Applying that disingenuous label to anyone who questions your methods or motives is exactly why AGW is a religious movement- whether its true or not.
Equating people who are merely questioning methods or motives with people who are flat-out stating that the methods and motives are nefarious based on deliberately not understanding context is disingenuous.
There are people who are sincerely skeptical and ask questions, and who are unfairly denigrated as being biased. When the only questions being asked are rhetorical, though, that person isn't part of that group. Then, the "disingenuous label" fits perfectly and correctly.
Medieval Warm Period (a period from about 850-1100 of extremely mild weather. Grapes grew in London vineyards
LOL. There was no intervening time that grapes weren't grown in England. So saying they grew during a warm period is both true and meaningless. As is saying there was a warm period in Europe. Hint: This was not shared by the entirety of the globe.
modern climate theory says it never happened.
LOL. Seriously, you're causing AGW with all your straw-man burning.
It's actually funny how many of the standard anti-GW points are based on misunderstanding things we only know because of climatologists, then claiming the climatologists don't know about or deny the existence of those things.
Good work telling everyone that fixing things fixes them.
I see you've never had a disagreement with a mechanic or plumber over the definition of "fixed".
Personally I'm very glad they went to the trouble to figure out that "fixing" them according to the procedure is the same as "fixing" them according to our long-term strategic nuclear stockpile goals.:P
No, they started calling it "climate change" because they knew advanced thinkers like you couldn't wrap your heads around non-monotonic behaviors, and would actually think "if the globe is warming, why was it so cold this winter?" is a legitimate criticism.
Seriously, you're absolutely correct. The NSA has every incentive to improve the security of Windows, not compromise it. They did the same for Linux, where you can see the changes they made. In the past, they've made suggestions for improvements to encryption algorithms that academic researchers later realized had a sound mathematical basis. The NSA is as much about strengthening computer systems as they are compromising them. Hell, if in a particular situation they want to compromise the security of a system, all they usually have to do is ask (see: AT&T et. al.).
The thing is, they know that important information they want to be kept secret is going to exist on Windows machines. On Linux machines. On [x] machine that isn't necessarily controlled directly by the NSA.
And even outside such "National Security" secrets... The NSA may want to listen in on your phone calls, but it doesn't help them at all for every Tom, Dick, and Sally to have their credit card information stolen, their bank acccounts phished and plundered, and so on.
My cousin is an electrical engineer of great skill, and a former NSA employee of over ten years. He assures me that I'd be completely disappointed, disillusioned, and bored if I knew what they really did.
I tell him that's what his bosses wanted him to think.;)
OK, maybe a brick wasn't a good example. But photons do have kinetic energy, so maybe bouncing a ball off a vertical wooden wall would be a better example.
Well you could say photons are all kinetic energy, but that wasn't the point. The point was there was excess energy in the brick that was not present after impact thus creating a large transient pressure spike, completely unlike the laser.
But energy isn't really the point either. We know the laser transmits tons of energy, but it isn't necessarily transmitted as kinetic energy. The question is whether the force exerted by the laser (or bouncy balls) is sufficient to destroy something. And we've already done that math, and it isn't anywhere close.
Shock waves occur when the target medium is compressed faster than the speed of sound in that medium. So a step up in force of sufficient amplitude would do the trick.
The key being "sufficient amplitude". The shock wave is going to be proportional to the force that creates it, with a ratio of less than 1. That radiation pressure exists, exerts force and thus could hypothetically damage things, is not and never was in question. That "A laser that powerful would convey enough impulse to make a hole without needing to heat the target" is what is in question, and is simply not true.
I honestly don't know if radiation pressure shock waves actually occur in reality
Of course they do, they're just tiny. Your bouncy-ball example is literally going to exert more pressure and create a bigger shock wave than this megawatt laser.
That said, I made my original comment with laser fusion in mind, where laser beams are used to compress a target bead. My mistake was twofold: the laser power used there is more than thousand times greater, and the compression occurs by a thermal shock wave, instead of radiation pressure. So yes, radiation pressure would be insignificant next to that.
Yes, indeed. What this tells you is that there is basically no application where radiation pressure is significant since for even the most optimistic estimates of how reflective a target could be, the amount of damage from heating will be many times greater than damage from pressure. So if your laser is so powerful just its radiation pressure could hypothetically destroy the target, then the target would be vaporized by the laser before pressure had a chance to do anything anyway, and for that matter you could have just used a much weaker laser.
