Then why has Obama adopted so many of McCain's positions, including on Iraq?
Do you have sources for this, or are you just making it up? Obama's stated position is a 16 month timetable for withdrawal of the main forces. He has had this proposal for months, and it was endorsed by Maliki when Obama visited Iraq before angry noises from Washington forced him to backpedal. McCain's Iraq page has no such timetable, although he started suggesting expedited withdrawal as a possible option after Maliki's announcement undermined his "100 years if necessary" position.
Huntington is certainly an excellent scientist, but his socio-political theories about why wars are fought are better left to experts in that field
I disagree with your first claim. Huntington has a well-established record of fabricating history to suit his ideas. The standard example is his claim that South Africa in the 1960s under Apartheid fit his definition of satisfied society. To back up his claim, he falsely asserted that there were no notable protests or uprisings during this time. Fortunately, there were ample news archives that contradicted him. Unfortunately, people still listen to his bold pseudoscientific pronouncements about societies and their interactions.
You can find the same flavor nonsense in pretty much anything written by his student Fareed Zakaria.
We shouldn't let journalists dope either. Case in point: this article.
I agree. Tierney in particular likes to present himself as someone who comes up with insightful ideas that buck conventional wisdom. However, the evidence suggests that he typically gives a cursory examination to a complex problem, and then offers an "easy way out" solution that is already rather popular among a large group of people.
I'm not an expert in this field, but my impression is that with our current technology, this experiment is in fact less precise than ones that have been done previously. I would consider it worthwhile in the sense that it is always worthwhile to check that we haven't collectively gone bonkers, but any statistically significant deviation from the expected behavior is more likely than not to be a failure of methodology, e.g., some uncontrolled source of noise.
Sorry, way over my head. It's just that I do trust even the article summary, not to mention the real research proposal the article is about, more than an AC post saying it ain't so.
That's too bad, because the article summary is completely wrong. GR predicts that anything in free fall follows a geodesic in spacetime, including matter, antimatter, and other stuff like photons that are their own antiparticles. Consequently, you should expect the gravity of a massive object to deflect the trajectory of matter and antimatter in exactly the same way. Naturally this sort of hypothesis is something one should test, but that has been done years ago. Other comments before this one have pointed out experimental data from supernovas and particle accelerators that show that any difference in behavior is bounded above by about one part in a billion. In particular, antimatter has been known not to fall up for quite some time.
The neutrinos are released as the degenerate gas at the stellar core collapses to neutronium; they pass through the surrounding material as if it wasn't even there, and set out into the universe immediately.
This is mostly true. During core collapse, the high density drops the mean free path of a neutrino to a few meters, and the neutrinos become energy carriers in a short-lived equilibrating process. The resulting neutrino-neutron reactions are what allow elements heavier than Bismuth to form (s-process products tend to be too neutron-heavy to survive), and the net outward transfer of energy contributes to the rebound shock.
if two particles are quantum-entangled, and you separate them, they remain entangled and you can monitor the state of one using the other.
This is pretty much where you went wrong. Entanglement can produce correlated measurements for distant particles, but the particles are only entangled as long as you don't do anything to them. Once you disrupt the state of one of the particles (e.g., by measuring it) the entanglement is lost. You cannot use an entangled pair to continuously send information.
The article is about an observation of the dynamics of the jets, not any recent theoretical development regarding the mechanism behind them. Blandford and Znajek proposed the process behind jet formation 30 years ago.
Thermodynamics, heat engines (which is as efficient as energy transfer gets), and Carnot. If you can beat 40% efficiency transferring one form of energy into another, you win a Nobel Prize. I would cast serious doubt on whoever claims to have gotten 42.7% efficiency. But it's not up to me to teach you high school physics.
I think you may have misunderstood the applicability of Carnot's theorem. It is an upper bound on our ability to extract mechanical energy from temperature differences, but it does not restrict our ability to convert e.g., mechanical energy to electrical energy and back, which is the objective of regenerative brakes. In fact, the Wikipedia article you linked makes this very clear from the perspective of reversibility. If you could make a heat engine that meets or breaks Carnot's bound, then you could create a perpetual motion machine by running an identical device in reverse to generate more thermal gradient. This may seem counterintuitive, since the reverse device is running at greater than 100% efficiency, but such superunital efficiency is quite common in practice, and is in fact one reason that heat pumps are more common than resistive heaters or fuel-burning heaters in carbon-poor countries like Japan.
