|MadSci Network: Evolution|
Jonathan: I found your question a little confusing, because the "subject" question suggests that you think there is some scientific evidence that the Earth is only 12,000 years old (there is not), yet the body of your question suggests that you do not hold this belief. I am going to answer by assuming that the question body was what you really meant to ask, and that the subject line was not. Carbon-14 radiometric dating is actually usable, with decreasing precision, to ages greater than 70,000 years. However, it is true that you cannot use radiocarbon dating to measure the age of things that are millions of years old. Fortunately, there are many radioactive isotopes, all of which have been shown by physicists to decay at constant rates, and some of these isotopes have half lives much longer than that of carbon 14. Radiometric dating of objects millions of years old depends on use of other isotopes, such as those of uranium and argon. Of course, radiometric dating is not the only scientific method of dating ancient objects. Many geological methods provide relative dates, and these can be combined with radiometric dates to absolutely date things that do not themselves provide radiometric dates. Some dates are more precise than others, and any date given for an ancient object must include the confidence interval. For instance, 13.5 million plus or minus 350,000 years means there is a high probability that the age is between 13,150,000 and 13,850,000 years. The confidence interval is usually either + or - one standard deviation (about 67%) or 90%, or 95%, and in scientific publications you are always told exactly what is meant. If you want to learn more about methods of dating other than radiometric dating, then I suggest you consult a textbook on physical geology, historical geology, or stratigraphy. Some of these should be understandable even if you don't have any geologic training. A good physical geology textbook is by Press and Siever, and the 1974 edition was called Earth (I think the latest edition has a slightly different name). The theory of evolution is a scientific theory, which means it has been rigorously tested by many people trying to show scientifically that it is not valid. No one has ever been able to provide any scientific evidence falsifying the theory of evolution, which is probably the most thoroughly supported scientific theory there is, except the theory of gravitation! The theory of evolution makes reliable predictions about changes in biological systems over time, which is what it is supposed to do. It has nothing to do with origins. Creation is a religious concept. It is not supposed to be tested scientifically. It is supposed to be accepted on faith (or not, as one's religion dictates). It has everything to do with origins. I consider religion a personal matter. However, I would be happy to further discuss the science of geology with you. If you want to learn more about the creation-evolution controversy, then I suggest you visit this web site: http://www.natcenscied.org/ It is the home page of the National Center for Science Education. They particularly concern themselves with the nature of science, the nature of religion, and the relationship between the two. I hope I have helped you with your questions. David Kopaska-Merkel Geological Survey of Alabama PO Box 869999 Tuscaloosa AL 35486-6999 (205) 349-2852 FAX (205) 349-2861 web site www.gsa.state.al.us
Try the links in the MadSci Library for more information on Evolution.