It's gone downhill so fast it's been like a toboggan ride.
That may be an exaggeration, but I kind of agree. I've been using ubuntu since Edgy, steadily upgrading, and am now using Karmic. Starting with Jaunty, and now continuing with Karmic, I've been having multiple serious problems with sound. Karmic is also causing me several problems where they changed something and made sure it worked with Gnome, but it doesn't work properly with other WMs: 1, 2.
I'm basically on board with McGovern, but some of the particulars stuck out to me as half-baked: "Add Washington's propping up of dictatorial, repressive regimes in order to secure continuing access to oil and natural gas -- widely (and accurately) seen as one of the main reasons for the invasion of Iraq and Afghanistan." I think it's true that the US props up dictatorial, repressive regimes in the Middle East and southern Asia (Kuwait, Pahlavi's Iran,...). I think it's true that we would never have gone to war in Kuwait/Iraq in 1991, Afghanistan in 2001, or Iraq in 2003, if this hadn't been an oil-producing region. This is clearest in the case of Kuwait, and also reasonably clear in the 2003 Iraq invasion, since the WMD pretext was obviously bogus. The least clear one is Afghanistan, which really did have at least some reasonable justification in the immediate aftermath of the 9/11 attacks -- although if the region had never had oil, it would have made more sense to invade Saudi Arabia, from which 15 of the 19 9/11 terrorists originated.
But how can McGovern say that "one of the main reasons for the invasion of Iraq and Afghanistan" was "to secure continuing access to oil and natural gas?" This doesn't make any sense. Saddam Hussein was exporting oil before we invaded in 2003. The invasion devastated oil production. And Afghanistan has never been a big oil producer.
I think it would be more accurate to say that we went to war in Kuwait in 1991 in order to stabilize the Middle East oil producing region, and we went to war in Afghanistan in 2001 and Iraq in 2003 as knee-jerk reactions to the 9/11 attacks (which is pretty pathetic, because the whole purpose of terrorism is basically to cause a knee-jerk reaction).
He makes a big deal out of how nobody admits that one of the main motivations for terrorist attacks on the US is anger about Israel. This is undeniably true. The problem is, what the heck can we do about it now? We tried to hand democracy and territory to the Palestinians on a silver platter, and they messed up. Is there some obvious solution to the Israel problem that I'm missing?
I know, why isn't the solution ever "Use an alternative PDF viewer?" Instead of "Update Adobe Acrobat to another version filled with gaping security flaws."
Well, I use xpdf and evince on linux, and they work fine for me. However, I had an interesting experience getting people to switch away from AR on windows. I teach at a community college, we were trying to whip the software on the student computer lab machines into shape, and I was the faculty guy who was supposed to be the liason to IT to get this done. I suggested ditching AR and switching to Foxit. Everybody seemed okay with it. Then we switch, and all of a sudden people are complaining about goofy bugs in Foxit, like fonts showing up in rainbow colors. They were extremely upset, and guess who they blamed?
I can also see how a lot of people could look at the options on linux and decide they wanted AR. Xpdf is fast as hell, which is why I like it, but it's a throwback to 1996. Evince is very slow on certain types of files (with lots of big bitmaps in them), and it's also very bare-bones.
People in publishing really do use some of the fancy features in AR. For example, it can tell you all kinds of data about your file to help you figure out whether it's likely to work properly on someone else's printer. There are tools on linux that can do that (e.g., pdffonts), but they're command-line tools, and a lot of people only know GUIs.
The reason for all the security bugs in AR is javascript, which you can just turn off. The reason javascript is in AR is because it's used for forms that you fill in. This is not a completely stupid thing to want. What's the alternative -- tell everyone they have to open a Word file in order to fill out a form? That would be *much* worse in terms of standards and interoperability, and probably no better in terms of security.
The rest of NASA's science work, however, appears to be up the same standards you'd find anywhere else. Look at all the planetary science and material science work: you can't fake that.