Okay, I'm not sure the perpetual motion argument is that convincing without serious thinking about heat pumps. A more quantitative way to look at it is that an engine running at Carnot's ideal efficiency is adding zero entropy to the universe. If you just want to store energy and release it in the same form later (as in the case of regenerative braking), Carnot says that the best you can do is by releasing a very small amount of entropy by an almost-reversible process, but there is no thermodynamic obstruction to getting arbitrarily close to 100% efficiency.
Oh I agree there are devices that try to "harness" the energy from the downhill runs (and deceleration) via hydraulics or pneumatics, and "boost" the engine when needed (startup, uphill). And all self respecting scientists know that you will never approach 100% efficiency (40% being the theoretical max).
I am curious about this 40 percent figure, since I haven't heard of any hard obstructions to storing and retrieving this kind of energy. Is there a thermodynamic reason this can't be done arbitrarily efficiently, or is it just a problem with our current motor/generator technology?
Some web searching reveals unsourced estimates of 42.7% efficiency for hydraulic storage systems and 31.3% for electric regenerative braking systems currently in use, so your theoretical ceiling may be a bit low. Naturally, it would be nice if people actually pointed to primary sources when quoting them so we could verify the claims.
In fact, it's a basic theorem that given sufficient time, human-level intelligence can always beat any system with less than human-level intelligence (aside from trivial cases like a complete firewall).
How could you possibly call this a theorem? You're using terms like "human-level intelligence" that aren't even well-defined, and you haven't specified the parameters of the game. Are you saying humans can win any game against a computer? Not true. There's no rigor here.
This is because the human's theory of mind can fully encompass the lesser system (so you can understand how it works), while the reverse is not true.
We have the same problem as before. What is a lesser system? Are you referring to some kind of Kolmogorov complexity? One problem with defeating computers at certain games (like checkers, which has been completely solved computationally) is that the human brain cannot store very much abstract symbolic information. If you ask an unaided human to play checkers against a suitably programmed computer, the human will be unable to keep track of enough information to avoid mistakes. It doesn't matter what your "theory of mind" is (whatever that means) if you can't remember enough of a system to understand how to exploit it.
This doesn't mean that a computer system can never be good enough to solve this problem. However, it does mean that if you could build a computer system that could solve it, then it would insist on being paid.
Not necessarily. The problem of gaming search results is more of an economic question than an AI-theoretic one. The goal is to arrange matters so that any successful strategy for gaming the system realizes limited benefits, and requires a large investment in resources. Brute force computational solutions often make economic sense, because they can scale better.
If you recall many of Greek heroes, such as Hercules, had gods for parents, which explained why they were so powerful. Achilles was more like the Incredible Hulk, in that exposure to magic (the waters of the River Styx in the case of Achilles, gamma rays in the case of the Hulk) give them their powers. But Odysseus is like Batman- he doesn't have any superpowers, he's just clever.
Minor nitpick: Achilles was also half-divine, according to the Iliad. His mother was Thetis. Odysseus also had divine ancestors, but they were more distant.
So far as we know, an electron is a point particle, and the electrons in an atom aren't any different from a free electron. They are a collection of little points located at various definite positions. There's no "fuzziness" and they aren't "smeared out" in any sense at all.
I agree that electrons are point particles to the best of our knowledge. However, they are smeared out in the sense that they don't admit position eigenstates, so they are not located at definite positions. If you want to calculate a scattering amplitude, you have to integrate over a distribution of possible events, and I think it is reasonable to describe this as fuzziness.
They're smaller than visible wavelengths, but their actual size is a specific fraction of a visible wavelength. Let's see the atoms colored with the color that's a harmonic multiple.
I think you have a failure of uniqueness. If you have an atom with diameter 100pm, there are about three thousand wavelengths of visible light that are integer multiples of that. Which one will you choose?
