From: "Rich Gauszka" 

I wasn't aware of the 300 year 'barrier' either. I just got curious about
radioactive dating mechanisms after seeing your post. It also looks like
anything that dies after 1940 will be harder to date due to our nuclear era
( reactors, bomb tests )


"Mark"  wrote in message news:442415a7$1{at}w3....
> Hmm, interesting. I was just going by what the article said they'd be
> doing.
>
> "Rich Gauszka"  wrote in message
> news:4424105b$1{at}w3....
>>I don't think they would use carbon dating.
>>
>> http://www.bbc.co.uk/dna/h2g2/A637418
>> Radiocarbon dating is a reasonably reliable method for dating objects
>> between 300 and 30,000 years old. However it is not 100% accurate, and
>> there are many factors limiting its accuracy.
>>
>> http://www.howstuffworks.com/carbon-142.htm
>>
>> Because the half-life of carbon-14 is 5,700 years, it is only reliable
>> for dating objects up to about 60,000 years old. However, the principle
>> of carbon-14 dating applies to other isotopes as well. Potassium-40 is
>> another radioactive element naturally found in your body and has a
>> half-life of 1.3 billion years. Other useful radioisotopes for
>> radioactive dating include Uranium -235 (half-life = 704 million years),
>> Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14
>> billion years) and Rubidium-87 (half-life = 49 billion years).
>>
>>
>> "Mark"  wrote in message
news:442408b7$1{at}w3....
>>> It'll be interesting to see what the carbon dating confirms.
>>>
>>> "Adam"
<""4thwormcastfromthemolehill\"{at}the field.near the
bridge"> wrote
>>> in message news:4423c033{at}w3....
>>>> http://news.bbc.co.uk/1/hi/world/south_asia/4837988.stm
>>>>
>>>> Not far off being older than the USA....
>>>>
>>>> "A tortoise that once belonged to British colonial
general Clive of
>>>> India in the 18th Century has died in a zoo in Calcutta.
>>>>
>>>> Adwaita, "the only one" in Bengali, was found
dead by keepers in
>>>> Alipore
>>>> Zoo on Wednesday. His shell cracked some months ago and a wound had
>>>> developed.
>>>>
>>>> West Bengal officials said records showed Adwaita was at least 150
>>>> years
>>>> old but other evidence pointed to 250.
>>>>
>>>> The shell of Adwaita, an Aldabra tortoise, will now be carbon-dated.
>>>>
>>>> Forestry minister in the West Bengal government, Jogesh Barman said:
>>>> "Historical records show he was a pet of British
general Robert Clive
>>>> of
>>>> the East India Company and had spent several years in his sprawling
>>>> estate before he was brought to the zoo about 130 years
ago." "
>>>>
>>>>
>>>> Adam
>>>
>>>
>>
>>
>
>

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