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The smaller designs, including L-M, Polywell, and Tri-Alpha are much more likely to end up in commercial designs than tokamaks.
Then there's this guy, who has an interesting laser-driven design. It has however a tiny problem in that it uses pulsed magnetic fields of ~ 10kT.

now that sounds really cool doing your own laser reflection but are you using facility scope? Have amateur astronomers done this before? Does it require a really powerful laser, i.e. the kind that guvmint doesn't want in hands of individuals?

Now you people commenting of they don't think this is possible, this is one of these reflectors wwphx is talking about, http://spie.org/Images/Graphic...

Ok, let's go to the Maths then : the OTF gives you how spatial frequencies are transferred through your optical system. You understand that it is equivalent to an auto-correlation of the aperture, right?
Well, if the aperture is circular (a disc function, for a perfect system), the auto-correlation is equal to the area of the intersection between two shifted discs (of equal radius). This shift represents the spatial frequency : at 0 spatial frequency (the DC component), the discs are aligning perfectly and you get the highest transfer (=1); at high frequency, the two circle are shifted a lot and you have only the area corresponding to a very small cat's eye shape; at the cut-off, only a single point is common between the two discs; finally, after the cut-off the two discs are not intersecting anymore and thus the transfer function is EQUAL TO 0.

In the case of your experiment, what was the cut-off frequency? (1.0/(Lambda F) where F is the F-Number of your optical system)
Did you made measurements after that frequency?

You can also read that kind of resource.

Sorry, I don't think it is based on the paper below, and the previous citation.

Light propagation explains our inverted retina

In summary, the retina has developed its inverted shape to improve the directionality of intercepted light beams, to enhance vision acuity, increase immunity to scatter and clutter, concentrate more light into the cones, and overcome chromatic aberration. We are now assessing the effect of ocular aberrations on acuity to explore what happens when the beam hitting the retina is more spread and its phase is more random.

SPIE is an international society advancing an interdisciplinary approach to the science and application of light.

Previous: Is the Backwards Human Retina Evidence of Poor Design?

Also, note:

Introduction to: Cephalopod Vision

There are differences between vertebrate eyes and those of cephalopods. Perhaps the most surprising difference given the amazing ability of cephalopods to change color is that most cephalopods are completely color blind (Hanlon and Messenger 1996). How do we know? We can train octopuses to pick black objects over white objects, white objects over black objects, light grey objects over dark grey objects and vice versa but we can not train them to differentiate between colorful objects that look the same in grayscale (Hanlon and Messenger 1996). Also, most cephalopods only have one visual pigment. We have three.

If we had eyes like nearly all squids, we would be color blind. Does Dawkins think that is superior?

Sorry, I don't think it is based on the paper below, and the previous citation.

Light propagation explains our inverted retina

In summary, the retina has developed its inverted shape to improve the directionality of intercepted light beams, to enhance vision acuity, increase immunity to scatter and clutter, concentrate more light into the cones, and overcome chromatic aberration. We are now assessing the effect of ocular aberrations on acuity to explore what happens when the beam hitting the retina is more spread and its phase is more random.

SPIE is an international society advancing an interdisciplinary approach to the science and application of light.

Previous: Is the Backwards Human Retina Evidence of Poor Design?

Also, note:

Introduction to: Cephalopod Vision

There are differences between vertebrate eyes and those of cephalopods. Perhaps the most surprising difference given the amazing ability of cephalopods to change color is that most cephalopods are completely color blind (Hanlon and Messenger 1996). How do we know? We can train octopuses to pick black objects over white objects, white objects over black objects, light grey objects over dark grey objects and vice versa but we can not train them to differentiate between colorful objects that look the same in grayscale (Hanlon and Messenger 1996). Also, most cephalopods only have one visual pigment. We have three.

If we had eyes like nearly all squids, we would be color blind. Does Dawkins think that is superior?

Well, quantum mechanics says we can't be sure what has happened exactly or more importantly will happen. However, we can clearly exclude some things which will not happen (e.g. if we have a waveguide with a single wavelength width, the particle will not be in the middle; almost anywhere else, but not exactly in the middle (see the second of the images on this page; e.g. the electron in a semiconductor will not have an energy in the bandgap). In this case, conservation of angular momentum will apply, so solutions in which Japan moved and the world did not are ruled out. A large number of people observed that Japan moved, and so the rest of the world must have moved proportionally.