Or maybe the color should be derived from the "texture" of the atom, just like the actual color of macroscopic materials. If a carbon atom has 12 electrons evenly distributed around a sphere in shells (2, 8 and another 2 in valence), let's see it get colored accordingly. Maybe the inner shell's diameter harmonic color in the visible range, divided by 2 and scaled back into the visible, overlapped with the same algorithm for the outer 8 in the second shell, then again for the 2 in the outermost shell.
Your sentences are difficult to parse. Are you suggesting that they use false color to reflect the electronic structure of the material? That seems to be exactly what they are doing. The specifics of your suggestion seem to be a bit suspect, though (including your apparent confusion between atomic number and atomic mass). One advantage of the techniques used here is that they can tell us about bonds between atoms, rather than just the atoms themselves.
This is determined by the uncertainty principle as well. The uncertainty (and thus average time) is determined by the energy. The larger the energy, the larger the uncertainty in the time, and so longer before the atom decays.
I think the reverse is true. Large energy transitions tend to have short characteristic time scales (think of reaction rates in chemistry). The uncertainty principle gives you a lower bound on the product, not the quotient. Also, there are often obstructions due to, e.g., nonconserved angular momentum, which can make metastable states very long-lived.
In another reply, someone said that photons 'collide' by decaying into other particles, which then collide with each other.
Photons don't directly interact in perturbative QED, but if you happen to have some charged matter (such as electrons) lying around they can interact with that. You have a nonzero amplitude for pair production anywhere, and this is enhanced in regions with high EM field strength. In theory, you can get nonlinear corrections to Maxwell's equations in a vacuum by interacting with them, but I haven't heard of any experimental observations. There are a lot of Feynman diagrams with only photons as external edges, but photon-photon interactions require at least fourth order in the coupling constant (which is rather small). I think the interactions you hear about involve some kind of medium made of atoms.
This seems to be a poor analogy. It is much more difficult to relocate to a different country than it is to choose a different restaurant. You lose your network of friends and family, and you may be surrounded by people who speak a different language and follow different cultural norms.
It's also common in mathematics - Sir Isaac Newton stole copiously from Huygens, Descartes, Hooke, and anyone else stupid enough to let him. Or perhaps not stupid - the only person to resist Newton's claim of ownership did die rather soon after.
Do you have a good source for this? I'm curious, because his most important contributions (e.g. optics, gravitation, laws of motion) seem to be attributed to Newton alone, or in the case of infinitesimal calculus, discovered independently.
Apparently the white hair on polar bears acts like optic fibre. It collects light over a larger surface than the bare skin of the animal and channels it to the body to keep it warm.
If that were true, the bear would look black (at least at near-IR frequencies). Also, this article asserts that the fiber optic hypothesis has been demonstrated false. The translucent fur is most likely a camouflage adaptation.
Can you propose a mechanism for star formation that would give the sun a sufficiently large positive charge to accelerate ions at large distances? That voltage difference had to come from somewhere, and large charge imbalances counteract the gravitational attraction needed for nuclear fusion.
Maybe I'm wasting my time. It seems clear that "alternative cosmologies" means the electric universe theory, which doesn't make any useful, testable predictions.
One more London to Sydney option is to build a large tube in the ocean, remove all of the air and water from the tube, and run a maglev through the vacuum. This eliminates air resistance and problems with moving parts, at the expense of considerable capital investment and some heat dissipation issues. There don't seem to be any fundamental obstructions to making this trip in under an hour, although the acceleration may be a bit uncomfortable - you need about 1.4g to do 20000km in 40 minutes.
(It's also the same thing that creates the first flaming fireball in the nuke. The shockwave compresses the air so hard, it becomes glowing plasma.)
I think you have it somewhat backwards. The fireball is created by the air around the exploding weapon absorbing the high energy thermal radiation emitted by the weapon itself. The shockwave compression happens after hydrodynamic separation, and in fact, the opacity of the incandescent gas causes the fireball to appear dimmer. See this bit for details.
The summary: improvised explosives involve pretty nasty stuff that you'd be hard pressed to mix in an airplane lavatory without killing yourself in the process.
