[Starbreed]

Wow! what are these other ways. Don't leave us in suspense. Or else we'll think you're spoofing.

General statements as rebuttal don't wash. Gotta have numbers from the scientists. The circular reasoning in question at least had terms I could identify with. Just give a few external indicators and the name of that radioisotope they help calibrate for accuracy...

[Aracelis]

Need someone to do your homework for you? I won't do that but I will give you the following radioisotopic half-lives and their daughter products which are useful in radiometric dating:

• Samarium 147 to Neodynmium 143 - >100,000,000 years
• Rubidium 87 to Strontium 87 - >100,000,000 years
• Thorium 232 to Lead 208 - >200,000,000 years
• Uranium 238 to Lead 206 - >100,000,000 years
• Uranium 235 to Lead 207 - >100,000,000 years
• Potassium 40 to Argon 40 - >100,000 years
• Carbon 14 to Nitrogen 14 - 0 to 80,000 years.

In addition, researchers may use fission track dating, relative time scales, dendrochronology, thermoluminescence, electron-spin resonance, and varve analyses to support and confirm radiometric dating.

Any of these terms may be found on the web.

[general_re]

Piltdown_woman has listed the some of the multiple was in which artifacts are dated - generally speaking, they all tend to agree on the dating of artifacts, despite the variety of isotopes measured. In addition, verification of dating for events near us in time allows calibration for earlier events - dating can be confirmed by historical records of known events, tree-ring data for events within a certain range, et cetera.

What should we presume, if we calibrate radioisotope measurements by dating items of a known age, and then find that a half-dozen different measurements all generally agree on the age of some ancient artifact? What would lead you to believe that we shoulf presume those measurements are in error?