MIT Students Show How the Inca Leapt Canyons 185
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.""
Incas vs. Inca-pables? (Score:1)
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The ones you don't see (Score:1)
w00t (Score:5, Interesting)
Re:w00t (Score:5, Funny)
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What... is your quest?
What... is the capital of Assyria?
Re:w00t (Score:5, Informative)
Because the higher, the fewer.
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Re:w00t (Score:5, Informative)
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In a different time and place that phrase would have a completely different meaning. (whistling "Let's twist again!"...)
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Great! Another series to add to my overflowing reading list.
Re:w00t (Score:4, Interesting)
Re:w00t (Score:5, Funny)
Re:w00t (Score:4, Funny)
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The problem with that plan is that you need to take a really looooong string along with you. By the time you reach the other side, your string is wound between trees, looped around rocks, etc. You'd have a lot of trouble pulling it taut.
Re:w00t (Score:5, Insightful)
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Getting the initial thin ropes across you just have them drop them from the opposing sides tie them together and away you go. Now it gets fun it the bridge is over a river or a very,very deep valley, in thoses cases it looks like they would shoot from one side let gravity and the force carry the projective and rope across to the other side and then climb down.
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For the really big threads I imagine that they probably used Rosie's legs.
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Was one of the purposes of the project to prepare crypto-archeologists for the threats that they will be facing for when they travel to remote places to prevent ancient powerful artifacts from falling into the hands of evil geniuses?
If so: Well done!
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Re:w00t-A close team. (Score:5, Informative)
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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.
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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.
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]
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Don't give the Europeans credit for Gunpowder. Poor choice for the example.
It's not about who invented the gunpowder.
Europeans in the Americas had huge advantages because they made use of the inventions and discoveries made by a large number of people over a long period of time, whereas American natives were much more isolated. Even within the Americas, discoveries didn't move around as much, because the Americas are mostly North/South and discoveries move more easily along similar latitudes (because of cli
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I understand that this is the canon view, but seriously: where were you educated?
I'm 40 so my main primary education was in the 70s in
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Public school. The basic teaching was 'Here, look at these great Roman people, look what wonders they built. Oh and China was doing some interesting stuff too, but hey look! Conquistadors, weren't they great? Those silly Native Americans, not knowing how to use guns, too bad for them.'
Every history class I've been in has treated the Roman culture as significantly more advanced than anything before or at the same time, and the
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Yep. Just look at the Neanderthals. Based on the evidence we have to go on (brain size), they were a lot smarter than us. Yet look how we portray them.
Admittedly part of this may be because they were discovered very shortly after the success of Darwin, and so automatically became the "missing link," and remained that way in the public consciousness. Maybe if they had only bee
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Yeah I know you wrote flamebait on purpose.
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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.
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.
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This is pretty common in ancient stonework. For example, the famous Inca stonework at sites like Sacsayhuaman look fantastic - the joints look almost organic, they're so close - but that's just the outer edges of the blocks. Behind the surface, the block edges are quite rough.
The real engineering miracles in large structures like the pyramids are of social organisation and agricultural produ
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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:
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How they did it (Score:2, Insightful)
From Red Dwarf:
Rimmer: No, Lister, I mean like the pyramids. How did they move such massive pieces of stone without the aid of modern technology?
Lister: They had massive whips, Rimmer. Massive, massive whips.
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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
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I think that you missed the point. Enough of us are not so ethnocentric that we think that every other culture is backwards and stupid. When their injunuity is presented to us as "news" it only points out the stupidity of those who think that it's neat. P
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Injunuity: noun.
The annual return of previously invested Native Americans.
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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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Indeed: http://despair.com/achievement.html [despair.com]
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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
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Have you considered the cost of doing this by 'trial and error'? You need a lot of people, it takes a lot of time, a lot of materials, and you have to expend immense political capital even to motivate one attempt. Certainly designs evolve over time, but serious engineering thought clearly went into the original undertakings. I can't imagine how you can think otherwise.
Then again, perhaps you consider any application of the empirical method to be 'trial and error'—in which case what we do today is no
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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
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Precisely.
Re:Science! (Score:5, Insightful)
Um... Trial and error *IS* science.
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I can take 20 different jars of baby food and give a spoonful of each to a baby until I find a list of flavors that she likes, that's some pretty basic trial and error. But at the end of the day, have I accomplished an
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I fail to see how the Incas were a non-western civilisation. The lived in 'the west' (compared to europe), and they certainly had an advanced civilisation, even if they didn't have the wheel or horses.
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.
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I'm still waiting for modern society to perform a feat that is inherently greater than the building of the Great Pyramid of Khufu, or one of the other, non-surviving wonders of the ancient world. I agree that they didn't have the theoretical physics or chemistry that we had. So? We don't have the combination of government, culture, philosophy, religion, and engineering that the ancient Egyptians had. Until we build something as beautiful, awe inspiring, and lasting, as the Great Pyramid of Khufu, our claims to superiority based on our theoretical science rings as empty as your claim to superiority based on the fact that the British Isles were too far away and insignificant to be of interest for conquest to the Egyptian Empire. (Even the Mongols, the largest contiguous empire in history, couldn't find anything of interest in the British Isles.)
To put this in some context, there are more scientists alive now than people living in that ancient Egyptian empire. In my view, a year of effort probably yields as much scientific progress as everything up to the Age of Enlightenment (say around 1700 CE), but it doesn't look that impressive because the problems are harder. That knowledge with luck will outlast any physical object including the Solar System.
Meanwhile, European engineers, without those engineering insights, built an enormous ocean liner out of high-carbon steel, that was so brittle that it sank after hitting a chunk of ice.
I assume you are refering to the Titanic. The brittleness of the steel wasn't a big factor in
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You might want to look again. Eight years before the Titanic sank, the Japanese navy sank two-thirds of the Russian navy without taking significant losses at the Battle of Tsushima [wikipedia.org].
Spaniards (Score:1)
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No. They took silver, too.
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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).
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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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Been there, done that, IIT Madras (Score:2, Interesting)
Roman bridges had a maximum span of 95 feet? (Score:2, Interesting)
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What the article says is:
"The Inca suspension bridges achieved clear spans of at least 150 feet, probably much greater. This was a longer span than any European masonry bridges at the time. The longest Roman bridge in Spain had a maximum span between supports of 95 feet." (my emphasis)
Trajan's bridge was long destroyed by the time of the Spanish Empire, and it wasn't in Spain, thus the Inca bridges had longer spans than anything the Conquistadores had ever seen. They were duly impressed, as they certai
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And what the post you replied to said is:
"Roman bridges in Spain that still exist extend over 800 meters."
The grandparent post was consciously directly contradicting the article, so I don't see your point.
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"Ok. Say, looks like you're building a bridge or som
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You would've made a "good" Inca king (at least by their standards).
Wait a second. I thought the Inca empire died out by the time the Spaniards came. The Aztec empire was the active one.
Re:Disppointed and not what I expected (Score:4, Informative)
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.
Re:Disppointed and not what I expected (Score:5, Informative)
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2) Incan Empire, Peru, Pizarro, 1532-1535 (occasional resistance until 1570 or so)
3) Mayan Empire, Mexico, was more of a federation of cities, First contact in 1517, a couple failed expeditions 1527-1535, success in 1540-1546 (last city only conquered in 1697 though)
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.
Re:Wise beyound years. (Score:4, Funny)
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More seriously, it's an interesting story. Teaching a bunch of extremely sharp, motivated people like MIT students to collaborate on a basic physical task that requires high quality control and doesn't have a lot of shortcuts must have been a fascinating task.
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
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I think they call that a "space elevator".