who's that under the bridge
29 posts • joined 13 Mar 2008
I can't believe that is true, what information are you basing that upon?
When its cloudy I need the lights on in my office, when its not, I don't. There are 4 banks of 4x18W tubes in my office, so that's an additional 288W needed to keep a decent level of lighting in my (fairly small) office.
I think the real issue aside from cloud cover (you may be able to fly above the clouds but I'm not sure what you'd see :) is the angle at which places further from the equator are angled to the sun.
The UK gets drastically less energy per square metre than somewhere on the equator.
You are thinking of photovoltaic right? Not the solar hot water heaters? A nice toasty bath on a plane is all well and good but something's gotta power the engines.
So lets assume that the guy you're targeting is an unrealistically far 5000m away. Assume the laser beam travels there at near enough the speed of light in a vacuum (3x10^8 m/s) and then has to get back to your scope, so 10000m at 300000000m/s gives 33 micro seconds. Is that really too much dwell?
I fully agree moisture in the air/dust could be a problem.
I'd love to know just what there $5 laser detectors people or discussing are. Granted they're probably using IR and black and white video cameras/webcams will pic it up easily enough, but this $5 gadget must be pretty clever or they'll be targets diving for cover every time someone changes channel on the telly. IR DETECTED FIND COVER!!!!!
yeh just like alcohol and cars and motorbikes. All far too dangerous and much too much fun, it should never have been allowed :)
in fact glass can go too, much too easy to cut yourself and there plastics instead, and pins, they're a bit risky aren't they, lets have blue tack instead.
having looked at laser induced cavities in water I'm aware of a few phenomena around this, the most interesting I believe to be the oscillating bubble. A cavity/bubble created by heating (that is the process we're talking about right?) the water expands whilst it is powered, then when the light stops, the surrounding water compresses the bubble. As it compresses the gas within gets hotter and after a finite compression it begins to expand again (though obviously not to its original size because of thermodynamic losses) and so on in an oscillatory fashion until extinct. Now with all these little bubbles popping up and down and changing size, and the fact it takes a little time (ms not ns or even near fs) I'm wondering if you could even transmit anything of worth.
OK you might squeeze a little data through such a method, but encrypt it and send anything of size/worth, doubtful.
further to ACs comments about (non)knockoffs, he's entirely incorrect about LiPo batteries, just watch a you tube clip of a LiPo from an RC model being overcharged
similar things happen if you dent them bad enough to perforate the container.
this was reported some time ago (weeks I believe) if only I could remember where.
Has it not been shown that whilst CCTV reduces crime in city areas by 5% bright white lighting reduces it over 30%?
I'm in favour of lights at night, lets face it, you don't really need them any other time. The point that should be made is that lights should have cowls to direct the light downwards, and appropriate wavelengths used.
All this talk of lasers not being tunable is wrong. Argon ion lasers are tunable across a large part of the visible spectrum, we had one at uni, it was cool :)
Even less special lasers are tunable within certain limits, changing the tilt on the stepped grating at the back of a gas laser for instance.
If you want to go diode then I guess you could have a gattling arrangement of frequency shift crystals, though this may be too course.
As for "the military have glasses that are laser safe" that is a very subjective statement. Even glasses tuned to stop the wavelength of light I work with are no use if you cop it straight in the eye. If they could stop it then they'd be black and thick.
If you stop all the wavelengths then your glasses will be black.
I'm only trying to correct a few statements, don't think for one minute that I think this thing has a chance in hell of actually working. Reflective glasses, turning your back, or even trying to aim the damn thing across 2.4Km is going to be a show stopper.
By the way, I've managed to hit someone whilst being sick (there was beer involved:)
68mpg isn't amazing to begin with but I don't really understand...
"or to cut fuel consumption on the open road"
how does lugging around an extra weight of batteries and motor cut fuel consumption on the open road? Surely you don't need four wheel drive on the open road, and if you consider a very long straight, constant speed open road I really can't see the benefit of lugging all this kit around.
Granted if you've just built up some charge breaking here and there, then the road opens up then there might be something in it, but cruise for a hundred miles or more and I'll bet you're just lugging dead weight
stuff all this weight mass mumbo jumbo, they just need to build a giant weighing scales, rockets on one end, giant bath tub on the other. Fill with water until balanced then shift bath tub on said bull dozers down the walk way. If it sinks, cracks, slips, you lose some water. If not then you're probably safe to shift the real rocket. Do it a few times to be sure, maybe even on a windy day. Daft civil engineers and surveyors panicking when all they need is me giant tub.
