Gee. My closest blonde (female) friend has a first authorship on a paper in JACS, and just got back from studying solid state and laser physics in Sweden. Oh, and she's still an undergrad. I'll let her know that she's an idiot; I'm sure that she'd be interested.
I think the big problem is the combination of cell phone and SUV...of course, even there there is the issue of cause and effect.
Hypothesis: Cell phones make you stupid, then stupidity makes you buy an SUV.
This has been done before using fibre optics, I believe, so that you would effectively see through the person because they wore an outfit consisting of thin fibre optic wires routeing light straight through them.
It's a thought, but again, you're stuck with something that only really works from one or two directions--and then, it works badly. Anybody who's worked in laser optics knows it's bloody difficult to get light to couple efficiently into a fibre, and that's working with collimated laser light.
You might be able to "see through" someone, but the image you'd get would be quite dim, unless you amplify somewhere in the middle. This is--difficult. (Understatement.)
I suppose this is a great idea, if you only have one person to hide from, and you always face them, and you have access to a lot of little detectors and light sources.
Although pronouncing it "C-sharp" is a little counter intuitive; my first thoughts are always "C-pound". The maybe the first `Obfuscated C#' contests can center on it's name.
I believe it was The Register which approached this topic in some detail. For me, I've found that the best cross-cultural pronunciation is "C-hash". "C-octothorpe", though perhaps the most precise and technically correct, doesn't roll off the tongue nearly as fluidly.
Alas, what comes of posting too quickly. To clarify my position...
This device, through the small quantities of chlorine plus nasty (biochemically speaking) radicals generated through normal water electrolysis will probably very easily kill nearly anything that's actually in the water that passes through the device. I stand by my assertion that there is little or no residual purifying ability to the liquid that comes out, and the notion that a "dry mist" (whatever that is) from it will kill anthrax sounds like nonsense.
No doubt the electric field applied causes small bubbles to form within the solution, and then rapidly collapse. This collapse leads to extroardinarily high temperatures and pressures, which in turn cause nuclear fusion to take place. Stray gammas generated by this fusion result in the destruction of nearby pathogens.
Seriously, this technique sounds like a load of crap, for the most part. I can buy the electrochemical action bit, sort of. Pure molten NaCl (salt, hereafter) will electrolyze to form sodium and chlorine gas, sure enough. With a little creative engineering, it is possible to separate these to products and collect them for later use. Indeed, this is exactly what is done for commercial production of these two elements.
On contact with water, pure Na will form a solution of (aggressively basic) sodium hydroxide plus some hydrogen gas. (This, I assume, is the catholyte we hear about.) Chlorine in water forms an acidic solution which is, to be fair, definitely germicidal.
I see two problems. The first is technical. In a water solution, the electrolytic yields of sodium and chlorine are typically both very low, because oxygen and hydrogen gas are preferentially formed first. (There are sound thermodynamic reasons for this.) Maybe these experimenters have gotten around this somehow, perhaps using exotic catalysts or something.
The second problem is a bit more difficult. If the two component solutions (sodium + water and chlorine + water) are kept separate, individually they would be quite toxic. Brought together, there is a very quick reaction that brings us right back to salt and water--not a particularly powerful disinfectant, and what we started with before we had a mystical black box.
I can think of some other more creative possibilities, as well. Perhaps they're talking about generating some sort of activated state oxygen to do the dirty work (the salt just makes the water conductive)--in which case, they're definitely frauds. There just aren't any activated oxygen states that are stable long enough (in water) to get to the surface to be disinfected. Atomic oxygen might do it, but that's already been invented--and I'm pretty sure it won't last very long in solution either.
Finally, from the article, we have the quote:
f a letter is suspected of containing anthrax spores, it could be passed through a dry mist made from the Emerald solution and the letter would be sterilized.
The letter wouldn't even get wet. Anyone exposed to the spores could bathe in the solution and be germ free.
Erm. Dry mist. Sure. What's in this dry mist, exactly? Chlorine? Nope--it's way toxic. Sodium? Nope--it's a metal. Hydrogen? Um. Yeah. Oxygen--maybe, but atomic oxygen generators already exist (they're used for restoring artwork and whitening teeth). Singlet oxygen will kill things, but it only lasts a few nanoseconds in water.
