it seems to me that to release the zero-point energy of empty space, you have to leave that space in a lower energy state after you're done.
Indeed it would seem that way to me too, if you were truly "extracting" the zero point energy from the vacuum.
We don't know if such a lower-energy state even exists.
And we might hope that such a state doesn't, because it would mean that the current vacuum state is a "false vacuum" meaning that it is unstable and will eventually decay into the true vacuum....and in the true vacuum, physics as we know it may not hold, portending the end of a universe capable of sustaining life as we know it!
I hate to sound like a stuffy academic, but I have a PhD in physics, and the whole thing sounds goofy to me.
Sounds goofy to me too, and I haven't finished the PhD yet....but then again, most of the stuff I do for my research sounds pretty goofy to me as well:-)
I seriously think this idea has more potential than the 'no energy used' idea because after all, entropy must increase in a forward-time universe.
Actually, that is not the case: entropy must not DECREASE in physical processes, but there is no requirement that it INCREASE. In fact, reversible physical processes are those in which entropy remains the same...irreversible physical processes are those in which entropy increases.
That being said, I would agree with you that this reliability and recovery would be the truly amazing part of these systems...although I submit that I don't understand what these statements really mean in terms of the physics (i.e. based on the first article, I'm a tad skeptical of the statements being made.....).
The short answer is "NO": there are no observations that can only be attributed to singularities. But, then again, there are no observations that CAN be attributed to singularities. That's what the singularity theorems say: gravitational collapse (even in GTR) can not result in a "naked" singularity, that is, a singularity which is not hidden from view. In the case of non-extreme black holes, the singularity would be hidden from view by the event horizon; and all known extreme black hole solutions are unstable, so they probably can't ever be formed in the first place! Unfortunately, I don't think these "no-go", or "cosmic censorship" theorems have been proven (although I don't really know, since I haven't followed the field closely in the last year or so).
It must be pointed out that the "singularity" that we are talking about at the bottom of the black hole probably doesn't actually exist, even in the absence of the censorship theorems - the existence of a singularity (or non-removable infinities) tells us simply that we don't know what happens in the neighborhood of the points. In this context, it means that the local space-time curvature in the neighborhood of the classically predicted infinity exceeds the value at which you need to consider the quantum properties of gravity - i.e. we need a quantum theory of gravity.
I haven't read this paper that is referenced, but I would guess that either: 1) the paper doesn't say what the article says that it says, or 2) the guy is a kook. I say this since thousands of physicists over the last 80 odd years have done the mathematical proof that black holes exist in GTR (and in fact, they exist in any metric theory of gravity, I believe); that is not the same as saying that you can physically create a black hole, but most astophysicists don't see a reason why it wouldn't happen - the dynamic (computer based) models show the formation of black holes under realistic conditions that we KNOW exist in the universe does occur: put enough material in a small enough area, and you get a black hole...and once you have one, they are stable. The other thing to note is that GTR properly predicts the evolutions of stars, the existence of white and brown dwarfs, and the existence of neutron stars...the exact same equations that predict the existence of black holes.
Hawking radiation is a quantum effect that leads to stuff "tunneling out of the black hole", but it occurs at a phenomenally miniscule rate for any black hole of the type formed in stellar collapse. It is a long, but straightforward derivation based on GTR and quantum field theory. Hawking radiation would only be visible in the final stages of evaporation of very light black holes that would only have formed at the time of the big bang.
...the GPL does make code free, not just for now, but for ever.
I'm not attempting to start a flame, and I am not asking for a legal opinion (and IANAL), BUT...and I'm just picking a nit here, but maybe not such a tiny nit...I just haven't seen this addressed before:
My understanding, from reading RMS's and other's comments at various times, is that the GPL and its protection of code is based on copyright law...copyrights are limited in time...after which, the "protected work" enters the public domain.
Doesn't this mean that the GPL is a time limited (granted, for a very long time in computing terms...) monopoly, not something that extends "for ever" as some of these comments have been stating? And how does that interact with requirements that derived works be under GPL? How much does derived code have to differ in order to become independently copyrightable (clearly, changing a single character is not enough as you can easily see from literary publications!) ?
I realize that this isn't a near term concern, but I am just curious what others have think about this issue....
Didn't your lawyer tell you not to talk about this case in public? If not, find a new lawyer....in either case, shut up before you shoot yourself in the foot.....
I wonder if there are enough particles in the universe to run a finite elements simulation for more than 4 hours in a 750 GHz CPU.
There are more than enough to keep such a CPU busy for nearly all eternity....A 750GHz CPU (even assuming 1 flop/cycle average throughput) would still have a hugely difficult time just doing QCD calculations of the interactions inside a SINGLE proton in anything approaching days! (I have a colleague doing lattice QCD who was just telling me about their new algorithms for hacking time off of certain types of lattice simulations, and they are talking about running for 16 CPUyears on a brand new 90Gflop machine! At 750 Gflops, you're still talking 2 CPU years! Don't ask me for details, though, as I don't know any....not my field).
For further consideration, there are about 10^80 particles in the universe (give or take a few orders of magnitude.....). Let's assume it only takes 10flops to update a single particle for one timestep (not even close, but let's run with it shall we?) That means we update 75 x 10^9 particles every second...let's round up and call it 10^11. That means it would take about 10^69 seconds to update one time step. Or 10^61 years. Which is roughly 10^45 times the age of the universe. Not to mention the amount of RAM you'd need to run this simulation on (which would take more particles to build than there are in the universe itself, but I digress.....)
