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Archimedes Death Ray in San Francisco
Monkey-Man2000 writes "Following the recent demonstration by MIT students that Archimedes' death ray could have been used to burn Roman ships, the producers of the Discovery Channel's Myth Busters invited the MIT team to San Francisco to try their death ray on an 80-year old fishing boat. This time, even with perfect weather, they were unable to set the boat afire. From the article, "Peter Rees, executive producer of "Myth Busters," said the experiment at the Hunters Point Shipyard showed that Archimedes' death ray was most likely a myth.""
Having failed to do the experiments once and declare the thing as "most likely a myth"! Even today, many, if not most, of the experiments are non-replicable. Well, for most cases they are probably myths or hoaxes, but some of them are genuinely very hard to replicate. The reason can range from precision requirements to hazy details. The latter is the usual suspect, which, I believe, applies in this case as well.
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Error 500: Internal sig error
mythbusters just did it wrong. http://www.solardeathray.com/
Accept any challenge, No matter the odds.
"Hyneman has a degree in Russian language and literature. He has had a variety of careers, including scuba diver, wilderness survival expert, boat captain, linguist, pet shop owner, animal wrangler, machinist and chef."
"Adam Savage: Before becoming a TV host, he spent 10 years as an artisan in special effects, specifically modelmaking for companies such as Industrial Light and Magic, Warner Bros. and Disney. He worked on such films as Star Wars Episodes I and II, The Matrix sequels, Bicentennial Man, A.I., Space Cowboys, and others.
He has also been an animator, graphic designer, carpenter, set designer, toy designer, rigger, and has many sculptures on display in museums across the country."
http://en.wikipedia.org/wiki/Adam_Savage
http://en.wikipedia.org/wiki/Jamie_Hyneman
Remember that 7-Up commercial from a couple'a years back? The one that features a 7-Up machine on treads that rolled around and fired cans of soda at people?
Jamie built that.
His company, M5 Industries Inc., specializes in robotic designs for visual effects. He's got a lot of experience building, you know, robots. He's designed or been involved in designing things that are required to do a huge variety of bizarre and wacky things - from the aforementioned surly soda-firing vending machine robot to a motorized shoe-cycle to a articulated giant hand (as seen in the film Monkeybone).
And, to remind those of you who watched Battlebots when it was on:
He built Blendo.
So, yes, he's got engineering experience. He's got a lot of engineering experience. And, yes, special and visual effects work *does* require a lot of skill and talent - and the ability to judge whether something is practicable in the field.
(I'd also recommend that you look at the career of one James "The Amazing" Randi before commenting further. Take an especially close look at how often people claim that a stage magician shouldn't be trying to debunk so-called "real" paranormal events.)
http://web.mit.edu/2.009/www/lectures/10_Archimede sFAQ.html#FAQi
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Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
As a picky guy, I noticed a space. It is "MythBusters". See the official Web site. No space! Also, no Mythbusters.
Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
The fact is that the mythbusters guys often engage in poorly constructed 'experiments' which a scientifically literate person would recognize as being inadequate for the purposes in question. Many of their efforts are laughably incomplete or rely on misunderstandings of the phenomena that contibute to whatever they're testing.
No gods, no demons, and no masters. Secular Humanism!
I saw the original Mythbusters episode where they tested Archimedes death ray and they tried fairly hard to replicate the design components of a roman ship of the time. The conclusion of their tests was that it would be nearly impossible to focus enough mirrors in one spot for a long enough time to be able to generate enough heat to set wood and pitch on fire. Were they able to make Archimedes death ray? No, because no plans exist of the device, hence it being a myth. They did, however, make a fairly plausible case against the existence of such a device.
Hi.... It's my first post here..... I really like this site! Now.... The other thing to remember is that at the time of Archimedes, good quality glass was not discovered yet - most mirrors at the time were made from malachite. Such a mirror would not have reflected nearly the amount of light that a modern glass mirror would have done. Good quality glass did not come into Rome until about 250 years after Archimedes. I actually looked into this pretty carefully for my book "The Light of Alexandria" - http://www.lightofalexandria.com/ . Some of the other inventions that Archimedes made for the defense of Syracuse were pretty amazing, though........ JM
iv) Does the intensity of the reflected light not decrease the with square of the distance.
