MIT Students Show How the Inca Leapt Canyons

PCOL writes "When Conquistadors came to Peru from Spain in 1532, they were astonished to see Inca suspension bridges achieve clear spans of at least 150 feet at a time when the longest Roman bridge in Spain had a maximum span of 95 feet. The bridges swayed under the weight of traffic terrifying the Spanish and their horses, even though, as one Spaniard observed, they were almost as "sturdy as the street of Seville." To build the bridges, thick cables were pulled across a river with small ropes and attached to stone abutments on each side. Three of the big cables served as the floor of the bridge, two others served as handrails and pieces of wood were tied to the cable floor before the floor was strewn with branches to give firm footing for beasts of burden. Earlier this year students at MIT built a 70-foot fiber bridge in the style of the Incan Empire. The project used sisal twine from the Yucatan Peninsula and anchored it by wrapping it around massive concrete blocks. The weekend's burst of activity was preceded by 360 hours of rope-twisting as the 50 miles of sisal twine was turned into rope. Working together as a group was part of the exercise. "A third of the time was spent learning to work together," one of the students said. "But after a while, we were banging those cables out.""

Comments

w00t

[Zackbass]

Haha, talk about a late story at a completely random time. I was one of the leaders on the project, lots of late nights twisting twine together. If anyone has any questions feel free to ask.

Science!

[proudfoot]

People here seem to be missing the point - it isn't that this stuff isn't trivial compared to todays engineering, it is. But it's more revealing about the fact that non-western civilizations had an advanced grasp of the physics/science behind this stuff. They knew how to take advantage of rope tension. A bridge like this isn't so impressive today. It's easy to build. But to come up with the design is the hard part.

Re:Science!

[Volante3192]

Actually, the engineering of the pyramids is still surprising us; not only was the construction of the pyramid incredible, but the actual quarrying and shaping of the stones is still unsurpassed. Sheets of paper won't fit through the gaps between blocks, and there's no mortar.

Attempting to build a duplicate pyramid today would still be a massive undertaking that would take years; hardly a trivial task.

Re:Science!

[kklein]

Okay, a lot of people are already saying this, but they're not being modded up, and I don't have mod points, so I'll just join in:

But it's more revealing about the fact that non-western civilizations had an advanced grasp of the physics/science behind this stuff.

There is absolutely no reason to think the Incas knew anything of the sort, any more than "nature" knows how to fly, because there are birds. It's evolutionary. Ideas that work stick around and propagate. Ideas that don't result in smashed Incas at the bottom of a ravine. Those ideas don't stick around.

Most good cooks can't tell you the complex series of chemical reactions that result in deliciousness; they just learned via trial, error, and someone showing them what to do.

How's your understanding of English grammar? Do you know how to diagram sentences down to the morphological level? Do you know how the tense/aspect system works in English? Do you know about semantic features, etc? I do, but I had to go to grad school to learn it. I have, however, been successfully speaking English for at least 31 years!

Success at any task is not necessarily indication of an understanding of the theory behind it.

I get so tired of people praising stone-age cultures as though they were so much more advanced than we like to think just because they could pile some damn rocks really high or, given several millennia of sky-watching, could notice patterns in the night sky. None of this is special and none of it is indicative of the kind of detailed, theoretical knowledge that the modern, largely Western, world has developed and is continuing to develop. If these filthy savages had been so great, they would have colonized us and our stupid hunter-gatherer lifestyles would have been destroyed (which, of course, did happen, when the Roman Empire came all the way up to the hellhole that was the British Isles, from whence my family originally hails).

It's just simple evolution. Useful ideas that strengthen communities survive, others do not. That doesn't mean that the willful genocide of various primitive peoples the Europeans ran into was the "right" thing to do, but the destruction of their cultures and the re-appropriation of their resources was inevitable. I have no "white guilt," and I'm not sorry that I grew up on land my ancestors stole from people who had no written language, lived in animal-skin huts, and hadn't even developed farming. I don't feel any need to pretend any of these cultures were anything more than Paleo- to Neolithic cultures lost in time while the rest of the world (i.e. the cultures of Eurasia, each leading during different epochs) went on without them.

Is the ability to build such bridges cool? Hell, yes! But it is not particularly special.

Re:w00t-A close team.

[Zackbass]

Not on purpose as far as I remember, but when the rope reached a certain size it couldn't just be reeled up by hand anymore and we had to have two people act as a reel, twisting the rope around themselves as they walked down the hall. Eventually they'd be tied right up against each other with something like 70lb of rope around them.

Re:Wise beyound years.

[ozmanjusri]

ancient men weren't idiots

According to Mayan glyphs found carved in stones near one of the bridges, Bolontiku, Ixzaluoh and Ac Yanto were in fact idiots. Ixzaluoh in particular, was believed to have had difficulty finding his ass, despite using both hands.

The traditional bridge builders still do this

[psychgeek]

The descendants of the original bridge builders still do this each year at one of the original sites, using techniques handed down by previous generations. Photos here:
http://en.wikipedia.org/wiki/Inca_rope_bridge#Renewing_the_last_bridge