Oh hey I just thought of one though -- you could use lasers to boost your solar sail ship (with the laser not on the ship obviously) when it gets too far from the sun for solar wind to be effective. But that's kinda silly... it'd make more sense to use the laser as beamed power for some other kind of drive.
The topic of discussion was the radiation pressure of the laser. ByteSlicer was hypothesizing that a laser this powerful would have enough momentum to destroy things just with that, but they are quite wrong.
The actual energy of the laser ("mega-watt class" according to tfa) is of course sufficient to cause significant damage; the whole point of this demonstration. But it's not doing it's damage by the photons imparting their momentum to the target.;)
Yes, yes it would. It would hurt tremendously. It has hurt tremendously to the extent that we've used them.
The tactics of WW2 (mass bombardment, armored warfare, submarine warfare, etc) aren't very relevant here but we could certainly learn a thing or two from the way the Greatest Generation behaved on the battlefield. Tying one hand behind our backs and following the rules when our enemies refuse to do the same is extremely foolhardy. You don't fight fair -- you fight to win. We used to understand that. Our enemies still do.
What you need to understand is that "win" means different things in different conflicts, and the "win" in state-vs-state warfare like WWII is monumentally different than "win" in a counter-insurgency nation-building conflict like we are now engaged in. Our enemies understand this, but many still don't understand that even though it already bit us in the ass in Vietnam, then again in Iraq and Afghanistan. Because they refuse to see that these wars are not just different from WWII tactically, but in their fundamental objectives.
To fight an insurgency you need intelligence from the locals. To get intelligence from the locals, they need to be on your side. For them to be on your side, you do need to fight "fair". Refusing to take prisoners, shooting anyone who looks like they might be an insurgent, "rigorously interrogating" suspected insurgents, being cavalier about "collateral damage" -- all these things lose the support of the locals, and thus cause us to lose the war.
Fighting to win? You're talking about fighting to lose. The rules of engagement that our soldiers abide by are critical to ensuring that we can succeed. Does "tying one hand behind our backs" make it hard to succeed? Absolutely, but without that it would be impossible to succeed. Don't like fighting wars where you must tie one hand behind your back to have a hope of winning? Well maybe you shouldn't get into that kind of war. There's another lesson you should learn.
So on the target area, there is suddenly extra force applied.
"Extra" in the sense of more force than before, not "extra" as in more than what the laser imparts. If the force imparted by the laser is insignificant (it is), then this "shockwave" will also be insignificant.
It's like dropping a brick on a table: the weight will create a shock on impact and constant pressure afterwards.
No, the kinetic energy of the falling brick will create a shock on impact. That creates "extra" force beyond the weight of the brick resting on the table. That's nothing like the situation here.
Instead imagine that you slide the brick onto the table from the side. Is there going to be a significant shockwave? If the table is easily able to handle the weight of the brick, then no matter how fast you transition the table from not supporting the brick to supporting the brick it's not going to break the table.
There's also the fact that this pressure difference is applied in a nanosecond or so.
Um, no. That's not how pressure works.
Pressure is force per unit area, and force is change in momentum per second. For the same power laser it makes no difference if the laser pulse is a nanosecond, or a year long, the pressure is the same. That's why I worked from watts, not joules -- because I don't know the pulse length, and it doesn't matter for figuring out the force exerted by the laser. A megawatt laser that pulsed for only a nanosecond would deliver far 1e-9 times as much energy as the same laser pulsed for a second. The force exerted by that laser would be the same, except obviously pushing on something with the same force only for 1e-9 times as long would have much less effect.
But given enough power and sufficient small target area, radiation pressure could get sufficiently large to puncture the hull.
It would have to be a ridiculously powerful laser, at least a gigawatt, for radiation pressure to be at all significant.
Also, I didn't want to do the math for laser divergence so I made a super-optimistic assumption, but there are physical limits on minimum laser divergence and thus target area at a given distance.
So... how did you encode what operation the ALU should perform? And wouldn't that then be the ISA? Couldn't you then make a "one-instruction microprocessor" where the only instruction is "move bytes to x86 processor instruction cache"?;)
Or was each possible ALU operation a different memory-mapped address? Was writing the operands to the addresses what caused the operation, or did you have to write to a "do-it" ?