So, to conclude this lengthy post--I call bullshit!
For what it's worth, regular dance lessons (of pretty much any kind. I started with swing and proceeded into ballroom) will achieve the same result, teaching you to be more sociable and courteous -- especially with the opposite sex -- while also helping you get into better shape.
Couldn't agree more. I also have to recommend Irish dancing, of the sort one finds at a ceili. (Various transliterations abound--Gaelic is a fiendish language at times. Listen for something pronounced, KAY-lee.) It's sort of an Irish square dance. There's a caller, and you're told what to do before and (usually) during the song. One of the more difficult aspects of swing dancing (I've found) is the need to improvise as you go along--it's something I'm just not very good at.
I have two left feet. But as long as you're moving in about the same direction as everyone else, there's nothing to fear. The ability to count to eight is helpful as well--but that shouldn't be a problem in this crowd. You get the opportunity to dance with lots of partners (or groups, or lines)--or not, if you prefer--and it is excellent exercise. Don't be afraid to take a breather now and then--there's usually good imported Irish stout available on site as well.
I was only exposed to the concept earlier this year, and I haven't looked back. Now, all of my friends are doing it--a motley assortment of physicists, chemists, and biologists, with wildly varying amounts of coordination, innate talent, and attention span.
The stone could have come from Mars, according to expert on Earth impacts Dr Benny Peiser, of Liverpool John Moores University.
The stone could be a charcoal briquette that fell off the roof next door--the college students in the adjacent building were having one last barbecue before going back to school.
One of the students was being severely beaten by his friends for posting a message to Slashdot containing the phrase "3. Profit!!!". When his head hit the grill, the briquette was ejected over the edge of the roof.
My father is a lawyer. I set up his law firm's computers. I've known many other lawyers and set up their law firm's networks. What you said was true 3-5 years ago, but most of them have now switched to Word.
The unfortunate downside to Word--which we have seen in more than one high profile case--is its propensity for keeping invisible records of revisions within a document.
The last thing you want to send out with a draft contract or other legal document is a complete revision history. For paralegals that are used to using 'Reveal Codes', I imagine that it would be very unusual for any sort of hidden document features to sneak out the door.
People on dial ups in rural America are watching and praying.
Apologies to all those folks in rural America, but they're still screwed. Actually, this technology would be much more difficult to implement in the United States and Canada than in Europe.
The U.S. power grid typically delivers moderately high voltage to each little neighbourhood--a small handful of homes at most. At that point, there is a small transformer (a "pole pig"--no ethnic slur intended) for the last step down to 110 volts.
European grids usually step down to 220 volts, and do it further from the homes. There are significantly fewer transformers per capita, as each transformer serves more homes.
The problem is this. The high frequency data signal gets flattened out going through a transformer--those big coils act as a low pass filter that eats your data. You have to pick up the signal from the server before the high voltage side of the transformer and reintroduce it on the low voltage side (and do the same thing in the other direction for upstream signals).
In Europe this is not an insurmountable problem: you just need to hop over a few transformers in a handful of central locations. In the U.S., you have to install some sensitive electronics on every pole pig--exposed to the elements in a lot of widely separated, awkward to service locations.
Oh, and rural America has it even worse--some homes have their very own transformer, and would need their very own jumper for signals. Also, if there is a long enough length of power line back to the substation, the inductance of the power line will be enough to eat any high-bandwidth signal.
No, becaue what you're REALLY bothered about is your ability to pirate stuff.
Well, no, not quite. What I would be concerned about is being forced to pirate the software after the original CD goes pfft! and dies.
Any company that tries to use a broken CD format to stop piracy is probably going to fold fairly quickly--and then how am I supposed to get replacement media?
The South Pole is the only permanently inhabited place on Earth that cannot see geosynchronous communication satellites, a fact that severely restricts communication with the base.
I take it that the North Pole is not permanently inhabited? I'm actually kind of surprised by this--it's much easier to get to the North Pole than the South, and there are other permanent settlements much closer at hand. (CFB Alert, which is responsible for watching for Russian ICBMs and bombers coming over the Pole, comes to mind.)
ofc, this might require an adjustment to the os you're using...
