None of those things need to be in the paper; the presumption in scientific papers is that the authors are familiar with the basic tools and methods of their research area. Unless you have a specific cause to doubt that, you have no justification for questioning their results because they did not include those details. As a practicing scientist, I can honestly say that this isn't how it works.
Obviously there are innumerable details with respect to running any experiment, so not every detail can be included in a scientific paper. In particular, "common practice" in the field can usually be described in short hand by using the proper terms (and referencing previous work as needed).
However, no scientist will read a paper and glibly assume that the experimenters "did everything properly" without evidence that this is so (where "evidence" is a combination of reputation, details of procedure, showing raw data, and demonstration that one understands pertinent issues). It is expected (nay, required, for high-quality science) to mention precautions taken, alternate explanations for results, shortcomings in methodology, and so forth. Omitting a critical self-analysis and details of one's procedure makes a paper very suspect. It is the job of the publishing author to convince the community that they are right, and so they must present sufficient evidence (and sufficient experimental detail) to make their case adequately. To do otherwise makes for bad science.
So, in short, while much knowledge can be presumed when writing technical papers, it is never the overriding presumption in science that everyone is doing science properly. We attack each other's work precisely to keep quality high: and if a paper does not provide sufficient detail to back up their claims, the paper is ignored until such time that further credible evidence is brought into the debate.
The full research article (PDF) is only 3 pages long. The experimental description and discussion of results are so terse that they are barely informative. There are not enough details to know whether they handled the experiment properly or not.
In addition to the problems you mentioned, I'm worried by the fact that they don't describe in detail what they mean by "placebo." For instance, they mention "two separate rooms" in their experimental section, but don't explain why they have two rooms; if one was "real" and the other "placebo" then the variability could easily be ascribed to minor variations in the rooms (lighting, ambient sound, odor, etc.). The RF transmitter is placed immediately beside the person's head (there is a photo in the article), which worries me because they never mention measuring or accounting for audio effects: a high-pitched whine from a running device could easily explain the differences (it wouldn't even have to be consciously audible to influence the subjects).
Combined with the very large standard-deviations on their results, I'm hesitant to ascribe any significance to this finding just yet. More details, and corroborating independent verification, are definitely necessary before raising any public alarms.
You point out that few desktop tasks require parallel processing... but think about the flip-side of this: if we could speed-up many tasks, how would that affect desktop computing?
There are plenty of tasks that people do routinely on computers that are not "instantaneously" fast (spreadsheets, photo-editing, etc.). Furthermore there are many aspects of modern user interfaces that would be better if they were faster (generating thumbnail previews, sorting entries, rescanning music collections, searching, etc.). Also, it's important to realize that the commonplace desktop elements of tomorrow may not have been imagined today. Many things that we don't even consider (and certainly don't consider as "necessary") may become possible (and thus "necessary") with greater computer power (complex graphs/images/previews that update in realtime as a user slides a control, instantaneous re-encoding of video when you drag-and-drop to an external device, etc.).
My only point is that it is tempting to say that computers are "fast enough" and yet in my own computer-use (and watching the computer use of others) there are definitely times when the user must wait for the computer to finish a task (whether it is a split-second page render or a many-seconds refresh of a spreadsheet or a many-minute generation of a complex image). Until all of these tasks are "instantaneous" (shorter than human reaction time), then there is definite room for improvement in computer speed; and moreover improvements that the end-user will appreciate and come to rely on.
You'll notice that of the examples I've mentioned, many of them could in principle be parallelized (and thus benefit from multi-core systems).
Captain Copyright, on the other hand, wearing a cape, a smile, and a costume that says "Don't steal MY music" would go over much better.
Well, it didn't go over too well in Canada.
A "Captain Copyright" character was indeed used for awhile in Canada to promote "rights of artists." Not surprisingly, the character and comics supporting a "copyright maximalist" slant, making no mention of fair dealing (Canadian version of fair use). Furthermore, there were a few incidents where it was shown that the Captain Copyright website was, in fact, infringing copyright.
Because of all the negative press, the character was withdrawn and the site shut down. So it looks like a cape-wearing copyright crusader is not long-lived. And luckily IP law will prevent anyone else from resurrecting that particular idea.
I refuse to click on the links or RTFA because this is clearly another Dvorak "grab-clicks-by-posting-inflammatory-tripe" attempt. Seriously, the quotes from the summary are precisely the standard criticisms that have been leveled against OLPC many times before (and are even summarized on the Wikipedia article). The rebuttals are pretty obvious and have been provided in innumerable Slashdot discussions on the topic.
Dvorak's argument is both a straw man and a false dichotomy. A straw man, because no one is advocating giving laptops to that segment of the world population that is so poor that starvation is truly their overriding concern. A false dichotomy, because spreading knowledge and education is not mutually exclusive with addressing issues of poverty and starvation. In fact, the best way to help a people better themselves is to address immediate threats (such as war and imminent starvation), but to also educate and provide the populace with the tools to take control of their situation and improve it.
OLPC is not trying to send laptops into regions where the social and technical infrastructure cannot support them. The aim is to help those countries that want to improve education and spread of knowledge. The list of participating countries makes this pretty clear. These are not countries of "absolute poverty" that Dvorak conjurs up--these are countries that are trying to improve themselves and succeed in a competitive international market.
There are a lot of people (see above) that are just saying "Whoda thunk there's misinformation on the internet," but this is not the point of the article. The point is that misinformation is being ranked higher than videos showing the scientific truth. It is indeed an interesting finding. However I wonder to what extent the data is skewed by a self-selection bias. I mean, there is probably strong overlap between the class "people who seek medical advice on random Internet sites" and the class "people who believe vaccines are bad." So, basically, there is a group of people who are actively seeking, watching, and rating this kind of material. By comparison, the YouTube videos about how "safe and good" vaccines are just don't show up on the radar of people who generally seek their medical advice from doctors or trustworthy websites.
What I'm saying is that I think a certain amount of this effect is simply related to the fact that the anti-"mainstream medicine" crowd has a definite interest/desire in making, watching, and rating anti-vaccine videos... whereas the pro-"mainstream medicine" crowd probably don't even think to do such things. So, as often happens, the minority viewpoint becomes over-represented.
Still, we should indeed be concerned if even a small portion of the population is getting medical advice from things like YouTube. The overall point, I suppose, is that many people are indeed gullible, and that the medical establishment should work harder to spread the truth to people who might otherwise ignore it.
Re:so much DRM, most data will be inaccessible
on
Security in Ten Years
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· Score: 3, Insightful
We will have become used to having a small number of portals that provide the vast majority of the data we will be allowed to access (for a fee, of course)... Users simply won't have much incentive to surf freely from site to site as there will be so little free data available. While I agree that DRM is a danger we must be wary of, I don't agree with your prediction that we will end up with a small number of "Internet portals," and will lose the "pluralistic" web we currently have.
I had the same worry as you some years ago, but I would guess we are now beyond that particular tipping point. Quite simply, the diversity of the web is now "mainstream." The public at large is now very much used to having billions of web-pages out there, and are also getting used to the idea of self-publishing. The number of blogs and commenting systems is growing by massive amounts. I agree that some of this is hype that will die down, but my point is that now that people are accustomed to such things, they are not going to be willing to give them up. (Put otherwise, there will remain a market for such things.)
