Given the fact that, according to the Bible, Adam was created on the sixth day of our planet’s existence, we can determine a biblically-based, approximate age for the earth by looking at the chorological details of the human race. This assumes that the Genesis account is accurate, that the six days of creation were literal 24 hour periods, and that there were no ambiguous gaps in the chronology of Genesis.
The genealogies listed in Genesis chapters 5 and 11 provide the age at which Adam and his descendants each fathered the next generation in a successive ancestral line from Adam and Abraham. By determining where Abraham firs into history chronologically and adding up the ages provided in Genesis 5 and 11, it becomes apparent that the bible teaches the earth to be about 6000 years old, give or take a few hundred years.
What about the billions of years accepted by most scientists today and taught in the vast majority of our academic institutions? This age is primarily derived from two dating techniques: radiometric dating and the geologic timescale. Scientists who advocate the younger age of about 6000 years insist that radiometric dating is flawed assumptions, while the geologic timescale is flawed in that it is founded upon a series of faulty assumptions, while the geologic timescale is flawed in that it employs circular reasoning. Moreover, they point to the debunking of old earth myths, like the popular misconception that it takes long periods of time for stratification, fossilation and the formation of diamonds, coal, oil, stalagmites, etc, to occur. Finally, young earth advocates present positive evidences which they debunk. Young-earth scientists acknowledge that they are in the minority today but insist that their ranks will swell over time as more and more scientists reexamine the evidence and take a closer look at the currently accepted old-earth paradigm.
Ultimately the age of the earth cannot be proven. Whether 6000 years or billions of years, both viewpoints rest on faith and assumptions. Those who hold billions of years trust that methods such as radiometric dating are reliable and that nothing has occurred in history that may disrupt the normal decay of radio-isotopes. Those who hold 6000 years trust that the bible is true and that other facts explain the apparent age of the earth, such as the global flood, or God’s creating the universe in a state that appears to give it a very long age. As an example, God created Adam and Eve as fully-grown adult human beings. If a doctor had examined Adam and Eve on the day of their creation, the doctor would have estimated their age at 20 years when, in fact, Adam and Eve were less than one day old. Whatever the case, there is always good reason to trust the Word of God over the words of atheistic scientist with and evolutionary agenda.