Oh yes, quite true. I ought to have said something about that. Trapped in a Win 98 et. al. world (not my computer at work, and too much inertia at home) my choices of browser are limited. I'm also hooked on tabbed browsing, which among the major browsers showed up first (I think) in Opera.
Before I die of shame, I can at least proudly say that I use PuTTY to connect to a *nix box for my mail, which I read and write in PINE...please, don't revoke my nerd credentials.
Between Opera, IE, and Mozilla, the speed difference is small enough for your average user not to know the difference.
True enough for the mythical 'average user' whose desktop machine is less than two years old. As a university student who is working on a four-year-old PII-300 at home, and a PI-133 with 64 MB of RAM at work (age unknown), every last cycle is precious. Particularly since I'm usually multitasking.
The footprint--in memory, in terms of clock cycles eaten, on my tiny hard drive--of my browser actually a very important consideration for me, and probably for others. The F12 for quick menus (to kill popups, mostly), the clean file transfer monitoring box, and the tabbed browsing (fewer windows on my task bar) are worth their weight in gold.
Opera has also been quick to respond to bugs and make critical fixes--something that some companies are loathe to do. (Ahem. Microsoft. Certificates. Ahem.)
And it really is the fastest (of IE, Moz, and Opera) browser on earth.
Well actually one of the problems I have is the ridiculous distance for an AU. I'd think it would have made more sense to make an AU 100 Millions miles or 1 billion miles so as to make calculations easier.
First, as has already been pointed out in other replies, miles are also an absurd, arbitrary unit as far as science is concerned. We could get a 'round' unit if we took, say, about.65 AU, as the 'new' astronomical unit--exactly 10^11 m.
But then the AU would be a pretty useless yardstick. Earth's orbit is very nearly circular, which means that over a period of six months, the Earth moves a net distance of (almost) exactly 2 AU. Using this knowledge, it is possible to measure the distance to nearer stars. As the position of earth changes, the apparent positions of nearby stars will also appear to change relative to much more distant stars--a parallax effect. To get a precise measure of this distance, you want to move the Earth as far as possible, to get the maximum apparent shift in position. 2 AU is as far as we can readily move the earth.
There is even a unit of measure that is defined on this basis. The distance at which the apparent parallax shift of a star is equal to one second of arc is defined as one parsec. Parsec measures can be directly obtained from astronomical images taken six months apart, so they are the preferred unit of measure for some types of observational astronomy.
Of course, this also works backwards. If we could see a planet orbiting a star one parsec away (about 3.26 light years--this is a hypothetical case) and its orbital motion was across one apparent second of arc, we would know it orbited its sun at a distance of 1 AU.
But the system leaks...
on
Haiku vs Spam
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· Score: 2, Funny
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Wave will also deploy peer-to-peer clients on the Gnutella network from its security research and development network (honeynet) which will offer files with popular song titles derived from the Billboard Top 100 maintained by VNU eMedia. No copyright violations will take place, these files will merely have arbitrary sizes similar to the length of a 3 to 4 minute MP3 audio file encoded at 128kbps.
Wait! Isn't this the sort of thing that we're usually all up in arms about when the **AA threatens to do it?
Fake mp3's, with popular song titles, on a popular p2p network, wasting our bandwidth and time...go figure.
I offer this conspiracy theory: Information Wave is a front for the RIAA. Watch for black helicopters in your neighbourhood.
On a more serious note, I applaud this move. The RIAA and its affiliates and members see no problem with wasting our bandwidth with bogus clients and files. That bandwidth costs our ISPs, backbone providers, and--ultimately--us, money. It's almost as bad as spam in that respect, though at least there are nontrivial bandwidth costs on the RIAA's side in this case. Dinging their signal to noise ratio (possibly, hopefully) might make it too costly to annoy the rest of us. Throwing some of the RIAA's crap back at them seems like a reasonable, proportionate response if handled carefully and responsibly. (I hope Information Wave gets some good legal advice before they start doing this.)
This method is neither new or novel, it's called Quantum Encruption.[sic]
Well, er, not exactly.