I see the worry that people will increasingly get locked into content-portals like Facebook or whatever (where their data is captive)... but there are corresponding efforts to keep content open and free (Wikipedia, Creative Commons, OpenDocument, etc.). These efforts are also growing, and it may very well be that they will cross a tipping point soon enough (maybe they already have?) and they will be too "mainstream" to die.
(Note: My post, of course, is subject to the usual inaccuracy of futurism: I could be totally wrong.)
For rich hypocondriacs. Indeed. And therein lies a significant danger.
For instance, high-resolution full-body scans (a CT scan of every inch of your body) are frequently criticized because they are so accurate and exhaustive that they will nearly always find something. Even a perfectly healthy individual will have a variety of benign masses of tissues which will show up on CT. Some experts have even estimated that a full-body scan will statistically reduce your health (or chance of survival or whatever) since it increases your risk due to unnecessary secondary tests more than it reduces your risk due to early detection.
Yet many (overly rich?) people want full-body scans because they want to make sure that any possible disease is caught... not realizing that you expose yourself to risk with each medical test.
I worry this kind of gene-sequencing will do the same thing: many people will see their results, not properly interpret the risks, and go rushing out for secondary tests (some of which have a small danger associated with them). Worse, some people may read their results and change their lifestyle without medical consultation, in order to "manage" a condition that they have not actually expressed yet. (And, again, you can do more harm than good when you try to manage a condition you don't have, at the expense of doing things that would actually make you more healthy.)
Obviously it's a personal choice if you want to gather this extra information about yourself. I just hope that the companies offering this service make the risks clear and help the customers actually understand the data and probabilities.
I heard RMS give a talk where he criticized Creative Commons (the organization) because not all of the licenses they publish guarantee freedom. As he put it (paraphrasing from memory): "If you take the intersection of all the licenses offered by Creative Commons, you get nothing. There are no core freedoms that all the licenses guarantee."
Basically, RMS thinks that some of the licenses are great (the ones that allow redistribution, derivative works, and promote share-alike), but thinks others are terrible. RMS is famous for being careful with words, and dislikes the fact that when you say "this is available under a Creative Commons license" it basically means nothing (until you know which specific license is being used, you don't know what freedoms are being guaranteed).
Of course the FSF's intention is to promote freedom, whereas the Creative Commons organization has as its core mandate something more along the lines of "promote understanding of copyright law, and show copyright holders that they don't have to use a maximal, all-rights-reserved copyright, but that they can distribute under more permissive licenses, too." The creative commons organization emphasizes author choice instead of user freedom.
Still, all that having been said, there is some clear overlap between the CC licenses and the GPL. So, an appropriate license can certainly be compatible, and I'm fairly confident that RMS approves of those freedom-granting licenses.
Sounds about right. I just ran it through some simple effusion equations (kinetic gas laws). Assuming that the amount of air escaping is 1.3 kg (1.14 m^3), and that the volume of the room it is escaping from is ~200 m^3 (apparently the total final size of the ISS is 1000 m^3), and that the ISS is pressurized to 101.3 kPa (the Wikipedia article says that it is), then we can calculate the time for 1/200 of the air (0.5%) to escape, as a function of the hole diameter. It turns out that a hole of diameter 0.15 mm will lead to that kind of rate of pressure loss (1 m^3 in the first day).
Needles to say, the effusion equations have various assumptions built into them, and I had to make all kinds of assumptions about the values... but at least to within order-of-magnitude, this suggests a pinhole-sized leak.
Details for anyone who cares: The effusion equation can be derived similar to the conventional gas law expressions, by calculating the number of molecules per unit area that impinge on a wall section of a certain size (the hole). (We assume a container in vacuum, so that any molecule that impinges on the hole is lost irreversibly to the outside.) The equation, as you might expect, turn out to be exponential decays (since the derivation incorporates the decreasing internal pressure as air is lost):
N(t)/N_total = exp( -(A/V)*sqrt(k*T/2*pi*m)*t )
or
t = ( -(V/A)*sqrt(2*pi*m/k*T) )*ln(N(t)/N_total)
where:
t, time (until the given loss of atmosphere)
V, volume of container
A, surface area of hole
m, mass of gas molecules
T, temperature (~300 K for room temperature)
k, Boltzmann constant
N(t), # molecules at time t
N_total, total # molecules (initial quantity)
Network Neutrality refers to ISPs double dipping on charging/extorting fees... It does not refer to protocol-based QoS. Unfortunately when it comes to the definition of Net Neutrality, there isn't yet consensus (e.g. see various definitions offered here, and associated references). Maybe we need to come up with new terms, like "Strict Net Neutrality" versus "General Net Neutrality" to distinguish between various implications of the term. As usual, though, it's very hard to get people to agree on definitions.
And, of course, the definitions vary in part because people have different opinions on what is "important." Supporters of net neutrality agree that data carriers should at a minimum be source/destination neutral (the version of neutrality you are referring to). However some people do indeed believe that carriers should also be neutral with respect to the devices allowed to connect to the network, and the types of traffic sent over the network.*
So, in short, there is a diversity of opinion about what the term means (or "should" mean, I guess).
[*] As an aside, my mind isn't made up, but I understand the logic for saying that traffic neutrality may be ultimately a good thing. Yes, it prevents certain QoS strategies on shared carrier networks (but not on closed private networks, of course)... but then again, do you trust your ISP (which has its own interests) to pick the QoS strategy that actually works best for you? (Or even for most customers?) Also, any QoS strategy inherently makes a judgment call about what is "important" and what isn't. So, it inherently limits new technologies/protocols we haven't yet dreamed of. And, it would seem inefficient because any QoS which degrades protocols that customers are interested in will be circumvented (e.g. by masking your traffic as a type of traffic that is "approved" for high-speed delivery). Certainly we wouldn't let other carriers discriminate based on the content (e.g. postal service that delivers boxes that contain videotapes slower than boxes that contain paper; phone carrier that delays voice calls to prioritize fax calls...).
Canada has its own laws, and its own legislature. It can choose to withdraw from the treaties (very unlikely since there a major downsides to leaving WIPO). Yes, this is largely about complying with international treaties which Canada has already agreed to. So, to a large extent, the complaint is that said treaties should never have been signed in the first place. The WIPO provisions for DMCA-like legislation greatly over-reaches. So, even though this treaty has been signed, it should not be followed. Signatories should "do the right thing" and repeal their support for said treaties. (Wishful thinking, I know.) Just because a treaty has been signed does not, of course, make it proper and correct.
This is not about bending to the will of America, it is about complying with international treaties. Well, actually Michael Geist explains the situation as:
The new Canadian legislation will likely mirror the DMCA with strong anti-circumvention legislation - far beyond what is needed to comply with the WIPO Internet treaties - and address none of the issues that concern millions of Canadians. The Conservatives promise to eliminate the private copying levy will likely be abandoned. There will be no flexible fair dealing. No parody exception. No time shifting exception. No device shifting exception. No expanded backup provision. Nothing.
(Emphasis added.)
