Barnes and the Earth's magnetic field Here is a copy of the post I put up when the questio

Master Index Current Directory Index Go to SkepticTank Go to Human Rights activist Keith Henson Go to Scientology cult

Skeptic Tank!

Barnes and the Earth's magnetic field Organization: Jet Propulsion Laboratory From: tjt@Jpl.Nasa.Gov (Tim Thompson) Message-ID: <26l3eq$> Reply-To: tjt@Jpl.Nasa.Gov Newsgroups: 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. INTERnet/BITnet: NSI/DECnet: jplsc8::tim SCREAMnet: YO!! TIM!! GPSnet: 118:10:22.85 W by 34:11:58.27 N


E-Mail Fredric L. Rice / The Skeptic Tank