The technique described in the press release describes a technique for hiding a polarization modulation signal in the polarization state noise inherent in the ring laser system the experimenters used. It's clever, but it's very much not quantum encryption. In principle, it would be possible to siphon a few photons off the fiber and squeeze information out of them, though it would be very difficult.
Quantum encryption, as described in the article referenced in the parent post, is a very different technique. It relies on measurements of the polarization states of single photons, not continuous beams. It is immune to (undetected) interception, because tapping the beam irretrievably loses some data (hooray for quantum mechanics.) It is not well-suited to fibre systems--it's difficult to push single photons down a fibre and reliably measure and retain their polarization. It would excel, however, for communcations that could take place over line-of-sight spans, even very long ones.
'Microsoft was worried that the NSA's releasing open- source software would compete with American proprietary software,'
Indeed. We ought not have the government funding university labs, because releasing medical research to the public domain might interfere with pharmaceutical company profits.
Not everything that's good for General Motors is good for the country, or its people, or its economy.
At larger distances with a given speed, the rate of energy transfer would of course be lower. So shouldn't density matter?
Sure, the rate of energy transfer would be lower. But we're not interested in how much energy moves, just how fast the wavefront (region of higher pressure) moves out from the sound source.
Whether the molecules travel large distances between collisions or short distances has a nearly negligible effect. Many short steps or a few long ones take essentially the same amount of time, since under normal conditions, collisional transfer of energy is an extremely fast process. The molecules themselves are still travelling at the same speed, because for a given gas that's a function of temperature alone. (Temperature is tied directly to the average kinetic energy per molecule.)
This interpretation gets us away from questions about non-ideal gases and on to the firm (*wink*) footing of statistical mechanics. We only get into trouble at extremely high densities--not really a problem at an atmosphere or pressure or less.
Sound travels slower because the air is colder, not thinner.
Quite right. Temperature--and only temperature--determine the speed of sound in a given gas. (If we neglect certain very small effects.)
Thinner doesn't affect speed of sound, and here's why in a nutshell.
Loosely speaking, sound propagates through energy passed from one molecule of air to the next by collisions between molecules. (No one can hear you scream in space because there's no chain of colliding molecules between the screamer and the audience.) Large groups of molecules with a slightly larger (or smaller) than average amount of kinetic energy appear to be the regions of high (and low) pressure we know as sound waves.
The speed with which these waves move is controlled by how quickly molecules can move their energy out from the sound source, to pass to molecules further out. Since this energy is transferred through collisions, each molecule must physically traverse the distance between interactions. The speed with which each molecule moves is directly related to its kinetic energy--in other words, its temperature. And only its temperature.
Pressure will affect the rate of sound attenuation in a gas, but not the speed at which sound travels.
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Gee. My closest blonde (female) friend has a first authorship on a paper in JACS, and just got back from studying solid state and laser physics in Sweden. Oh, and she's still an undergrad. I'll let her know that she's an idiot; I'm sure that she'd be interested.
I think the big problem is the combination of cell phone and SUV...of course, even there there is the issue of cause and effect.
Hypothesis: Cell phones make you stupid, then stupidity makes you buy an SUV.
It's a thought, but again, you're stuck with something that only really works from one or two directions--and then, it works badly. Anybody who's worked in laser optics knows it's bloody difficult to get light to couple efficiently into a fibre, and that's working with collimated laser light.
You might be able to "see through" someone, but the image you'd get would be quite dim, unless you amplify somewhere in the middle. This is--difficult. (Understatement.)
I suppose this is a great idea, if you only have one person to hide from, and you always face them, and you have access to a lot of little detectors and light sources.
I believe it was The Register which approached this topic in some detail. For me, I've found that the best cross-cultural pronunciation is "C-hash". "C-octothorpe", though perhaps the most precise and technically correct, doesn't roll off the tongue nearly as fluidly.
This device, through the small quantities of chlorine plus nasty (biochemically speaking) radicals generated through normal water electrolysis will probably very easily kill nearly anything that's actually in the water that passes through the device. I stand by my assertion that there is little or no residual purifying ability to the liquid that comes out, and the notion that a "dry mist" (whatever that is) from it will kill anthrax sounds like nonsense.
