The Earth is > 10,000 Years Old

Rebuttal of Pro's Case Pro's case rests entirely on the validity of the assumptions behind the process of formulating an age for a given rock using radioisotope dating. The three main assumptions which I will be addressing, in the context of U-Pb dating, are: initial isotope ratios, lack of contamination, and constant decay rate. As previously stated, I have no reason to doubt the reliability of current measured isotope ratios and decay rates, nor the math involved in the calculations. Rather, I will simply show why any age produced by such means is totally unreliable. Assumption #1 - Initial Isotope Ratios This first assumption is entirely unknowable, to state the obvious. If one is no present to record data, one is left with pure speculation. Clearly it is impossible to know for sure what the initial ratio of isotopes were in any given rock sample. If a particular sample had any amount of Pb at its conception, assuming a zero amount for the sample would grossly inflate the age. No geologists were present when most rocks formed, so they cannot test whether the original rocks already contained daughter isotopes alongside their parent radioisotopes. My opponent addresses this issue with the usage of zircon crystals which indeed seem to control for the problem of initial ratios. Regardless, this assumption remains model-dependent. Assumption #2 - Lack of Contamination As with the first assumption, assuming no contamination is speculative at best. Both assumptions are model-dependent in that they require a model such as the accretion model of the Earth's formation from molten rock. If the biblical account be true, then even zircon crystals could have been formed with Pb already in them; and the Flood could have provided a medium for plenty of isotopic exchange between rocks. Since not much more can be said about these assumptions other than that they are ultimately unknowable, allow me to focus most of my addressal to the following assumption. Assumption #3 - Constant Decay Rate Indeed, decay rate constancy seems to be the most impervious to dissent. Yet, utilizing certain methods of dating other than radioisotopes, such as that of planetary magnetic field decay, have revealed that the Earth could not be much older than 6,000 years. Thus, it is clear that decay rates are likely to have drastically varied in the past. One clear example is the presence of detectable amounts of helium in zircon crystals which have been dated to be 1.5 billion years old. It was found that, "up to 58% of the helium that the nuclear decay would produce was still in the zircons. This was surprising because helium diffuses (leaks) rapidly out of most minerals" (. http://creation.com...). The presence of helium in these zircons is linked directly to U-Pb decay as it is a byproduct of the decay process. For the helium to be present in these zircons, radiodecay would have had to be over 100,000 times faster in the past. Defense of Planetary Magnetic Field Decay Pro argues that either a linear decay or exponential decay curve can be fir to the data. Well what determines the case is the actual mechanism by which the Earth's field is created. Humphrey's model provides a framework in which we can understand the magnetohydrodynamics of the Earth's core and its motions which effect the magnetic field. When Humphrey's model is applied, an exponential decay makes sense. But regardless of his model, the data itself is consistent with an exponential decay curve. ". . . both exponential and linear decay curves have two fitted parameters: Exponential decay (i = Ie-t/τ) requires the parameters I and τ. Linear decay of the general form y = mx + c requires the gradient m and y-intercept c. If the fit were similar, there is no statistical reason to choose one over the other. The fit is very similar for the limited range of data available, with no significant difference between the two. However, it is a well-accepted procedure in modelling of regression analysis to use meaningful equations to describe physical phenomena, where there is a sound theoretical basis for doing so. This is the case here. Currents in resistance/inductance circuits always decay exponentially, not linearly, after the power source is switched off. For example, in a simple electric circuit at time t with initial current I, resistance R and inductance L, the current is given by i = Ie-t/τ, where τ is the time constant L/R—the time for the current to decay to 1/e (~37%) of its initial value. For a sphere of radius a, conductivity σ and permeability μ,τ is given by μσR²/π². A linear decay might look good on paper, but it’s physically absurd when dealing with the real world of electric circuits. In fact, linear decays are rare in nature in general. Conversely, exponential decay is firmly rooted in electromagnetic theory" (. http://creation.com...). Also in consideration of whether or not Humphrey's model should be accepted on an evidential basis: "Dr Humphreys also proposed a test for his model: magnetic reversals should be found in rocks known to have cooled in days or weeks. For example, in a thin lava flow, the outside would cool first, and record earth’s magnetic field in one direction; the inside would cool later, and record the field in another direction. Three years after this prediction, leading researchers Robert Coe and Michel Prévot found a thin lava layer that must have cooled within 15 days, and had 90° of reversal recorded continuously in it. And it was no fluke—eight years later, they reported an even faster reversal. This was staggering news to them and the rest of the evolutionary community, but strong support for Humphreys’ model. . . in 1984, Dr Humphreys made some predictions of the field strengths of Uranus and Neptune, two giant gas planets beyond Saturn. His predictions were about 100,000 times the evolutionary dynamo predictions. The two rival models were inadvertently put to the test when the Voyager 2 spacecraft flew past these planets in 1986 and 1989. The fields for Uranus and Neptune were just as Humphrey's had predicted. " Conclusion I have provided evidence for my claims and have shown why radioisotope dating is untrustworthy and indeed in discordance with other more reliable dating methods such as planetary field decay. Thank you for your time.