I can't answer all the questions that you've raised w.r.t the Turin Shroud.
Like you, I wonder about the somewhat tenuous argument in your first
question. Neither have I ever heard of the Sudarium of Oviedo; a pity,
because I visited the University of Oviedo some years back.
I agree with Joel that this whole Turin Shroud issue is a prime example of a
bias hat can, and often does, creep into scientific investigations. The
clamor surrounding the Shroud may well a good topic to be used in classroom
discussions on science and religion. You may remember that the Vatican
fought tooth and nail to prevent the age dating of the Shroud ("what if it
isn't as old as we think it is"). Scientists of the skeptical bent were
enthused when an apparent age of ~900 years (give or take a bit) was found
("we told you it was a fraud").
I question the following statement on the web page that Joel referred to,
"As the image was formed by some sort of radiation phenomena [sic], the
radiation waves could have thrown off any attempt to date the Shroud by
using radiocarbon dating." An earlier date could be caused by additional
C-14 in the Shroud, and it's difficult to pick a nuclear reaction that would
create C-14, considering the absence of information on the "radiation
phenomena [sic]." It would be interesting to see if this same radiation
would have created any appreciable amounts of other isotopes, radioactive or
stable.
One has to wonder how much we will be able to learn from this piece of
cloth, considering that its history is shrouded (no pun intended), how much
contamination is has picked up over the years, and what any information can
be provided. To those who believe, by faith, in the Resurrection, no proof
is needed.
Chuck Vandergraaf
Pinawa, MB