No doubt the electric field applied causes small bubbles to form within the solution, and then rapidly collapse. This collapse leads to extroardinarily high temperatures and pressures, which in turn cause nuclear fusion to take place. Stray gammas generated by this fusion result in the destruction of nearby pathogens.
Seriously, this technique sounds like a load of crap, for the most part. I can buy the electrochemical action bit, sort of. Pure molten NaCl (salt, hereafter) will electrolyze to form sodium and chlorine gas, sure enough. With a little creative engineering, it is possible to separate these to products and collect them for later use. Indeed, this is exactly what is done for commercial production of these two elements.
On contact with water, pure Na will form a solution of (aggressively basic) sodium hydroxide plus some hydrogen gas. (This, I assume, is the catholyte we hear about.) Chlorine in water forms an acidic solution which is, to be fair, definitely germicidal.
I see two problems. The first is technical. In a water solution, the electrolytic yields of sodium and chlorine are typically both very low, because oxygen and hydrogen gas are preferentially formed first. (There are sound thermodynamic reasons for this.) Maybe these experimenters have gotten around this somehow, perhaps using exotic catalysts or something.
The second problem is a bit more difficult. If the two component solutions (sodium + water and chlorine + water) are kept separate, individually they would be quite toxic. Brought together, there is a very quick reaction that brings us right back to salt and water--not a particularly powerful disinfectant, and what we started with before we had a mystical black box.
I can think of some other more creative possibilities, as well. Perhaps they're talking about generating some sort of activated state oxygen to do the dirty work (the salt just makes the water conductive)--in which case, they're definitely frauds. There just aren't any activated oxygen states that are stable long enough (in water) to get to the surface to be disinfected. Atomic oxygen might do it, but that's already been invented--and I'm pretty sure it won't last very long in solution either.
Finally, from the article, we have the quote:
f a letter is suspected of containing anthrax spores, it could be passed through a dry mist made from the Emerald solution and the letter would be sterilized.
The letter wouldn't even get wet. Anyone exposed to the spores could bathe in the solution and be germ free.
Erm. Dry mist. Sure. What's in this dry mist, exactly? Chlorine? Nope--it's way toxic. Sodium? Nope--it's a metal. Hydrogen? Um. Yeah. Oxygen--maybe, but atomic oxygen generators already exist (they're used for restoring artwork and whitening teeth). Singlet oxygen will kill things, but it only lasts a few nanoseconds in water.
So, to conclude this lengthy post--I call bullshit!
Couldn't agree more. I also have to recommend Irish dancing, of the sort one finds at a ceili. (Various transliterations abound--Gaelic is a fiendish language at times. Listen for something pronounced, KAY-lee.) It's sort of an Irish square dance. There's a caller, and you're told what to do before and (usually) during the song. One of the more difficult aspects of swing dancing (I've found) is the need to improvise as you go along--it's something I'm just not very good at.
I have two left feet. But as long as you're moving in about the same direction as everyone else, there's nothing to fear. The ability to count to eight is helpful as well--but that shouldn't be a problem in this crowd. You get the opportunity to dance with lots of partners (or groups, or lines)--or not, if you prefer--and it is excellent exercise. Don't be afraid to take a breather now and then--there's usually good imported Irish stout available on site as well.
I was only exposed to the concept earlier this year, and I haven't looked back. Now, all of my friends are doing it--a motley assortment of physicists, chemists, and biologists, with wildly varying amounts of coordination, innate talent, and attention span.
The stone could be a charcoal briquette that fell off the roof next door--the college students in the adjacent building were having one last barbecue before going back to school.
One of the students was being severely beaten by his friends for posting a message to Slashdot containing the phrase "3. Profit!!!". When his head hit the grill, the briquette was ejected over the edge of the roof.
The skies be praised! Nobody felt the need to add,
2. ????
3. Profit!
Finally, that stupid meme has been expunged.
Oh. Wait. Damn.
The unfortunate downside to Word--which we have seen in more than one high profile case--is its propensity for keeping invisible records of revisions within a document.
The last thing you want to send out with a draft contract or other legal document is a complete revision history. For paralegals that are used to using 'Reveal Codes', I imagine that it would be very unusual for any sort of hidden document features to sneak out the door.