I didn't mean to claim that no good science was done at NASA. I do claim that they have two specific areas where they have problems: Breakthrough Propulsion Physics, and crewed spaceflight. If it was just the BPP thing you could dismiss it as an aberration. But they also have all these outrageous claims they make that the crewed spaceflight program is justified by all the good science it does, and that is just totally false. I have the greatest respect for the science they're doing with uncrewed probes.
NASA's results would have been discredited long ago if they weren't engaging in legitimate research.
There are lots of varieties of bad science. The BPP thing is the kind of bad science that doesn't risk making any testable predictions. In a normal scientific research environment, you have a lot of ways of discrediting incorrect work. Peer reviewers can point out its flaws, so that it doesn't get accepted by peer-reviewed journals. Federally funded labs undergo periodic peer review to evaluate whether they are healthy enough to deserve continued funding. BPP and science related to crewed spaceflight are insulated from these pressures, because they have a gravy train of money from congress that's motivated by nationalism rather than by science.
What makes me very dubious about these claims is that the structures are so small that they'd have to be nanobacteria, and yet the so-called "nanobacteria" on Earth turn out to be non-living.
B) The scientific word "prove" is more about the lack of any valid competing hypotheses. If you can't come up with a reasonable alternative explanation for the data, you have to accept the presented explanation.
No. One does not have to accept an extraordinary scientific claim just because one does not yet have another explanation. There is lots of data on UFOs. For some of this data, there is no reasonable alternative explanation. That doesn't mean that I have to start believing in UFOs. It just means that UFOlogy is a field where the data are all a big pile of doggy doo. Science has many subfields in which the state of the art is so terrible that reputable people don't want to get involved, and no progress is being made. Two good examples that spring to mind are nanobacteria and IQ testing.
I am very skeptical about extraordinary scientific claims coming from NASA. NASA has not succeeded in instituting a culture of proper scientific peer review. For instance, the Breakthrough Propulsion Physics Project does crank stuff, and has ties to characters like Harold Puthoff, who specializes in things like telepathic visits to Jupiter. In a way it's not surprising that NASA has problems with proper peer review. They're the handmaiden of Congress. Congress wants the crewed space program to be run as a national prestige project, but they also want to be able to give justifications for the crewed space program that don't sound like pure nationalism. Therefore they coax NASA into coming up with bogus scientific justifications for programs like the shuttle and the ISS. In a culture that's all based on puffing up bad or nonexistent scientific achievements, it's not surprising that they're susceptible to kookiness.
Extraordinary claims require extraordinary evidence. It is not sufficient to say that there is no alternative explanation for these structures in the meteorites, and therefore they must have arisen from living organisms. No geologist has ever been to Mars. We know far less about Mars's geological history than we do about the earth's. It's not at all surprising that we find geological samples where we can't explain how they were formed. That doesn't mean that we immediately have to leap to the conclusion that they were made by nanobacteria.
It would be very interesting to hear more details on this end of things. The entire blog entry was completely about search, but google is really in the ad business, not the search business.
From the blog, it sounds like they are probably no longer going to have employees or offices in China. That seems like it would put quite a crimp in their ability to do ad business there. The Chinese government will presumably start blocking lots of google servers, and this would seem to make it difficult for them continue to accept payments from Chinese advertisers, or to make sure that their ads get shown to Chinese consumers.
The impression I get is that for a Chinese person who's educated and technically sophisticated, and especially if his English is good, it's really not all that hard to get uncensored information in China. The Chinese government only really cares about the possibility that dissent will grow into a mass movement.
More importantly, instead of carrying a USB drive, you can now use Google Docs as a more convenient option for accessing your files on different computers.
I know very few people who use USB keychain drives for this kind of thing. I teach physics lab courses, and when students need to bring home a spreadsheets or something, they just email it to themselves. I don't think the size limit is the main reason they don't use flash drives. One reason is that they don't know in advance that they're going to need one. The other is that email is less of a hassle.
