Hammer found in Cretaceous rock (75 to 100 million years old), page 2
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reply posted on 14-10-2004 @ 01:42 PM by Off_The_Street
Browha says:

“Carbon dating hasneverclaimed to give an accurate date... it works out roughly how many half-lives have passed, room for error increases crazily every half life that passes. radioactive decay is not that predictable.”

That is incorrect. Radioactive decay is very predictable.

Carbon-14 (C14) dating is considered accurate to within about five percent of the actual date, as cross-checked by other dating methods, including dendrochronology and historical written records.

The C14 atoms that cosmic rays create combine with oxygen to form carbon dioxide, which plants absorb naturally and incorporate into plant fibers by photosynthesis. Animals and people eat plants and take in C14 as well. The ratio of normal carbon (carbon-12) to C14 in the air and in all living things at any given time is nearly constant, about 1 C14 to a trillion C12 The C14 atoms are always decaying, but they are being replaced by new C14 atoms at a constant rate. At this moment, your body has a certain percentage of C14 atoms in it, and all living plants and animals have the same percentage.

As soon as a living organism dies, it stops taking in new carbon. The ratio of C12 to C14 at the moment of death is the same as every other living thing, but the C14 decays and is not replaced. The C14 decays with its half-life of 5,700 years, while the amount of C12 remains constant in the sample. By looking at the ratio of C12 to C14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of a formerly living thing fairly precisely.

Because the half-life of C14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old; by this time the residual C14 level has dropped to about 0.0018 of its original level -- which was, remember, only one in a trillion atoms of C12 to begin with! So the problem is that our best equipment simply can't measure deltas that small; nonetheless, the half-life process is remarkably consistent.


reply posted on 14-10-2004 @ 02:17 PM by Nygdan
Originally posted by DrHoracid
The hammer is real. Been there seen it.

No one disputes if the thing exists
C14 dating is not reliable.

Yes, it certainly is. Its given 'wrong' dates when used completely inappropriately. Radio-carbon dating is extremely reliable.

Fact, testing in 1000 year old living pine in CA showed to be 25,000 years old.

See.
C14 dating does not account for variations in the surrounding environment. Fire, etc, etc.

'etc etc' eh? Waving one's hands in the air doesn't make radiometric dating disapear.

Mans current "tech" is not yet up to Pre-flood times.

Since there was no flood, this is kind of a silly statement.

Also the atmosphere has changed since the flood. Castings made in an experiment at 2.5 current atmospheres and increased O2 levels produced similar "steel" composition.

Why would one think thats a valid method to determine the prehistoric atmosphere?

Is baugh thought radiometric dating was innaccurate, then why'd he agree to do it? (Well, I have a good idea as to what the answer to that is.)

mrmonsoon
Think about all the changes in the earth that would occur over 100 million years. Ours is a planet in constant change.

But there -are- things left over from 100 mya. There are even some rather delicately preserved fossils. At the least there should be radioactive piles, or lumps of weird isotopes, or heck, fossilized cemetaries.

browha
radioactive decay is not that predictable.

Yes it is, its one of the more predictable things in the universe.


reply posted on 14-10-2004 @ 03:53 PM by DrHoracid
No I was not refering to dating rock. Two different subjects.

Read this :
This note touches on a few questions about radiocarbon dating, especially regarding its reliability, and how we can know whether, and by how much, the dating may vary. Knowing where C14 comes from is a good start.

C-14 is produced in the atmosphere primarily by thermal neutron interaction with ordinary nitrogen-14 [specifically: N14 + n -> C14 + p]. The rate of *natural* C-14 production can be increased either by an increase in cosmic radiation (leading to increased neutron production), such as happens with a solar flare and the cycle from sunspot-minimum to sunspot maximum; or by an increase in atmospheric nitrogen.

Increased cosmic radiation should result in increased amounts of *other* cosmogenic radionuclides such as beryllium-10 (half-life 2,700,000 years) and chlorine-36 (half-life 380,000 y). The impact of increasing atmospheric nitrogen I leave to the reader's imagination.

"Based on track etch studies of meteorites, the cosmic ray fluence rate has remained more or less constant for at least 2000 years. Studies based on terrestrial cosmic ray induced and meteoritic radionuclides suggest that the fluence rate had not changed by more than a factor of 2 over the past 10^9 years (UNSCEAR 1977). Maximum levels occurred 700,000 years ago as a result of magnetic field reversals, but only represented a 10 percent increase in fluence rate."

I referred to natural C14 production above. "Unnatural" C-14 levels rose dramatically in the decades after Hiroshima, thanks to testing fallout; the peak was 70% greater than that from natural sources, and occurred in 1965. The ratio has been falling off ever since.[2]

The burning of fossil fuels has been *reducing* the C14/C12 ratio for as long as we've been burning them in quantity, releasing into the atmosphere "old" carbon, C12 -- the C14 having largely decayed away.

Incidentally, "[E]quilibrium is reached between [human] tissue and atmospheric CO2 after about 1.4 year,"[3] so if Eldridge's curious source is right and C14 is increasing "28-37% over its decay rate", we should be seeing that same increase in human tissue -- with its attendant dose concerns. Ordinarily you can expect that you receive about one mrad per year from cosmogenic (non-fallout) C14 [4].

"In addition, comparison of radiocarbon dates with tree ring values has shown some fluctuation in the C14 concentration in the atmosphere between 1400 and 1700 BC. Comparison of radiocarbon determined ages with ages of archeological materials accurately established by other methods have revealed that for the period from 100 BC to 1400, radio- carbon dating gives values that are too large; prior to 100 BC the radiocarbon values are too small. At about 1600 BC, the radiocarbon values are about 175 years (5%) too small, increasing to about 300 years (6%) at 3000 BC. The discrepancy appears to be a result of slight variations in the earth's magnetic field over the years, which would alter the cosmic ray intensities and hence C14 production near the earth. Suitable corrections are available, however, and the useful range of radiocarbon dating is at least 1000 to 100,000 years; in the range of 1000 to 50,000 years, the time frame of great archeological significance, the uncertainty in the method is less than 5 per cent (Aitken 1974, Baxter and Walton 1971)." [5]

[1] Kathren, Ronald L., _Radioactivity in the Environment: Sources, Distribution, and Surveillance_, 1984, p. 23.
[2] Ibid., pp. 111-112.
[3] Ibid., p. 112.
[4] Ibid., p. 36.
[5] Ibid., pp. 366-367.




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