You'd think a suicide bomber would have an easier time just (taking a page from the drug mules) swallowing a large number of condoms full of plastic explosives, timer, and detonator. This is a rather obvious solution: no carry-on, no luggage, no hassle.
How would you prevent this sort of attack? You could try to find traces of explosive on the bomber's person, using swabbing, some kind of breathalyzer, or more invasive procedures. More pragmatically, you could try to disrupt the network of people who procure the necessary supplies. I suppose that is the purpose of our intelligence services.
I've taken more mathematics than you, Asperger's reject. The chance of your vote making a difference (being the deciding vote) is 1 in (x=0 to n-2 ||| sum 2^x) where n is the number of voters total. Yes, that number does asymptotically approach zero with increasing n.
I don't think that is how it works. The probability of your vote being the deciding vote is the probability of your side winning by one. Enumerating this probability is a bit tricky, since it depends on your assumptions, e.g., I think the answers are skewed if we have preexisting information about voter bias.
For simplicity, let's assume all n people who vote flip a fair coin to decide between two choices. Then the probability of your side winning by one is about (n choose n/2)/2^n. Stirling's formula gives an asymptotic estimate of about sqrt(2/(n*pi)), which approches 0, but not nearly as quickly as you suggest. If you have a local election with n about 10^4 in this idealized system, the vote will be decided by 1 person a little under 1 percent of the time.
Medium in this case refers to a material through which the light is passing, such as air, glass, water, etc. The atoms of these media interact with the light passing though, slowing its propagation. Gravitational fields do not qualify, since they do not couple with electromagnetic fields to any appreciable extent (except perhaps if the black hole is extremely small).
Slashdot Mirror
Do you have sources for this, or are you just making it up? Obama's stated position is a 16 month timetable for withdrawal of the main forces. He has had this proposal for months, and it was endorsed by Maliki when Obama visited Iraq before angry noises from Washington forced him to backpedal. McCain's Iraq page has no such timetable, although he started suggesting expedited withdrawal as a possible option after Maliki's announcement undermined his "100 years if necessary" position.
I disagree with your first claim. Huntington has a well-established record of fabricating history to suit his ideas. The standard example is his claim that South Africa in the 1960s under Apartheid fit his definition of satisfied society. To back up his claim, he falsely asserted that there were no notable protests or uprisings during this time. Fortunately, there were ample news archives that contradicted him. Unfortunately, people still listen to his bold pseudoscientific pronouncements about societies and their interactions.
You can find the same flavor nonsense in pretty much anything written by his student Fareed Zakaria.
I agree. Tierney in particular likes to present himself as someone who comes up with insightful ideas that buck conventional wisdom. However, the evidence suggests that he typically gives a cursory examination to a complex problem, and then offers an "easy way out" solution that is already rather popular among a large group of people.
Here's another example, this time about women in math.
I'm not an expert in this field, but my impression is that with our current technology, this experiment is in fact less precise than ones that have been done previously. I would consider it worthwhile in the sense that it is always worthwhile to check that we haven't collectively gone bonkers, but any statistically significant deviation from the expected behavior is more likely than not to be a failure of methodology, e.g., some uncontrolled source of noise.
That's too bad, because the article summary is completely wrong. GR predicts that anything in free fall follows a geodesic in spacetime, including matter, antimatter, and other stuff like photons that are their own antiparticles. Consequently, you should expect the gravity of a massive object to deflect the trajectory of matter and antimatter in exactly the same way. Naturally this sort of hypothesis is something one should test, but that has been done years ago. Other comments before this one have pointed out experimental data from supernovas and particle accelerators that show that any difference in behavior is bounded above by about one part in a billion. In particular, antimatter has been known not to fall up for quite some time.
This is mostly true. During core collapse, the high density drops the mean free path of a neutrino to a few meters, and the neutrinos become energy carriers in a short-lived equilibrating process. The resulting neutrino-neutron reactions are what allow elements heavier than Bismuth to form (s-process products tend to be too neutron-heavy to survive), and the net outward transfer of energy contributes to the rebound shock.
