Geomagnetic field decay
Geomagnetic field decay is based on observations regarding the strength of Earth's magnetic field for over the last 150 years. Dr. Thomas Barnes determined that it is decaying and these findings imply a young age of the Earth because if the decay is projected back 20,000 years, the heat produced by the electric current that generates the Earth's magnetic field would have liquefied the Earth. Naturally this would make life impossible.
Evolutionists have proposed a solution to this problem called the magnetic-dynamo model. The idea is that the current is generated by a self sustaining dynamo, powered by the planet's spin. The result is complex currents in the planet's core that causes the field to fluctuate from time to time, and reversing itself about every 500 - 700 thousand years .
Experiments have been performed to try to reproduce such a dynamo. The Madison Dynamo Experiments from the University of Wisconsin Madison first experimented by using water in a sphere trying to mimic the flows of the alleged dynamo. The water was set in motion by counter-rotating propellers.
The next set of experiments uses a large stainless steel sphere. It is expected to demonstrate how molten iron uses the planet's rotation to generate the self perpetuating magnetic field. The sphere is filled with 200 gallons of molten sodium (at 110o C) and has propellers spinning in opposite directions, in an effort to recreate the same kinds of flows thought to exist at the Earth's outer core. As of 2008, turbulence in the sphere did not allow an external magnetic field to excite a magnetic field in the sphere that would continue when the external field was removed . Numerical simulations indicated another possibility of using baffles to limit turbulence in future runs of the experiment.
Even if they generate a self perpetuating magnetic field, it would have been jump started by the Earth's or some other external magnetic field. No known magnetic field would have existed when the Solar System is alleged to have formed. Also these experiments do not reproduce conditions in the Earth's outer core in terms of pressures, temperatures, and electrical resistance. Finally, the Earth does not have counter rotating propellers.
It is claimed that there is evidence for past reversals. It consists of variations in the magnetism of rocks, on both sides of the mid-oceanic ridges. Some claim that these are not actual reversals, but I have yet to find confirmation of this. The theory is that as lava cools, the magnetic fields of the atoms align with the Earth's field, that as the sea floor spreads a record of Earth's past fields is preserved.
The way the theory is illustrated  is with present magnetic field direction and reverse magnetic field direction in nice neat strips  across the ocean floor, as produced by the theory. In reality the pattern is not so neat and regular,  and the tendency is for the positive and negative areas to be mixed up and this is the case all over the world.
It gets worse when you look vertically, the tendency is for positive and negative to be mixed up. Actual data seem to be inconsistent with uniformitarian theory, but is consistent with:
- A rapid spreading coupled with rapid magnetic reversals.
- A stretching with cracking and a single reversal.
- Temporary local magnetic reversals.
- Reversals resulting from stress in the rocks.
Other problems with the geomagnetic reversal theory
- Life would periodically be exposed to deadly solar radiation.
- It cannot explain the lack of a planetary magnetic field on Mars. Mars' rotation is similar to Earth's, so it should have a similar magnetic field.
- It cannot explain the existence of the magnetic field of Mercury. It rotates too slowly to have a self sustaining dynamo and so it should not have a magnetic field.
- It cannot explain the orientation of the magnetic fields of, Uranus and Neptune. The magnetic axis of each planet is tilted about 60 degrees, with respect to the rotation axis, so that the magnetic poles are near the equator. Furthermore the source of each planet's field is offset from the center, by about one third of a planetary radius. According to the dynamo theory, the magnetic and rotation axes should nearly always be closely aligned, except for a very relatively short time during a field reversal. When Voyager 2 passed Uranus, the pundits explained that the planet is in the act of flipping. However, Neptune's magnetic tilt made this highly unlikely, since the odds of two reversals occurring at the same time is too small to explain both fields.
- It cannot explain how planetary magnetic fields get started. It would need a strong enough external magnetic field and no such field exists, nor is there any theoretical basis for such a field.
Dynamic Decay Theory
Dynamic Decay Theory developed by Dr. Russell Humphreys—a scientist with the Institute for Creation Research—uses an alignment of the magnetic fields of the planet's molecules, to jump start the planet's magnetic field, along with fluctuations and possibly even reversals during and shortly after the Flood. Projecting back in time based on magnetic field energy gives a maximum age for the Earth of 8,700 years. The fluctuations would drain field energy, so depending on the degree of fluctuation, they could reduce the age of the Earth to 6,000 years.
This is supported by archaeological magnetic data. Before 4000 years ago there is evidence of significant magnetic field fluctuations, and it is consistent with a date for the flood of 2400 - 3600 BC.
- The origin of planetary and stellar magnetic fields.
- The orientation of the magnetic fields of Uranus and Neptune, both the tilt of about 60 degrees with respect to the rotation axis and the field's source being about one third of a planetary radius offset from the center. It involves the field's source being in the planet's solid core, which could be displaced by material falling into the planet and sinking through outer planetary oceans of fluid. Such a displacement could influence both magnetic and rotational tilts. The Dynamo theory cannot consider this possibility since the field-generating mechanism cannot work in a solid.
- The existence of the magnetic field of Mercury, since the field's source is a decaying current in its core and it is not related to spin.
- The residual magnetism on the Moon and Mars, despite the lack of planetary magnetic fields.
The strengths for the magnetic fields of Uranus, Neptune, and the 4 large moons of Jupiter all fall within the range predicted by Dynamic Decay Theory. In fact, the magnetic fields of all planets and moons are less than the maximum predicted by Dynamic Decay Theory.
The Dynamic Decay Theory is the best model for the Earth's magnetic field and observed data places the age of Earth at 6,000 – 8,700 years.
- The Earth’s Magnetic Field is Still Losing Energy
- The earth's magnetic field: evidence that the earth is young
- The Creation of Planetary Magnetic Fields by D. Russell Humphreys. CRSQ Volume 21, Number 3 (December 1984)
- Earth's Magnetic Age: The Achilles Heel Of Evolution by Thomas G. Barnes. ICR Impact No. 122 August 1983
- The Earth’s Magnetic Field is Still Losing Energy by Russell Humphreys. CRSQ Vol 39 No 1 pp 1-11 June 2002
- The Mystery of Earth's Magnetic Field by Russell Humphreys, Ph.D. ICR Impact No. 188 February 1989
- Voyager II Supports Creation by Russell Humphreys, Ph.D. ICR Impact No. 203 May 1990
- Magnet Ostriction
- THE SOLAR SYSTEM — NEW DISCOVERIES PRODUCE NEW MYSTERIES
- The Young Earth
- Planetary Dynamo On The Desk
- Madison Dynamo Experiment
- Introduction to Plate Tectonics
- Magnetic Stripes revisited
- Problems with Plate Tectonics