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19-Year-Old Makes Homemade Solar Death Ray
An anonymous reader writes "Concentrated solar power has the potential to generate immense amounts of energy — but it can also be amazingly destructive. American student Eric Jacqmain has assembled over 5,800 mirrors into his own parabolic 'solar Death Ray'."
Looks like the mythbusters can redo this myth one more time.
This is what a science education lets you do. Stay in school kids!
Move sig!
You could get a nasty case of sunstroke from that thing.
http://michaelsmith.id.au
I mean the focus is close enough that he could kill anything anyway by smacking it over the head with the reflector. Be nice if the focus was a bit further away.
Once I was a four stone apology. Now I am two separate gorillas.
Like ~2,000 years ago. Talk about an old story.
vos nescitis quicquam, nec cogitatis quia expedit nobis ut unus moriatur homo pro populo et non tota gens pereat.
I have seen back yard solar barbecues that size or larger. Its just a cheap parabolic mirror with a bracket at the focus. This one lacks the bracket but otherwise he could have just bought it in the shop.
http://michaelsmith.id.au
5800 mirrors, the size of fingernails. Glued on an already parabolic disc.
He used an old satellite dish.
Couldn't he just have spray canned it with some reflective paint??
Or glued aluminum foil over it. Or chrome plated it. He chose the most cumbersome way. Everyone who works cutting glass gets some nicked fingers from time to time, imagine cutting 5800 tiny pieces.
I imagined at least 10x10cm mirrors. Now that would have been "solar power".
True, if there had been 5800 10x10cm mirrors. For the same surface size, the smallest the mirrors are the better focus he will get. Ideally, the surface should have an infinite number of infinitely small mirrors, i.e. it would be a smooth parabolic surface.
He said it was destroyed in a shed fire. He must have left it near a window in the shed. Now that's funny.
There are no loopholes. It's either legal or it's not.
More specifically, there are two issues with your suggestion. Firstly, lasers are not power-limited by input light, but rather by the design of the lasing cavity and how efficiently it stimulates further emission. Many types do need a decent kick to get them going, but beyond that a bright source offers little or no benefit.
Secondly, even if more input light was useful, this mirror doesn't actually provide that much power. It's just the use of the parabolic reflector to concentrate the energy into a small energy that makes it look impressive. Looking at the dish, it's a few square metres in area, at most. That's only a few kW of light in total, of which only a tiny portion is at any one wavelength which would be useful for pumping a laser. An appropriate pump laser or even a decent flashlamp would be vastly better than this for stimulating laser emission.
Also, LASER. Light Amplification by Stimulated Emission of Radiation.
The tiny mirror pieces are from a mirror ball. Yes, I actually do go out sometimes.
How To Keep Your Solar Death Ray Safe:
...
Step 1) When not burning things, keep your Sola Death Ray covered with an opaque fabric.
Step 2)
Step 3) Profit!!
It's already in use - arrays of mirrors all pointing at a tower. The heat melts salt (which requires 538C minimum) which is then used to power steam generators.
http://en.wikipedia.org/wiki/Solar_thermal_energy#Power_tower_designs
Please consider this account deleted, I just can't be bothered with the spam anymore.
Dude, 5800 mirrors is nothing. I hold in my hand a solar death ray device that has probably billions of nanomirrors on it, each carefully aimed to focus light at a point.
My thought exactly. This merely focuses sunlight. It doesn't generate any energy, or even convert it for that matter.
The whole point of the death ray is to be able to adjust the focus point.
The Mythbusters tried to set a boat on fire... which was assumed to be an enemy boat passing along the coast.
You can't reasonably expect the enemy boats to sail exactly at the focus point of your death ray... or to either come closer or go further away in case they are not at the focus point of your death ray.
This 19-year-old hasn't made the focus point adjustable... so you can't set a moving target at a variable distance on fire with it.
Any dish shaped thing with mirrors has a focus point - especially satellite dishes - so this isn't exactly rocket science.
"The 19-year old claims that his solar device has the intensity of 5,000 suns."
Surely it has the intensity of 5,800 x the amount of solar energy collected by a tiny mirror 93m miles away from the sun?
It is the intensity (in W/sqm) not the energy or power. Given that he uses 5800 small mirrors concentrating the radiation on 1 sq.cm... here you go.
Questions raise, answers kill. Raise questions to stay alive.
In the Himalayas, parabolic mirrors around this size are commonly used to boil kettles of water for tea/cooking.
It works at those altitudes, because the sunlight is more intense (less having been absorbed by the atmosphere), and because water boils at a lower temperature at the lower atmospheric pressure.
http://en.wikipedia.org/wiki/Solar_cooker#Solar_kettles
> This is surely a wonderful, novel demonstration of human ingenuity and cleverness. =/
Everyone is missing the real point --- in actuality, he only did it to be able to collect the insurance money on his (over-insured) shed without raising the suspicions of the investigators.
These mirrors are pretty thick, and when glued on the surface of the dish, he actually ended up with the mirror surface being out of alignment, so the focus point is far more smeared than that of the original, precisely designed and aligned dish.
The proper thing to do would have been to chemically deposit a very thin silver layer on the dish surface. This is actually not difficult to achieve. The mentioned spray paint or aluminum foil solutions are also better than his really, really crude approach.
for that long doing a menial task.
The Internet's nature is peer to peer - 20050301_cs_profs.pdf
The concentrated spot of light cannot even be quite 1 x the brightness of the sun. Never mind ">5000 times brighter". The laws of thermodynamics say so. You cannot focus an image of a light source so as to make the intensity at that focus more intense than the light source itself. Kudos for good execution of his idea, but that ">5000 times brighter" claim is just plain wrong.