Not that making such a processor isn't cool. Cus it's cool. Making just about any kind of processor in school is cool.:)
Just when I read "one instruction processor" I was thinking of something more traditional, where instructions map to execution units. So like a machine where the only instruction is NAND with memory arguments. Now that would be a bitch to program.;)
Each photon in the beam transfers its momentum to the target. For total reflection it transfers twice its momentum. This will result in radiation pressure exerting a very localized force (so high pressure)
Hm... I can't find anything specific about the power, just "mega-watt class". So let's call it a megawatt and we can multiply the result as necessary. I'm also going to guess it's a 1.315um COIL laser. Momentum per photon is h/lambda = 5.039e-28 kg*m/s, energy is hf = 1.511e-19 J. The megawatt laser therefore produces 6.618e24 photons/s, so assuming total reflection that's a force of about 0.0066 N.
I don't know how tightly the beam is focused, but if it's 1mm^2 (which seems pretty damn tight, someone else can calculate the divergence), that's a pressure of about 6600 Pa, or about 6% of standard atmospheric pressure. How many atmospheres do you need to damage a plane?
I dunno, I have a hard time believing radiation pressure is going to be a significant factor in the effectiveness of a laser.
That's pretty standard, and it's basically a way to distinguish on-die cores from pieces of silicon what contain cores (since you can have varying amounts of each).
The "Processing" in "SMP", though, is not making the same distinction. The processor/core distinction only really exists when specifically talking about multi-core chips, not in general architecture parlance.
Technically is a single Core2Duo/Quad or Core iX CPU considered SMP? I would guess no they are not.
Funnily enough, a single Core i7 or Opteron is SMP, but if you have multiple, then it isn't, it's NUMA because not all the processors have Symetric access to memory.
There is also a solution that most people never think of: come up with a new algorithm that is faster then the current one
Oh yeah, nobody ever thinks of coming up with a more efficient algorithm. It's not like Day 1 of Code Optimization 101 is "you get more out of coming up with a better algorithm than you do by tweaking your existing one." It's not like there's a whole sub-field of CS devoted to coming up with better algorithms for things.
Or maybe... just maybe... they have thought of the "come up with a new algorithm" solution, but that this is as hard to do as it is trivial to say.
People are working on it, but it's not easy, and sometimes no better algorithm exists. And even if it did, there would still be a use for that much hardware -- you could simulate bigger things.:P
Perhaps a poor choice of words, but the meaning was apparant.
Maybe it should be but I still don't understand. How is banks divesting themselves of dollars and thus the value of the dollar decreasing unnatural, in any sense? And I don't mean why is that word being used, I mean please explain to me what the difference is? It sounds to me like one of the actions that should necessarily affect the value of a currency. When you flood the market with a commodity, whether by an institute selling their holdings, or by issuing more, the value should go down. Sorry, I'm confused.
Naw, that doesn't work, though the real answer is still simple. You have to use the relativistic energy/momentum relation. E^2 = (pc)^2 + (m0*v^2)^2, which for a photon is simply E = pc. Also, E = hf, so you get hf = pc, or p = hf/c = h/lambda, Plank's Constant divided by wavelength.
Michelangelo: I've got it! I've got it! We'll call it "The Last But One Supper"!
Pope: What?
Michelangelo: Well there must have been one, if there was a last supper there must have been a one before that, so this, is the "Penultimate Supper"! The Bible doesn't say how many people were there now, does it?
Pope: No, but...
Michelangelo: Well there you are, then!
Pope: Look! The last supper is a significant event in the life of our Lord, the penultimate supper was not! Even if they had a conjurer and a mariachi band. Now, a last supper I commissioned from you, and a last supper I want! With twelve disciples and one Christ!
Slashdot Mirror
Applying that disingenuous label to anyone who questions your methods or motives is exactly why AGW is a religious movement- whether its true or not.
Equating people who are merely questioning methods or motives with people who are flat-out stating that the methods and motives are nefarious based on deliberately not understanding context is disingenuous.
There are people who are sincerely skeptical and ask questions, and who are unfairly denigrated as being biased. When the only questions being asked are rhetorical, though, that person isn't part of that group. Then, the "disingenuous label" fits perfectly and correctly.