So what is the UV source (Excimer laser?)

Like Intel and others buy lithography machines from ASML and competitors, we buy our (E)UV sources from other companies as well; Cymer, Ushio, and Gigaphoton are producers of such sources. (source). The idea is that you hit a suitable material with a gigantic laser pulse or electrical discharge, thereby heating it to something like 10^5 kelvins such that it starts emitting EUV radiation, along with loads of other wavelengths that you have to filter out. (at 10^5 K, the thermal radiations peaks at about 25 nm). Here is an old (2006) article about EUV sources.

and what optical elements are you using. Its it mostly reflective or are there materials sutable for deep UV?

Deep UV usually means 190 nm, for that there are lenses. In EUV (13 nm), mirrors are used. The reason for the large jump in wavelength is that inbetween, there are neither suitable mirrors, nor lenses; at least so I believe.

the website is the typical marketing tripe.

I think the ASML website has white papers with more technical background, but you can find more information in patents and proceedings from semiconductor-industry conferences. I'm not allowed to tell you anything here that is not already published. :-)

(Opinions are mine, not ASML's)

But other jobs get created elsewhere. This is why Germany has a booming photovoltaic industry despite having insolation similar to Alaska, for example.

Maybe you should have paid attention in Econ 102.

There is some work being done with laser stimulation of nerve endings which may have some application for that.
http://spie.org/x8731.xml

It would be a form of virtual reality.

With current technology, its impossible to see the flag on the moon. I didn't check this site's math, but it confirms what I've read several times before. According to their calculations, we'd need a telescope with an aperture of approximately 800 feet to just barely see the flag. But even with adaptive optics, atmospheric distortion would still be the limiting factor. The Keck telescope has a best angular resolution of about 5 milliarcseconds with adaptive optics. The flag from Earth is about a 10th of that (4.716 x 10^-4 arc seconds).

Regarding the "blurriness" of the ISS photo. I've dabbled in some astronomy and astrophotography and its really amazing (or frustrating) just how much shifting and blurring you see while looking through a telescope at high magnification.

http://spie.org/x26516.xml

So, if patent exhaustion is more expansive than previously thought.

If we purchase a DVD, should we not have also (included with the purchase) rights to the patent used in the product, i.e. the compression algorithms?

The used the "IP" to produce the product and paid the license to do so. Why should we be further encumbered? It isn't as if we are creating new content with the codecs, we'd use free ones for that.

Any lawyers want to start a class action for EVERYONE that owns a DVD player?

I'm currently at the SPIE advanced litography conference. For those unaware, photolithography is the most costly, critical manufacturing step in all of semiconductor chip production. It is where the 45nm pattern is generated and transfered to the wafer. I've seen dozens of presentations scheduled from Intel and hardly any from AMD. The cost of R&D in this business is *brutal* and it is the lifeblood for progress. If AMD is going to become competitive again - it's definitely not because of any technological/manufacturing advantage.

Other people have suggested potentially more practical electostatic interferometric displays, like this one. The advantages of this technology, like the classic electrostatic e-paper with the microscopic dual-color beads in oil, is that it doesn't require any power to maintain the display.

Even so, this technology has been around for ten years, and is still in the very early research stages.

Thad Beier

Bell is a great lab, but credit where it's due: the laser was demonstrated by Theodore Maiman at Hughes Aircraft..

I believe x-rays of these energies (a couple of hundred keV) can go through many meters of air (tens to hundreds) -- at least enough of them to register on the detector. Some luck involved, of course, but they looked long enough to get it.

Second thing, although you are absolutely right that bremsstrahlung gets more efficient with higher Z (and with higher energy), it will never be more than about 10 to 20% of the energy loss for electrons of these energies (about an MeV, give or take a factor of a few). Most of the loss will still be by ionization and excitation of air. So bremsstrahlung won't suddenly take over and start dominating the physics, I think, for this reason and because there will be just a lot more air around than evaporated wire. If I were a real lightning physicist I could address your idea that there is heating due to pinching by the magnetic field, but I won't try.

As for the x-ray intensity, I get the impression that it's much less than a chest x-ray, and lasts much less time as well.