Really monstrously fantastically mind-bogglingly large numbers are really really fun:-)
Wierd Al doesn't get his ass sued off for two reasons: his songs actually ARE covered under the parody exception, but he also asks permission from the artists (although not necessarily the actual copyright holder....) before doing so, and the artists wouldn't want to be associated with a lawsuit by the music company after they've given their permission.
Apparently the coupling constant decreases below 1 at high enough energies so that perturbation theory sort of starts to work.
Indeed...the "scale" of QCD (where it becomes strong) is about 1GeV, give or take a few factors of order 1 (right around the mass of the proton and neutron, but I digress...)...perturbative QCD starts to work somewhere above that scale, but really can't be trusted for a while...say 30-40 GeV. By the time you get to LEP energies (200GeV, give or take), the coupling (actually, alpha_strong = g^2/4 PI) is down to about 0.12, and perturbation theory works well.
The professor also said that the coupling constants converge to some common value at about 1e15 GeV.
They do, more or less (but not exactly in the Standard Model). This curious coincidence is one of the best hints for Grand Unification of the three forces.
The fact that they don't meet exactly in the Standard Model is considered (by some!) evidence for Supersymmetry, since in the Minimal Supersymmetric extension of the Standard Model (called the MSSM), the couplings actually DO meet exactly (well, at lest within the current measurement error bars) at somewhere around 10^16 GeV (more or less).
The thing is, the spacecraft gains more forward momentum in step 2 than it looses in step 4....In both cases, I keep wanting to find that missing bit of reverse momentum that leaves the spacecraft vibrating uselessly in place, but I just don't see it!
You're not seeing it, because you aren't looking in the right place:-) If you decide that you are going to rely on a relativistic effect in step 1, then you need to apply a properly relativistically covariant approach to the whole problem. Since energy-momentum is conserved in special relativity, you will find when you carry out the correct analysis, you will be right back where you started: no gain in net momentum for the space-craft if there is no reaction mass expelled.
Think about these questions, and you should be able to find the flaws in your logic: where does the energy come from to heat the mass? When you extract that energy, what happens to the body you extracted it from? What happens to the spacecraft overall if you "radiate the heat away into space" (or, what is heat?).
There's no free lunch; you can't get something for nothing; and you still haven't shown how to violate the second law of thermodynamics or the relativistic versions of Newton's Laws.
Not sure if it's relevant, but does anyone have links to the (theoretical) behaviours of magnetic monopoles? Are there any quirks of nature we would expect to see if these beasties came up?
Sorry, no links, but you might want to grab a hold of a graduate quantum mechanics, quantum field theory, or electromagnetism text book. Magnetic monopoles come in many shapes and sizes, and are predicted in many extensions to the standard model of particle physics. Perhaps the neatest property is that if there is EVEN ONE magnetic monopole, we have an explanation of why electric charges are quantized (see t'Hooft-Polyakov or Dirac magnetic monopoles).
They would have to be extremely heavy objects, though, or else we would already have seen them and their effects.
As a practicing particle theorist, let me tell you what you got right and what you got wrong (more right than wrong!):
You cannot prove that a scientific theory is the correct description of the universe as we observe it...you CAN disprove a theory by showing that it conflicts with experiments. You CAN prove that a scientific theory is logically correct, but that doesn't prove that it is physically correct.
Quantum mechanics HAS been confirmed time and time again, but we ALREADY KNOW that QM is incomplete, just like we know that Newtonian Mechanics is incorrect (the point particles of quantum mechanics have been replaced by the quantized fields of Quantum Field Theory). QM is, however, "accurate enough" for almost all purposes where Newtonian Mechanics fails, and in the correct domain of application (anywhere where the corrections from QFT are small), QM is still used. I would go so far as to say that there are no practicing physicists who don't believe in the validity of QM; it would take some truly astonishing discovery to unseat quantum theory (it may happen, but I wouldn't hold my breath, just like I wouldn't hold my breath for any evidence that Newtonian mechanics ever fails on macroscopic scales).
There are four generally accepted forces (gravity, strong, weak, and electromagnetic), and there is a QFT model that "unites" the weak and electromagnetic force (and is called the electroweak force), although it isn't technically proper to call it a "single" force, but that is a nitpicking detail (having to do with the fact that the gauge theory describing electroweak interactions is not based on a "simple Lie group", but that is neither here nor there for purposes of this discussion...).
There is currently NO accepted quantum theory of gravity, although string theory provides a mathematically consistent physical theory which includes gravity. String theory (probably) has no currently testable consequences (we need a lot more work before we'll be able to ask questions that experiments have a real hope of answering).
While it WOULD be extremely surprising to discover a fifth force that operates over macroscopic distances, most (particle) physicists fully expect that there are additional microscopic forces that will be discovered in the next decade (supersymmetry is the sexiest these days, but there are many others: topcolor, technicolor, etc.)
QCD is well accepted as the proper description of the strong force, and is well tested at HIGH energies (not low). At LOW energies, it is a very hard theory to perform calculations in, and we have to resort to lattice monte carlo methods, which are computationally speaking, among the most demanding computer applications yet devised (for those with undergraduate physics backgrounds: you can't do a pertubation expansion in the low energy theory, as the coupling constant is a number of order 1, not a small expansion constant, and technically, we can't calculate what the fundamental degrees of freedom are in the low energy limit.)
