Earth Magnetic Field Still Decaying
Old-earth belief tries to paper over a disturbing fact with speculative models, but 160 years of measurements show the strength of our planet’s magnetic field is dropping fast.
How do secular geophysicists deal with one of the longest-running measurements in the history of science? The strength of the magnetic field was first measured 183 years ago by Karl Friedrich Gauss in 1835. For the past 160 years or so, continuous measurements have been made. Early measurements show the field was 5% stronger than it is now. Continuous measurements plotted on a curve show an exponential drop in the overall strength of the field year by year. If this were to continue, it would put life at risk on the planet in mere thousands of years. Extrapolating backward, a stronger field would have made the earth uninhabitable a few tens of thousands of years ago.
The secular geophysicists have comeback arguments, of course. They postulate magnetic reversals based on field measurements showing the orientation of the north/south poles in rocks. While reversals probably occurred, as the data indicate, that does not necessarily solve the problem. A reversal does not increase the strength of the field without a mechanism to pump energy into the field.
A press release from the University of Rochester waltzes past these difficulties in its discussion about reversals that supposedly took place hundreds of thousands of Darwin Years ago. They postulate that a “South Atlantic Anomaly” may shed light on patterns of behavior in the field over long ages. John Tarduno of U of Rochester is excited about the opportunity to take a trip to Africa.
“We were looking for recurrent behavior of anomalies because we think that’s what is happening today and causing the South Atlantic Anomaly,” Tarduno says. “We found evidence that these anomalies have happened in the past, and this helps us contextualize the current changes in the magnetic field.”
Despite the data taken from “ancient clay remnants from southern Africa dating back to the early and late Iron Ages,” Tarduno’s team does not know how reversals occur or whether we are due for another one. No mechanism is proposed for how these occur, when they occur, or whether they form a pattern of field behavior. Most importantly, reversals do not provide a power source that could build the strength of the field back up and maintain it for long ages.
The press release was echoed by NASA’s Astrobiology Magazine, and Tarduno’s research was funded by the National Science Foundation. Perceptive readers should notice the clear admissions that the field strength is dropping:
- “We’ve known for quite some time that the magnetic field has been changing, but we didn’t really know if this was unusual for this region on a longer timescale, or whether it was normal,” one team member said.
- Nearly 800,000 years ago, the poles were switched: north pointed south and vice versa. The poles have never completely reversed since, but for the past 160 years, the strength of the magnetic field has been decreasing at an alarming rate.
- A weakening of the magnetic field might also mean more harmful radiation reaches Earth—and trigger an increase in the incidence of skin cancer.
- Even if a complete pole reversal is not in the near future, however, the weakening of the magnetic field strength is intriguing to scientists, Tarduno says. “The possibility of a continued decay in the strength of the magnetic field is a societal concern that merits continued study and monitoring.”
In his book Spacecraft Earth: A Guide for Passengers, Dr Henry Richter spends most of the time discussing evidences of design that challenge evolutionary theory. For one chapter, though, he engages readers with the mystery of the decay of earth’s magnetic field. Without being dogmatic, he asks whether the evidence suggests that the long-age view is wrong.
There are only three possibilities to generate a magnetic field, he writes: (1) a permanent magnet, (2) a dynamo generated by currents in the earth’s core and mantle, or (3) residual currents from the earth’s origin that are decaying away. The first possibility is ruled out because the core would exceed the temperature at which a permanent magnet could exist. The second possibility, a dynamo, requires input energy, or it will decay also, because there is no such thing as a perpetual motion machine. On earth, we can keep dynamos running with hydroelectric power, wind, fossil fuels or nuclear power, but none of those work in the earth’s core. Richter says:
This leaves the third explanation, that there are residual electric currents in the interior of the earth which are slowly decaying as they do anywhere in a laboratory or in our machinery. Let us surmise that perhaps these electric currents were created when the earth was formed. Electric currents die away because electrical resistance dissipates their power. On the other hand, currents tend to be maintained because of the phenomenon called inductance, which is an interaction between magnetism and electricity that tends to keep currents flowing if the current decreases.
We know that the rocks of the interior of the earth possess both resistance and inductance. If some simple calculations are made about the resistivity of the rocks of the earth’s mantle and outer core, and also of the inductance characteristic of such matter, we can calculate the expected decrease of the current. (p 142)
Richter shows that the calculated decrease matches the measurements of magnetic field over the past 160 years. This provides powerful support for the third source, because it is based on laboratory experience with electomagnets, and empirical data from the earth itself. A consequence of magnetic field decay is that the earth cannot be billions of years old. Richter explains what would happen if the empirically measured trend were extrapolated back in time:
What this inevitably leads to (and it certainly led me to), is the realization that our Spacecraft Earth is young. Instead of an earth that is 4.5 billion years old (an assumption never questioned by earth scientists and evolutionary biologists these days), it must be only thousands of years old. Why? If the earth were more than 12,000 to 15,000 years old, life could not exist. If we extrapolate backward in time the observed decay rate, huge magnetic fields would have existed at that time, and the earth would be physically unstable. Electric currents that powerful, flowing in the mantle to create these huge magnetic fields, would cause tremendous heating, to the point of melting the earth’s crust.
Can secular geophysicists rescue their long age beliefs, on which evolutionary theory depends? Tarduno’s paper in Geophysical Research Letters discusses anomalies, reversals and patterns, but provides no power source to sustain the field.
Earth’s dipole magnetic field is presently undergoing a rapid decay, best expressed by a deepening area of low field called the South Atlantic Anomaly (SAA). This apparent collapse of the geomagnetic field, and speculation about a future field reversal, has captured the public imagination. But we know little about the history of the SAA, limiting our ability to place current changes within a long-term context. Here we present a new magnetic record from sites of southern Africa. The new record supports our prior inferences that the SAA is just the most recent manifestation of a recurring phenomenon in the core beneath Africa—called flux expulsion—that is having a profound impact on the expression of the geomagnetic field.
Nothing in this statement, or in the rest of the paper, answers the question of how the decay of the field’s intensity can be reversed. A “flux expulsion” only affects a particular region of the field centered on southern Africa. Even then, the team’s field measurements can only account for behaviors back to the first millennium: i.e., the days of the Roman empire. What about those billions of years? Did they even exist?
Creationists have pointed to the decay of the earth’s magnetic field for decades as prima facie evidence that the earth is young. Evolutionists laugh it off because they just ‘know’ that the earth is old, because it has to be old for Darwin’s theory to work. This paper and press release show that models to keep it going are based on speculation, not the hard data going back 160 years. They realize that the field is decaying “at an alarming rate.” Science should follow the evidence where it leads, not depend on rescue devices to sustain a favored philosophy.
Richter prefers empirical data to speculation:
However, let me comment that science can only accurately examine what it can measure. No geophysicist has witnessed a reversal of the earth’s magnetic field. The variations, moreover, are independent of the field strength. Think of a flashlight spinning slowly as its batteries wear down; it’s that kind of thing. The magnetic energy is radiated out to space, where it cannot be used to regenerate the field.” (p. 137).
Richter’s book Spacecraft Earth is available from CMI, the publisher.