In fact, there is a concern that while legislation is being proposed to conform to treaties, the opportunity will be seized to extend the laws beyond what is strictly required. In particular, it was found that some members of Canadian government are being influenced (financially, etc.) by U.S. lobbies. So, there is a real danger that overly restrictive laws get put in place in order to appease U.S. corporations (or the U.S. government, depending on how you want to look at it).
It's not as simple as saying that Canada must comply with the treaties it has signed. As you say, the law can be implemented in various ways, and we must all do our best to insure that they are implemented in sane, democratic, and freedom-preserving ways. (Which may mean not implementing them at all.)
I would think the first step would be to boost the planet to an orbit further away from the sun. Changing the orbit of a planet is not really an option. The energy required to do is ridiculously large. Not to mention the difficulty of actually applying the required forces to a planet (without ruining it). Attach rockets? Launch asteroids into it (and bit by bit change its velocity)? In any case it would be very, very costly, and would require a long, long time.
But all that is unnecessary anyway, because Venus' orbit is not too far outside the habitable zone. One could, I suppose, eject a large percentage of the Venutian atmosphere in order to reduce atmospheric pressure, temperatures and greenhouse effects (via controlled explosions, perhaps?). To further reduce and control temperatures would require some geo-engineering. For instance, one could place a huge number of thin solar reflectors at the Lagrange point between the planet and the sun. These thin floating mirrors would reflect away some percentage of the sun's rays, thereby casting a "shadow" of sorts on the planet and reducing temperatures. This would of course be ambitious, requiring billions of lightweight reflectors to be placed into the proper orbit, but it's not unthinkable to do it. (Actually, some people are even suggesting it as a potential solution to control Earth's climate.)
After stabilizing the temperature there would still be many other things to deal with: the atmospheric makeup isn't very hospitable, and it would probably require millenia of active modification to bring it even close to being hospitable to simple forms of life (e.g. extremophiles). Presumably one would engineer these initial life forms so that they would convert the atmosphere as required (especially, to generate oxygen). So, it's probably possible in principle to make Venus habitable... but by no means easy.
You're making a few mistakes...
Space is not a total vacuum, it's true. However, the density of particles of matter in space is, for the most part, so low that space can be treated as a vacuum. It's like rounding 0.1xE-25 to just 0. Rounding and approximations cannot be treated as glibly as you are doing. Approximating outer space as a perfect vacuum is a reasonable approximation for many calculations, but not all. For instance when calculating the properties of light traveling through outer space over short distances (e.g. less than a light year) saying it is a "perfect vacuum" is fine. But when doing calculations over long distances (billions of light years), the thin interstellar medium does indeed induce absorption and polarization effects that must be considered.
So you cannot always assume that "near vacuum" and "perfect vacuum" are the same thing. In the case of solar wind interacting with the interstellar medium, you can't approximate either as having zero density: to do so would ignore some very real physics that occurs when the pressure of the high-velocity solar wind impinges on the nominally static interstellar medium.
And as for the whole thing about sound travelling faster in space, you just made that up. Every material (even low-density materials like the interstellar medium) have a "speed of sound." The interstellar medium is no different. It has a "speed of sound" on the order of 10 km/s to 100 km/s (by comparison the speed of sound for air on Earth is 0.3 km/s).
Sound travels faster and farther through more solid materials. You're being imprecise by saying that sound travels faster in more "solid" materials. The equation is:
v = sqrt( C/d )
where v is the speed of sound, C is the coefficient of stiffness, and d is the density. So, actually, more dense materials have a lower speed of sound (all other things being equal). The reason that liquids and solids have higher speed of sound is not because they are dense, but rather because they have strong cohesive forces binding the constituent atoms/molecules together (that's why they are condensed into a solid or liquid, after all). These strong forces lead to a very high coefficient of stiffness, compared to a gas (more than enough to offset the higher density).
For something like the interstellar medium, the stiffness is quite low, but the density is exceedingly low, which produces a correspondingly large speed of sound.
Sound, however, is caused waves of physical compression. In other words, one particle bumps into the next, which bumps into the next, and so on. You're quite right. However nothing prevents compression waves from traveling in low-density materials. The atoms of the material are free to fly large distances, and they will indeed statistically bump into each other, transfer momentum, and so on. This collective motion will indeed be compression waves. Of course you will not be able to set up very large-amplitude compression waves using, e.g. your vocal cords in such a low-density medium... but the high-speed collision of the solar wind with the interstellar medium will most certainly lead to all kinds of expanding pressure waves, whose behavior is dependent on the local speed of sound.
These pressure-wave effects are of course difficult to measure in such a low-density medium, but they are certainly real.
Where is this increased productivity of which you speak? I think it's easy to miss the increased productivity because our standards rise very quickly with enabling technologies.
For instance, I can sit down on my computer, grab dozens of scientific articles in a few minutes, write a summary of them, and have it typeset to publication-quality with a few clicks. I can then launch a professional-quality graphics art program to make a few figures. I then put it all together and send it to someone (who gets it within seconds).
The same operation would previously have taken much more time and money, not to mention specialist talent. (E.g. numerous trips to library, typing and re-typing a manuscript, hiring a graphic artist to make a figure, and mailing the finished product would have taken weeks of time, hundreds of dollars, etc.) And I haven't even mentioned things that are inherently compute-bound (e.g. how long would it take to run a complicated simulation today vs. ten years ago?).
In short, these technologies have enabled the individual to do things that previously only specialists could do, and have allowed everyone to complete their work faster than before. It's easy to dismiss this since the promised "additional free time" from increased productivity never materializes: instead we merely increase our standards of quantity and quality. Many people don't even see this as progress (e.g. many people would prefer handing off tasks like typing and typesetting to others, whereas nowadays the norm is for everyone to do this themselves).
Nevertheless, the net amount of "stuff" that a person produces (documents, designs, computations, admin tasks completed, etc.) has indeed increased in breadth, quantity and quality, due to the use of computers, networks, and our modern clever user-interfaces.
I, for one, am much more productive using a computer than I would be otherwise. And if anyone thinks that their computer isn't making them more productive, then I challenge them to try to complete daily tasks without it, and see how long/arduous things actually are without.
The talk was titled "Nanotechnology; Is there a Risk?", and was given by Dr. John Howard, Director of the National Institute of Occupational Safety and Health (NIOSH).
Unfortunately no handouts or slides were made available with the talk. However, there is some good information on the NIOSH Nanotechnology page, and a detailed report on current progress [PDF] has been published. Also, if you do some searches for the obvious terms (NIOSH, Nanotechnology, safety, John Howard, etc.) you will find other statements/discussions on the same topics (e.g. this or this).
As I mentioned in my other comments, I work in the field (specifically studying nanoparticles and block-copolymer patterning right now), so if you have any other questions you think I might be able to answer, I'm happy to help.
The example has a number of things which either (1) are fair uses, (2) aren't infringements at all or (3) aren't subject to copyright at all. You're right in many ways... but unfortunately the situation is not so clear cut. The very fact that we are debating the finer points of whether some of these things are infringements or not shows that copyright law, in its present form, is so vague and over-broad that a "normal person" cannot really be sure that they are in compliance. Moreover, even if many of the examples would in fact be covered by "fair use" doesn't help much for the average person, since "fair use" is a legal defense with limited coverage. An average person doesn't have the money or inclination (or perhaps courage) to fight those kinds of things in court, which means that copyright law can have a chilling effect even when no infringement has occurred.