Apologies to all those folks in rural America, but they're still screwed. Actually, this technology would be much more difficult to implement in the United States and Canada than in Europe.
The U.S. power grid typically delivers moderately high voltage to each little neighbourhood--a small handful of homes at most. At that point, there is a small transformer (a "pole pig"--no ethnic slur intended) for the last step down to 110 volts.
European grids usually step down to 220 volts, and do it further from the homes. There are significantly fewer transformers per capita, as each transformer serves more homes.
The problem is this. The high frequency data signal gets flattened out going through a transformer--those big coils act as a low pass filter that eats your data. You have to pick up the signal from the server before the high voltage side of the transformer and reintroduce it on the low voltage side (and do the same thing in the other direction for upstream signals).
In Europe this is not an insurmountable problem: you just need to hop over a few transformers in a handful of central locations. In the U.S., you have to install some sensitive electronics on every pole pig--exposed to the elements in a lot of widely separated, awkward to service locations.
Oh, and rural America has it even worse--some homes have their very own transformer, and would need their very own jumper for signals. Also, if there is a long enough length of power line back to the substation, the inductance of the power line will be enough to eat any high-bandwidth signal.
Well, no, not quite. What I would be concerned about is being forced to pirate the software after the original CD goes pfft! and dies.
Any company that tries to use a broken CD format to stop piracy is probably going to fold fairly quickly--and then how am I supposed to get replacement media?
The South Pole is the only permanently inhabited place on Earth that cannot see geosynchronous communication satellites, a fact that severely restricts communication with the base.
I take it that the North Pole is not permanently inhabited? I'm actually kind of surprised by this--it's much easier to get to the North Pole than the South, and there are other permanent settlements much closer at hand. (CFB Alert, which is responsible for watching for Russian ICBMs and bombers coming over the Pole, comes to mind.)
Oh yes, quite true. I ought to have said something about that. Trapped in a Win 98 et. al. world (not my computer at work, and too much inertia at home) my choices of browser are limited. I'm also hooked on tabbed browsing, which among the major browsers showed up first (I think) in Opera.
Before I die of shame, I can at least proudly say that I use PuTTY to connect to a *nix box for my mail, which I read and write in PINE...please, don't revoke my nerd credentials.
True enough for the mythical 'average user' whose desktop machine is less than two years old. As a university student who is working on a four-year-old PII-300 at home, and a PI-133 with 64 MB of RAM at work (age unknown), every last cycle is precious. Particularly since I'm usually multitasking.
The footprint--in memory, in terms of clock cycles eaten, on my tiny hard drive--of my browser actually a very important consideration for me, and probably for others. The F12 for quick menus (to kill popups, mostly), the clean file transfer monitoring box, and the tabbed browsing (fewer windows on my task bar) are worth their weight in gold.
Opera has also been quick to respond to bugs and make critical fixes--something that some companies are loathe to do. (Ahem. Microsoft. Certificates. Ahem.)
And it really is the fastest (of IE, Moz, and Opera) browser on earth.
It's kind of like being in Iowa.
First, as has already been pointed out in other replies, miles are also an absurd, arbitrary unit as far as science is concerned. We could get a 'round' unit if we took, say, about .65 AU, as the 'new' astronomical unit--exactly 10^11 m.
But then the AU would be a pretty useless yardstick. Earth's orbit is very nearly circular, which means that over a period of six months, the Earth moves a net distance of (almost) exactly 2 AU. Using this knowledge, it is possible to measure the distance to nearer stars. As the position of earth changes, the apparent positions of nearby stars will also appear to change relative to much more distant stars--a parallax effect. To get a precise measure of this distance, you want to move the Earth as far as possible, to get the maximum apparent shift in position. 2 AU is as far as we can readily move the earth.
There is even a unit of measure that is defined on this basis. The distance at which the apparent parallax shift of a star is equal to one second of arc is defined as one parsec. Parsec measures can be directly obtained from astronomical images taken six months apart, so they are the preferred unit of measure for some types of observational astronomy.