The reflected light does not decrease in intensity with the square of the distance from the mirror. If this were the case, there would be no hope whatsoever for the myth (or a laser pointer) to work, even in modern times. The attenuation of the reflected light from a flat mirror is only related to how much the beam disperses geometrically before it hits the target (e.g., our 1 ft square tile's reflection spread to an area of 3 square feet at a distance of 100ft, so the attenuation was a factor of 3). Low power laser pointers can project bright points over very long distances because they have a very tight, coherent beam (i.e., it does not increase in diameter with distance).
Since it DOES decrease with the square of the distance. it is some constant times the square of the distance. That constant can be very small, but it is there nontheless. For proof, just look at the example:
if it spread out to 3 square feet at 100' distance, what would it spread out to at 200' distance?
low power laser pointers have a tight almost columnar beam, which can be more easily achieved because it is monochoromatic. coherence is not necessary for the tightness. Even this beam widens according to the inverse square law. (In fact, very tight beams can be achieved even with white light, using aplomatic lens designs to compensate for chromatic abberation)
It hurt to read that part. the rest looks ok at first glance...
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What exactly is your idea of "a lot farther north"?
Both San Francisco and Syracuse (Italy) are both between 37 and 38 degrees north latitude.
A flat mirror has negligible dispersion when reflecting sunlight. Sunlight striking a small portion of the Earth's surface can be treated as truly parallel rays unless you are reflecting it to astronomical distances. That's why a mirror from a make-up compact makes such an effective signalling device: even at large distances it is still extremely bright. Dispersion of light sources is more aptly applied to point sources where the rays radiate outward in all directions. Far enough from a point source, however, the rays are effectively parallel over shorter distances.
:-)
The dispersion from the mirror would basically be due only to whatever deviations from truly flat the mirror has.
Sunlight at the Earth's surface is about 1000 W/m^2. Flat mirrors all pointing to reflect the sun's light to a single area would basically produce an area of light equivalent in size to that of the mirrors with an intensity equal to the amount of sunlight on one mirror multiplied by the number of mirrors. For example, 300 square mirrors with an edge length of 0.5 meters would deliver approximately 75,000 W of power onto 0.5 x 0.5 meter area if correctly aligned.
If you have enough mirrors you can burn just about anything. Another example of "give me a lever long enough and I can move the world."
Disclaimer: I have a B.S. in Physics (UNC-Chapel Hill), so I have a vested interest in the laws of physics and my opinions may therefore be non-neutral. Also, I have something like the flu, so you should check my math...
Life is short: void the warranty.
"If you investigate paranormal events with the mindset that it's all fake, then you're just as bad as the `true believers' you're trying to discredit. Scientific exploration of anything requires an open mind."
Oops! Mind the deep philosophical waters there. Now you've splashed truth all over yourself; let's try to dry you out a bit.
The history of the philosophy of science (a mouthful were there ever one) is complicated, and I think that it's fair to say that there's no widespread agreement on the exact details of what science is. A popular view, however, is that it proceeds in three parts. First, a hypothesis is developed. The hypothesis should be precise, predictive, useful, and falsifiable. Second, the most rigorous possible attempts are made to falsify the hypothesis. Third, as attempts at refutation fail, the hypothesis gradually becomes an accepted theory, meaning that others will build new hypotheses atop it. Of course, the theory could still be falsified at any time; if so, a new hypothesis is created by adjusting or discarding current theory, consequences of the change upon other hypotheses and theories are evaluated, and the process begins again.
A variant of this process particularly popular in modern science is known as "statistical hypothesis testing". The basic idea is to reject the "null hypothesis" that no effect of some action exists by statistically testing the data. "Failure to reject the null hypothesis" triggers rejection of the contrary hypothesis that an effect exists.
By these definitions of what science is, it really only "requires an open mind" in the hypothesis formation stage. In the hypothesis testing stage, it requires the exact opposite: intense efforts to falsify ("debunk") the hypothesis. In this view, Randi is quite credibly a scientist, and real scientists debunk things all the time.
There. Looks like that was dry enough to do for you. March on!
This is why you don't put your faith in freshmen (or 1/3 of the stuff in medical journals, but that's a separate issue).
