HBO

A freshly hatched dragon perches on the shoulder of Daenerys in "Game of Thrones."

This the Year of the Dragon, and not just because of the Chinese calendar: Dragons play big roles in HBO's "Game of Thrones" TV series as well as the upcoming film version of "The Hobbit." Those fire-breathing, leathery-winged reptiles have been gripping the human imagination with their sharp talons for millennia, and it's worth wondering why.

Some folklorists trace the dragon myth back to a variety of sources in ancient China, Rome, Greece and India, and speculate that it had its genesis in the discovery of fossil bones from the strange creatures we now know as dinosaurs:

• Scythian lore described griffins with lionlike bodies and birdlike beaks. In the year 77, Pliny the Elder passed down the Scythian stories of gold-guarding griffins with peculiar ears and wings.
• During his travels in northern India, the first-century Greek philosopher Apollonius of Tyana reported that "no mountain ridge was without" a dragon to its name. The locals said they used magic to lure the dragons out of the earth and pry out the gems embedded in their skulls.
• Chinese accounts of "dragon bones" go back thousands of years — and as recently as 2006, ground-up dinosaur bones were being used in traditional medicine by villagers who believed they came from dragons. (The hard-to-crack dragon eggs depicted in "Game of Thrones" may well trace their lineage back to fossilized dinosaur eggs.)

Classical folklorist Adrienne Mayor, who relates all these tales in her book "The First Fossil Hunters," ascribes the reports to discoveries in fossil-rich regions such as the Altai Mountains in Central Asia, the Gobi Desert in China and Mongolia, or the Siwalik Hills in the Himalayas. Not knowing any better, adventurers interpreted the dinosaur bones as representing the remains of dragons, griffins and other mythical monsters.

The gold hoarding? That may have arisen because gold deposits were found close to the fossil beds along ancient Issedonian trade routes.

And the gems? "I think the Indian lore about special gems prised out of dragon skulls alludes to the crystals that can form on mineralized bones," Mayor wrote. "The detailed observations of the first modern investigator of the Siwalik fossils confirm my theory: large, glittering calcite crystals and tubular selenite crystals are common in the Siwalik fossils."

Hard-wired for dragons?
Anthropologist David Jones went even further in his book "An Instinct for Dragons," published in 2000: He proposed that the fables about winged, poison-spewing, fanged and clawed creatures combined three of the top threats to ancient pre-human primates: raptors like the one that may have preyed on a now-fossilized ape-boy known as the Taung child nearly 2 million years ago; poisonous snakes like the ones that may have driven the evolution of big brains and improved vision in primates millions of years ago; and big cats like the ones our pre-human ancestors had to watch out for in Africa.

"The world-dragon was formed by the nature of our own shadowy progenitors' encounters with the creatures who hunted them over millions of years," Jones wrote. The way he sees it, our brain came to be hard-wired with an instinctive fear of dragons.

Paul Jordan-Smith, a folklorist and storyteller who wrote a fiery critique of Jones' book for the journal Western Folklore, thinks the idea that our ancestors somehow evolved a dragon instinct just doesn't hold up. For one thing, Jones' claim that multiple cultures had the same conception of dragons as dangerous beasts is "demonstrably untrue," he said.

"My take on the mythic image of the dragon is that there is no one 'authentic' image, and no one 'true' meaning," Jordan-Smith told me in an email. "The dragon has been a guardian, a thief, a hoarder (like Smaug, in 'The Hobbit') and a dispenser of wisdom (especially in Chinese tales)."

For another thing, the dragon doesn't show up fully formed in ancient tales.

"It's interesting that dragons do not appear in cave paintings," Jordan-Smith wrote. "What does appear are the beasts that they hunted or that were dangerous. ... Where you do see constructs that aren't literal depictions, they're of humans merged with animals. And when you get civilization, you don't see dragons until much later. ... You don't get dragons until you get stories that have dragons in them."

Who's gripping whom?
But once dragons become part of a culture's mythic milieu, they don't fade away. Perhaps that explains why dragons hang around, in Chinese New Year festivals, in European fairy tales, and in American movies and TV shows. Here's what Jordan-Smith had to say about that:

"A dragon, like most mythic imagery, is 'plastic,' in the sense of being adaptable. It can look like whatever the singer of tales wants it to, can serve whatever purpose needed, and can mean just about anything. And some of the traditional qualities may not be incompatible with one another. A dragon that guards a treasure (or an abducted maiden) may be waiting for the right hero that will liberate it from its responsibility. A dragon that threatens to destroy a village may be a wake-up call to rectify misdeeds. Some dragons are enchanted and must be slain to regain their true form. But not all dragons are meant to be slain.

"And what of the hero? He must be changed somehow by the encounter, or else the game is not worth the candle. But what kind of change? In some cultures, to slay a fearsome beast was tantamount to assimilating its powers. ... In Tolkien's books, the Ring exerts its power so thoroughly that its wearer little by little becomes like Gollum. Perhaps there's a particular kind of danger, much more deadly than merely being killed. And perhaps when the hero slays the dragon, he himself is slain, to be reborn as the human incarnation of the dragon. For good or ill? Ask the storyteller."

Maybe it's not the dragon that has a grip on us. Maybe we're the ones who are hanging onto the dragon — and we don't want to let go.

More about dragons and 'Game of Thrones':

• Origin of Komodo dragons revealed
• Chinese villagers ate dinosaur 'dragon bones'
• Sword science plays a role in 'Game of Thrones'
• All about 'Game of Thrones' on The Clicker

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

All swords are not created equal, particularly when it comes to "Game of Thrones," the HBO series based on George R.R. Martin's character-rich sword-and-sorcery saga. When the series opens its second season on Sunday, some of the swords you'll see are made of cheap resin, others are metal blades just meant to look good — and a few of them have been custom-crafted using a technique reminiscent of the story's fictional, magic-laden Valyrian steel.

