5 ms·

Methodology question: why is there no mention of radiocarbon dating? It's one of our most reliable methods, it works on bones, and it doesn't have the same feel

Methodology question: why is there no mention of radiocarbon dating? It's one of our most reliable methods, it works on bones, and it doesn't have the same feel as "they used this other random technique and magically got 300,000 years old so lets go with that".

tqkxzugoaupvwqr 9y ago
As far as I know, the radiocarbon method is only reliable up to 50,000 years ago. Past that you need other dating methods.
- genieyclo 9y ago
  Why?
  - hasbroslasher 9y ago
    Presumably because the amount of Carbon-14 in the sample passes below the error in the measurement equipment
  - exacube 9y ago
    from googling: http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/cardat.html http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/cardat.ht... "The low activity of the carbon-14 limits age determinations to the order of 50,000 years by counting techniques."
  - simonebrunozzi 9y ago
    Physics.
  - yongjik 9y ago
    Carbon 14 has a half-life of 5,730 years. After 57,300 years, only 1/1024 of the original carbon 14 will remain. After 300,000 years, about 1.73 * 10^-16 of the original carbon will remain, which is obviously too little.
    - jessriedel 9y ago
      > which is obviously too little To fill in the detail: Carbon-14 has an abundance of about 1 part in 10^12, and one gram of carbon contain about 10^23 carbon atoms, so about 10^11 C-14 atoms. Every single C-14 atom will have decayed in about 200k years.
    - rurban 9y ago
      Carbon-14 decay is only usable up to max 70.000 years. But there exist many other long-lived isotopes to measure. The uranium-thorium method, the potassium-argon method, and the rubidium-strontium method. Samples containing radioactive beryllium could be dated as far back as 10–30 million years. A newer method of radioactive tracing involves the use of a new clock, based on the radioactive decay of 235 uranium to 231 protactinium. We'd really like to know why the known accurate methods didn't work in this case, and why they had to fall back to indirect measurements of the flint stones.

tqkxzugoaupvwqr 9y ago

As far as I know, the radiocarbon method is only reliable up to 50,000 years ago. Past that you need other dating methods.

genieyclo 9y ago
Why?
- hasbroslasher 9y ago
  Presumably because the amount of Carbon-14 in the sample passes below the error in the measurement equipment
- exacube 9y ago
  from googling: http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/cardat.html http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/cardat.ht... "The low activity of the carbon-14 limits age determinations to the order of 50,000 years by counting techniques."
- simonebrunozzi 9y ago
  Physics.
- yongjik 9y ago
  Carbon 14 has a half-life of 5,730 years. After 57,300 years, only 1/1024 of the original carbon 14 will remain. After 300,000 years, about 1.73 * 10^-16 of the original carbon will remain, which is obviously too little.
  - jessriedel 9y ago
    > which is obviously too little To fill in the detail: Carbon-14 has an abundance of about 1 part in 10^12, and one gram of carbon contain about 10^23 carbon atoms, so about 10^11 C-14 atoms. Every single C-14 atom will have decayed in about 200k years.
  - rurban 9y ago
    Carbon-14 decay is only usable up to max 70.000 years. But there exist many other long-lived isotopes to measure. The uranium-thorium method, the potassium-argon method, and the rubidium-strontium method. Samples containing radioactive beryllium could be dated as far back as 10–30 million years. A newer method of radioactive tracing involves the use of a new clock, based on the radioactive decay of 235 uranium to 231 protactinium. We'd really like to know why the known accurate methods didn't work in this case, and why they had to fall back to indirect measurements of the flint stones.