Naturalistic science will usually retort that examination of present materials and processes enables us to extrapolate backwards so as to determine what must have occurred. But here again, forsaking his own basic methods, the scientist is speculating (not observing) on the course of historical development; he assumes (but cannot show experimentally) that not only is nature uniform now but always has been, that processes seen today have always worked as they do now.
Yet, the same site has several articles and videos that measure the current rate of decay in the earth's magnetic field and extapolate it backwards to what it would have been 6,000 years ago.
We have been able to measure the strength of the magnetic field for over a century, and not surprisingly, the earth’s magnetic field is indeed decaying. Every century, the magnetic field decays by about 5 percent. Since the earth’s magnetic field gets weaker as time moves forward, it must have been considerably stronger in the past. Approximately 6,000 years ago, the magnetic field would have been quite a lot stronger, but still perfectly suitable for life.
However, if the earth were many millions of years old, then the geomagnetic field would have been so strong in that alleged distant past, that life would not have been possible.
Answers in Genesis is a self-conflicting website, yet everything is presented, literally, as God-given truth. Go figure.
They also promote the RATE Project which published radiometric dating results ranging from a few thousand to 500 million years. Guess which results aren’t mentioned in their general articles.
If you dig into the complete published document, the old dates are explained away by assuming a short period of miraculously rapid radioactive decay. In other words, modify physical constants as needed to fit the predetermined age.
I can live with people who believe in miracles, but I have problems with people who claim to be scientific until it is inconvenient.