One more cool thing in closing: there are groups trying to trigger lightning with a laser (of a suitable wavelength to cause ionization, I presume), and apparently the Japanese have already done so a couple of times: http://www.spie.org/app/publications/magazines/oer archive/july/jul99/laserlight.html

Cheers,

--David

Maiman did develop the first operational laser, but not for AT&T ... they (Bell Labs, that is) come into the story because their researchers Arthur Schawlow and Charles Townes wrote the seminal papers. Good background info sources

http://www.bell-labs.com/about/history/laser/index .html

http://www.spie.org/web/oer/august/aug00/maiman.ht ml

This is a common misconception and completely untrue. It is impossible for ground based telescopes (ANY ground based telescope) to take images that Hubble can.

OK let's assume for a moment that you're correct, can you give us some more detailed information to make your case? As far as I recall the deep-field photos were sustained week-long exposures, something which of course would be impossible on a terristrial scope.

But most scans don't require week long exposures, especially since the terrestrial scopes have over 60X the light-gathering capacity of Hubble's primary mirror. As far as I recall there are at least 2 major projects using optical and infra-red interferometry between 3 or 4 8-meter mirror arrays. 4X10meters plus the resolving power of interferometry(distance of say 200meters between mirrors) results in pound-for-pound a much more versitile viewing instrument than Hubble. Don't get me wrong Hubble was a great scope, but interferometry and adaptive optics are the future of optical astronomy.

If you end up responding, please explain clearly why I'm wrong because I would like to know.

The abstract on the Nature website wasn't doing it for me. I wanted to see a picture. After a quick bit of searching I found the PDF that explains more and has three colourised pictures. http://www.spie.org/paper/FirstSelf.pdf

SED displays are CRTs, after a fashion. They have electron guns that fire modulated electron beams through a vacuum at phosphor screens. As such, they have the brightness, color purity, and response rate of regular CRTs. What is different is that there is an electron gun for every pixel, instead of just one that is scanned across the screen. This allows the screen to be flat and shallow, and gives the geometric flatness and sharpness usually associated with LCDs.

This was attempted before with a slightly different technology, and went by the acronym/buzzword FED, for Field Effect Display. As this article points out, there was tremendous anticipation of this technology quite some time ago, they were planning to go into production in 1996. FED's had an array of tiny, very sharp needles behind the phosphor screen. Unfortunately, the production and maintenance of this array of needles proved to be next to impossible.

SED's use a much more producable and durable semiconductor array of electron guns. The technology of creating large, dense arrays of semiconductors on substrates has been developed and perfected by the LCD process, so I feel that there is hope this time around that the machines will actually be mass-produced on the aggressive schedule that Canon and Toshiba have laid out.

The first generation of SED's, it is claimed, will unfortunately not have the resolution that would make them good for computer displays or home TV's, as the spacing of the pixels will be somewhat large. They'll be used for business displays of various kinds. But, in the not-too-distant future (three-to-five years) Canon and Toshiba predict that SED's will come to dominate TV and monitor production.

We'll see.

Thad Beier

I've had that twilight anesthesia when I had a broken wrist. It was stuck in a bent position and the doctor had to sort of "break" it loose so he could set it in the correct position to put the cast on. It was an interesting experience. Things get kind of fuzzy and dizzy and you don't really know or care much about what's going on around you, but you don't really go all the way out.

I hadn't heard of the crawling pill yet. I had just heard about the Given Imaging pill that just gets pushed along by your normal intestinal movement while filming and transmiting video.

And don't worry about the link--even though we are discussing items emerging from the GI tract, this is a goatse-free post.

I guess it's a chemical laser, and probably uses things like flourine gas (nasty nasty nasty, but very energetic). You can read some info about these kinds of things here

This old report from 1999 actually suggests it uses some other strong oxidisers like hydrogen peroxide and halogens - chlorine and iodine.

Basically you don't want to be breathing these things in, but you there's a lot of energy available in their reactions.

I'm glad to see this slashdotted but the technology is old (oil-submersion microscopy has used it for decades). All of the major stepper/scanner manufacturers already have submersion litho systems, already in full testing.

At this past years SPIE (www.spie.org) conference on microlithography there were a slew of papers on this technology.

I'm a RIT uE grad, so YAY RIT, but, eh it's old news.

As one of the engineers who is working on getting the shuttles back up and flying, I take offense to that. Just getting them back up to the ISS is extremely expensive and difficult. Examining the thermal protection system for damage is no simple task. And that's just detecting and measuring damage. Fixing damage in space is far more difficult and expensive to develop. Finally, the necessity for an alternate return method, i.e., a lifeboat, can't be met going to Hubble.