Of course, this also works backwards. If we could see a planet orbiting a star one parsec away (about 3.26 light years--this is a hypothetical case) and its orbital motion was across one apparent second of arc, we would know it orbited its sun at a distance of 1 AU.
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Ha! I got a spam through!
You should be glad it's not yours.
The three lines of a haiku should have 5, 7, and 5 syllables, respectively.
Wait! Isn't this the sort of thing that we're usually all up in arms about when the **AA threatens to do it?
Fake mp3's, with popular song titles, on a popular p2p network, wasting our bandwidth and time...go figure.
I offer this conspiracy theory: Information Wave is a front for the RIAA. Watch for black helicopters in your neighbourhood.
On a more serious note, I applaud this move. The RIAA and its affiliates and members see no problem with wasting our bandwidth with bogus clients and files. That bandwidth costs our ISPs, backbone providers, and--ultimately--us, money. It's almost as bad as spam in that respect, though at least there are nontrivial bandwidth costs on the RIAA's side in this case. Dinging their signal to noise ratio (possibly, hopefully) might make it too costly to annoy the rest of us. Throwing some of the RIAA's crap back at them seems like a reasonable, proportionate response if handled carefully and responsibly. (I hope Information Wave gets some good legal advice before they start doing this.)
Well, er, not exactly.
The technique described in the press release describes a technique for hiding a polarization modulation signal in the polarization state noise inherent in the ring laser system the experimenters used. It's clever, but it's very much not quantum encryption. In principle, it would be possible to siphon a few photons off the fiber and squeeze information out of them, though it would be very difficult. Quantum encryption, as described in the article referenced in the parent post, is a very different technique. It relies on measurements of the polarization states of single photons, not continuous beams. It is immune to (undetected) interception, because tapping the beam irretrievably loses some data (hooray for quantum mechanics.) It is not well-suited to fibre systems--it's difficult to push single photons down a fibre and reliably measure and retain their polarization. It would excel, however, for communcations that could take place over line-of-sight spans, even very long ones.
'Microsoft was worried that the NSA's releasing open- source software would compete with American proprietary software,'
Indeed. We ought not have the government funding university labs, because releasing medical research to the public domain might interfere with pharmaceutical company profits.
Not everything that's good for General Motors is good for the country, or its people, or its economy.
No images.
No Outlook macros.
No problem. And I really have to want to look an attachment before I'll go to the trouble of opening it.
Sure, the rate of energy transfer would be lower. But we're not interested in how much energy moves, just how fast the wavefront (region of higher pressure) moves out from the sound source.
Whether the molecules travel large distances between collisions or short distances has a nearly negligible effect. Many short steps or a few long ones take essentially the same amount of time, since under normal conditions, collisional transfer of energy is an extremely fast process. The molecules themselves are still travelling at the same speed, because for a given gas that's a function of temperature alone. (Temperature is tied directly to the average kinetic energy per molecule.)
This interpretation gets us away from questions about non-ideal gases and on to the firm (*wink*) footing of statistical mechanics. We only get into trouble at extremely high densities--not really a problem at an atmosphere or pressure or less.
Yes, because cultural homogenization never occurs...thank heavens for that.
1. Decide that everyone should like the same stuff.
2. ...
3. Open a GAP.
4. Profit!
Wait...someone already did that. Sigh. Maybe it's not too late to patent the business method.
Quite right. Temperature--and only temperature--determine the speed of sound in a given gas. (If we neglect certain very small effects.)
Thinner doesn't affect speed of sound, and here's why in a nutshell.
Loosely speaking, sound propagates through energy passed from one molecule of air to the next by collisions between molecules. (No one can hear you scream in space because there's no chain of colliding molecules between the screamer and the audience.) Large groups of molecules with a slightly larger (or smaller) than average amount of kinetic energy appear to be the regions of high (and low) pressure we know as sound waves.
The speed with which these waves move is controlled by how quickly molecules can move their energy out from the sound source, to pass to molecules further out. Since this energy is transferred through collisions, each molecule must physically traverse the distance between interactions. The speed with which each molecule moves is directly related to its kinetic energy--in other words, its temperature. And only its temperature.
Pressure will affect the rate of sound attenuation in a gas, but not the speed at which sound travels.