Medieval Warm Period (a period from about 850-1100 of extremely mild weather. Grapes grew in London vineyards
LOL. There was no intervening time that grapes weren't grown in England. So saying they grew during a warm period is both true and meaningless. As is saying there was a warm period in Europe. Hint: This was not shared by the entirety of the globe.
modern climate theory says it never happened.
LOL. Seriously, you're causing AGW with all your straw-man burning.
It's actually funny how many of the standard anti-GW points are based on misunderstanding things we only know because of climatologists, then claiming the climatologists don't know about or deny the existence of those things.
Good work telling everyone that fixing things fixes them.
I see you've never had a disagreement with a mechanic or plumber over the definition of "fixed".
Personally I'm very glad they went to the trouble to figure out that "fixing" them according to the procedure is the same as "fixing" them according to our long-term strategic nuclear stockpile goals. :P
No, they started calling it "climate change" because they knew advanced thinkers like you couldn't wrap your heads around non-monotonic behaviors, and would actually think "if the globe is warming, why was it so cold this winter?" is a legitimate criticism.
Seriously, you're absolutely correct. The NSA has every incentive to improve the security of Windows, not compromise it. They did the same for Linux, where you can see the changes they made. In the past, they've made suggestions for improvements to encryption algorithms that academic researchers later realized had a sound mathematical basis. The NSA is as much about strengthening computer systems as they are compromising them. Hell, if in a particular situation they want to compromise the security of a system, all they usually have to do is ask (see: AT&T et. al.).
The thing is, they know that important information they want to be kept secret is going to exist on Windows machines. On Linux machines. On [x] machine that isn't necessarily controlled directly by the NSA.
And even outside such "National Security" secrets... The NSA may want to listen in on your phone calls, but it doesn't help them at all for every Tom, Dick, and Sally to have their credit card information stolen, their bank acccounts phished and plundered, and so on.
My cousin is an electrical engineer of great skill, and a former NSA employee of over ten years. He assures me that I'd be completely disappointed, disillusioned, and bored if I knew what they really did.
I tell him that's what his bosses wanted him to think. ;)
I though Piccard was saying he was "the cutest aboard". That all makes more sense now.
Well he was. Especially aboard the Borg Cube. But maybe he was just speaking his mind about the Enterprise, now that he was free of it.
It's easily (ish) to stimulate a neuron externally using optical stimulation
That's clearly cheating, since we've been doing that without knowing it was what we were doing for millenia. ;)
OK, maybe a brick wasn't a good example. But photons do have kinetic energy, so maybe bouncing a ball off a vertical wooden wall would be a better example.
Well you could say photons are all kinetic energy, but that wasn't the point. The point was there was excess energy in the brick that was not present after impact thus creating a large transient pressure spike, completely unlike the laser.
But energy isn't really the point either. We know the laser transmits tons of energy, but it isn't necessarily transmitted as kinetic energy. The question is whether the force exerted by the laser (or bouncy balls) is sufficient to destroy something. And we've already done that math, and it isn't anywhere close.
Shock waves occur when the target medium is compressed faster than the speed of sound in that medium. So a step up in force of sufficient amplitude would do the trick.
The key being "sufficient amplitude". The shock wave is going to be proportional to the force that creates it, with a ratio of less than 1. That radiation pressure exists, exerts force and thus could hypothetically damage things, is not and never was in question. That "A laser that powerful would convey enough impulse to make a hole without needing to heat the target" is what is in question, and is simply not true.
I honestly don't know if radiation pressure shock waves actually occur in reality
Of course they do, they're just tiny. Your bouncy-ball example is literally going to exert more pressure and create a bigger shock wave than this megawatt laser.
That said, I made my original comment with laser fusion in mind, where laser beams are used to compress a target bead. My mistake was twofold: the laser power used there is more than thousand times greater, and the compression occurs by a thermal shock wave, instead of radiation pressure. So yes, radiation pressure would be insignificant next to that.
Yes, indeed. What this tells you is that there is basically no application where radiation pressure is significant since for even the most optimistic estimates of how reflective a target could be, the amount of damage from heating will be many times greater than damage from pressure. So if your laser is so powerful just its radiation pressure could hypothetically destroy the target, then the target would be vaporized by the laser before pressure had a chance to do anything anyway, and for that matter you could have just used a much weaker laser.