Can the shuttle be made to go to Hubble safely. Probably. But the expense and time involved would be astronomical. It'd probably be cheaper to build and send up a new Hubble on a rocket.

But if you think the problem is people making excuses, you're full of crap. Real engineers are working their asses off just to get the shuttles to return to the ISS. Hubble is a magnitude more difficult and expensive to reach. It's simply been decided that it is not worth it. Nobody is burying their head in the sand here.

I am not saying we shouldn't go to Hubble. But the problem, as I see it, is that nobody has even come close to demonstrating that the effort and expense are worth it yet. Yes, some areas of scientific work will suffer for a few years, but these are just a small fraction of the whole field of astronomy. There are alternatives to some of this work, like the Keck I and II observatories and other adaptive optics telescopes which can rival or better Hubble in many areas. Yes, admittedly, there are some wavelengths that can't be matched by ground-based. But I have yet to hear any convincing argument about why the work in these wavelengths over the few lost years of Hubble would be significant enough to make the expense and effort to get the shuttles safely to Hubble worth it. For the most part, it sounds more like impatience with a little bit of "spoiled" whining thrown in. (That is, a lot of "We've been able to use Hubble before so why should we give it up now.") No, I don't believe that is the "best" level of argument for keeping Hubble, but it's hard to find the good arguments through all the "noise".

To me, the "bullshit-mongers" are those who suggest that NASA isn't looking at this seriously, or those who seem to think Hubble is some sacred god that must be saved at any expense. Most people arguing it needs to be saved don't understand the amount of time, expense, and effort to do so. The opposite also applies somewhat, those who would have to make this effort (and time and expense) don't fully understand the importance of this apparently "short-term" loss of data over a "few" wavelengths. You'd do much better to make your case on why this is necessary than spewing untrue claims and insults about "heads in the sand". My mind is open, but all I'm hearing is insults and contempt, not reasons.

I think it's very interesting that as we get closer to being able to reproduce the capabilities of human intelligence, we consistently return to the basics of our 7th-grade Life Sciences classes (apologies for the American-centric illustration).

Carbon, carbon, carbon....

For (another) example, eyes are made of carbon.

Cute, but not very effective

1) Clear flyable weather. While you can detect the thermal blooms of launch, you can't rely on that for tracking, thus the need for a ranging laser. Will this work if you've got 5-10k ft of cloud cover to visually confirm the target? How about minor-major turbulance?

2) Total aerial supremancy. As with AWACS, you'll need to dominate the skies to the point where SAMs are not making the plane suddenly jink and miss the shot at the wrong time

3) Target overload. If there are a "lot" of thermal blooms, how long will it take to determine which one is shooting the real missle? ...

4) Equipment. How long to reload between shots? Fast enough to take a second shot? What sort of stress does this put on the plane and the internal equipment? If you do miss, can you still track the missed target

5) Limited range. From the description it can cover a few hundred square miles....

Lets assume this company is doing the prediction through
ELF/ULF electromagnetic monitoring. According to some things I've read (see link), the bigger the earthquake, the longer and louder the ELF/ULF warning signs. That would probably be why they claim 90% accuracy for those over 6.

Accually, something that is said to be a very good early warning sign about earthquakes is ULF (ultra-low frequency). Basically, its an electromagnetic wave between 0.5Hz and 5Hz, pulses of extremely low "vibration" normal humans cant hear/feel (unless you're Travolta in the movie Phenomenon).

The theory is that many animals can feel such vibrations, which can give you a few hours or at most a few days warning about an earthquake. Anyway,
this site should give you a little more interesting information about ULF/ELF and earthquake prediction.

Firstly, my sympathy to all involved.

Next. Has anyone seen the SPIE Proceedings Vol. 2455 (b=abstracts) particularly Paper #: 2455-23 Shearographic nondestructive evaluation of Space Shuttle thermal protection systems

The abstract says

It is estimated that 90% of tile TPS damage on the orbiter `belly' results from debonding SOFI during ascent.

This paper is in the proceedings of the SPIE meeting in 1995 on "Nondestructive Evaluation of Aging Aircraft, Airports, Aerospace Hardware, and Materials"

I know that they have optical telescopes that do this now. Keck Observatory come to mind. Here is a link to a page that describes what they are doing and the resolution they are getting. The VLT (Very Large Telescope) is another example of combining the beams of multiple telescopes.