For Martin, swords are serious business.

"The one thing I can say is that he is very, very knowledgeable about history, including weaponry," said Chris Beasley, the proprietor of Valyrian Steel, the Michigan-based company that produces licensed replicas of "Game of Thrones" swords. "When designing the swords, and he is highly involved in the design process of our book replicas, he doesn't want something to look cool. He is more concerned with realism — who made it, why, and how?"

For example, let's talk about Valyrian steel. In the "Game of Thrones" TV series and Martin's "Song of Ice and Fire" book series, the Valyrian blades were created ages earlier by a vanished civilization, using a blend of alloys forged with magic spells. There's actually a real-life analog, minus the magic, known as Damascus steel. Damascus swords are famous for their resilience and the intricate, flowing patterns that are imprinted on the blades, but the secret of their forging has been lost for centuries.

A few years ago, researchers found that at the microscopic level, Damascus steel contains carbon nanotubes — structures that seem like 21st-century technological magic dropped into the 17th century. The super-strong nanostructures are mixed in with softer metal in the sword. That solves the classic dilemma of sword-making: how to make a blade that is hard enough to do damage, yet supple enough not to break.

HBO

Young King Joffrey (Jack Gleeson) sits on an Iron Throne made from the swords of enemies.

Modern-day Valyrian steel
Today, swordsmiths use a process known as "pattern welding" that produces results similar to the lost art of Damascus steel. Multiple layers of steel, with different amounts of carbon and other elements, are forge-welded together to create a blade that combines strength and suppleness. When all the layers of metal are flattened and folded together, over and over, it's like having two blades — or, more accurately, 200 blades — in one.

Some of the best-known Valyrian blades seen in the "Game of Thrones" TV series, such as the swords nicknamed Ice and Longclaw, were made using the pattern-welding technique.

"Ice was the main weapon to get right," Tommy Dunne, the weaponmaster for the series, said in a Westeros.org interview. "From the concept to the construction, it was about three weeks to make, as the blade was hand-forged by pattern welding, and the blade was drawn using machine hammers. But as with any good weapons, there's some other secrets that will remain secret!"

Beasley's business also sells some swords made with pattern-welded steel. "Those could technically be used, but we never recommend it," he told me. "Our swords are limited-edition collectibles, and no sword is impervious to damage. If used, they will get nicks, and chips, and scratches."

Beasley recalls that Valyrian Steel's Longclaw replica originally sold for $600, but after the swords were sold out, one customer reported receiving an offer of $3,000 to $4,000 for his sword. "I wouldn't recommend that anyone risk damage to something so valuable," Beasley told me.

Needle at work
If real fake Valyrian steel is too expensive for your taste, you can shell out $170 for Needle, the kid-sized sword that pre-teen Arya Stark learns to uses with deadly effect in "Game of Thrones." Beasley said Martin had a hand in designing the replica.

"Reading the books, I and many others thought, 'OK, this is a small rapier,'" Beasley recalled. "George very quickly put that notion to rest. He said that Mikken, the Winterfell smith who made it, would never have seen a rapier in his life, so how could he make one? That is why the book version of needle is more or less a small, slim longsword, and not a rapier."

Martin was so pleased with the result that he had one of Valyrian Steel's Needles sent to the actress who plays Arya so she could practice with it. And she's not the only one.

"One customer did tell us that they use Needle in their offhand to increase strength and coordination," Beasley told me. "They keep it in their office, and when on the phone or otherwise occupied they just jab and thrust with their left hand." (Remind me not to burst into that office unexpectedly.)

New twists in an old trade
Some of the secrets from the golden age of swordsmithing may have been lost over the past few centuries, but technology is adding new twists to the trade. There's been a lot of research into the use of alloying elements such as carbon, manganese, chromium, nickel, titanium and molybdenum. Materials scientists also are developing metallic materials infused with carbon nanotubes, just like in the good old days of Damascus steel.

"In more modern times, steel can be precisely made, and the overall material creation process can be more scientific so that you can get precisely the steel with the hardness and flexibility you desire," Beasley said. "So materials science has probably made modern swords stronger than older ones, but construction methods have not changed — though, obviously, power tools and other equipment have replaced arm power."

Ah, power tools — I'll bet the swordsmiths of King's Landing would have shelled out hundreds of silver stags for a good belt grinder. Are you in a mood to geek out over the science and technology of "Game of Thrones"? Feel free to indulge yourself in the comment section.

Update for 6 p.m. ET March 30: Veteran sword designer Kit Rae, who has created replicas for a variety of swords made famous by Hollywood, agrees with the parallel between the Valyrian steel of George R.R. Martin and the Damascus steel of real-life swordsmithing. "George Martin's universe is a parallel to what I would guess is the 12th to 14th century in our history," Rae told me. "Around the 10th century, that's when we were really starting to get into properly quenched and hardened steel."

There is a difference between the fictional and the factual universe, however. In "Game of Thrones," it's no longer possible to make brand-new swords with Valyrian steel. In the real world, there's a wide spectrum of swords and knives being made with the "Damascus steel" label — ranging in price from less than $200 to much more than $1,000.

"There are people who will argue that we don't have the technology to make something that compares with what the master swordmakers in Japan or Europe did. That's a bunch of bull," Rae said. "We're actually much farther along than that. But in that regard, you get what you pay for." 

More angles on 'Game of Thrones':

• Teens rule in bloody 'Game of Thrones'
• 'Game of Thrones' headed to PS3, Xbox 360
• George R.R. Martin previews his next book
• All about 'Game of Thrones' on The Clicker
• Medieval knights may have had PTSD

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.