[_ Old Earth _] The age of earth

[TING]

http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html

It may seem surprising that bacteria can leave fossils at all. However, one particular group of bacteria, the cyanobacteria or "blue-green algae," have left a fossil record that extends far back into the Precambrian - the oldest cyanobacteria-like fossils known are nearly 3.5 billion years old, among the oldest fossils currently known.

 

[cubedbee]

That's just the age of the oldest fossil. The Earth is a billion years older than that.

 

[NRoof]

That's just the age of the oldest fossil. The Earth is a billion years older than that.

Check these out:

http://www.answersingenesis.org/docs2002/carbon_dating.asp

Here are some non-Christian sites

http://www.ndt-ed.org/EducationResources/CommunityCollege/Radiography/Physics/carbondating.htm

http://www.mnsu.edu/emuseum/archaeology/dating/radio_carbon.html

Radio-carbon dating is a method of obtaining age estimates on organic materials. It has been used to date samples as old as 50,000 years.
...
After about 50,000 years, the amount of C14 remaining will be so small that the fossil can't be dated reliably.

 

[cubedbee]

Fossils are not organic, and are not carbon dated. However, there are multiple other radiometric methods, similar to carbon dating, which have the power to date over billions of years.

http://www.talkorigins.org/faqs/faq-age-of-earth.html

 

[NRoof]

Fossils are not organic, and are not carbon dated. However, there are multiple other radiometric methods, similar to carbon dating, which have the power to date over billions of years.

http://www.talkorigins.org/faqs/faq-age-of-earth.html

I understand that. It is actually addressed in the first link I posted.

Here is the problem in a nut shell.

Lets say I make a compound that contains 50% Uranium 238 and 50% Lead. If I make the assumption that the lead content came from the Uranium then Radiometric Dating would put the sample at 704 billion years old (half life of Uranium 238) even though I just made it. The problem is in the original assumption that the Lead came from the Uranium which in this case we know is wrong.

Hence the real problem with any form of radiometric dating is we don't know what the original makeup of the sample is.

 

[cubedbee]

Not all radiometric dating requires an assumption on the initial amount of the element present. Here's an article on isochronic dating. http://www.talkorigins.org/faqs/isochron-dating.html#q2

Basic concept is simple. Atoms contain both neutrons and protons. What element something is depends on number of protons. For every element, however, there are multiple forms that contain different numbers of neutrons--isotopes. Different isotopes behave identically in chemical processes, but we can measure the differences.

Now, in your example of Uranium and lead, we know that UR decays to PB---but to a specific isotope PB206. PB206 is the primary isotope of lead found in nature---but there is also PB204. So, once that rock is formed, the amount of PB204 is fixed, but the amount of PB206 can increase (as the amount of UR decreases), and my examining the ratios across several samples, the age can be determined.