The researchers used six physical properties they refer to as the Magnetite Assay for Biogenicity (MAB) to compare all the magnetic material found in the ancient meteorite -- using the MAB as a biosignature.

Earlier, a number of other scientists observed chemical and visible (through an electron microscope) formations indicitive of biology. NASA astrobiologist Dr. Richard Hoover explains in an interview from December '96:

Carbonate is a mineral that on earth is commonly produced by the action of microorganisms. Limestone is an example. Furthermore, the carbonate globules in ALH84001 are similar in size and texture to carbonate precipitates that are often formed by terrestrial bacteria. [David S. McKay et al. of JSC] demonstrated that these carbonate globules contained fine-grained secondary phases of single domain magnetites and iron sulfides. These minerals probably formed in water solutions at temperatures amenable to microbial life. This result is extremely significant.

Furthermore, on the skepticism, Dr. Hoover points out:

The biggest controversy is over whether or not the rock contains evidence of microorganisms, and therein lies the most fundamental question. There's the frequently quoted saying, "Extraordinary results require extraordinary proof." It's true that scientists must always exercise careful skepticism. However, skepticism can reach a point where valid evidence can be rejected simply because it does not fit into the conventional view of the world at that time. Sometimes scientists also oppose new ideas because they may contradict ideas that one has published in a paper years earlier.

See my other comment on this story with links to pictures and more supporting background information.

SPIE-The International Society for Optical Engineering captured the bulk of Dr. Hoover's presentation in an interview published in their December '96 magazine. This September 1998 article offers pictures of the fossils found, as does a July 1997 article. Another story announces a fossil find in another meteorite that fell on Murchison, Victoria, Australia.

Many people question the science, but it would seem people should question the scientific community which has held its hands over its eyes when faced with the prospect of life on other planets. The community is just now peeking between its fingers and beginning to accept that there might be life elsewhere. In the presentation I attended, Dr. Hoover noted that NASA set up rules in advance of the Viking missions - that any one of the several (4?) tests coming back positive would be indicative of life on the red planet, but once some of the tests came back positive, they decided that all of the tests had to be positive to confirm the existence of life on Mars. Such has been the distinctly non-scientific approach of the community when confronted with the distinct possibility of life on other planets.

More links:

• Evidence of Biomarkers and Microfossils in Ancient Rocks and Meteorites abstract.
• A collection of NASA (and other) news releases pertaining to evidence of extraterrestrial life.

SPIE-The International Society for Optical Engineering captured the bulk of Dr. Hoover's presentation in an interview published in their December '96 magazine. This September 1998 article offers pictures of the fossils found, as does a July 1997 article. Another story announces a fossil find in another meteorite that fell on Murchison, Victoria, Australia.

Many people question the science, but it would seem people should question the scientific community which has held its hands over its eyes when faced with the prospect of life on other planets. The community is just now peeking between its fingers and beginning to accept that there might be life elsewhere. In the presentation I attended, Dr. Hoover noted that NASA set up rules in advance of the Viking missions - that any one of the several (4?) tests coming back positive would be indicative of life on the red planet, but once some of the tests came back positive, they decided that all of the tests had to be positive to confirm the existence of life on Mars. Such has been the distinctly non-scientific approach of the community when confronted with the distinct possibility of life on other planets.

More links:

• Evidence of Biomarkers and Microfossils in Ancient Rocks and Meteorites abstract.
• A collection of NASA (and other) news releases pertaining to evidence of extraterrestrial life.

It was, at least in 1999, according to this article. It hasn't been mentioned as a problem in recent articles, such as this

An older approach is the Munsell system. His system, which he began in 1898 with the creation of his color sphere, or tree, saw its full expression with his publication, A Color Notation, in 1905. It is not mathematically based, but rather each step corresponds to an actual equal perception step.

Even though there are surprisingly large discrepancies between CIE L*a*b* and isotropic observation-based color spaces, such as Munsell, a good bet is to convert your LAB into Munsell and go from there.

http://www.cnn.com/2000/TECH/space/07/20/speed.of. light.ap

http://www.spie.org/web/oer/july/jul00/lightlimit. html

what's the next story in "science", MAN HARNESSES LIGHTNING CREATES ULTRASAFE RAIN-FREE OCEAN.