"Absorbing your worst..."
he is probably getting somewhere close to 1000W
Judging from the size of the reflector it's less than 500W. A small arc welder putting 25 amps at 20 volts will put out 500W on a small spot and melt steel instantly, so it's not such a big deal
You're retarded, small focused flat mirrors are more efficient and less prone to scatter than a non perfect parabolic shape. Not to mention the reflectivity of actual mirror is far superior to any sprays or sheeting you could cheaply purchase. There is a reason the cells of production solar plants use flat mirrors that they combine to form a parrabolic array.
According to Wikipedia:
The largest solar pumped laser is currently being operated by a research faciliy in Uzbekistan. It is a 1 MW NdYAG type laser, operating at 3,000 Degrees C. It is cooled by distilled water.
A megawatt of continuous wave laser power is nothing to be sneered at.
Yeah, I used to burn ants with a magnifying glass too when I was much younger than 19. Solar death rays are pretty common at that age.
Seven puppies were harmed during the making of this post.
Stirling Energy System's SunCatcher uses this system to drive a stirling engine mounted on a parabolic mirror. It always seemed like a better, simpler solution than photovoltaic cells to me.
If all else fails, immortality can always be assured by spectacular error.
Given the parabolic dish, it should already be pretty well concentrated at the focal point. If you wanted to move the focal point a bit, for whatever reason, you could place an appropriately sized lens a bit before the focal point, to either move it out a bit, or move it a bit closer.
Whether or not it would melt would depend on how efficient the lens is. An ideal lens(100% transmission, no absorption, internal reflection, or other funny stuff) wouldn't even notice. A real lens, with less than 100% transmission, would end up eating some of the energy. Its behavior would depend on how good the cooling provided by its mount and the surrounding airflow is. If it reaches thermal equilibrium at a point lower than its melt point, no problem. If it doesn't, game over.
A well cleaned glass lens nicked from some fairly high power application would probably shrug(a Real Serious fused quartz lens would likely shrug under almost any circumstances). A scratched or dirty plastic lens would probably melt. A small cooling fan might well make all the difference. When doing brute-force thermal engineering, forced air can frequently be substituted for elegance.
The tiny mirror pieces are from a mirror ball. Yes, I actually do go out sometimes.
apparently not since the seventies :D
The 19-year old claims that his solar device has the intensity of 5,000 suns.
Yeah right! Sure!
Doesn't he know no one will care until it's over 9000 ?
If all else fails, immortality can always be assured by spectacular error.
In the Himalayas, parabolic mirrors around this size are commonly used to boil kettles of water for tea/cooking.
It works at those altitudes, because the sunlight is more intense (less having been absorbed by the atmosphere), and because water boils at a lower temperature at the lower atmospheric pressure.
http://en.wikipedia.org/wiki/Solar_cooker#Solar_kettles
Screw the Himalayas. I was 12 when our year 7 (1st year of junior high for you Americans) science class constructed solar ovens out of aluminium foil, a large tin can, coat hangar wire and masking tape. They were good enough to cook sausages and eggs and this was at sea level. It wasn't lame but it wasn't exactly difficult for a 12 year old. A smart but not genius 8 year old could do it.
The parabolic reflector is only one design. Just Google solar oven science project for kids
http://www.crystal-clear-science-fair-projects.com/solar-oven-science-project.html
http://www.columbiascientific.com/science-fair-experiments/garretts-solar-oven-science-project
This should not have been a slashdot story.
These posts express my own personal views, not those of my employer
Believe me,
I do not want you to see my "adult projects"
thats something for the privacy of the home, you pervert.
seriously,
what i meant to imply (and you obviously failed to grasp); Slashdot needs to filter away stuff that is far from impressive. If his mirror had had a diameter of 10m, than that would have been newsworthy for a 19-year old. I'm sure younger kids have achieved more impressive results than sticking some glass chips on a 1m metal plate.
also, is 19-years not being an adolescent?
Why are other peoples sig's always more witty ???
Well, in reality, it only requires a little reading and some common sense.
Considering that only 705 Watts fall on a square meter of the earth, and calling this dish a square meter is generous, he has roughly a poorly-focused 700W light source.
Even if this was in space, it would only have 1336 Watts of power.
The entirety of Earth only receives 174 Petawatts from the sun.
The approximate luminosity of the sun at its location is 384.6 Yottawatts.
Nice try kid, this thing is neat, but don't go hyperbole on us and claim that it has 192,300,000,000,000,000,000,000,000,000 Watts of power.
If the only way you can accept an assertion is by faith, then you are conceding that it can't be taken on its own merits
And, bearing that size in mind, a quick back of the envelope suggests that 1 MW is the input power of the light, not the delivered power of the laser. A quick search doesn't turn up any papers or detailed articles relating to this solar tower specifically, but other examples of such solar-pumped NdYAG lasers suggest a conversion efficiency of about 10 W laser power/m^2 of mirror, or about 1% of the incident radiation [1].
So, assuming that lasing efficiency for this system, this is not a 1 MW CW laser, but a 10 kW CW laser pumped with over a megawatt of input power, which necessitates significant cooling to keep the thing from melting. Compared to traditional laser designs, this is still not that impressive, especially given the effort involved in its manufacture.
[1] A solar-pumped Nd:YAG laser in the high collection efficiency regime
My death ray goes up to 11,000
I recall reading that the Spanish plundered gold and silver discs that were several feet in diameter in their conquest of the South American peoples. It was suggested that they were solar concentrators similar to the one demonstrated, since smaller ones are known to have been used in lighting ritual fires, the larger ones may have had a more practical purpose, including shaping stone.
If focused was computer controlled. Each tiny mirror needs servo controls.
more cowbell