Oh hey I just thought of one though -- you could use lasers to boost your solar sail ship (with the laser not on the ship obviously) when it gets too far from the sun for solar wind to be effective. But that's kinda silly... it'd make more sense to use the laser as beamed power for some other kind of drive.
The topic of discussion was the radiation pressure of the laser. ByteSlicer was hypothesizing that a laser this powerful would have enough momentum to destroy things just with that, but they are quite wrong.
The actual energy of the laser ("mega-watt class" according to tfa) is of course sufficient to cause significant damage; the whole point of this demonstration. But it's not doing it's damage by the photons imparting their momentum to the target. ;)
It wouldn't hurt.
Yes, yes it would. It would hurt tremendously. It has hurt tremendously to the extent that we've used them.
The tactics of WW2 (mass bombardment, armored warfare, submarine warfare, etc) aren't very relevant here but we could certainly learn a thing or two from the way the Greatest Generation behaved on the battlefield. Tying one hand behind our backs and following the rules when our enemies refuse to do the same is extremely foolhardy. You don't fight fair -- you fight to win. We used to understand that. Our enemies still do.
What you need to understand is that "win" means different things in different conflicts, and the "win" in state-vs-state warfare like WWII is monumentally different than "win" in a counter-insurgency nation-building conflict like we are now engaged in. Our enemies understand this, but many still don't understand that even though it already bit us in the ass in Vietnam, then again in Iraq and Afghanistan. Because they refuse to see that these wars are not just different from WWII tactically, but in their fundamental objectives.
To fight an insurgency you need intelligence from the locals. To get intelligence from the locals, they need to be on your side. For them to be on your side, you do need to fight "fair". Refusing to take prisoners, shooting anyone who looks like they might be an insurgent, "rigorously interrogating" suspected insurgents, being cavalier about "collateral damage" -- all these things lose the support of the locals, and thus cause us to lose the war.
Fighting to win? You're talking about fighting to lose. The rules of engagement that our soldiers abide by are critical to ensuring that we can succeed. Does "tying one hand behind our backs" make it hard to succeed? Absolutely, but without that it would be impossible to succeed. Don't like fighting wars where you must tie one hand behind your back to have a hope of winning? Well maybe you shouldn't get into that kind of war. There's another lesson you should learn.
So on the target area, there is suddenly extra force applied.
"Extra" in the sense of more force than before, not "extra" as in more than what the laser imparts. If the force imparted by the laser is insignificant (it is), then this "shockwave" will also be insignificant.
It's like dropping a brick on a table: the weight will create a shock on impact and constant pressure afterwards.
No, the kinetic energy of the falling brick will create a shock on impact. That creates "extra" force beyond the weight of the brick resting on the table. That's nothing like the situation here.
Instead imagine that you slide the brick onto the table from the side. Is there going to be a significant shockwave? If the table is easily able to handle the weight of the brick, then no matter how fast you transition the table from not supporting the brick to supporting the brick it's not going to break the table.
There's also the fact that this pressure difference is applied in a nanosecond or so.
Um, no. That's not how pressure works.
Pressure is force per unit area, and force is change in momentum per second. For the same power laser it makes no difference if the laser pulse is a nanosecond, or a year long, the pressure is the same. That's why I worked from watts, not joules -- because I don't know the pulse length, and it doesn't matter for figuring out the force exerted by the laser. A megawatt laser that pulsed for only a nanosecond would deliver far 1e-9 times as much energy as the same laser pulsed for a second. The force exerted by that laser would be the same, except obviously pushing on something with the same force only for 1e-9 times as long would have much less effect.
But given enough power and sufficient small target area, radiation pressure could get sufficiently large to puncture the hull.
It would have to be a ridiculously powerful laser, at least a gigawatt, for radiation pressure to be at all significant.
Also, I didn't want to do the math for laser divergence so I made a super-optimistic assumption, but there are physical limits on minimum laser divergence and thus target area at a given distance.
"No one writes jokes in base 13"
Yeah, even Intercal stops at base 7.
So... how did you encode what operation the ALU should perform? And wouldn't that then be the ISA? Couldn't you then make a "one-instruction microprocessor" where the only instruction is "move bytes to x86 processor instruction cache"? ;)
Or was each possible ALU operation a different memory-mapped address? Was writing the operands to the addresses what caused the operation, or did you have to write to a "do-it" ?