GO HUMANS!

What would normally considered good material for internal discussion, but not publication, by most academic institutions, is publicly paraded by NASA.

According to the article, DiGregorio is presenting this report to a conference on astrobiology sponsored by the International Society for Optical Engineering (part of their annual meeting in San Diego). This isn't a NASA report; it's written by someone who is predicting that a future NASA or European mission can resolve this question. Moreover, it's for a conference about what technical methods could resolve such questions.

(I should have checked out SPIE's website before this post; I think it could have cleared up some of this confusion.) I see nothing inappropriate about this sort of press.

Thermal imaging is nothing. A number of companies are being funded by the Department of Justice to develop a new type of radar that would allow police to scan somebody on a sidewalk to see if they had a gun - without their even knowing it. Details here...

If I understand correctly, full-color pixels are possible with OLEDs rather than 3 separate RGB pixels. Would this make Microsoft's eBook ClearType patent irrelevant?

Well, we could remove them with high-power lasers. This has already been proposed, and is quite feasible:

In-depth article on ORION space debris removal project
Photonics Spectra discussion of ORION project
ORION summary
ORION details
Military Discussion of LISK-BROOM
High power laser ablation conference

The article referenced in this post is a bit short on information, but readers can get a more detailed view of the story from this article.

The technique involved is refered to as resonant hole burning. Rufus Cone and his optical group at MSU have been working on many applications of this technique for years, including optical storage and stabilization of diode lasers (how's 20Hz linewidth for stabilization of a diode laser?) highly accurate clocks, metrology and so forth. Cone has a link to a nice power-point presentaion on his web page.

Cone and his group have been using crystalline materials, while this Japanese group is using glass. The advantage of glass is that the storage medium can be tailored to a specific shape. This abstract, published by the Active Glass Project, indicates other interesting research, including the up-conversion of photons using glass.

We are still in the dark ages as to what the brain actually does and how it actually does it; and we won't be able to use any of our discoverie in information processing technology for the forseeable future.

In part, I would agree with you. But only to a certain extent. Yes, we don't know a lot. But you make it out to be a lot worse than it is. We also know probably as much as we don't know.

I wish I had a link to back up what I'm about to say, but I read about it in Ray Kurzwiel's book, "The Age of Spiritual Machines." Groups of scientists have actually reverse engineered specific neural networks of human and other animal brains. One group has even re-implemented the visual cortexes of several animal brains (including humans, if I remember correctly) in high-density analog neural networks. There is also currently tons of work being done in other analogous areas.

Hey, a quick search on Google turned up this article: A Little Piece of (Silicon) Cortex.

Read up before your spout off.

Also, I recommend everybody read Kurzwiel's book "The Age of Spiritual Machines."

If you are in the SF bay area and interested in this subject, Photonics West is currently happening at the San Jose Convention Center (through Thursday.) For information check here.

You mean, like this?

http://atrey.karlin.mff.cuni.cz/~clock/twibright/r onja/

or this?

"Lighthouse Communications Inc., Littleton, CO Constructed and tested an optical through-the-air communications system with a 10 mile range. Proposed methods and wrote description of a wide area, high speed information broadcasting service. Service would provide terabytes of library type information to subscribers at high data rates. No FCC approval needed."

http://www.djandassoc.com/projects.html

or, like this?

http://www.fas.org/spp/military/budget/peds_98a/06 03006a.htm

(and we humans are quite stupid).

Speak for yourself.

The ammount of power needed to trasnmit data through a light beam in open space is really big,

No, it isn't.

turning the whole process whortless.

Lasers can removed "whorts," too.

That's why we use laser light in a restricting environment (aka optic fiber). Sorry, but it's the worst use for a telescope I could ever imagine....

Laser light communications holds great promise for providing high bandwidth, line-of-sight communication between points that cannot be spanned by cable. A few years ago, some astronomers pinged a laser modulator off the Galileo space probe when it passed near Earth. If Galileo had been equiped with an optical demodulator, it would have been able to decode our signals as it zipped by at thousands of miles an hour.

