Re: Was the hebrew bible written by Romans?

On May 18, 1:38 pm, Dragonblaze <dragonbl...@xxxxxxxxxxxx> wrote:
On May 18, 12:12 am, Inabón Yunes <bori...@xxxxxxxxxxx> wrote:
(snip)
I have no problem accepting the date of the Pyramids, or the "Book of the Dead" in Egypt.  But, can we be certain of  the date of something that we are not certain if it is an original?

We can be sure for the abovementioned reasons.
(snip)

I don't know enough about this specific case, but certain materials
(limestone and any ceramic) can be dated with limited contextual
information under specific circumstances. The date might not tell you
a whole lot, but you can obtain it.

In the case of limestone, the techniques are AMS and neutron
activation. These allow you to determine isotope ratios. Certain
nuclei will absorb cosmic rays and alter isotope, but only to a
limited depth. By determining the ratio of the isotopes in the
material vs. the ratio of the isotopes in naturally-occurring deposits
from the same layer of rock, you can determine the level of exposure.
The reference source will have had essentially no exposure, so will
always give you the baseline. This ONLY works on limestone that is
near or at the surface, however. It cannot be used to date material
that is buried to any significant depth. (Trying will simply tell you
the length of time the limestone was exposed to the surface before
being buried, but it won't tell you when that was.) This is extremely
hard to manipulate, as it's rather hard to generate very high energy
particles on the cheap, so when it works, it's considered very
reliable.

(You can date a sufficiently-deep inscription in a limestone block by
this method. The limestone exposed by the act of carving into the rock
will only have been exposed to cosmic rays since the time the
inscription was carved, whereas the remainder of the surface will show
a geological age. Provided both parts of the surface are dated, it is
essentially impossible for a forger to have either carved the
inscription or exploited erosion to look like a fragmented
inscription.)

Ceramics are slightly easier but, for the same reason, slightly less
safe. Any ceramic, on being heated, will alter in structure to the
lowest energy state. From the time of cooling down until next heated,
it will absorb background radiation. By re-heating the ceramic, this
energy is released as heat/light, which can be measured. The date from
last heating is then proportional to the energy released from the
ceramic. Usually. If the ceramic has been exposed to a suitable
radiosource, a sufficiently sophisticated forger may be able to
manipulate the results. However, the forger would need to be careful
as the source would have to be every bit as even as natural background
(or it'd be obvious) and the forgery can't alter the isotope ratios or
leave the object radioactive. The chances are that the isotopes would
be measured, simply to determine point of origin, and that will expose
the sort of back-alley forgeries that take place. Because it measures
total exposure to easily-obtained radioactive sources, though, a good-
enough forger could potentially massage the date. As such, it's not
quite as safe as dating via cosmic rays.

These techniques cannot be used in all cases, as is obvious from the
way they work. However, they do illustrate an important concept, which
is that you can get away with having limited information on an object
when dating it, provided the circumstances match up with one of the
dating methods that is not purely circumstantial. This is particularly
important in archaeology as carbon-14 dating is only accurate over a
relatively narrow period of time in comparison to either of the
methods outlined above - mere thousands of years, in comparison to
tens or hundreds of thousands. C14 also only tells you when the
organic matter died, it doesn't tell you when it was used. So if you
had peat being used as a building material, dating the peat by C14
will be a useless exercise.

It is important to note that C14 dating is also dating by measuring
isotope ratios - C12 to C14, in this case. However, because these are
extremely close isotopes, you need to make very sensitive measurements
to get useful results. And, in consequence, you also have to have a
very clean environment. Any contamination can throw the results off.
Typically, C14 dating will be done by taking multiple samples and
having different labs perform the dating. On the assumption that most
labs will get things right most of the time, it is assumed that valid
results will cluster around the correct date and invalid results will
be wildly different and not cluster to anything. This only works, of
course, if the collection process was valid. If the material was
collected inappropriately, the results will cluster around the age of
the contaminating material and not the age of the material being
tested. It is assumed, in C14 dating, that you've some good idea of
what the date should be, to provide some sort of a sanity check for
these kinds of situation.

In general, C14 dates should be regarded less as absolute dates and
more as evidence of a connection to something else that can be dated
by some other method. There are situations where there are no other
dates, however. In that case, you're stuck with C14. Under those
circumstances, you would obviously want to be extra-rigorous and
perform many more tests that you would normally. (A typical C14 date
will have been obtained by performing 3 tests by independent labs. If
you've no means of sanity-checking the results, you'd probably opt for
5 or more.)
.

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