That's not quite what the problem is, although it's close...under this new system, you would never have to dial that leading 1 to tell the system "Yes, I really mean to make a toll call" (although the article is truly terrible at making this point clear). ALL calls, local or long distance, would use 10 digits, as in exactly 10 digits, never more never less; the 1 for toll calls would be excised and tossed onto the dustbin of history (where it belongs, frankly). And the issue the "consumer advocates" have is that you you wouldn't be able to tell by looking at a number whether you were about to make a local or long distance call if you didn't already know. Which you can't necessarily do now ANYWAY, so I don't really understand what their problem with this change is....
So, in your example, you'd probably still get the number you were looking for (because you dialed an extra digit at the end). Your example would be more apt if you accidentally add a number in the first two or three digits and get vectored across the continent:-) But that can already happen, so this wouldn't be much of a change.
Question to the audience: do most of you actually remember and type numbers when you place a call? I don't think I've dialed a number in months. The vast majority of the numbers I called are just programmed into the phone and I push the speed dial button. Those that aren't are people or businesses that I don't call often, so I just go through information to find the number and connect me.
I think you missed the point that people are complaining about (not that I blame you...I KNEW what the problem was (from my dad, who works in the industry), and I had to read the article three times to find it).
This would be 10 digit dialing to everyone, everywhere in the USA, all the time. You would NEVER have to dial 1 for a toll call; all calls 10 digits, all the time (0, 911, 311, 411, 611 excepted of course). So, some "consumer advocates" are concerned that people would be too stupid to figure out whether they are making a toll call when they don't have to dial a 1 (even though most people don't know what the leading 1 really means anyway).
Not having to assign special meaning to the leading 1 means that another 100 area codes open up, and the system not having to figure out whether you will be dialing 10 or 7 digits means that you can add exchanges starting with 0 and 1, for another 2x10^6 numbers per area code. Plus, the system becomes much LESS confusing for the users, as it will always be the same procedure for making a call, and you will never have your phone number (area code) changed out from under you again.
As well as you've argued your points here, I still have to disagree with you. The two dominant party bias is not built into the Electoral College system; it was added by the state legislatures after the people made it clear that they preferred to have a two party system, by the way they voted in the first 100 years of the Republic.
While I agree that TODAY it would be impossible for a three way split to result in a third party president, if the system were not so biased by history towards two parties, that would not at all be the case. If the two party bias did not exist, then a three way split of the electoral vote would likely be mirrored in the House, resulting in the necessity of compromise, which people otherwise are not prone to doing.
Which leads me to (partially) agree with you last point, that the parties tend to agree more than disagree: and this is precisely one of the reasons that the founders decided to require a majority, and not a plurality, vote. The college has a moderating effect on political discourse; parties and candidates at the extremes tend to be the most destructive to constructive governance (or so the Founder's arguments went), so they designed a system that would make it very hard to end up with a starkly polarized electoral outcome that would damage the long term survival of the Nation. In order to get elected president, you have to prove to the majority of the people's representatives (the Electors or Representatives) that you have at the very least listened to the competing sides on any issue, and that you aren't a wacko that will disregard the rule of law. So, in many ways, the "middle-of-the-road" outcome that we (always!) seem to get is a direct and desired result of the EC system.
Does that mean that we couldn't find a better system that does all the good stuff that the EC does without all the bad? No, it doesn't, and I would agree that some types of changes may be necessary. But, I feel very strongly that most of the proposed changes would toss out the good that the EC brings, without eliminating most (or any!) of the "bad". And that, I think, would be a true shame.
Yes, but you fail to notice that the vote wasn't 50/50, give or take the noise...I'm curious as to how you think things would be any different in Canada if they HAD been? Politics being what it is (a Lorentz invariant?:-), I highly doubt things would be much different, if Candadian law permits recounts and contests.....
If Florida choose it's electors in proportion to the popular vote, this would be a non-issue. If the president was elected via popular vote, this would be a non-issue.
This is specious reasoning...there is NO ELECTION SYSTEM that can deal with close contests near the boundaries. If you changed the rules to choosing electors in proportion to the popular vote, then rather than fighting over a few thousand votes in ONE state, you'd be fighting over a few thousand votes in ALMOST ALL states...since now, you'd be talking about somewhere around 30 disputed votes rather than 25, but in literally hundreds of jurisdictions. Similarly, a popular vote would result in disputes and contests in literally THOUSANDS of jurisdictions, all across the country.
Note that I'm NOT arguing that the Electoral College system is flawless or should even be the system we use. What I AM saying is that ALL election systems have pathological cases, and you CAN NOT design a system to eliminate all the pathologies...and this particular election is an example where the pathologies would have affected NEARLY ALL election systems. When the popular vote differences are buried in the noise (as they probably are, both in Florida AND nation wide), we HAVE TO rely on something outside the actual count of votes to determine what the votes "mean", and in this case, that is the proper application of previously passed laws, and the interpretation of courts of law as to the proper application of those laws.
Further, polarization into two party systems tend to be the norm in "democratic" societies. You need only look at the US, Canada, UK, etc. Yes, there are third parties in those places, but they are largely ineffective. And nations with large numbers of parties tend to have a different, and no less difficult, set of pathologies (see Italy, Israel, Austria, etc.)
I guess my point is that EVERY system has pathologies, and they tend to be drawn out when the system encounters boundary conditions...and no nation or electoral system is immune.
While I used to agree with you (and I DO read all my manuals (and howtos and man pages, etc. etc.), I no longer do. I shouldn't HAVE to read all that crap to get basic stuff done...and that is all that most people ever do! Furthermore, why should they bother to read the manual to learn how to use features that they'll never actually use? Which is all most software features are. Read it when you need it...