See also:

http://www.spie.org/web/abstracts/1400/1417.html

or

http://www.spie.org/web/abstracts/1800/1866.html

"In the Galileo Optical Experiment (GOPEX), optical
transmissions were beamed to the Galileo spacecraft by
Earth-based transmitters at Table Mountain Observatory
(TMO), California, and Starfire Optical Range (SOR),
New Mexico. The demonstration took place over an
eight-day period (December 9 through December 16) as
Galileo receded from Earth on its way to Jupiter. At 6
million kilometers (15 times the Earth-Moon distance),
the laser beam sent from Table Mountain Observatory
eight days after Earth flyby covered the longest known
range for laser transmission and detection.!"

You mean, like this?

http://atrey.karlin.mff.cuni.cz/~clock/twibright/r onja/

or this?

"Lighthouse Communications Inc., Littleton, CO Constructed and tested an optical through-the-air communications system with a 10 mile range. Proposed methods and wrote description of a wide area, high speed information broadcasting service. Service would provide terabytes of library type information to subscribers at high data rates. No FCC approval needed."

http://www.djandassoc.com/projects.html

or, like this?

http://www.fas.org/spp/military/budget/peds_98a/06 03006a.htm

(and we humans are quite stupid).

Speak for yourself.

The ammount of power needed to trasnmit data through a light beam in open space is really big,

No, it isn't.

turning the whole process whortless.

Lasers can removed "whorts," too.

That's why we use laser light in a restricting environment (aka optic fiber). Sorry, but it's the worst use for a telescope I could ever imagine....

Laser light communications holds great promise for providing high bandwidth, line-of-sight communication between points that cannot be spanned by cable. A few years ago, some astronomers pinged a laser modulator off the Galileo space probe when it passed near Earth. If Galileo had been equiped with an optical demodulator, it would have been able to decode our signals as it zipped by at thousands of miles an hour.

See also:

http://www.spie.org/web/abstracts/1400/1417.html

or

http://www.spie.org/web/abstracts/1800/1866.html

"In the Galileo Optical Experiment (GOPEX), optical
transmissions were beamed to the Galileo spacecraft by
Earth-based transmitters at Table Mountain Observatory
(TMO), California, and Starfire Optical Range (SOR),
New Mexico. The demonstration took place over an
eight-day period (December 9 through December 16) as
Galileo receded from Earth on its way to Jupiter. At 6
million kilometers (15 times the Earth-Moon distance),
the laser beam sent from Table Mountain Observatory
eight days after Earth flyby covered the longest known
range for laser transmission and detection.!"

Actually, they both use visible red; CDs use 780nm, and DVDs use 635-650nm. (http://www.microserve.net/~tpetchy/DVD .shtml)

The blue laser diode developed by Shuji Nakamura of Nichia Chemical Industries Limited, Tokushima, Japan, can be made for wavelengths between 390nm and 440nm.

Shuji says that "In 1991, the 3M company announced the first II-VI-based blue laser diode. Since that time, II-VI has been very popular for the development of blue laser diodes. However, the degradation of II-VI-based blue laser diodes and LEDs was so large that nobody succeeded in commercializing II-VI-based blue laser diodes and LEDs. Presently, the lifetime of II-VI based green laser diodes (Sony) is only 100 hours under CW operation at room temperature. The wavelength is still green, not blue." His "InGaN MQW laser diode" has a peak wavelength of 404.3nm.

He goes on to say "The main application is digital versatile disk (DVD) for optical data storage. Currently, with a red laser diode you can store 4.7 gigabytes/side on these newly developed compact discs. With a blue laser you should be able to store 15 gigabytes/side, three times as much. Other applications include laser printers and laser full color displays."

Finally, a comparison stolen from CMP techweb:

I'm only going to include the wavelength factor and not compression or improved tracking. They have it wrong, anyway, saying you can only get 7 albums on a normal CD, when we all know it's 11 or greater (Using mp3 compression.)

860nm (Near infrared) is capable of handling one album on a CD.
635nm (Red) can handle two.
430nm (Blue) should be good for four albums on a single CD.
350nm (Ultraviolet) will theoretically let us stash 9 albums on a CD, just by virtue of wavelength alone.

This of course all assumes that we're going to be able to make CDs that have the holes punched in them at the right frequencies; I suspect we'll move on to some more realistic technology, perhaps extra-fine-grade CD-R or CD-RW (Probably CD-R for distribution anyway.)

Got carried away making assumptions about what the people reading my message would know about the money funding AI research: military. For example: "Pulse-coupled neural networks for cruise missile guidance" can be found here.