Copyright law is generally *civil*, not criminal. In general, this means that a lot of wrongs are ignored by potential plaintiffs, just as a matter of tradition, convenience and politeness, just as they are with a lot of other civil wrongs -- nuisance, trespass, assault** (especially among children), etc..... Nobody goes around saying "Look at how many acts of trespass you committed today. We need to fix trespass law." You're right... but then again no one would be raising a fuss if this were purely academic. The fact is that a certain segment of the population is aggressively exploiting copyright laws, in order to control markets and sue people for large sums of money.
Put otherwise, if selected individuals were being sued for hundreds-of-thousands of dollars using tresspass law because they walked across a privately-owned parking lot on their way to work, then we would absolutely be yelling "Look at how many acts of trespass you committed today. We need to fix trespass law."
So they are all worried about grey goo? No, not at all. The "grey goo" scenario (where self-replicating nano-robots consume all available resources and turn all materials into a giant amorphous glob of nanomachines) is not taken seriously both because it is unlikely to be plausible (with respect to things like complexity of design and thermodynamics of matter conversion and pattern replication); and because our current research in nanotechnology is too primitive compared to the molecular nanotechnology that would be required for that scenario to even be remotely possible.
No, the current concerns with nanotechnology are much more mundane: things like nanoparticles causing health concerns by passing into people's bodies and accumulating in organs. There is already some research suggesting that (some) nanoparticles can actually absorb into tissues or even pass through cell membranes. One of the reasons that nanoparticles might be great for biological applications is that they can be made to be at a size-scale that many biological processes ignore. The lack of an immune response is great in some ways, but it also means that the body may not be able to deal with possible negative side-effects.
Other possible health, safety, and environmental concerns are just variants of what we're already worried about: carcinogens, flammability, toxicity, accumulation in the environment, etc. Associated with all this is coming up with the right procedures for filtering out dangerous materials, disposing of them safely, and so on. All these conventional concerns must be reconsidered when dealing with nanomaterials, since their behavior is different and sometimes non-intuitive.
Disclosure: I do research in the (overly-broad) field of "nanotechnology."
I went to a talk recently discussing the safety issues surrounding nanotechnology (health effects of nanoparticles, in particular). Several possible problems were identified, and there is vigorous ongoing research to determine the full health and environmental implications of this technology.
In short, I get the impression that scientists are trying to "get it right this time." That is, we are all keenly aware that numerous scientific breakthroughs had unintended health side-effects (e.g. the originally unknown effects of radiation, carcinogens, etc.). So the scientific community is determined to identify the safety concerns as quickly as possible, before these technologies become widespread. This is, obviously, a good thing. Though possibly overly-cautious, this strategy should minimize the risk of public health concerns and evironmental damage.
In any case, as you said it's hardly surprising that the people most intimately familiar with the technology are best able to predict its problems/shortcomings. Also worth noting is that the scientists working with these technologies/materials have a vested self-interest in identifying health problems, since they are the ones being exposed to these materials.
explain whether light moving through the curved space past a mass doesn't just "pull" the mass and light closer, but does it also change the energy in the light, which I would expect to be measurable as a lowered frequency? Light is affected by gravitational fields (as explained by Einstein/relativity), so a beam of light is deflected by the presence of a massive object. Note, however, that light (photons really) have no mass hence they do not attract (or "pull") the mass in any way. A beam of light is deflected by a star or planet because spacetime itself is "curved", as you say. The photons don't really lose/gain any energy in the process, but their wavelength/frequency is indeed shifted by the gravitational field (energy is conserved because of the sum "frequency energy" and "gravitational potential energy"). So light falling in towards a planet is blue-shifted, and light escaping from massive stars is gravitationally red-shifted. The effect is usually quite small, but is measurable (even GPS has to make corrections for it).
is there a way to make nanoscopic light frequency shifters by moving masses closer/farther near light's path, perhaps shining in a vacuum channel? In theory, yes. By moving a mass you could shift the frequency, which would change how the light would interact with materials for instance. (Note that this shift wouldn't be "permanent"; that is the frequency shift that occurs to light as it passes near a mass is exactly "undone" when it passes away from the mass and leaves the gravitational field. So the shift only occurs while the light is nearby...)
However, it's important to keep in mind that the shift you would introduce by using a nano-sized chunk of mass would be very, very, very, very small. So small, that the light's frequency would be randomly shifted by other effects (e.g. nearby cars driving by) far more than the little mass could control. Even in an isolated environment, the frequency shift would be very small (things like thermal noise and Heisenberg uncertainty would be far larger). It's only really relevant on the scale of planets and stars.
What if the mass weren't matter, but more light - could that make a photonic "transistor" that either deflects or frequency-shifts light with solely photonic control? Light doesn't interact with itself. Photons have no mass hence they don't generate gravitational fields (and don't attract each other), and photons have no charge hence they can't affect each other through electric/magnetic effects. So there is no way for light to interact with light in a vacuum (except of course for light that is "coherent"; that is two beams that the same frequency and are phase-locked to each other will interfere).
However, light can interact with light in a material if the material exhibits certain "non-linear" properties (actually all materials exhibit these effects but some are more pronounced than others). This idea of a "photonic transistor" has actually long been sought in photonics: it would make for amazing all-optical computing. The idea is to interact two beams of light in a non-linear material, so that one beam can switch the other beam on and off. One simple example is a "photo-refractive": a material where the refractive index actually changes when light passes through it. The idea being that you could alter the path of one "data beam" by using a "trigger beam" (when the trigger passes through, the refractive index goes above some critical value which deflects the data beam from one exit port to another...).
Thanks for taking the time with this esoteric stuff My pleasure... it's always fun to get an actual scientifically-interesting conversation going on Slashdot!
It seems to me that the quantum nature of these effects should offer lots of "no strings attached" ways to interact with 100% "elasticity" that human scale matter's statistical average behavior makes impossible. Actually it seems more like the opposite (unfortunately): quantum effects tend to ruin any hopes of a 100% anything. In a classical system, you can construct something that is trapped within a "potential energy well", but in quantum mechanics, tunneling means that there will always be a non-zero probability of the "thing" escaping from the trap by tunneling through the barrier (this is, for example, how radioactivity works: by nucleons tunneling out of the strong binding in the nucleus). You can make a trap good (low probability of escape) but never perfect (zero probability of escape).
it seems that even light with a wavelength that does not match any of the quantum levels of the atoms of a translucent material can somehow be absorbed by that material. You're right. But it's not that there is a quantum level that matches the wavelength of the light, but rather the Heisenberg indeterminacy principle basically allows for "blurring" of everything (the wavelength, the energy gap, etc.). So there is always a non-zero probability of interaction/absorption. Of course, the probability can be made very small. Impurities, as you note, tend to provide a wider range of possible absorption bands, so that the probability of one being close enough to the wavelength of the light is higher. (It's also worth remembering that absorption doesn't only occur because of energy levels associated with electrons bound to atoms: the degrees of freedom for molecular translation, rotation, and vibration also have quantum levels that can absorb light.)
