The age-old debate over the Shroud of Turin is being resurrected this Easter — thanks to the attention of a new pope, the creation of a "Shroud 2.0" app, and a new book that claims the cloth dates back to Jesus' time.

The claim immediately faced a wave of criticism, including a harsh statement from Turin's archbishop that some say has driven a stake into the book's heart.

Believers say the centuries-old shroud bears the imprint of Jesus, chemically captured in the cloth at the time of his resurrection. Skeptics say it's a cleverly done medieval fake, wrapped up in highly debatable scientific claims that just won't die.

The newly published Italian-language book — "Il Mistero Della Sindone," or "The Mystery of the Shroud" — recycles some of those claims, adds in some fresh results from single-fiber tests, and makes the argument that the shroud shows the difficult-to-reproduce image of a man who lived sometime between 280 B.C. and the year 220.

If that's not enough to bring the shroud back into the spotlight, there's also the news that Pope Francis, who was named to lead the Roman Catholic Church just last month, will appear on Italian TV on Holy Saturday to introduce a RAI Uno TV appearance of the shroud. "It will be a message of intense spiritual scope, charged with positivity, which will help (people) never to lose hope," the Italian ANSA news agency quoted Turin Archbishop Cesare Nosiglia as saying.

And then there's Shroud 2.0, a free app for Apple's iPad/iPhone (and soon for Android) that lets users zoom in on high-definition images of the shroud and get factoids about its history. The app is being offered by Haltadefinizione, which took photos of the relic in 2008 and collaborated with church officials on the project. Shroud 2.0 is being offered as an "evangelization tool," according to the Vatican's News.va website.

Antonio Calanni / AP file

A photo from 2000 shows the Shroud of Turin displayed at Turin's cathedral.

Scientific links
The Catholic Church has taken no official stand on the authenticity of the shroud, which is kept under lock and key in Turin and is only rarely brought out for public display. But over the years, some researchers have tried to show that the shroud goes back to biblical times rather than to the 14th century.

"The Mystery of the Shroud" is the latest book of this genre. It was written by journalist Saverio Gaeta and Giulio Fanti, an engineering professor at the University of Padua. Fanti is part of a controversial research group that has claimed the image on the cloth couldn't possibly have been created by natural means. The new book refers to those past claims, plus a new angle.

That angle has to do with single fibers that were purportedly vacuumed up from the shroud during scientific testing. Fanti and his colleagues put the fibers through a series of mechanical and chemical tests. "Combining the two chemical methods with the mechanical one, it results [in] a mean date of 33 B.C., with an uncertainty of plus or minus 250 years at 95 percent confidence level, that is compatible with the period in which Jesus Christ lived in Palestine," the publishers say in a news release.

Skeptical views
Fanti's claims drew a quick reaction from Joe Nickell, a research fellow at the Committee for Skeptical Inquiry who regularly counters claims from Fanti and other shroud researchers.

"As is typical of a religious rather than scientific agenda, their news was shrewdly released just in time for Easter," Nickell said in a blog posting. "That alone casts doubt on the claims, but there is more."

Nickell pointed out that Fanti's tests "involve three different procedures — each with its own problems — which are then averaged together to produce the result." He said that stands in contrast with 1988's mass spectrometry tests, which yielded a date range between 1260 and 1390. Fanti says those earlier tests were not "statistically reliable," but Nickell and most scientists are sticking with the verdict rendered in 1988.

As a professional skeptic, Nickell can be expected to voice doubt about the book. But criticism also came from Archbishop Nosiglia.

Because there's "no degree of security" as to the authenticity of the fiber samples, the shroud's custodians "cannot recognize any serious value to the results of these alleged experiments," Nosiglia said in a statement quoted by La Stampa's Vatican Insider. The archbishop's comments "put stakes into Fanti's work," Vatican Insider reported.

Somehow I suspect that shroud science is not truly dead, but what do you think? Feel free to weigh in with your own verdict in the comment section below.

More about science and the shroud:

• Was resurrection story inspired by cloth?
• Experts re-create the face in the shroud
• Cosmic Log archive on Shroud of Turin

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

The controversial effort to find out whether a long-lost Leonardo da Vinci masterpiece lies beneath a fresco in Florence has been suspended without resolving a mystery that some have compared to a "Da Vinci Code" riddle.

