The Earth's Magnetic Field Strength

A typical creationist argument centres on the Earth's magnetic field. The claim is made that on the basis of the magnetic fields current rate of decay that prior to ten thousand years ago it would have been impossibly strong.

Barnes (1071) stated that over a period since 1835 the strength of the Earth's magnetic field had decreased between 6 & 7 percent. His conclusion was that the Earths dipole (the north/south parts of a bar magnet field) must be decaying exponentially with a half-life of some 1,400 years. He concluded that the absolute age of the Earth could be no more than ten thousand years. Humphreys (1989) added further detail to these claims by explaining how the magnetic field had formed and how & when it began its decay. He claimed that the christian god, when creating the Earth, had formed the magnetic dipole by ensuring that the spin axes of atomic nuclei all pointed in the same direction.

Though Barnes is correct concerning the magnetic field strength during the 19th century his conclusions and experimental method do not stand up to test. Barnes completely ignored the dipole content of the field and he failed to state (either intentionally or otherwise) that the total measured magnetic field i.e. both dipole and non-dipole components was almost constant over this period. Barnes also presented no evidence to support his decaying field theory or to indicate that the Earth's magnetic field was stronger in the past.

Such evidence exists in the form of metallic iron particles (partially magnetised) that line themselves up with the Earth's magnetic field. Evidence from these particles indicate that some 6500 years ago the Earth's magnetic field was 20% weaker than today whilst a mere 3000 years ago it was some 45% stronger. So, rather than a steady decrease in strength the Earth's magnetic field has, in fact, fluctuated in intensity. Humphreys (1989) admits this to be the case but claims that the reversals occurred during the Noahic flood at a rate of about 1 per week. Unsurprisingly he is unable to produce any evidence to substantiate such a claim.

Examination of sea floor rocks demonstrate a mirror-image pattern of magnetic field on each side of the rifts where tectonic plates are moving away from each other. This offers evidence as a permanent record of the variations n the Earth's magnetic field over a vast period of time and cannot be explained away by creationist claims of local magnetic variations produced by intense heat ... that would have produced entirely variable patterns rather than the striped ones found.

The Earth's magnetic field does decay but is constantly refreshed by motion of liquid core of Earth. Evidence for this is fossil magnetism record which shows irregular repeating reversals of the pole and fluctuations (both decrease and increase) in the earths magnetic field. In fact some 171 reversals have occurred over 76 million years and there have been times when the Earth's magnetic field has been demonstrated to have not existed at all (zero measurement) and in the mid to late 50's a similar magnetic reversal was observed within the sun itself.

In the light of the above evidence it can be seen that there is no basis for Barnes & Humphrey's extrapolation of the magnetic field data as one constant period of decreasing strength nor the subsequent association with the claims of it being evidence to justify a young Earth.

To put it simply “We can safely relegate Barnes's magnetic field argument to the junk heap of crackpot ideas. Barnes' work lacks the scientific integrity, competence, and judgment one expects from a scientific work.” Matson (1994)

1. “Information for all biologists”, Morden (1995)
2. “Creationists and 'Magnetic Field Decay'”, Lenny Flank (1995)
3. “Young Earth Proof #11” Dave Matson (1994)