If you're getting up into the amounts of data that can't go in an email attachment, then you probably need a full-fledged file synchronization utility like unison anyway. Unison is smart about recognizing data that haven't changed, and it also takes away the hassle and confusion that people experience with trying to keep straight all the different versions of files they have when they try to use a keychain drive for this. If you don't have a decent tool like this, then mirroring large amounts of data is likely to be slow, labor-intensive, and error-prone. TFA says:
In addition to uploading any file into Google Docs, our Google Apps Premier Edition customers will be able to seamlessly upload many files at once and sync them with their desktop in real time using third party applications.
Presumably the "Premier Edition" part means you'll have to pay. So for the majority of applications where you have this much data, Google will give you convenience or zero cost, but not both.
One exception I can think of is that this could be a nice, convenient way to make off-site backups of a certain amount of personal data (that novel you've been writing,...) in case of fire or earthquake.
Yep. What you said. If they have these scanners at the airport the next time I fly, I want to make sure to ask for a pat-down rather than a scan, which I understand they're supposed to allow you to do according to the current rules. Can any slashdotters report on practical experiences at airports that use these things? Is there some kind of clear signage that lets you know that this is one of the airports that uses them, and that the door-frame you're about to step through is it? If enough people ask for the pat-down, it could actually be a very effective form of civil disobedience. The system is set up under the assumption that only a tiny number of passengers will ask for one.
It is a nice exercise to play with alternative theories of gravity, and see how they are similar or different. However, general relativity has a crucial deviation from the inverse square law, which results in the anomalous orbit of Mercury, for example. This does not mean GR is the final correct answer, of course.
This isn't really a correct interpretation. Although it's true that a slight deviation from 1/r2 in a force law will give you precession of perihelion like Mercury's, that isn't a correct way of understanding the GR effect that leads to the effect on Mercury. It has to do with the fact that GR describes gravity as a curvature of spacetime. For instance, if GR only predicted a deviation from 1/r2 on a background of flat spacetime, then you wouldn't get the geodetic effect, or frame-dragging, or black holes. In particular, if gravity was just a force with some r-dependence, then a black hole would simply be an object whose escape velocity was greater than c -- but you don't need to be going faster than c to get out of a gravity well. A nice way of understanding Mercury's perihelion precession is to imagine the more extreme case where Mercury's orbit took it inside the event horizon of a black hole. Then it would spend infinite time at perihelion, i.e., never come out. In the less extreme case of our actual solar system, GR makes Mercury spend just a little extra time near perihelion, so it covers more angle before coming back out.
I suddenly feel a little bit smug having only spent $25 on my vibrator, and the occasional pocket change on lotion and AA batteries. Why anyone would spend hundreds of dollars on a sex toy is beyond me. It feels good to be a girl right now. ^___^
But wait! TFA says:
'According to True Companion's Web site, [Roxxxy] "can carry on a discussion and expresses her love to you and be your loving friend. She can talk to you, listen to you and feel your touch."'
I want to go this trade show and ask them to let me test-drive Roxxxy's physical capabilities. And then I'll say, "Hang on, can you demo how she can express love for me and be my loving friend as well?" And see if the sales rep can get through the whole thing without laughing.
Sun does own the IP, because it is the only company that is allowed to sell non-free copies of MySQL. MySQL's business model is to sell non-free copies to people who don't want to run OSS for whatever reason and use that money to pay for development, so this is very important, and why it isn't so easy to fork the project.
You're absolutely right about dual-licensing being one of the most important answers to the OP's question 'What does "Acquire" mean?'
But I disagree that this makes it harder to fork the project. You want to fork MySQL, you fork MySQL. Nobody's stopping you. People have forked it. The only thing is, if you fork it, you're not going to be able to dual-license it and make money from nos-OSS copies sold. Most OSS doesn't have this type of gravy train to support development. PostgreSQL is considered by many people to be better than MySQL, and it doesn't have a dual-licensing system.