You also provided the perfect example of this: the VCR...most people don't care to figure out how to program their VCR because they only use their VCR to watch rental movies...and most of us don't bother to "solve" the blinking 12 because we
don't need a 10th, horribly inaccurate, (or 20th or 30th....) clock in the house, and
the power goes out frequently enough that it becomes a real PITA to keep fixing the damn clock.
It isn't because people are too stupid (okay, maybe I speak too quickly...most people probably ARE too stupid:-), but because it just doesn't bring a large enough return on investment (in economic terms, maximizing utility).
You need to square each term....
(dS)^2 = (dx)^2 - (dt)^2
where we measure time in length units (set c=1, the way real physicists do it:-). We could have chosen time units overall, and measured physical lengths in time units, but I chose not to, since it usually isn't done that way. The quantity dS is the spacetime interval between the two events, dx is the physical distance between the two events as measured in a particular inertial reference frame, and dt is the time elapsed between the two events as measured in the same frame. The important thing is that dS is a frame independent (Lorentz invariant) quantity, so all observers will agree on the measurement of dS^2, although not necessarily dx or dt.
When ds^2 > 0, the two events are spacelike separated, meaning that the two events could not have affected each other (they are not causally connected, in the lingo), as they are farther apart in space than the distance light signals could propogate given the measured time difference.
When dS^2 timelike separated, meaning the two events could have affected each other (light could have propagated from one to the other in the time measured, with time left over, meaning (potentially) other types of particles could have travelled from one to the other).
Finally, when dS^2=0, the two events are null separated, or light-like separated, since the two events could only have affected each other by light signals.
Using measurements of intervals from many different events, we can (approximately) reconstruct the metric.
...WIPO and NAF were close to 80/20 in "complainant wins" to "respondent wins" cases, whereas eResolutions was closer to 50/50, which, IMO, is a more realistic expectation of a fair system.
I would have to disagree with you here...in a fair system, you would only bring a dispute in those cases where you expected to win on the merits; the net result in the long run (not necessarily the short run, while precedents are being made and people are trying to find out what the rules really are) would be the complainant winning much more often, because you would just be wasting your money to bring a case without merit. Thus, I think that in the long run you would expect basically the same stats as we are seeing now.
Which is not to say that I necessarily think things are fair now, just that I don't think "fair" would equate with 50/50 outcomes.
I like the preferential and instant run-off schemes as well...but take a look at this month's discover magazine, where they discuss some different types of voting systems. The basic gist of the article was that, even if every vote is cast by a rational person making a rational choice, there is no fraud, and there is no error in the count, you CAN NOT have a voting system that will always obtain the "correct" result. They give good examples...in fact, the best one is the example which shows that, given four voting systems and picking one system at random to use to "elect" which voting system to use in the next election, no system would ever be able to choose itself! Kind of contrived, but the point being that there is no "perfect" system...there will always be cases where someones rational definition of the "correct" outcome fails.
Here are the current Center of Mass frame energies of the colliders:
LEP: 200GeV electron-positron
Tevatron: 1.8TeV proton-antiproton (starting next year, they go to 2TeV)
LHC: 14TeV proton-proton machine (2005ish?). Later, they might also do many-TeV lead-lead collisions
RHIC: don't remember the energy, but they do gold-gold collisions, I believe.
What is likely to happen, is that LEP data will be able to rule out a Standard Model Higgs boson up to about 110GeV in mass, or "discover" a slightly lighter Higgs (where "discover" means a very particular thing, not just seeing a few events), while the Tevatron (I think) will be able to rule out a Higgs up to something like 140GeV and discover one up to 130GeV (these may be wrong, but they're in the right ballpark). LHC will be able to discover any Higgs up to about a TeV (with the exception of a small range right around where the limits are at now). So, if the Higgs is lighter than about 140GeV, it will be discovered by the Tevatron long before LHC turns on. RHIC, however, is not the right type of machine to study these phenomena, and so is not really a concern for LEP in the Nobel search:-)
On the other hand, RHIC may be the machine to confirm the existence of the quark-gluon plasma at high nuclear density. There is tantalizing evidence from the SppS (I think) collider at CERN, but not confirmation. If RHIC isn't big enough, LHC should be (in lead-lead mode). So the race is on there too.
The next few years will be extremely exciting on the experimental front (Higgs physics, supersymmetry/technicolor discovery, CP violation physics, neutrino oscillations). It's a great time to be a physicist:-)
The flip side of course is that the construction contracts for LHC contain large penalty clauses for delays caused by CERN. A year of data collection would pretty much wipe out the LHC budget completely, just paying for the delays. Compared with the miniscule chance of actually confirming the Higgs - remember, from the note, that there is only one detector (ALEPH) out of four with a potentially notable excess in one channel. From the perspective of many of my colleagues (theoretical particle physicists), there is little chance (given the lack of supporting evidence in other channels and detectors, and the history of such "potential discovery" announcements) that this is actually the real thing.
Just a passing note for those that never learned or don't remember this stuff, random fluctuations to the 1 sigma level would occur in 1/3 of all experiments set up and performed exactly the same way; and 2 sigma is about a 5% chance of random fluctuation. And that is assuming perfect knowledge of all the uncertainties, which is never the case. The number of "well established" three-or-more sigma "discoveries" that have evaporated in the face of more data is well in excess of what you would expect from chance. Bottom line for a physicist (and I don't remember where I first saw this):
1 sigma: write a Letter
2 sigma: write a Paper
3 sigma: bet your graduate student's career on it.