Fair enough but the MIT team did achieve ignition using fixed mirror placements and just 127 flat 1 square foot mirrors.
The 'freshmen' failed because there was no visual reference point for aiming. When 100 other 'bright spots' are aiming at the same target you, there is no way of telling which bright spot is yours so it's impossible to make the proper adjustments to focus your beam onto the target.
So, the only real constraint is providing a means of manually aiming the mirror properly. I'm not an optics expert...but if there's a way to design a sighting device, perhaps like a sextant, then the myth of 3000 soldiers with 5'-square bronze shields incinerating a ship could easily be true.
(1 square foot)X127=127(MIT achieved ignition with this, roughly 1100 F)
vs.
(5 square feet)X3000=15,000(Grecian army w/ bronze shields)
That's a massive magnification factor of about 120X. 120X the ignition luminance(cd/m2) could vaporize the target instead of igniting it.
The government has a defect: it's potentially democratic. Corporations have no defect: they're pure tyrannies. -Chomsky
When completed in 1978, the National Solar Thermal Test Facility cost just over $21 million. The NSTTF is an array of 222 focusable mirrors, or heliostats, covering 8 acres (7 football fields), located on the grounds of Sandia National Laboratory at the edge of Albuquerque, New Mexico.
The mirrors (facets) are focused onto a receiver or target mounted on a tower. The NSTTF tower is 200 feet tall, and its 8-foot-thick foundation is 50 feet below ground. The mirrors can direct up to 5 megawatts of solar radiation onto the receiver or other experimental objects. An uncooled object placed in the beam can be quickly raised to temperatures of over 4000 degrees F.
The mirrors are mounted on individual frames that are tipped up and down and rotated east to west by small motors much like those used in electric clocks. The motors are controlled by a computer which determines how to position each heliostat so that its reflection hits the receiver at any time of the day and any day of the year. The mirrors are made of two layers of glass with reflective silver between the glass layers. The quality of the glass is like that in your windows at home. The silver in one heliostat (25 mirrors-in one frame) weighs only about 1 ounce. Rain, snow, and other natural forms of moisture actually help keep the mirrors clean by washing away accumulated dust. Hail and dust storms have not harmed the mirrors. Only hail over 1 inch in diameter is likely to break the mirrors.
The US is considerably further north than where this would have originally have been used. "The Med" is so much closer to the equator that the sun's rays hit it much more directly and thus will generate more heat/power. Plus during this time of year in the S.F. Bay area, it's relatively cool getting down to as low as 45 degrees. Plus the sun is at a much greater angle than if it were during the summer. On top of that, there's a constant cool breeze blowing off the water which will pretty much cool anything off extremely quickly. You can expect an extremely rapid cool down on just about anything in these conditions and it takes much more heat to accomplish the same job.
I don't mean to belittle anything that's been done thus far, but the bay area is a cold place when along the waterfront...even during the summer. Mark Twain once said the coldest winter he ever endured was the summer he spent in San Francisco. Since combustion is directly related to heat, and the amount of "power" generated from the sun's energy would be considerably greater if you get a more direct path, it would seem to me that it's possible to do this in the right conditions.
Besides, I don't really hold too much stock in the Myth Busters anyway. They aren't scientists, they're special effects guys, and I've seen several myth's they've busted that I've seen happen.
The sun takes up .5 degrees in the sky. The light hitting the mirror from the "top" of the sun is not coming in parallel to the light from the "bottom" of the sun. There is an angle of .5 degrees. If the mirror were a point then at 100 feet the dispersion (in feet) would be approx. d= 100 * tan (.5) which is .87 feet. Now move to a 1 sq ft mirror. The top of this mirror is going to reflect light from the top of the sun down by .25 degress and light from the bottom of the sun up .25 degrees. Similar logic applies to the bottom of the mirror. So the light from the top at 100 feet is off of parallel by 100*tan(.25) or .436 feet and same for the bottom. This gives a height of 1.87 feet. Now do the same for the sides of the mirror and you get 1.87 for the sides so square it to get 3.49 square feet. Now the light in the central square foot is going to be more intense, but you are getting dispersion at 100 feet due to the angle of the sky that the sun occupies. BTW, the MIT site agrees with my math if you care to look it up.
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