It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
a reply to: bloodymarvelous
However we know exactly how this cut was made. It was an experiment by some researchers attempting to use a copper tube drill and sand abrasive. If these marks are similar, and don't indicate the tool's feed rate, then probably the ones in the other situations also don't indicate the tool's feed rate. (But if you can see clear differences, then a high feed rate is still on the table.)
originally posted by: bloodymarvelous
originally posted by: bluesfreak
My apologies for using the ‘D’ word on here ( Dunn) but unfortunately he is talking my language in engineering terms:
Below is a piece of stone from Abu Rawash, that clearly shows a large circular saw did the cutting.
The stone does not lie here. Dunn also shows the correct method for determining the size of the circular blade used by using an equation that gives you the diameter by using 2 points on the circular striations made by the tool. I myself have used this calculation on numerous occasions in the workshop to determine radius. What Dunn shows is correct.
The stone also shows the feed rate of the tool in relation to modern day measurements in mm.
This tool sliced into the stone at just under 1mm per revolution of the (large) circular saw blade.
I see these striations everyday working on a milling machine where rotating circular cutters are passed over various materials, the tool will leave its signature .
I can’t read hieroglyphs , but I can read these, it’s part of my job, and whatever you opinions on Dunn and the ‘fringe’ his method here is correct.
a reply to: Harte
If you look at this picture posted earlier by Harte, there also look to be marks that would seem to indicate a feed rate.
However we know exactly how this cut was made. It was an experiment by some researchers attempting to use a copper tube drill and sand abrasive. If these marks are similar, and don't indicate the tool's feed rate, then probably the ones in the other situations also don't indicate the tool's feed rate. (But if you can see clear differences, then a high feed rate is still on the table.)
originally posted by: bloodymarvelous
originally posted by: peter vlar
originally posted by: UniFinity
do you have any source about the validity of carbon dating. If I google it than it is evident that it is not valid for older dates, as I said in my previous posts already.
Valid for which older dates? Nobody has ever claimed that 14C testing is useful beyond 50-60KA and I know a lot of people who aren't comfortable using ascribed dates of more than 45-50KA. But it's pretty irrelevant in this particular thread as we're talking about a structure that is younger than the half life of 14C making the margin of error so negligible that a date to within a couple of decades +/- is easily accomplished. One of the best methods of calibrating your reading is by comparing dendrochronology. If I take a core sample from a 6000 year old tree for example, I'm going to give a sample of that core to someone else to run 14C and mass spectrometry, before I count my tree rings. Then we compare our results. The results always line up unless there is contamination. As I pointed out earlier, no one dating method is ever accepted. There is always cross referencing with other dating methods and there is always a known margin of error included with any date.
The fact a date is younger than the half life of C14 doesn't matter to that question.
The abundance of C14 is all that is being measured. If the object started out with less C14, then it would appear to have aged quite a bit even mere seconds after the creature/plant had died.
originally posted by: bloodymarvelousAll that matters is if there is good reason for us to believe the field was stronger by enough of a magnitude to affect the C14 content dramatically. I'm reluctant to believe the field has suffered a rapid decline. How can it have been present for over 300 million years, protecting the formation of life, and then in just 10,000 or 20,000 years time it decides to just up and blink out?
It doesn't strike me as probable.
originally posted by: Harte
originally posted by: bloodymarvelous
originally posted by: peter vlar
originally posted by: UniFinity
do you have any source about the validity of carbon dating. If I google it than it is evident that it is not valid for older dates, as I said in my previous posts already.
Valid for which older dates? Nobody has ever claimed that 14C testing is useful beyond 50-60KA and I know a lot of people who aren't comfortable using ascribed dates of more than 45-50KA. But it's pretty irrelevant in this particular thread as we're talking about a structure that is younger than the half life of 14C making the margin of error so negligible that a date to within a couple of decades +/- is easily accomplished. One of the best methods of calibrating your reading is by comparing dendrochronology. If I take a core sample from a 6000 year old tree for example, I'm going to give a sample of that core to someone else to run 14C and mass spectrometry, before I count my tree rings. Then we compare our results. The results always line up unless there is contamination. As I pointed out earlier, no one dating method is ever accepted. There is always cross referencing with other dating methods and there is always a known margin of error included with any date.
The fact a date is younger than the half life of C14 doesn't matter to that question.
The abundance of C14 is all that is being measured. If the object started out with less C14, then it would appear to have aged quite a bit even mere seconds after the creature/plant had died.
Not exactly the case.
What is measured is the ratio of C14 to C12. As was stated, that ratio is known for various eras from dendrochronology and other methods. This is how C14 dating is calibrated.
originally posted by: bloodymarvelousAll that matters is if there is good reason for us to believe the field was stronger by enough of a magnitude to affect the C14 content dramatically. I'm reluctant to believe the field has suffered a rapid decline. How can it have been present for over 300 million years, protecting the formation of life, and then in just 10,000 or 20,000 years time it decides to just up and blink out?
It doesn't strike me as probable.
What field is this? I must have missed it - or forgot about it.
Harte
originally posted by: Hanslune
a reply to: Harte
It would take generations of steady practice to relearn and become competent at such tasks - even if we knew exactly how they did it - which we don't.