Not that making such a processor isn't cool. Cus it's cool. Making just about any kind of processor in school is cool. :)
Just when I read "one instruction processor" I was thinking of something more traditional, where instructions map to execution units. So like a machine where the only instruction is NAND with memory arguments. Now that would be a bitch to program. ;)
Each photon in the beam transfers its momentum to the target. For total reflection it transfers twice its momentum. This will result in radiation pressure exerting a very localized force (so high pressure)
Hm... I can't find anything specific about the power, just "mega-watt class". So let's call it a megawatt and we can multiply the result as necessary. I'm also going to guess it's a 1.315um COIL laser. Momentum per photon is h/lambda = 5.039e-28 kg*m/s, energy is hf = 1.511e-19 J. The megawatt laser therefore produces 6.618e24 photons/s, so assuming total reflection that's a force of about 0.0066 N.
I don't know how tightly the beam is focused, but if it's 1mm^2 (which seems pretty damn tight, someone else can calculate the divergence), that's a pressure of about 6600 Pa, or about 6% of standard atmospheric pressure. How many atmospheres do you need to damage a plane?
I dunno, I have a hard time believing radiation pressure is going to be a significant factor in the effectiveness of a laser.
Just fyi, your window manager has nothing to do with your Blender window not being hardware accelerated.
That's pretty standard, and it's basically a way to distinguish on-die cores from pieces of silicon what contain cores (since you can have varying amounts of each).
The "Processing" in "SMP", though, is not making the same distinction. The processor/core distinction only really exists when specifically talking about multi-core chips, not in general architecture parlance.
Surely there is an easier way for computer nerds to get pussy?
Yeah, just visit your local Humane Society or animal shelter.
Don't tell them what you plan on doing with it, though.
Technically is a single Core2Duo/Quad or Core iX CPU considered SMP? I would guess no they are not.
Funnily enough, a single Core i7 or Opteron is SMP, but if you have multiple, then it isn't, it's NUMA because not all the processors have Symetric access to memory.
Core 2 is SMP for all standard configurations.
There is also a solution that most people never think of: come up with a new algorithm that is faster then the current one
Oh yeah, nobody ever thinks of coming up with a more efficient algorithm. It's not like Day 1 of Code Optimization 101 is "you get more out of coming up with a better algorithm than you do by tweaking your existing one." It's not like there's a whole sub-field of CS devoted to coming up with better algorithms for things.
Or maybe... just maybe... they have thought of the "come up with a new algorithm" solution, but that this is as hard to do as it is trivial to say.
People are working on it, but it's not easy, and sometimes no better algorithm exists. And even if it did, there would still be a use for that much hardware -- you could simulate bigger things. :P
Ah, so there are people of Chinese descent in the 'verse, you just wouldn't know it from actually watching the show. Got it.
I kid, because I love. ;)
Perhaps a poor choice of words, but the meaning was apparant.
Maybe it should be but I still don't understand. How is banks divesting themselves of dollars and thus the value of the dollar decreasing unnatural, in any sense? And I don't mean why is that word being used, I mean please explain to me what the difference is? It sounds to me like one of the actions that should necessarily affect the value of a currency. When you flood the market with a commodity, whether by an institute selling their holdings, or by issuing more, the value should go down. Sorry, I'm confused.
Naw, that doesn't work, though the real answer is still simple. You have to use the relativistic energy/momentum relation. E^2 = (pc)^2 + (m0*v^2)^2, which for a photon is simply E = pc. Also, E = hf, so you get hf = pc, or p = hf/c = h/lambda, Plank's Constant divided by wavelength.
Michelangelo: I've got it! I've got it! We'll call it "The Last But One Supper"!
Pope: What?
Michelangelo: Well there must have been one, if there was a last supper there must have been a one before that, so this, is the "Penultimate Supper"! The Bible doesn't say how many people were there now, does it?
Pope: No, but...
Michelangelo: Well there you are, then!
Pope: Look! The last supper is a significant event in the life of our Lord, the penultimate supper was not! Even if they had a conjurer and a mariachi band. Now, a last supper I commissioned from you, and a last supper I want! With twelve disciples and one Christ!
Michelangelo: One?!