If the CERN staff didn?t need to empty the tunnel for the LHC installation you can be sure
it (the LEP) would be running as long a it could produce data.
In fact, LEP may live again! The magnets, RF cavities, and other stuff (but not the detectors, I don't believe, although I could be wrong), will be put into storage, on the chance that CERN decides to convert the LHC to an electron-proton machine at some point in the distant future (much like HERA at DESY in Germany), after its planned program is completed.
Slashdot Mirror
it seems to me that to release the zero-point energy of empty space, you have to leave that space in a lower energy state after you're done.
Indeed it would seem that way to me too, if you were truly "extracting" the zero point energy from the vacuum.
We don't know if such a lower-energy state even exists.
And we might hope that such a state doesn't, because it would mean that the current vacuum state is a "false vacuum" meaning that it is unstable and will eventually decay into the true vacuum....and in the true vacuum, physics as we know it may not hold, portending the end of a universe capable of sustaining life as we know it!
I hate to sound like a stuffy academic, but I have a PhD in physics, and the whole thing sounds goofy to me.
Sounds goofy to me too, and I haven't finished the PhD yet....but then again, most of the stuff I do for my research sounds pretty goofy to me as well :-)
I seriously think this idea has more potential than the 'no energy used' idea because after all, entropy must increase in a forward-time universe.
Actually, that is not the case: entropy must not DECREASE in physical processes, but there is no requirement that it INCREASE. In fact, reversible physical processes are those in which entropy remains the same...irreversible physical processes are those in which entropy increases.
That being said, I would agree with you that this reliability and recovery would be the truly amazing part of these systems...although I submit that I don't understand what these statements really mean in terms of the physics (i.e. based on the first article, I'm a tad skeptical of the statements being made.....).
The short answer is "NO": there are no observations that can only be attributed to singularities. But, then again, there are no observations that CAN be attributed to singularities. That's what the singularity theorems say: gravitational collapse (even in GTR) can not result in a "naked" singularity, that is, a singularity which is not hidden from view. In the case of non-extreme black holes, the singularity would be hidden from view by the event horizon; and all known extreme black hole solutions are unstable, so they probably can't ever be formed in the first place! Unfortunately, I don't think these "no-go", or "cosmic censorship" theorems have been proven (although I don't really know, since I haven't followed the field closely in the last year or so).
It must be pointed out that the "singularity" that we are talking about at the bottom of the black hole probably doesn't actually exist, even in the absence of the censorship theorems - the existence of a singularity (or non-removable infinities) tells us simply that we don't know what happens in the neighborhood of the points. In this context, it means that the local space-time curvature in the neighborhood of the classically predicted infinity exceeds the value at which you need to consider the quantum properties of gravity - i.e. we need a quantum theory of gravity.
I haven't read this paper that is referenced, but I would guess that either: 1) the paper doesn't say what the article says that it says, or 2) the guy is a kook. I say this since thousands of physicists over the last 80 odd years have done the mathematical proof that black holes exist in GTR (and in fact, they exist in any metric theory of gravity, I believe); that is not the same as saying that you can physically create a black hole, but most astophysicists don't see a reason why it wouldn't happen - the dynamic (computer based) models show the formation of black holes under realistic conditions that we KNOW exist in the universe does occur: put enough material in a small enough area, and you get a black hole...and once you have one, they are stable. The other thing to note is that GTR properly predicts the evolutions of stars, the existence of white and brown dwarfs, and the existence of neutron stars...the exact same equations that predict the existence of black holes.
Hawking radiation is a quantum effect that leads to stuff "tunneling out of the black hole", but it occurs at a phenomenally miniscule rate for any black hole of the type formed in stellar collapse. It is a long, but straightforward derivation based on GTR and quantum field theory. Hawking radiation would only be visible in the final stages of evaporation of very light black holes that would only have formed at the time of the big bang.
I'm not attempting to start a flame, and I am not asking for a legal opinion (and IANAL), BUT...and I'm just picking a nit here, but maybe not such a tiny nit...I just haven't seen this addressed before:
My understanding, from reading RMS's and other's comments at various times, is that the GPL and its protection of code is based on copyright law...copyrights are limited in time...after which, the "protected work" enters the public domain.
Doesn't this mean that the GPL is a time limited (granted, for a very long time in computing terms...) monopoly, not something that extends "for ever" as some of these comments have been stating? And how does that interact with requirements that derived works be under GPL? How much does derived code have to differ in order to become independently copyrightable (clearly, changing a single character is not enough as you can easily see from literary publications!) ?
I realize that this isn't a near term concern, but I am just curious what others have think about this issue....
Didn't your lawyer tell you not to talk about this case in public? If not, find a new lawyer....in either case, shut up before you shoot yourself in the foot.....
There are more than enough to keep such a CPU busy for nearly all eternity....A 750GHz CPU (even assuming 1 flop/cycle average throughput) would still have a hugely difficult time just doing QCD calculations of the interactions inside a SINGLE proton in anything approaching days! (I have a colleague doing lattice QCD who was just telling me about their new algorithms for hacking time off of certain types of lattice simulations, and they are talking about running for 16 CPUyears on a brand new 90Gflop machine! At 750 Gflops, you're still talking 2 CPU years! Don't ask me for details, though, as I don't know any....not my field).
For further consideration, there are about 10^80 particles in the universe (give or take a few orders of magnitude.....). Let's assume it only takes 10flops to update a single particle for one timestep (not even close, but let's run with it shall we?) That means we update 75 x 10^9 particles every second...let's round up and call it 10^11. That means it would take about 10^69 seconds to update one time step. Or 10^61 years. Which is roughly 10^45 times the age of the universe. Not to mention the amount of RAM you'd need to run this simulation on (which would take more particles to build than there are in the universe itself, but I digress.....)
