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Archimedes Death Ray
Werner Heuser writes "Ancient Greek and Roman historians recorded that during the siege of Syracuse in 212 BC, Archimedes (a notably smart person) constructed a burning glass to set the Roman warships, anchored within bow and arrow range, afire. The story has been much debated and oft dismissed as myth ... Intrigued by the idea and an intuitive belief that it could work, MIT's 2.009ers decided to apply the early product development 'sketch or soft modeling' process to the problem."
Flash ignition!
In an instant there is a large, open flame. The volatiles liberated from the wood ignite at roughly 1100 F.
Open, sustaining flame occurred less than 10 minutes after the sun was in a clear patch of sky!
You can also clearly see that there are still 3 mirrors not aimed correctly.
Now that Mythbusters is wrong, are there other myths that could be true?
With all due respect, I don't think the Mythbusters are as smart as Archimedes was. You shouldn't impugn someone just because they lived a long time ago.
...just my 2 gil.
There seem to be a few people pointing this out, but the logic is flawed. While Mythbusters is certainly an interesting and entertaining show, the fact that their attempt did not work does not mean that it cannot be done.
The logic can work around the other way. If a single attempt works, then the concept is plausible. If a single attempt fails, then all you can really deduce is that that particular attempt failed. Sure, have enough independent trials fail, and you may start to question the feasibility, but that is not the case here.
Of course by the same logic, showing that the idea is feasible does not mean that Archimedes was able to do it. You're going to be pretty hard pressed to find decent evidence that a "death-ray" was successfully used by the Greeks, even if it were true.
I dont think the resin would be all that protective. It was pitch - a long chained hydrocarbon that would burn like buggery once it was hot enough to vaporise.
Actually, they only disproved their own design and construction methods on this one. A properly-designed and -constructed working model was demonstrated on BBC Two's practical archeology programme, What The Ancients Did For Us
Yes, Archimedes was a very smart cookie, but he was surrounded by other smart cookies, who were also geting up to interesting things. IMO, ancient Greece was pretty much as technologicly advanced as 15th century Europe. Why we ended up having the industrial revolution, and the Greeks did not, becomes a very interesting question.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
What on earth makes you think the greeks were so backward as to be without technology so basic as a simple stand for their mirrors?
"...would have had people holding the mirrors" is an assumption of stupidity on the part of the greeks they don't deserve. Especially since the one credited with the plan is Archimedes, who was almost certainly smarter than you or I.
For the record. Coastal Greece is generally a very sunny place, as thousands of holydaymakers can attest. I can imagine these resuts would easily be possible with a couple of hundred bronze mirrors. Since this is a military operation who's to say he didn't employ several hundred troops for the job?
True. Although I think the larger assumption in this case was scale. Archimedes was used to creating large stuctures and this experiment proved that size matters. Arcimedes would probably have had many able and willing hands to help him align the mirrors. Also, if his helpers were trained soldiers as one would expect when defending a city, they would be discplined. They could quickly follow orders to align a multitude of mirrors simultaneously.
The MythBusters experiment was small in scale and had relatively little manpower behind it. Even the experiment detailed in the article stated they would have been more effective if the helpers had been better trained and disciplined. Archimedes would have been more likely to have had the large disciplined workforce required to make his creation effective.
To be fair: They weren't trying to say it couldn't be done, they were trying to prove whether or not it could have been built with the tools available at the time. That's why it was a 'poor approximation of a parabolic mirror'.
The MIT team also built a poor approximation of a parabolic mirror too...
Next we will see that Mythbusters say that Stonehenge could not have been built with the tools of the time, or the Great Piramids....
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They run these unscientific experiments (most involving explosions or decaying corpses) and then "conclusively bust" myths. Some experiments are fun and interesting, but most don't deserve the hard conclusions they assign.
It's really annoying when people take accept their "proofs" as proofs.
Yep, but as ohters have said, the greeks used slave labour for their construction/manufacturing and therefore had little incitement to invent other things than warmachines (greek fire, imagine a giant roman candle) and toys (as in this example with 'agitated air' as he called it as far as i remember).