This is pretty much where you went wrong. Entanglement can produce correlated measurements for distant particles, but the particles are only entangled as long as you don't do anything to them. Once you disrupt the state of one of the particles (e.g., by measuring it) the entanglement is lost. You cannot use an entangled pair to continuously send information.
The article is about an observation of the dynamics of the jets, not any recent theoretical development regarding the mechanism behind them. Blandford and Znajek proposed the process behind jet formation 30 years ago.
I think you may have misunderstood the applicability of Carnot's theorem. It is an upper bound on our ability to extract mechanical energy from temperature differences, but it does not restrict our ability to convert e.g., mechanical energy to electrical energy and back, which is the objective of regenerative brakes. In fact, the Wikipedia article you linked makes this very clear from the perspective of reversibility. If you could make a heat engine that meets or breaks Carnot's bound, then you could create a perpetual motion machine by running an identical device in reverse to generate more thermal gradient. This may seem counterintuitive, since the reverse device is running at greater than 100% efficiency, but such superunital efficiency is quite common in practice, and is in fact one reason that heat pumps are more common than resistive heaters or fuel-burning heaters in carbon-poor countries like Japan.
Okay, I'm not sure the perpetual motion argument is that convincing without serious thinking about heat pumps. A more quantitative way to look at it is that an engine running at Carnot's ideal efficiency is adding zero entropy to the universe. If you just want to store energy and release it in the same form later (as in the case of regenerative braking), Carnot says that the best you can do is by releasing a very small amount of entropy by an almost-reversible process, but there is no thermodynamic obstruction to getting arbitrarily close to 100% efficiency.
I am curious about this 40 percent figure, since I haven't heard of any hard obstructions to storing and retrieving this kind of energy. Is there a thermodynamic reason this can't be done arbitrarily efficiently, or is it just a problem with our current motor/generator technology?
Some web searching reveals unsourced estimates of 42.7% efficiency for hydraulic storage systems and 31.3% for electric regenerative braking systems currently in use, so your theoretical ceiling may be a bit low. Naturally, it would be nice if people actually pointed to primary sources when quoting them so we could verify the claims.
How could you possibly call this a theorem? You're using terms like "human-level intelligence" that aren't even well-defined, and you haven't specified the parameters of the game. Are you saying humans can win any game against a computer? Not true. There's no rigor here.
We have the same problem as before. What is a lesser system? Are you referring to some kind of Kolmogorov complexity? One problem with defeating computers at certain games (like checkers, which has been completely solved computationally) is that the human brain cannot store very much abstract symbolic information. If you ask an unaided human to play checkers against a suitably programmed computer, the human will be unable to keep track of enough information to avoid mistakes. It doesn't matter what your "theory of mind" is (whatever that means) if you can't remember enough of a system to understand how to exploit it.
Not necessarily. The problem of gaming search results is more of an economic question than an AI-theoretic one. The goal is to arrange matters so that any successful strategy for gaming the system realizes limited benefits, and requires a large investment in resources. Brute force computational solutions often make economic sense, because they can scale better.
Minor nitpick: Achilles was also half-divine, according to the Iliad. His mother was Thetis. Odysseus also had divine ancestors, but they were more distant.
Thanks for the explanation. The linked article carried essentially no information.
What sort of geometry should we see on the Galois side of these functions?
I agree that electrons are point particles to the best of our knowledge. However, they are smeared out in the sense that they don't admit position eigenstates, so they are not located at definite positions. If you want to calculate a scattering amplitude, you have to integrate over a distribution of possible events, and I think it is reasonable to describe this as fuzziness.
I think you have a failure of uniqueness. If you have an atom with diameter 100pm, there are about three thousand wavelengths of visible light that are integer multiples of that. Which one will you choose?
Your sentences are difficult to parse. Are you suggesting that they use false color to reflect the electronic structure of the material? That seems to be exactly what they are doing. The specifics of your suggestion seem to be a bit suspect, though (including your apparent confusion between atomic number and atomic mass). One advantage of the techniques used here is that they can tell us about bonds between atoms, rather than just the atoms themselves.