Really monstrously fantastically mind-bogglingly large numbers are really really fun :-)
Wierd Al doesn't get his ass sued off for two reasons: his songs actually ARE covered under the parody exception, but he also asks permission from the artists (although not necessarily the actual copyright holder....) before doing so, and the artists wouldn't want to be associated with a lawsuit by the music company after they've given their permission.
Apparently the coupling constant decreases below 1 at high enough energies so that perturbation theory sort of starts to work.
Indeed...the "scale" of QCD (where it becomes strong) is about 1GeV, give or take a few factors of order 1 (right around the mass of the proton and neutron, but I digress...)...perturbative QCD starts to work somewhere above that scale, but really can't be trusted for a while...say 30-40 GeV. By the time you get to LEP energies (200GeV, give or take), the coupling (actually, alpha_strong = g^2/4 PI) is down to about 0.12, and perturbation theory works well.
The professor also said that the coupling constants converge to some common value at about 1e15 GeV.
They do, more or less (but not exactly in the Standard Model). This curious coincidence is one of the best hints for Grand Unification of the three forces.
The fact that they don't meet exactly in the Standard Model is considered (by some!) evidence for Supersymmetry, since in the Minimal Supersymmetric extension of the Standard Model (called the MSSM), the couplings actually DO meet exactly (well, at lest within the current measurement error bars) at somewhere around 10^16 GeV (more or less).
Good luck in the class by the way!
The thing is, the spacecraft gains more forward momentum in step 2 than it looses in step 4....In both cases, I keep wanting to find that missing bit of reverse momentum that leaves the spacecraft vibrating uselessly in place, but I just don't see it!
You're not seeing it, because you aren't looking in the right place :-) If you decide that you are going to rely on a relativistic effect in step 1, then you need to apply a properly relativistically covariant approach to the whole problem. Since energy-momentum is conserved in special relativity, you will find when you carry out the correct analysis, you will be right back where you started: no gain in net momentum for the space-craft if there is no reaction mass expelled.
Think about these questions, and you should be able to find the flaws in your logic: where does the energy come from to heat the mass? When you extract that energy, what happens to the body you extracted it from? What happens to the spacecraft overall if you "radiate the heat away into space" (or, what is heat?).
There's no free lunch; you can't get something for nothing; and you still haven't shown how to violate the second law of thermodynamics or the relativistic versions of Newton's Laws.
Not sure if it's relevant, but does anyone have links to the (theoretical) behaviours of magnetic monopoles? Are there any quirks of nature we would expect to see if these beasties came up?
Sorry, no links, but you might want to grab a hold of a graduate quantum mechanics, quantum field theory, or electromagnetism text book. Magnetic monopoles come in many shapes and sizes, and are predicted in many extensions to the standard model of particle physics. Perhaps the neatest property is that if there is EVEN ONE magnetic monopole, we have an explanation of why electric charges are quantized (see t'Hooft-Polyakov or Dirac magnetic monopoles).
They would have to be extremely heavy objects, though, or else we would already have seen them and their effects.
As a practicing particle theorist, let me tell you what you got right and what you got wrong (more right than wrong!):
You cannot prove that a scientific theory is the correct description of the universe as we observe it...you CAN disprove a theory by showing that it conflicts with experiments. You CAN prove that a scientific theory is logically correct, but that doesn't prove that it is physically correct.
Quantum mechanics HAS been confirmed time and time again, but we ALREADY KNOW that QM is incomplete, just like we know that Newtonian Mechanics is incorrect (the point particles of quantum mechanics have been replaced by the quantized fields of Quantum Field Theory). QM is, however, "accurate enough" for almost all purposes where Newtonian Mechanics fails, and in the correct domain of application (anywhere where the corrections from QFT are small), QM is still used. I would go so far as to say that there are no practicing physicists who don't believe in the validity of QM; it would take some truly astonishing discovery to unseat quantum theory (it may happen, but I wouldn't hold my breath, just like I wouldn't hold my breath for any evidence that Newtonian mechanics ever fails on macroscopic scales).
There are four generally accepted forces (gravity, strong, weak, and electromagnetic), and there is a QFT model that "unites" the weak and electromagnetic force (and is called the electroweak force), although it isn't technically proper to call it a "single" force, but that is a nitpicking detail (having to do with the fact that the gauge theory describing electroweak interactions is not based on a "simple Lie group", but that is neither here nor there for purposes of this discussion...).
There is currently NO accepted quantum theory of gravity, although string theory provides a mathematically consistent physical theory which includes gravity. String theory (probably) has no currently testable consequences (we need a lot more work before we'll be able to ask questions that experiments have a real hope of answering).
While it WOULD be extremely surprising to discover a fifth force that operates over macroscopic distances, most (particle) physicists fully expect that there are additional microscopic forces that will be discovered in the next decade (supersymmetry is the sexiest these days, but there are many others: topcolor, technicolor, etc.)
QCD is well accepted as the proper description of the strong force, and is well tested at HIGH energies (not low). At LOW energies, it is a very hard theory to perform calculations in, and we have to resort to lattice monte carlo methods, which are computationally speaking, among the most demanding computer applications yet devised (for those with undergraduate physics backgrounds: you can't do a pertubation expansion in the low energy theory, as the coupling constant is a number of order 1, not a small expansion constant, and technically, we can't calculate what the fundamental degrees of freedom are in the low energy limit.)