Yours Yazeran
Plan: To go to Mars one day with a hammer.
Everyone seems to forget that one of the things Archimedes was very good at was combining multiple techniques.
1) Ancient Greek mirrors were GOOD. A bronze mirror of the time could reflect 80% of the incident visible light, a sliver mirror could reach 90%. We're obsessed with silvered-glass because it's CHEAP compared to straight silver, but silver works pretty darn well, and defense of one's country rarely engenders frugality.
2) It's pretty simple to use a parabolic reflector of known structure to reflect lots of light into a secondary reflector set at the focal point (actually slightly below it) which reflects the beam into a lens or to another mirror off to the side. This allows the main reflector to point right at the sun, then the secondary reflector directs the light to a spherical mirror, which collimates the beam, then to a fourth mirror that is turned to direct it to the final target (a small mirror can turn the beam pretty darn fast, if you use a double-lever to turn it).
Even with a bronze main reflector, it wouldn't be difficult to do this, and the efficiency losses do not, at any point, require the mirror temperatures to approach the melt-point of silver-coated bronze (the likely material for the second and subsequent mirrors). Some examples of the separate parts of this concept are in Archimedes known works.
3) I can't say if this is how Archimedes would have done it, but he had the required parts.
you seem to forget that this Archimedes guy had more funds and manpower at his disposal then ten "very promising" undergrads. Also keep in mind that Archimedes by this point in his career was well beyond his first four years in college - he actually had experience to draw on.
Something like only needs to be used once to be effective. After that, the mere idea that it exists is a deterrent. Two other examples of this working:
1) The ancient Israelites carried a large gilded box called the Ark of the Covenant in front of them into battle. They believed it could summon up the wrath of God on their enemies. Their enemies were not 100% sure that the Israelites weren't right. There is no evidence that the Ark ever actually did summon up the wrath of God, but boths sides beleived it and the Israelites beat enemies who had superior numbers on a number of occasions.
2) How many atomic bombs were actually ever used? Two. But the mere thought that a country has nuclear weapons gives them a bargaining position. And the the fact that the wrong country even MIGHT be trying to obtain them is reason to go to war.
In the ancient world, this "death ray" would have struck fear in the enemies hearts and minds, despite the fact that it might have serious limitations, or may not even work at all except in controlled situations. And one or two prominant demonstrations of such a weapon would go a long way toward keeping this fear going.
That is, if you use mirrors that are mirrored on both sides, and have a hole in the middle. See, then all you have to do is hold the mirror up to the sun in such a way that the mirror casts a shadow on your own body. Then, looking at your reflection in the back of the mirror, simply line up the the reflected hole in the shadow with the hole in the actual mirror, while you can see the target through the hole.
The mirror is then at the proper angle. Keep using the hole to aim, and keep the shadow lined up, and you can easily track the target.
I saw a diagram of the geometry on-line somewhere, but I can't seem to find it now. It would make it a little easier to understand, if you can't parse my description.
What was the range of this (or a similar) device? Could you focus the light to set a moving ship on fire lets say 100 yards away?
The range is fixed to the focal point of the paraboloid. With a less curved paraboloid the
range increases to whatever you want it to be, but the accuracy requirements will go up quite considerably. Or failing to improve on accurracy, increase the size of the reflector.
I'm on the fence about whether Archimedes could pull this off. He certainly had the knowledge, but I doubt if the technology was there. What I am certain of is that mythbusters messed this one up, using far too few flat, or flat mirrors. If you're using flat mirrors, you need a lot.
They should try again with a bigger budget, with more focus on the mirrors (pun indended) and less on the boat.