But there never seems to be a "free lunch", even if you pay in advance and get a refund, even if you just smell the sandwich untouched:). Indeed! Every time we think we have science all figure out, it throws up another "no free lunch" roadblock! (e.g. thermodynamic rules against perpetual motion, entropy, quantum fuzziness,...)
The inefficiency in reflections is light converting to heat when interacting with the medium. What exactly is that mechanism called? There are a variety of effects that lead to losses. There is simple absorption, where light is converted to heat. Any real material will have a non-zero absorbance. Also, to achieve high reflectivity you want a high refractive index contrast. Vacuum has a nice low refractive index, but of course there is no material with an infinite refractive index, so you will always get some transmission into the material. Unless the surface is truly perfect you will also get some amount of scattering that sends off light in other directions.
There are similar problems with refraction: the refractive index contrast is not infinite, so some amount of light is always transmitted. At glancing angles (below the critical angle), you theoretically get perfect 100% internal reflection. This is how fiber-optics work: by having a glancing-angle internal reflection, the losses at the boundary are quite low. However the beam is then propagating inside a material, and there is absorption from the material itself. (Even if the absorption was somehow zero, the refraction at the boundary would never be perfect: imperfections and evanescent waves would cause some amount of light to escape.)
So, while theoretically one could build a light-trap using reflection or refraction, using any known material would involve some imperfections or losses preventing long-term trapping.
Has anyone worked on making devices or materials that channel light along a very long internal optical path folded up inside a small volume? It's a neat idea, and in real-world optics such tricks are sometimes used. For instance you can set up two mirrors, and have the beam bounce back-and-forth between them, in order to introduce a known delay into a particular beam path (you can increase the traveled path by a rather large amount). Another simple trick is just to launch a pulse into a big roll of fiber-optic.
The main problem with such techniques is losses. Even if your mirror is 99.9% reflective (and mirrors that good are expensive, by the way), you quickly lose all your signal intensity if you are reflecting thousands or millions of times. Your idea of using a photonic crystal is neat, but you would be hard-pressed to make a very long path length without making the crystal large, too. And if you cap the end with a mirror (to trap the light for longer), you run into losses from that.
That's one of the reasons the research mentioned in TFA is significant: in principle it allows a pulse to be trapped for an arbitrary amount of time with no losses (and for a broad range of wavelengths).
Now they have to think of a way to get the light "out" again. A specific device hasn't been built, but I imagine it would be optoelectronic: that is, they would design the material so that application of an electric field would turn off (or on) the metamaterial effect. If you could switch the capturing capability of the device with an electric current, then obviously you could integrate it into some sort of routing circuitry. In principle one could also design the material to have some unique non-linear optical properties, so that light alone was used to regulate its behavior (e.g. after enough light gets trapped it saturates and releases it), but this kind of "all optical routing/computing" is sorta the "holy grail" of telecom.
The other interesting thing is - if you don't let the light out, how much light can you put in there? In theory it would build up forever. In reality, any device will be imperfect and probably won't capture light "forever" (but a year or even a minute would be "effectively infinite" for most real-world applications). I imagine that if enough light got "trapped" inside, the resultant EM field in the material would get intense enough to alter the material properties. Eventually the material would break-down, stop being a meta-material, and release the captured light. As I alluded to before, if this were carefully designed it could have some interesting effects (e.g. a "light capacitor" that builds up a big pulse and then releases it all at once).
In any case, I wouldn't worry about the universe ending!
First off, for those interested (and with subscriptions) let me provide a reference to the actual paper (from last week's Nature):
Kosmas L. Tsakmakidis, Allan D. Boardman & Ortwin Hess 'Trapped rainbow' storage of light in metamaterials Nature 450, 397-401 (15 November 2007) | doi: 10.1038/nature06285. (See also summary comment box, doi 10.1038/450330a.)
They propose a method that might. The meta-materials needed to do this with visible light don't exist yet. Your caution is quite correct. The paper is theoretical. An actual device has not yet been built. However this result is still significant because what they are showing is that the various results on "slow light" and "trapped light" can be realized in optical metamaterials. This is significant because metamaterials are in principle more amenable to technological deployment than the more exotic techniques of slowing light (ultra-cold condensates, etc.).
It's also worth noting that metamaterials at various wavelengths (e.g. microwave band and IR) have already been made. We are getting very close to optical metamaterials. For instance, see this review of the field:
Vladimir M. Shalaev Optical negative-index metamaterials Nature Photonics 1, 41 - 48 (2006) doi: 10.1038/nphoton.2006.49.
We already have prototype metamaterials at wavelengths of 780 nm, which is on the edge of the visible spectrum. Significantly, we already have metamaterials that operate in the IR band, which is what is used for modern fiber-optics, telecommunications, etc. The materials to date are not optimized, so it will of course be awhile before all these great applications of metamaterials are implemented in real telecom devices. But, still, we are getting quite close to these applications. In particular, I expect we'll see a commercial 'rainbow trapping' device for communications before we see a commercial 'invisibility cloak'!
Slashdot Mirror
Obviously there are innumerable details with respect to running any experiment, so not every detail can be included in a scientific paper. In particular, "common practice" in the field can usually be described in short hand by using the proper terms (and referencing previous work as needed).
However, no scientist will read a paper and glibly assume that the experimenters "did everything properly" without evidence that this is so (where "evidence" is a combination of reputation, details of procedure, showing raw data, and demonstration that one understands pertinent issues). It is expected (nay, required, for high-quality science) to mention precautions taken, alternate explanations for results, shortcomings in methodology, and so forth. Omitting a critical self-analysis and details of one's procedure makes a paper very suspect. It is the job of the publishing author to convince the community that they are right, and so they must present sufficient evidence (and sufficient experimental detail) to make their case adequately. To do otherwise makes for bad science.
So, in short, while much knowledge can be presumed when writing technical papers, it is never the overriding presumption in science that everyone is doing science properly. We attack each other's work precisely to keep quality high: and if a paper does not provide sufficient detail to back up their claims, the paper is ignored until such time that further credible evidence is brought into the debate.
The full research article (PDF) is only 3 pages long. The experimental description and discussion of results are so terse that they are barely informative. There are not enough details to know whether they handled the experiment properly or not.
In addition to the problems you mentioned, I'm worried by the fact that they don't describe in detail what they mean by "placebo." For instance, they mention "two separate rooms" in their experimental section, but don't explain why they have two rooms; if one was "real" and the other "placebo" then the variability could easily be ascribed to minor variations in the rooms (lighting, ambient sound, odor, etc.). The RF transmitter is placed immediately beside the person's head (there is a photo in the article), which worries me because they never mention measuring or accounting for audio effects: a high-pitched whine from a running device could easily explain the differences (it wouldn't even have to be consciously audible to influence the subjects).
Combined with the very large standard-deviations on their results, I'm hesitant to ascribe any significance to this finding just yet. More details, and corroborating independent verification, are definitely necessary before raising any public alarms.
You point out that few desktop tasks require parallel processing... but think about the flip-side of this: if we could speed-up many tasks, how would that affect desktop computing?