The mystery surrounds a painting known as "The Battle of Anghiari," or "Fight for the Standard," which was commissioned by city officials for a meeting hall in the Palazzo Vecchio to commemorate a Florentine military victory in 1440. Contemporary accounts indicate that Leonardo began the wall painting in 1505 — but left it unfinished, due to problems he encountered with the experimental technique he was using to apply the paint.

Decades later, the city hall was enlarged and restructured, and in 1563 the Italian artist Giorgio Vasari painted a mural on one of the new walls. In the course of all that remodeling, Leonardo's painting disappeared. Today, it's known only from Leonardo's preparatory sketches and from copies inspired by the original.

Fast-forward to 1975: Maurizio Seracini, an Italian-born engineering professor and expert in art analysis at the University of California at San Diego, was back in his native Florence, studying Vasari's fresco. He noticed that a soldier in the fresco was waving a flag that read "Cerca Trova" (Seek and Ye Shall Find). Did this hint at the location of the lost Leonardo painting?

Over the years that followed, Seracini marshaled the expertise, technology and financial support needed to create a virtual reconstruction of the hall's layout before the remodeling took place. It looked as if there was a gap between the part of the wall where the "Cerca Trova" legend was painted and the older wall beneath. Armed with that information — plus funding from the National Geographic Society and backing from Florence's mayor, Matteo Renzi — Seracini won permission from Italian officials to drill six tiny holes into Vasari's wall and push camera-equipped endoscopic probes into the gap behind it.

The initial results were promising: Seracini said the team found "traces of pigments that appear to be those known to have been used exclusively by Leonardo." This March, National Geographic aired a documentary about the investigation, titled "Finding the Lost da Vinci." Heartened by the findings, Seracini asked for permission to conduct more sophisticated tests. The story was shaping up as a real-life "Da Vinci Code" thriller in the art world. (In fact, Seracini is mentioned in the Dan Brown novel as an art diagnostician who unveils "the unsettling truth" about a different work by Leonardo.)

Italian officials, however, were becoming increasingly unsettled about tampering with the 450-year-old Vasari mural. Some experts questioned whether there was really enough justification to go forward. "Vasari would never have covered a work by an artist he admired so much in the hope that one day someone would search and find it," Discovery News quoted Tomaso Montanari, an art historian at the University Federico II in Naples, as saying. "You would expect such a hypothesis from Dan Brown, certainly not from art historians."

In the end, cultural officials ruled that the scientists could drill one more hole for endoscopic tests, but couldn't do any further drilling after that. That meant the more sophisticated (and more intrusive) tests could not be conducted. Last month, Italian news outlets reported that the National Geographic Society was suspending the project "until further notice." 

Now Discovery News says that Florentine museum officials have given the go-ahead to fill in the six existing holes and take down the scaffolding that was used during the project. "This is how it ends," the Italian newspaper La Repubblica reported, "with strokes of stucco and paint, the search for Leonardo's mythical work."

More Leonardo da Vinci mysteries:

• Dig for Mona Lisa turns up a skeleton
• The anatomy that Leonardo couldn't copy
• Did Leonardo copy his famous 'Vitruvian Man'?
• Leonardo da Vinci ... fashion designer?
• Art experts hold mock 'Da Vinci trial

For more about the unsolved "Da Vinci Code" case, check out Rossella Lorenzi's report for Discovery News.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

A Roman trading ship from the time of the Caesars has been discovered off the coast of Italy, reportedly in such good condition that some of the food may still be preserved inside the storage jars.

Following up on a tip from local fishermen, police divers used a remotely operated vehicle to locate the ship, which was preserved within layers of mud at a depth of 230 feet (70 meters) in the waters near the port city of Genoa. The ship is thought to date back to sometime between the 1st century B.C. and the 2nd century — when Julius Caesar and his imperial heirs held sway in Rome.

Discovery News' Rossella Lorenzi reports that the ship sank on a trade route between Spain and central Italy with a cargo of more than 200 jars, known as amphorae. Some of the jars were caught in fishing nets, which led to the underwater search. Tests indicated that the jars contained pickled fish, grain, wine and oil.

"There are some broken jars around the wreck, but we believe that most of the amphorae inside the ship are still sealed and food-filled," Discovery News quotes Lt. Col. Francesco Schilardi of the police-diving unit as saying.

Police are guarding the site while archaeologists decide what to do with the wreck.

More about underwater archaeology:

Smuggled cargo found on Roman shipwreck

Wine-carrying ship goes back 2,300 years

Lost city of Atlantis believed found off Spain

Captain Morgan's lost fleet found?

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.