to 150 years of dipole data. I note in passing, his attitude clearly
implies that using the then giant CDC computer virtually guarantees that
his results can hardly be wrong. In comparing this exponential fit of
his to a standard linear fit, the probable errors in the fitting
coefficients are a few percent better for his exponential. He immediately
assumes the linear fit is wrong, the exponential is right, and proceeds
to the next step.

   Having satisfied himself of the exponential fit, to 150 years of data,
he then extrapolates the curve back 10,000 years, derives an enormous
magnetic field strength, denounces it as ridiculously large (at least
that much is true), and then dismisses the idea that the earth can
be more than 10,000 years old.

   Q.E.D.

   I found the book in the library at Cal State L.A., along with a number of
other creation science texts. A lot more could be said. Barnes fills pages
with irrelevant ramblings, including his ability to re-write equations
found in older works (Horace Lamb, and Maxwell) in more recent notation.

   I think I have covered what is relevant, enough to show that Barnes's
work lacks merit, and substance. I see no reason to believe that the
earths' magnetic field implies that the earth canot be over 10,000 years
old.

   However, like any good research, Barnes's work has sparked further inquiry.
If you don't have a sense of humor, quit now and don't read any further.

   I draw your attention to the paper "The Creation of Planetary Magnetic
Fields", by D. Russell Humphreys, Quarterly Journal of the Creation
Research Society, vol. 21, December, 1984. Recieved 3 January, 1984,
revised 14 August, 1984. This is a refereed, scientific journal. It says
that Humphreys has a PhD in physics, and is (was) a physicist at Sandia
National Laboratories. Here is the abstract of the paper:

   "God could have started magnetic fields in the solar system in a very
simple way: by creating the original atoms of the planets with many of
their nuclear spins pointing in the same direction. The small magnetic
fields of so many atomic nuclei add up to fields large enough to account
for the magnetism of the planets.

Within seconds after creation, ordinary physical events would convert the
alignment of nuclei into a large electric current circulating within each 
planet, maintaining the magnetic field. The currents and fields would
decay steadily over thousands of years, as Barnes has pointed out. The
present magnetic field strengths of the Earth, Sun, Moon, and planets
agree very well with the values produced by this theory and a 6000-year
age for the solar system. The theory is consistent with all the known
data and explains many facts which have puzzled evolutionists."

   Humphreys presumes that God made the sun, and all of the planets out
of water, which has a strong dipole. Line up enough dipoles, get a big
field, then God changes everything from water to the silicate/iron type
stuff we see now, leaving behind decaying magnetic fields.

   For those of you who still think scientific creationism is scientific,
I leave you with a paragraph from Humphreys' "conclusions" section:

   "The Bible is scientifically accurate. A straightforward reading of
Scripture supplied the essentials of this theory: the possibility of
initial alignment, the water composition, and the short time scale. The
fact that the theory fits the facts shows that the scientist can rely
on the Bible for new insight into the natural world.

------------------------------------------------------------
Timothy J. Thompson, Earth and Space Sciences Division, JPL.
Assistant Administrator, Division Science Computing Network.
Secretary, Los Angeles Astronomical Society.
Member, BOD, Mount Wilson Observatory Association.

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