There are plenty of tasks that people do routinely on computers that are not "instantaneously" fast (spreadsheets, photo-editing, etc.). Furthermore there are many aspects of modern user interfaces that would be better if they were faster (generating thumbnail previews, sorting entries, rescanning music collections, searching, etc.). Also, it's important to realize that the commonplace desktop elements of tomorrow may not have been imagined today. Many things that we don't even consider (and certainly don't consider as "necessary") may become possible (and thus "necessary") with greater computer power (complex graphs/images/previews that update in realtime as a user slides a control, instantaneous re-encoding of video when you drag-and-drop to an external device, etc.).
My only point is that it is tempting to say that computers are "fast enough" and yet in my own computer-use (and watching the computer use of others) there are definitely times when the user must wait for the computer to finish a task (whether it is a split-second page render or a many-seconds refresh of a spreadsheet or a many-minute generation of a complex image). Until all of these tasks are "instantaneous" (shorter than human reaction time), then there is definite room for improvement in computer speed; and moreover improvements that the end-user will appreciate and come to rely on.
You'll notice that of the examples I've mentioned, many of them could in principle be parallelized (and thus benefit from multi-core systems).
A "Captain Copyright" character was indeed used for awhile in Canada to promote "rights of artists." Not surprisingly, the character and comics supporting a "copyright maximalist" slant, making no mention of fair dealing (Canadian version of fair use). Furthermore, there were a few incidents where it was shown that the Captain Copyright website was, in fact, infringing copyright.
Because of all the negative press, the character was withdrawn and the site shut down. So it looks like a cape-wearing copyright crusader is not long-lived. And luckily IP law will prevent anyone else from resurrecting that particular idea.
You're absolutely right.
I refuse to click on the links or RTFA because this is clearly another Dvorak "grab-clicks-by-posting-inflammatory-tripe" attempt. Seriously, the quotes from the summary are precisely the standard criticisms that have been leveled against OLPC many times before (and are even summarized on the Wikipedia article). The rebuttals are pretty obvious and have been provided in innumerable Slashdot discussions on the topic.
Dvorak's argument is both a straw man and a false dichotomy. A straw man, because no one is advocating giving laptops to that segment of the world population that is so poor that starvation is truly their overriding concern. A false dichotomy, because spreading knowledge and education is not mutually exclusive with addressing issues of poverty and starvation. In fact, the best way to help a people better themselves is to address immediate threats (such as war and imminent starvation), but to also educate and provide the populace with the tools to take control of their situation and improve it.
OLPC is not trying to send laptops into regions where the social and technical infrastructure cannot support them. The aim is to help those countries that want to improve education and spread of knowledge. The list of participating countries makes this pretty clear. These are not countries of "absolute poverty" that Dvorak conjurs up--these are countries that are trying to improve themselves and succeed in a competitive international market.
What I'm saying is that I think a certain amount of this effect is simply related to the fact that the anti-"mainstream medicine" crowd has a definite interest/desire in making, watching, and rating anti-vaccine videos... whereas the pro-"mainstream medicine" crowd probably don't even think to do such things. So, as often happens, the minority viewpoint becomes over-represented.
Still, we should indeed be concerned if even a small portion of the population is getting medical advice from things like YouTube. The overall point, I suppose, is that many people are indeed gullible, and that the medical establishment should work harder to spread the truth to people who might otherwise ignore it.
I had the same worry as you some years ago, but I would guess we are now beyond that particular tipping point. Quite simply, the diversity of the web is now "mainstream." The public at large is now very much used to having billions of web-pages out there, and are also getting used to the idea of self-publishing. The number of blogs and commenting systems is growing by massive amounts. I agree that some of this is hype that will die down, but my point is that now that people are accustomed to such things, they are not going to be willing to give them up. (Put otherwise, there will remain a market for such things.)
I see the worry that people will increasingly get locked into content-portals like Facebook or whatever (where their data is captive)... but there are corresponding efforts to keep content open and free (Wikipedia, Creative Commons, OpenDocument, etc.). These efforts are also growing, and it may very well be that they will cross a tipping point soon enough (maybe they already have?) and they will be too "mainstream" to die.
(Note: My post, of course, is subject to the usual inaccuracy of futurism: I could be totally wrong.)
For instance, high-resolution full-body scans (a CT scan of every inch of your body) are frequently criticized because they are so accurate and exhaustive that they will nearly always find something. Even a perfectly healthy individual will have a variety of benign masses of tissues which will show up on CT. Some experts have even estimated that a full-body scan will statistically reduce your health (or chance of survival or whatever) since it increases your risk due to unnecessary secondary tests more than it reduces your risk due to early detection.
Yet many (overly rich?) people want full-body scans because they want to make sure that any possible disease is caught... not realizing that you expose yourself to risk with each medical test.
I worry this kind of gene-sequencing will do the same thing: many people will see their results, not properly interpret the risks, and go rushing out for secondary tests (some of which have a small danger associated with them). Worse, some people may read their results and change their lifestyle without medical consultation, in order to "manage" a condition that they have not actually expressed yet. (And, again, you can do more harm than good when you try to manage a condition you don't have, at the expense of doing things that would actually make you more healthy.)
Obviously it's a personal choice if you want to gather this extra information about yourself. I just hope that the companies offering this service make the risks clear and help the customers actually understand the data and probabilities.
I heard RMS give a talk where he criticized Creative Commons (the organization) because not all of the licenses they publish guarantee freedom. As he put it (paraphrasing from memory): "If you take the intersection of all the licenses offered by Creative Commons, you get nothing. There are no core freedoms that all the licenses guarantee."
Basically, RMS thinks that some of the licenses are great (the ones that allow redistribution, derivative works, and promote share-alike), but thinks others are terrible. RMS is famous for being careful with words, and dislikes the fact that when you say "this is available under a Creative Commons license" it basically means nothing (until you know which specific license is being used, you don't know what freedoms are being guaranteed).
Of course the FSF's intention is to promote freedom, whereas the Creative Commons organization has as its core mandate something more along the lines of "promote understanding of copyright law, and show copyright holders that they don't have to use a maximal, all-rights-reserved copyright, but that they can distribute under more permissive licenses, too." The creative commons organization emphasizes author choice instead of user freedom.
Still, all that having been said, there is some clear overlap between the CC licenses and the GPL. So, an appropriate license can certainly be compatible, and I'm fairly confident that RMS approves of those freedom-granting licenses.
Sounds about right. I just ran it through some simple effusion equations (kinetic gas laws). Assuming that the amount of air escaping is 1.3 kg (1.14 m^3), and that the volume of the room it is escaping from is ~200 m^3 (apparently the total final size of the ISS is 1000 m^3), and that the ISS is pressurized to 101.3 kPa (the Wikipedia article says that it is), then we can calculate the time for 1/200 of the air (0.5%) to escape, as a function of the hole diameter. It turns out that a hole of diameter 0.15 mm will lead to that kind of rate of pressure loss (1 m^3 in the first day).
Needles to say, the effusion equations have various assumptions built into them, and I had to make all kinds of assumptions about the values... but at least to within order-of-magnitude, this suggests a pinhole-sized leak.