When I try to think of projects that really need such an income stream, the ones that spring to mind are Firefox and Ubuntu. Firefox is a very large and complex project, it targets a rapidly changing set of standards, and it includes a lot of features that are needed by a small percentage of users. For instance, I'm really glad that it has good mathml support, but most users don't care about that. If they hadn't had their big revenue stream from search engine placement, maybe they wouldn't have implemented mathml, or wouldn't have done as good an implementation. Well, that would have been too bad, but it wouldn't be the end of the world. There are other browsers out there: galeon, konqueror.
Same deal with Ubuntu. Ubuntu is, IMO, significantly better than other Linux desktop distros, and they probably wouldn't have been so good if they hadn't had money from Shuttleworth. But if Ubuntu disappeared tomorrow, I'd still be able to run Linux.
Turing complete does not mean "must have access to whole system".
I didn't say that it did.
there exist exactly zero Turing complete systems in the "real world"
A Turing machine is of course a mathematical idealization. That doesn't mean that theorems about Turing machines don't tell us useful things. There's a mathematical theorem about mathematically ideal Turing machines that says that a Turing machine can't predict whether another Turing machine will halt. The real-world interpretation of this is that if real-world program A is written in something resembling a Turing-complete language (modulo the finite amount of memory, etc.), then in general it is not practical to write another such program, B, that can take programs like A as input and tell us anything useful about their behavior.
AFAIK a PDF can take "long enough" to print that it makes no difference whether it is ever going to halt or not.
The difference is that it's at least theoretically possible for an automatic computer program to look at a PDF at determine how long it will take to print. That's not even theoretically possible in the case of a PostScript file (again, modulo issues like finite memory, which do not invalidate the result for all practical purposes).
Wrong. Strangelets could crystallize all the matter of the Earth into dark matter. No black holes involved.
I didn't claim anything about strangelets, just about microscopic black holes. You're also incorrect to refer to the final state of the earth in this scenario as dark matter.
Anyway, see this paper and this paper for a discussion of the possibility of strangelets. The basic arguments against this scenario are: (1) strangelets would be positively charged, so they would be electrically repelled by ordinary nuclei, and (2) the LHC would produce them in smaller numbers than RHIC, which is already in operation.
All security problems are easy to solve if you have users who are sophisticated about security, and motivated to put up with inconveniences. The real world isn't like that.
A proposal like this inevitably requires that the user understand something about the sandbox, and also requires that the user go through various hassles because of the sandbox. They're going to perceive it as a hassle, because the sandbox is going to prevent them from doing things they would otherwise have done. If they're unsophisticated and unmotivated, they'll just see it as something to work around.
Not only that, but this isn't an optimal solution. A flash game has to be a Turing-complete program. A memo doesn't have to. The simple solution is just to stop embedding Turing-complete programming languages in file formats that don't require them. Adobe actually started by designing postscript as a Turing-complete language. That had some unfortunate consequences, since, e.g., you can't predict whether a program written in a Turing-complete language will halt, so in principle you can't predict whether a document will take forever to come out of the printer. The realized that that was a mistake, and when they designed pdf, they intentionally made it not Turing complete. Now we've come full circle, and they've added a Turing-complete language, javascript, back into pdf. That's just bad design. The solution for users is actually pretty easy: if you're using Adobe Reader, turn off javascript.
And an earth destroying black hole would require us to be wrong in a very specific way on par with, "Our knowledge of electricity could be wrong and some magical circuit with just the right components will end all of reality as we know it."
As a physicist, I'm not losing a lot of sleep over the LHC-ends-the-world scenario. However, I think you've overstated the case a little bit.
Here's what would have to happen for it to be the end of the world:
There would have to be extra dimensions, or else black holes could not be formed at the LHC.
The black holes would have to be stable against spontaneous decay.
The hypothetical mechanism of producing black holes would have to always produce electrically neutral ones (or else the earth would have already been destroyed by naturally occurring, charged black holes).
There would have to be some reason why naturally occurring, electrically neutral black holes haven't destroyed all the white dwarfs and neutron stars.