A witty
remember, this was supposedly used against ships trying to either get near sea walls or drop off soldiers onto walls / quays / seafronts... it would have been fairly easy for archimedes to ensure that the roman ships had to pass through restricted spaces (sinking boats round the harbour, laying chains, dropping piles of boulders etc etc); it may even have been the case that there were only a few places where the roman ships could get close to land simply because of the layout of the place. in which case, you wouldn't need lots of people trying to aim lots of moving mirrors at moving targets- a few pre-aimed ones covering strategic spots could be used whenever a ship was in the right place. if the ships where disgorging soldiers, they'd have to keep still for several minutes at least.
if i was archimedes and trying to attack moving targets with a weapon that was best used on stationary targets, my first thought would be to hamper the targets' movement.
it's a basic principle of fortification and defense - ensure the enemy has to pass through or in front of a concentration of your best firepower to get to you. it's why castles have gatehouses, un-aligned entrances, and towers with arrow-slits covering the area immediately in front of the walls. you don't need to attack the enemy while they're a hundred yards away - they'll come right up to you. if they retreat out of range, it means you're winning.
Why would the greeks have tried to set fire to the wood? It would me much easier to target the sails, and they would burn much more quickly. Once the sails are burning, the wood follows. I don't understand why modern people have such problems following logic, and instead have such faith in modern products, and complex solutions rather than simple ones.
... and then they built the supercollider.
I remember a Mythbuster episode where Adam & Jamie try to reproduce this myth/story. They were not able to set a boat hull on fire (they built a replica
I remember that episode, they couldn't set their replica on fire even when they poured gasoline on it and set that on fire!
Adam's credibility was busted, not Archimedes'.
You can't take the sky from me...
There's things about what Adam and Jamie does to "bust" myths that end up being "wrong" and they
bust myths that aren't myths. The chicken gun story is a prime example. They'd "proven" that
it was not possible to have what was described in the chicken gun- but what they did was miss
what the conditions were and didn't test the actual story's premise. When re-done in a recap
story trying to revisit the whole idea, they more closely duplicated the whole set of conditions
and ended up reversing the decision they'd come to on it. The cell-phone story was debunked
but it wasn't debunked appropriately- again they didn't reproduce the conditions. They used
a non flip-phone cell-phone with capacitive operated buttons. No way for the phone to EVER
introduce a spark into an environment. I'm of their opinon on that one- it's a myth, but to
claim that it is off of their test on the subject is bad science.
Don't get me wrong, Mythbusters' is a great show and the bulk of the stuff they do is highly
accurate; but they should never ever be held as a final authority because they're a much
about showmanship as they're about mythbusting and miss many things. The MIT project apparently
shows this situation to be another one of those, "they didn't get the conditions right to
properly test and prove/disprove anything" situations they're guilty of on a periodic basis.
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As an MIT person, I can honestly say I have no idea why anyone would include a course number in their submission and expect it to make any sense to anyone else. But then, people often include random acronyms or other jargon in their submissions that require explanation in the comments - so I don't think it's an MIT-only problem. Just in general, /.ers who either think "Oh, this is common knowledge!" when it's not, or "Hey, I'll show how extra-special I am by using terminology nobody else knows!"
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Thanks for the breath of fresh air, Tum.
WWF (aka All Georgia Pro Wrestling) = entertainment
Penn & Teller's "Bullshit" = acerbic entertainment
Mythbusters = geeky entertainment
Nothing on any of these shows is any more true than anything you'd see in Archie Comic Books. It's supposed to be fun, people, not a freakin' belief system!
I bet Archimedes could have easily got 1000-5000 soldiers. Or maybe even archers - who'd be good at this thing (decent eyesight, steady hands etc). Whether he was able to get enough flat bronze mirrors is another issue, but I won't be surprised if he was able to do that - Syracuse wasn't that poor.
It's not that difficult to aim the sun's reflection at a target. As some people have already mention, some methods would involve putting a hole in the flat bronze mirror and using the hole to aim.
I'm sure Archimedes would have figured out many other ways of doing it, possibly more practical given the circumstances. He definitely was smart enough.
So yeah, on a clear sunny day (not uncommon in that part of the world), if you see 1000 people each with a large flat bronze mirror reflecting sunlight to you, I think it'd be best to make a quick retreat and come on a cloudy day.
BTW, Archimedes also had other defenses against ships attacking the city walls by night.
I guess the persistence of the Romans worked in the end.
fast mirror:
u lt.html
http://deathray.bootnetworks.com/10_ArchimedesRes