Details for anyone who cares: The effusion equation can be derived similar to the conventional gas law expressions, by calculating the number of molecules per unit area that impinge on a wall section of a certain size (the hole). (We assume a container in vacuum, so that any molecule that impinges on the hole is lost irreversibly to the outside.) The equation, as you might expect, turn out to be exponential decays (since the derivation incorporates the decreasing internal pressure as air is lost):
N(t)/N_total = exp( -(A/V)*sqrt(k*T/2*pi*m)*t )
or
t = ( -(V/A)*sqrt(2*pi*m/k*T) )*ln(N(t)/N_total)
where:
t, time (until the given loss of atmosphere)
V, volume of container
A, surface area of hole
m, mass of gas molecules
T, temperature (~300 K for room temperature)
k, Boltzmann constant
N(t), # molecules at time t
N_total, total # molecules (initial quantity)
And, of course, the definitions vary in part because people have different opinions on what is "important." Supporters of net neutrality agree that data carriers should at a minimum be source/destination neutral (the version of neutrality you are referring to). However some people do indeed believe that carriers should also be neutral with respect to the devices allowed to connect to the network, and the types of traffic sent over the network.*
So, in short, there is a diversity of opinion about what the term means (or "should" mean, I guess).
[*] As an aside, my mind isn't made up, but I understand the logic for saying that traffic neutrality may be ultimately a good thing. Yes, it prevents certain QoS strategies on shared carrier networks (but not on closed private networks, of course)... but then again, do you trust your ISP (which has its own interests) to pick the QoS strategy that actually works best for you? (Or even for most customers?) Also, any QoS strategy inherently makes a judgment call about what is "important" and what isn't. So, it inherently limits new technologies/protocols we haven't yet dreamed of. And, it would seem inefficient because any QoS which degrades protocols that customers are interested in will be circumvented (e.g. by masking your traffic as a type of traffic that is "approved" for high-speed delivery). Certainly we wouldn't let other carriers discriminate based on the content (e.g. postal service that delivers boxes that contain videotapes slower than boxes that contain paper; phone carrier that delays voice calls to prioritize fax calls...).
In fact, there is a concern that while legislation is being proposed to conform to treaties, the opportunity will be seized to extend the laws beyond what is strictly required. In particular, it was found that some members of Canadian government are being influenced (financially, etc.) by U.S. lobbies. So, there is a real danger that overly restrictive laws get put in place in order to appease U.S. corporations (or the U.S. government, depending on how you want to look at it).
It's not as simple as saying that Canada must comply with the treaties it has signed. As you say, the law can be implemented in various ways, and we must all do our best to insure that they are implemented in sane, democratic, and freedom-preserving ways. (Which may mean not implementing them at all.)
But all that is unnecessary anyway, because Venus' orbit is not too far outside the habitable zone. One could, I suppose, eject a large percentage of the Venutian atmosphere in order to reduce atmospheric pressure, temperatures and greenhouse effects (via controlled explosions, perhaps?). To further reduce and control temperatures would require some geo-engineering. For instance, one could place a huge number of thin solar reflectors at the Lagrange point between the planet and the sun. These thin floating mirrors would reflect away some percentage of the sun's rays, thereby casting a "shadow" of sorts on the planet and reducing temperatures. This would of course be ambitious, requiring billions of lightweight reflectors to be placed into the proper orbit, but it's not unthinkable to do it. (Actually, some people are even suggesting it as a potential solution to control Earth's climate.)
After stabilizing the temperature there would still be many other things to deal with: the atmospheric makeup isn't very hospitable, and it would probably require millenia of active modification to bring it even close to being hospitable to simple forms of life (e.g. extremophiles). Presumably one would engineer these initial life forms so that they would convert the atmosphere as required (especially, to generate oxygen). So, it's probably possible in principle to make Venus habitable... but by no means easy.
So you cannot always assume that "near vacuum" and "perfect vacuum" are the same thing. In the case of solar wind interacting with the interstellar medium, you can't approximate either as having zero density: to do so would ignore some very real physics that occurs when the pressure of the high-velocity solar wind impinges on the nominally static interstellar medium. And as for the whole thing about sound travelling faster in space, you just made that up. Every material (even low-density materials like the interstellar medium) have a "speed of sound." The interstellar medium is no different. It has a "speed of sound" on the order of 10 km/s to 100 km/s (by comparison the speed of sound for air on Earth is 0.3 km/s). Sound travels faster and farther through more solid materials. You're being imprecise by saying that sound travels faster in more "solid" materials. The equation is:
v = sqrt( C/d )
where v is the speed of sound, C is the coefficient of stiffness, and d is the density. So, actually, more dense materials have a lower speed of sound (all other things being equal). The reason that liquids and solids have higher speed of sound is not because they are dense, but rather because they have strong cohesive forces binding the constituent atoms/molecules together (that's why they are condensed into a solid or liquid, after all). These strong forces lead to a very high coefficient of stiffness, compared to a gas (more than enough to offset the higher density).
For something like the interstellar medium, the stiffness is quite low, but the density is exceedingly low, which produces a correspondingly large speed of sound.
Sound, however, is caused waves of physical compression. In other words, one particle bumps into the next, which bumps into the next, and so on. You're quite right. However nothing prevents compression waves from traveling in low-density materials. The atoms of the material are free to fly large distances, and they will indeed statistically bump into each other, transfer momentum, and so on. This collective motion will indeed be compression waves. Of course you will not be able to set up very large-amplitude compression waves using, e.g. your vocal cords in such a low-density medium... but the high-speed collision of the solar wind with the interstellar medium will most certainly lead to all kinds of expanding pressure waves, whose behavior is dependent on the local speed of sound.
These pressure-wave effects are of course difficult to measure in such a low-density medium, but they are certainly real.
For instance, I can sit down on my computer, grab dozens of scientific articles in a few minutes, write a summary of them, and have it typeset to publication-quality with a few clicks. I can then launch a professional-quality graphics art program to make a few figures. I then put it all together and send it to someone (who gets it within seconds).
The same operation would previously have taken much more time and money, not to mention specialist talent. (E.g. numerous trips to library, typing and re-typing a manuscript, hiring a graphic artist to make a figure, and mailing the finished product would have taken weeks of time, hundreds of dollars, etc.) And I haven't even mentioned things that are inherently compute-bound (e.g. how long would it take to run a complicated simulation today vs. ten years ago?).
In short, these technologies have enabled the individual to do things that previously only specialists could do, and have allowed everyone to complete their work faster than before. It's easy to dismiss this since the promised "additional free time" from increased productivity never materializes: instead we merely increase our standards of quantity and quality. Many people don't even see this as progress (e.g. many people would prefer handing off tasks like typing and typesetting to others, whereas nowadays the norm is for everyone to do this themselves).
Nevertheless, the net amount of "stuff" that a person produces (documents, designs, computations, admin tasks completed, etc.) has indeed increased in breadth, quantity and quality, due to the use of computers, networks, and our modern clever user-interfaces.
I, for one, am much more productive using a computer than I would be otherwise. And if anyone thinks that their computer isn't making them more productive, then I challenge them to try to complete daily tasks without it, and see how long/arduous things actually are without.
The talk was titled "Nanotechnology; Is there a Risk?", and was given by Dr. John Howard, Director of the National Institute of Occupational Safety and Health (NIOSH).