I think the reverse is true. Large energy transitions tend to have short characteristic time scales (think of reaction rates in chemistry). The uncertainty principle gives you a lower bound on the product, not the quotient. Also, there are often obstructions due to, e.g., nonconserved angular momentum, which can make metastable states very long-lived.
Photons don't directly interact in perturbative QED, but if you happen to have some charged matter (such as electrons) lying around they can interact with that. You have a nonzero amplitude for pair production anywhere, and this is enhanced in regions with high EM field strength. In theory, you can get nonlinear corrections to Maxwell's equations in a vacuum by interacting with them, but I haven't heard of any experimental observations. There are a lot of Feynman diagrams with only photons as external edges, but photon-photon interactions require at least fourth order in the coupling constant (which is rather small). I think the interactions you hear about involve some kind of medium made of atoms.
This seems to be a poor analogy. It is much more difficult to relocate to a different country than it is to choose a different restaurant. You lose your network of friends and family, and you may be surrounded by people who speak a different language and follow different cultural norms.
Do you have a good source for this? I'm curious, because his most important contributions (e.g. optics, gravitation, laws of motion) seem to be attributed to Newton alone, or in the case of infinitesimal calculus, discovered independently.
If that were true, the bear would look black (at least at near-IR frequencies). Also, this article asserts that the fiber optic hypothesis has been demonstrated false. The translucent fur is most likely a camouflage adaptation.
Can you propose a mechanism for star formation that would give the sun a sufficiently large positive charge to accelerate ions at large distances? That voltage difference had to come from somewhere, and large charge imbalances counteract the gravitational attraction needed for nuclear fusion.
Maybe I'm wasting my time. It seems clear that "alternative cosmologies" means the electric universe theory, which doesn't make any useful, testable predictions.
One more London to Sydney option is to build a large tube in the ocean, remove all of the air and water from the tube, and run a maglev through the vacuum. This eliminates air resistance and problems with moving parts, at the expense of considerable capital investment and some heat dissipation issues. There don't seem to be any fundamental obstructions to making this trip in under an hour, although the acceleration may be a bit uncomfortable - you need about 1.4g to do 20000km in 40 minutes.
I think you have it somewhat backwards. The fireball is created by the air around the exploding weapon absorbing the high energy thermal radiation emitted by the weapon itself. The shockwave compression happens after hydrodynamic separation, and in fact, the opacity of the incandescent gas causes the fireball to appear dimmer. See this bit for details.
The summary: improvised explosives involve pretty nasty stuff that you'd be hard pressed to mix in an airplane lavatory without killing yourself in the process.
You'd think a suicide bomber would have an easier time just (taking a page from the drug mules) swallowing a large number of condoms full of plastic explosives, timer, and detonator. This is a rather obvious solution: no carry-on, no luggage, no hassle.
How would you prevent this sort of attack? You could try to find traces of explosive on the bomber's person, using swabbing, some kind of breathalyzer, or more invasive procedures. More pragmatically, you could try to disrupt the network of people who procure the necessary supplies. I suppose that is the purpose of our intelligence services.
I've taken more mathematics than you, Asperger's reject. The chance of your vote making a difference (being the deciding vote) is 1 in (x=0 to n-2 ||| sum 2^x) where n is the number of voters total. Yes, that number does asymptotically approach zero with increasing n.
I don't think that is how it works. The probability of your vote being the deciding vote is the probability of your side winning by one. Enumerating this probability is a bit tricky, since it depends on your assumptions, e.g., I think the answers are skewed if we have preexisting information about voter bias.
For simplicity, let's assume all n people who vote flip a fair coin to decide between two choices. Then the probability of your side winning by one is about (n choose n/2)/2^n. Stirling's formula gives an asymptotic estimate of about sqrt(2/(n*pi)), which approches 0, but not nearly as quickly as you suggest. If you have a local election with n about 10^4 in this idealized system, the vote will be decided by 1 person a little under 1 percent of the time.
Medium in this case refers to a material through which the light is passing, such as air, glass, water, etc. The atoms of these media interact with the light passing though, slowing its propagation. Gravitational fields do not qualify, since they do not couple with electromagnetic fields to any appreciable extent (except perhaps if the black hole is extremely small).