That's not quite what the problem is, although it's close...under this new system, you would never have to dial that leading 1 to tell the system "Yes, I really mean to make a toll call" (although the article is truly terrible at making this point clear). ALL calls, local or long distance, would use 10 digits, as in exactly 10 digits, never more never less; the 1 for toll calls would be excised and tossed onto the dustbin of history (where it belongs, frankly). And the issue the "consumer advocates" have is that you you wouldn't be able to tell by looking at a number whether you were about to make a local or long distance call if you didn't already know. Which you can't necessarily do now ANYWAY, so I don't really understand what their problem with this change is....
So, in your example, you'd probably still get the number you were looking for (because you dialed an extra digit at the end). Your example would be more apt if you accidentally add a number in the first two or three digits and get vectored across the continent :-) But that can already happen, so this wouldn't be much of a change.
Question to the audience: do most of you actually remember and type numbers when you place a call? I don't think I've dialed a number in months. The vast majority of the numbers I called are just programmed into the phone and I push the speed dial button. Those that aren't are people or businesses that I don't call often, so I just go through information to find the number and connect me.
I think you missed the point that people are complaining about (not that I blame you...I KNEW what the problem was (from my dad, who works in the industry), and I had to read the article three times to find it).
This would be 10 digit dialing to everyone, everywhere in the USA, all the time. You would NEVER have to dial 1 for a toll call; all calls 10 digits, all the time (0, 911, 311, 411, 611 excepted of course). So, some "consumer advocates" are concerned that people would be too stupid to figure out whether they are making a toll call when they don't have to dial a 1 (even though most people don't know what the leading 1 really means anyway).
Not having to assign special meaning to the leading 1 means that another 100 area codes open up, and the system not having to figure out whether you will be dialing 10 or 7 digits means that you can add exchanges starting with 0 and 1, for another 2x10^6 numbers per area code. Plus, the system becomes much LESS confusing for the users, as it will always be the same procedure for making a call, and you will never have your phone number (area code) changed out from under you again.
As well as you've argued your points here, I still have to disagree with you. The two dominant party bias is not built into the Electoral College system; it was added by the state legislatures after the people made it clear that they preferred to have a two party system, by the way they voted in the first 100 years of the Republic.
While I agree that TODAY it would be impossible for a three way split to result in a third party president, if the system were not so biased by history towards two parties, that would not at all be the case. If the two party bias did not exist, then a three way split of the electoral vote would likely be mirrored in the House, resulting in the necessity of compromise, which people otherwise are not prone to doing.
Which leads me to (partially) agree with you last point, that the parties tend to agree more than disagree: and this is precisely one of the reasons that the founders decided to require a majority, and not a plurality, vote. The college has a moderating effect on political discourse; parties and candidates at the extremes tend to be the most destructive to constructive governance (or so the Founder's arguments went), so they designed a system that would make it very hard to end up with a starkly polarized electoral outcome that would damage the long term survival of the Nation. In order to get elected president, you have to prove to the majority of the people's representatives (the Electors or Representatives) that you have at the very least listened to the competing sides on any issue, and that you aren't a wacko that will disregard the rule of law. So, in many ways, the "middle-of-the-road" outcome that we (always!) seem to get is a direct and desired result of the EC system.
Does that mean that we couldn't find a better system that does all the good stuff that the EC does without all the bad? No, it doesn't, and I would agree that some types of changes may be necessary. But, I feel very strongly that most of the proposed changes would toss out the good that the EC brings, without eliminating most (or any!) of the "bad". And that, I think, would be a true shame.
Yes, but you fail to notice that the vote wasn't 50/50, give or take the noise...I'm curious as to how you think things would be any different in Canada if they HAD been? Politics being what it is (a Lorentz invariant? :-), I highly doubt things would be much different, if Candadian law permits recounts and contests.....
If Florida choose it's electors in proportion to the popular vote, this would be a non-issue. If the president was elected via popular vote, this would be a non-issue.
This is specious reasoning...there is NO ELECTION SYSTEM that can deal with close contests near the boundaries. If you changed the rules to choosing electors in proportion to the popular vote, then rather than fighting over a few thousand votes in ONE state, you'd be fighting over a few thousand votes in ALMOST ALL states...since now, you'd be talking about somewhere around 30 disputed votes rather than 25, but in literally hundreds of jurisdictions. Similarly, a popular vote would result in disputes and contests in literally THOUSANDS of jurisdictions, all across the country.
Note that I'm NOT arguing that the Electoral College system is flawless or should even be the system we use. What I AM saying is that ALL election systems have pathological cases, and you CAN NOT design a system to eliminate all the pathologies...and this particular election is an example where the pathologies would have affected NEARLY ALL election systems. When the popular vote differences are buried in the noise (as they probably are, both in Florida AND nation wide), we HAVE TO rely on something outside the actual count of votes to determine what the votes "mean", and in this case, that is the proper application of previously passed laws, and the interpretation of courts of law as to the proper application of those laws.
Further, polarization into two party systems tend to be the norm in "democratic" societies. You need only look at the US, Canada, UK, etc. Yes, there are third parties in those places, but they are largely ineffective. And nations with large numbers of parties tend to have a different, and no less difficult, set of pathologies (see Italy, Israel, Austria, etc.)
I guess my point is that EVERY system has pathologies, and they tend to be drawn out when the system encounters boundary conditions...and no nation or electoral system is immune.