Unfortunately no handouts or slides were made available with the talk. However, there is some good information on the NIOSH Nanotechnology page, and a detailed report on current progress [PDF] has been published. Also, if you do some searches for the obvious terms (NIOSH, Nanotechnology, safety, John Howard, etc.) you will find other statements/discussions on the same topics (e.g. this or this).
As I mentioned in my other comments, I work in the field (specifically studying nanoparticles and block-copolymer patterning right now), so if you have any other questions you think I might be able to answer, I'm happy to help.
Put otherwise, if selected individuals were being sued for hundreds-of-thousands of dollars using tresspass law because they walked across a privately-owned parking lot on their way to work, then we would absolutely be yelling "Look at how many acts of trespass you committed today. We need to fix trespass law."
No, the current concerns with nanotechnology are much more mundane: things like nanoparticles causing health concerns by passing into people's bodies and accumulating in organs. There is already some research suggesting that (some) nanoparticles can actually absorb into tissues or even pass through cell membranes. One of the reasons that nanoparticles might be great for biological applications is that they can be made to be at a size-scale that many biological processes ignore. The lack of an immune response is great in some ways, but it also means that the body may not be able to deal with possible negative side-effects.
Other possible health, safety, and environmental concerns are just variants of what we're already worried about: carcinogens, flammability, toxicity, accumulation in the environment, etc. Associated with all this is coming up with the right procedures for filtering out dangerous materials, disposing of them safely, and so on. All these conventional concerns must be reconsidered when dealing with nanomaterials, since their behavior is different and sometimes non-intuitive.
(Disclosure: I do research in "nanotechnology.")
Disclosure: I do research in the (overly-broad) field of "nanotechnology."
I went to a talk recently discussing the safety issues surrounding nanotechnology (health effects of nanoparticles, in particular). Several possible problems were identified, and there is vigorous ongoing research to determine the full health and environmental implications of this technology.
In short, I get the impression that scientists are trying to "get it right this time." That is, we are all keenly aware that numerous scientific breakthroughs had unintended health side-effects (e.g. the originally unknown effects of radiation, carcinogens, etc.). So the scientific community is determined to identify the safety concerns as quickly as possible, before these technologies become widespread. This is, obviously, a good thing. Though possibly overly-cautious, this strategy should minimize the risk of public health concerns and evironmental damage.
In any case, as you said it's hardly surprising that the people most intimately familiar with the technology are best able to predict its problems/shortcomings. Also worth noting is that the scientists working with these technologies/materials have a vested self-interest in identifying health problems, since they are the ones being exposed to these materials.
is there a way to make nanoscopic light frequency shifters by moving masses closer/farther near light's path, perhaps shining in a vacuum channel? In theory, yes. By moving a mass you could shift the frequency, which would change how the light would interact with materials for instance. (Note that this shift wouldn't be "permanent"; that is the frequency shift that occurs to light as it passes near a mass is exactly "undone" when it passes away from the mass and leaves the gravitational field. So the shift only occurs while the light is nearby...)
However, it's important to keep in mind that the shift you would introduce by using a nano-sized chunk of mass would be very, very, very, very small. So small, that the light's frequency would be randomly shifted by other effects (e.g. nearby cars driving by) far more than the little mass could control. Even in an isolated environment, the frequency shift would be very small (things like thermal noise and Heisenberg uncertainty would be far larger). It's only really relevant on the scale of planets and stars. What if the mass weren't matter, but more light - could that make a photonic "transistor" that either deflects or frequency-shifts light with solely photonic control? Light doesn't interact with itself. Photons have no mass hence they don't generate gravitational fields (and don't attract each other), and photons have no charge hence they can't affect each other through electric/magnetic effects. So there is no way for light to interact with light in a vacuum (except of course for light that is "coherent"; that is two beams that the same frequency and are phase-locked to each other will interfere).
However, light can interact with light in a material if the material exhibits certain "non-linear" properties (actually all materials exhibit these effects but some are more pronounced than others). This idea of a "photonic transistor" has actually long been sought in photonics: it would make for amazing all-optical computing. The idea is to interact two beams of light in a non-linear material, so that one beam can switch the other beam on and off. One simple example is a "photo-refractive": a material where the refractive index actually changes when light passes through it. The idea being that you could alter the path of one "data beam" by using a "trigger beam" (when the trigger passes through, the refractive index goes above some critical value which deflects the data beam from one exit port to another...). Thanks for taking the time with this esoteric stuff My pleasure... it's always fun to get an actual scientifically-interesting conversation going on Slashdot!
There are similar problems with refraction: the refractive index contrast is not infinite, so some amount of light is always transmitted. At glancing angles (below the critical angle), you theoretically get perfect 100% internal reflection. This is how fiber-optics work: by having a glancing-angle internal reflection, the losses at the boundary are quite low. However the beam is then propagating inside a material, and there is absorption from the material itself. (Even if the absorption was somehow zero, the refraction at the boundary would never be perfect: imperfections and evanescent waves would cause some amount of light to escape.)
So, while theoretically one could build a light-trap using reflection or refraction, using any known material would involve some imperfections or losses preventing long-term trapping.
The main problem with such techniques is losses. Even if your mirror is 99.9% reflective (and mirrors that good are expensive, by the way), you quickly lose all your signal intensity if you are reflecting thousands or millions of times. Your idea of using a photonic crystal is neat, but you would be hard-pressed to make a very long path length without making the crystal large, too. And if you cap the end with a mirror (to trap the light for longer), you run into losses from that.
That's one of the reasons the research mentioned in TFA is significant: in principle it allows a pulse to be trapped for an arbitrary amount of time with no losses (and for a broad range of wavelengths).
In any case, I wouldn't worry about the universe ending!
Kosmas L. Tsakmakidis, Allan D. Boardman & Ortwin Hess 'Trapped rainbow' storage of light in metamaterials Nature 450, 397-401 (15 November 2007) | doi: 10.1038/nature06285. (See also summary comment box, doi 10.1038/450330a.) They propose a method that might. The meta-materials needed to do this with visible light don't exist yet. Your caution is quite correct. The paper is theoretical. An actual device has not yet been built. However this result is still significant because what they are showing is that the various results on "slow light" and "trapped light" can be realized in optical metamaterials. This is significant because metamaterials are in principle more amenable to technological deployment than the more exotic techniques of slowing light (ultra-cold condensates, etc.).
It's also worth noting that metamaterials at various wavelengths (e.g. microwave band and IR) have already been made. We are getting very close to optical metamaterials. For instance, see this review of the field:
Vladimir M. Shalaev Optical negative-index metamaterials Nature Photonics 1, 41 - 48 (2006) doi: 10.1038/nphoton.2006.49.
We already have prototype metamaterials at wavelengths of 780 nm, which is on the edge of the visible spectrum. Significantly, we already have metamaterials that operate in the IR band, which is what is used for modern fiber-optics, telecommunications, etc. The materials to date are not optimized, so it will of course be awhile before all these great applications of metamaterials are implemented in real telecom devices. But, still, we are getting quite close to these applications. In particular, I expect we'll see a commercial 'rainbow trapping' device for communications before we see a commercial 'invisibility cloak'!