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MIT Students Show How the Inca Leapt Canyons
Posted by
Zonk
on Sat Nov 17, 2007 08:33 PM
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.""
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w00t (Score:5, Interesting)
Re:w00t (Score:5, Funny)
Parent
Re: (Score:2, Funny)
What... is your quest?
What... is the capital of Assyria?
Re:w00t (Score:5, Informative)
Because the higher, the fewer.
Parent
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Re:w00t (Score:5, Informative)
Parent
Re: (Score:2)
In a different time and place that phrase would have a completely different meaning. (whistling "Let's twist again!"...)
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Re:w00t (Score:4, Interesting)
Parent
Re:w00t (Score:5, Funny)
Parent
Re:w00t (Score:4, Funny)
Parent
Re:w00t (Score:5, Insightful)
Parent
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Re:w00t-A close team. (Score:5, Informative)
Parent
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Re:w00t-A close team. (Score:5, Funny)
In the light of that, I have three questions:
Are you doing it again?
Do you need volunteers?
Are the rest of the volunteers likely to be hot, naked chicks?
I have to admit that if the answer to the third one is "no" I may not be very interested.
Parent
Science! (Score:5, Informative)
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Re:Science! (Score:5, Insightful)
Good article, I always enjoy learning about these sorts of things where someone tries to recreate an ancient feat, using authentic technology. They're almost always informative and teach us that we're not so far advanced beyond older cultures, and no one group has ever known the sum knowledge of the world, one group always seems to know more about one thing, and other groups about other things.
Parent
Re:Science! (Score:4, Informative)
Don't give the Europeans credit for Gunpowder. Poor choice for the example.
http://inventors.about.com/od/chineseinventors/a/gunpowder.htm [about.com]
Parent
Re: (Score:3, Interesting)
Yeah I know you wrote flamebait on purpose.
Re:Science! (Score:4, Insightful)
Take the Pyramides. Yes, it's trivial for us today to build something like that (ok, trivial... but take a few machines and you'll have one of those heaps of stones assembled quite quickly). But we're talking something around 3000 BC, so
Here some group sat down and showed us just how they did it back then. It's where archeology meets engineering... archeoengineering, if you want.
Ok, maybe it doesn't give us any new insight for our bridges of today. But it sure closes yet another gap and answers yet another question in our quest to find out about former civilisations and cultures.
Parent
Re:Science! (Score:5, Interesting)
Attempting to build a duplicate pyramid today would still be a massive undertaking that would take years; hardly a trivial task.
Parent
Re: (Score:3, Funny)
The finely finished blocks are only on the outside. Inside, the blocks are quite rough and don't fit together tightly.
Trust me, nothing's changed. The most common statements on a construction site today are:
Re: (Score:2)
Exactly. There are lots of things you could build today with old technology if you have the know-how. A valveless pulsejet engine is well within reach of early 19th century metalworking and fuel technology, for example, as is the airframe to fly it in -- but the techniques to make the engine, shape the wings, and control it weren't known.
The first major use of differential equations as relates to contruction wasn't until the construction of the Eiffel Tower, where they were used to calculate beam loadin
Re: (Score:3, Interesting)
Meh, trial and error becomes easy if you have countless slaves to practice with. What the Inca were REALLY famous for was their ability to direct and control the flow of water. Their canals were really impressive, apparently.
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I'm not sure how building a bridge displays knowledge of the science which is relevant to bridge building. I've seen a 2-year-old build a bridge and I'm pretty sure he wasn't au fait with the physics of beam bridges before he put one block on top of two o
Re:Science! (Score:5, Insightful)
Um... Trial and error *IS* science.
Parent
Re: (Score:3, Insightful)
The Inca apparently didn't use the wheel, and they had no system of writing. With thousands of miles of road and no good way to share knowledge I'd basically guarantee that the Incas figured out how to build these bridges by trial and error. They'd throw a bridge across a ravine and it would work, and so next they would try and throw one across a wider ravine and it would fail (probably throwing people to their death). They would then take a good hard look at where it failed, and they would try something
Re:Science! (Score:5, Insightful)
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:
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.
Parent
Re: (Score:3, Funny)
Injunuity: noun.
The annual return of previously invested Native Americans.
my thoughts when i saw it (Score:4, Interesting)
The rope bridge itself looked fun to walk on, but it had a sign saying no trespass. That sign was up the whole time the bridge was there, though it is possible people might have walked around the bridge for fun and jumped around to see how it swayed and bubbled. At that point the bridge might have been up a while and losing tension and so the sides of the shallow creek interfered with the hanging bridge aspect.
It's great to see thought provoking structures go up around campus. Rock on.
Re:my thoughts when i saw it (Score:5, Informative)
About the sign, we assumed it would be wholly ignored. We needed it to satisfy the safety office I think (I wasn't involved with that end of the planning much).
Parent
The traditional bridge builders still do this (Score:5, Informative)
http://en.wikipedia.org/wiki/Inca_rope_bridge#Renewing_the_last_bridge [wikipedia.org]
NOVA did an episode on this (Score:3, Informative)
Summary is incorrect.. (Score:4, Informative)
The difference is that the walking surface is not suspended from the overhead cables. It is instead supported by tension in the ropes that compose it.
The critical difference from the MIT bridge and the monkey bridges many of us made in the scouts is that it was supported by concrete blocks instead of lashed wooden A-frames and stakes. And that the MIT students put a rather impressive number of hours into making and thoroughly vetting their own rope and design.
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"Ok. Say, looks like you're building a bridge or som
Re:Disppointed and not what I expected (Score:4, Informative)
Parent
Re:Disppointed and not what I expected (Score:5, Informative)
Aztecs:
I, for one, welcome our Mesoamerican, Cortez-hating, Virgin of Guadalupe-worshiping, human-sacrificing, maize-and-bean-growing, empire-building Mexica overlords.
Incas:
I, for one, welcome our pre-Columbian, sun-loving-with-bare-titicas, Conquistador-fighting, Machu-Picchu coca leaf-chewing, Andean-whistling and bridge-building overlords.
Parent
Re:Disppointed and not what I expected (Score:5, Informative)
Parent
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No. They took silver, too.
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Re:Wise beyound years. (Score:5, Funny)
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.
Parent
Re:Wise beyound years. (Score:4, Funny)
Parent
Scoffing at the Ancients (Score:5, Funny)
"We tend to scoff at the beliefs of the ancients. But we can't scoff at them personally, to their faces, and this is what annoys me." - Jack Handey
-kgj
Parent
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