Or for similar money you could have the Nikon d40x.
Whilst I honestly prefer the canons operation the lens is shit. I know i know, this is an slr, the whole point it versatility and changing lenses, but when most lenses outprice the body you gotta seriously look at what stock lens comes with it.
Nikon made lenses, then to sell their lenses started making cameras, a few years later they're pretty good at it. Nikon = awesome out of the box, Canon = shit out of box, but potential for being a nice camera with a new lens.
All in all if you're on a budget opting for a samsung copy of a pentax slr (fully backwards compatible with their old manual lenses = cheap) is the way to go.
All of the mirror comments wont matter if they aren't kept clean, a spec of dust will begin to heat on the mirror surface and then burn it away, gold or not. As for peoples comments about it being kilowatt class and mirrors being useless at this power level, you can reflect gigawatt beams with no problem as long as you have the right wavelength (99.99% reflective) CLEAN mirrors.
And the bit that really bugs me: SILENT!!!!
you ever heard a laser melt something, or vap it entirely. Its not quiet.
I agree with the comments from David Giles, they sure do make some nasty waste. Infact if you totted up waste against usefullness these probably outweight a nuclear reactor.
Fire coz we all know burning stuff isn't silent
if this is causing significant problems to aircraft then perhaps they ought to protect themselves. I know in an ideal world we would punish the wrong-do'ers rather than forcing legislation on the airline companies, but they could very effectively fit their windscreens with wavelength selective blocking films. And yes I cam aware that you can't block all wavelengths or it'd go dark, but it wouldn't be hard to get rid off just 633 and 532nm.
suprised this is just mischeif so far, wonder if there's a terrorist application. many countries have banded about the idea of tanks capable of blinding entire battle fields of troops despite the geneva convention.
anyone ever shone one in a cctv camera, temporarily saturates the ccd rendering it useless, more mischeif.
what we need now is rear facing lasers on the back of my car to get that fool in his bmw off my tail.
i haven't changed my story one bit, in my opinion blackholes are at best unlikely, I never said they didn't exist, only that you should keep your mind open to the fact that they may or may not exist. I personally err on the side of their non existance but that is merely my view, not a fact. I wouldn't present it as one either.
And yes I'm sure you can find a million links to claims for black holes reality, but your overlooking the fact that there's money to be made from this bandwagon. There was a time when all you had to do was drop "blackhole" into the title of a paper and it would be practically guarenteed publishing (if you need publishing I'd now recomend saying something about nano technology).
How can you show such an inteligent view: questioning the existance of god, and yet swallow the science pill so easily.
All I'm saying is, real or not, don't believe all that you read - even when a whole load of people believe it is fact.
Cerainly not bipolar, just healthily eccentric as all should be.
I do exist, many can confirm this. There are laws of physics within which I can be described and I am aware of the curvature of the earth.
The maths which could be used to prove my existance, alegedly can be traced to a singularity which proves the existance of blackholes, however i've seen equally convincing forms of the equations which result in no such singularity.
I'm not saying black holes don't exist only that there is an equally good argument for them not to exist as there is for them to exist.
Please try and keep and open mind and not just swallow the media BS that you are obviously so fond of.
you all speak as though black holes exist! its a stupid idea dreamed up by excited scientists in desperate need of funding. Show me some actual evidence for their existence. And as for you beloved hawking, don't even get me started.
Stop - please stop refering to black holes as though there existence is factual.
All well and good but 50Gb bloated movies may take some time to transfer, and presumably you'll put them on a harddrive when you get home. What happens when that hdd crashes? you lose all you movies. my video player never crashed!
atleast with dvds you wont lose them in a hdd crash. could be frustrating watching your cherished movies dissapear before you eyes.
This is written as though this is some new discovery. Dr Santilli invented magnegas a long time ago. Even funded by the US military briefly, and Harvard, both of which quickly cut funding after oil companies/government/god intervened.
The US government new about such technologies and supressed them. Santilli was labelled eccentric at best. Now some other company has "reinvented" it and they're willing to listen? sounds like rubbish. Where's his credit?
When will the actual scientists who push technology forward be recognised rather than supressed for spin.
dead dodo, cos all us scientist may as well be!
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