While I used to agree with you (and I DO read all my manuals (and howtos and man pages, etc. etc.), I no longer do. I shouldn't HAVE to read all that crap to get basic stuff done...and that is all that most people ever do! Furthermore, why should they bother to read the manual to learn how to use features that they'll never actually use? Which is all most software features are. Read it when you need it...
You also provided the perfect example of this: the VCR...most people don't care to figure out how to program their VCR because they only use their VCR to watch rental movies...and most of us don't bother to "solve" the blinking 12 because we
- don't need a 10th, horribly inaccurate, (or 20th or 30th....) clock in the house, and
- the power goes out frequently enough that it becomes a real PITA to keep fixing the damn clock.
It isn't because people are too stupid (okay, maybe I speak too quickly...most people probably ARE too stupidYou need to square each term.... :-). We could have chosen time units overall, and measured physical lengths in time units, but I chose not to, since it usually isn't done that way. The quantity dS is the spacetime interval between the two events, dx is the physical distance between the two events as measured in a particular inertial reference frame, and dt is the time elapsed between the two events as measured in the same frame. The important thing is that dS is a frame independent (Lorentz invariant) quantity, so all observers will agree on the measurement of dS^2, although not necessarily dx or dt.
(dS)^2 = (dx)^2 - (dt)^2
where we measure time in length units (set c=1, the way real physicists do it
When ds^2 > 0, the two events are spacelike separated, meaning that the two events could not have affected each other (they are not causally connected, in the lingo), as they are farther apart in space than the distance light signals could propogate given the measured time difference.
When dS^2 timelike separated, meaning the two events could have affected each other (light could have propagated from one to the other in the time measured, with time left over, meaning (potentially) other types of particles could have travelled from one to the other).
Finally, when dS^2=0, the two events are null separated, or light-like separated, since the two events could only have affected each other by light signals.
Using measurements of intervals from many different events, we can (approximately) reconstruct the metric.
The full article is available without subscription to PRL ... you can get it from the lanl archive here.
I would have to disagree with you here...in a fair system, you would only bring a dispute in those cases where you expected to win on the merits; the net result in the long run (not necessarily the short run, while precedents are being made and people are trying to find out what the rules really are) would be the complainant winning much more often, because you would just be wasting your money to bring a case without merit. Thus, I think that in the long run you would expect basically the same stats as we are seeing now.
Which is not to say that I necessarily think things are fair now, just that I don't think "fair" would equate with 50/50 outcomes.
I like the preferential and instant run-off schemes as well...but take a look at this month's discover magazine, where they discuss some different types of voting systems. The basic gist of the article was that, even if every vote is cast by a rational person making a rational choice, there is no fraud, and there is no error in the count, you CAN NOT have a voting system that will always obtain the "correct" result. They give good examples...in fact, the best one is the example which shows that, given four voting systems and picking one system at random to use to "elect" which voting system to use in the next election, no system would ever be able to choose itself! Kind of contrived, but the point being that there is no "perfect" system...there will always be cases where someones rational definition of the "correct" outcome fails.
Here are the current Center of Mass frame energies of the colliders:
What is likely to happen, is that LEP data will be able to rule out a Standard Model Higgs boson up to about 110GeV in mass, or "discover" a slightly lighter Higgs (where "discover" means a very particular thing, not just seeing a few events), while the Tevatron (I think) will be able to rule out a Higgs up to something like 140GeV and discover one up to 130GeV (these may be wrong, but they're in the right ballpark). LHC will be able to discover any Higgs up to about a TeV (with the exception of a small range right around where the limits are at now). So, if the Higgs is lighter than about 140GeV, it will be discovered by the Tevatron long before LHC turns on. RHIC, however, is not the right type of machine to study these phenomena, and so is not really a concern for LEP in the Nobel search :-)
On the other hand, RHIC may be the machine to confirm the existence of the quark-gluon plasma at high nuclear density. There is tantalizing evidence from the SppS (I think) collider at CERN, but not confirmation. If RHIC isn't big enough, LHC should be (in lead-lead mode). So the race is on there too.
The next few years will be extremely exciting on the experimental front (Higgs physics, supersymmetry/technicolor discovery, CP violation physics, neutrino oscillations). It's a great time to be a physicist :-)
The flip side of course is that the construction contracts for LHC contain large penalty clauses for delays caused by CERN. A year of data collection would pretty much wipe out the LHC budget completely, just paying for the delays. Compared with the miniscule chance of actually confirming the Higgs - remember, from the note, that there is only one detector (ALEPH) out of four with a potentially notable excess in one channel. From the perspective of many of my colleagues (theoretical particle physicists), there is little chance (given the lack of supporting evidence in other channels and detectors, and the history of such "potential discovery" announcements) that this is actually the real thing.
Just a passing note for those that never learned or don't remember this stuff, random fluctuations to the 1 sigma level would occur in 1/3 of all experiments set up and performed exactly the same way; and 2 sigma is about a 5% chance of random fluctuation. And that is assuming perfect knowledge of all the uncertainties, which is never the case. The number of "well established" three-or-more sigma "discoveries" that have evaporated in the face of more data is well in excess of what you would expect from chance. Bottom line for a physicist (and I don't remember where I first saw this):
If the CERN staff didn?t need to empty the tunnel for the LHC installation you can be sure it (the LEP) would be running as long a it could produce data.
In fact, LEP may live again! The magnets, RF cavities, and other stuff (but not the detectors, I don't believe, although I could be wrong), will be put into storage, on the chance that CERN decides to convert the LHC to an electron-proton machine at some point in the distant future (much like HERA at DESY in Germany), after its planned program is completed.