Evaluating the plausibility of these:
I wouldn't bet a six-pack on it, but lots of theorists are working on theories involving extra dimensions. It's a long shot, but it's not crazy.
This requires a violation of the fundamental laws of quantum mechanics (unitarity and time-reversal symmetry). However, we already know that the fundamental principles of quantum mechanics are incompatible with general relativity, so this isn't as crazy as it sounds.
This would be very surprising, since there is no known reason for the production method to never produce anything with electric charge. Nevertheless, "surprising" isn't the same as "impossible."
This is similar to #3.
If you could assign probabilities to all of these, they'd be small probabilities.
Multiplying all the small probabilities together, you get a very small probability, which is why physicists aren't worried about the end of the world. Nevertheless, it's not completely impossible.
If you want a relatively high-probability end-of-the-world scenario, I'll give you one. Pakistan and India have a nuclear war. Current attempts to model nuclear winter say that such an exchange might actually cause a nuclear winter. Agriculture breaks down world-wide. The human race becomes extinct.
The natural collisions are spread out over a much larger area and much longer time.
This is irrelevant. The end-of-the-world scenario is one in which a stable black hole becomes gravitationally bound to the earth. You only need one of those, and then the earth is toast.
Also with natural collisions only one particle is moving at high velocity which might cause any harmful particle or black hole to move through the earth very quickly. In the LHC two particles of about the same velocity collide. This could cause any potentially harmful particles to linger by some or all of the momentum being canceled by the collision.
This is basically correct, except that with very high probability the products of LHC collisions are not quite at rest, they're moving at greater than the earth's escape velocity. The hypothetical danger would come from low-probability events in which black holes were produced at velocities less than escape velocity.
If my thinking is correct, I don't see how a microscopic black hole would be capable of any accretion.
This is a relatively short and nontechnical paper that discusses this. See p. 7. For more detail, see this paper, pp. 16ff and 79ff.
First you have to assume that black holes could be produced at the LHC (which requires some nonstandard physics like extra dimensions), and also that they don't evaporate immediately due to Hawking radiation (which violates basic principles of quantum mechanics). Then you have a black hole that is typically produced at a velocity greater than the earth's escape velocity. If it happens to be emitted in the downward direction, it passes through the earth once without stopping, and therefore accretes a negligible amount of mass. However, the velocities are random, and some small number could be produced with velocities less than the earth's escape velocity. These would oscillate permanently in the earth's gravitational field. They would therefore have unlimited time to do low-probability accretion events, so even though the cross-section is small, they can end up accreting significant amounts of matter.
Your calculation underestimates the radius for capture. This is discussed on pp. 16ff of the second paper. The radius for capture depends on the dynamics. For instance, if you release an atom at rest with respect to the black hole, then it will be absorbed with 100% probability from any radius, because it will simply slowly accelerate toward it; the radius for capture is infinite. In reality you have nuclei that are bound into atoms, and the black hole is zooming past at high speed. The actual radius for capture is therefore bigger than the Schwarzschild radius, but smaller than infinity. They estimate it to be about 10^-16 m, which is small, but not as ridiculously small as the Schwarzschild radius. (Your Schwarzschild is wrong, because the mass isn't equal to the mass of the proton. It's more like a TeV.)
Anyway I'm perfectly aware what makes a black hole a black hole, their Schwarzschild radius, and so on. Which is irrelevant here anyway, since when discussing orbits mass is the only thing that matters.
No, that's incorrect. There are three quantities that could be relevant: the mass of the primary M, the mass of the satellite m, and the radius of the orbit r. Contrary to your previous statements, m is irrelevant for a highly asymmetric system like the sun and Mercury. What quantifies the strength of the gravitational effects is the unitless quantity (G/c^2)(M/r), where m is the mass of the primary, and r is the radius of the orbit.
You are forgetting that all that matters in discussing whether the precession of orbit due to relativistic effects is not insignificant, is the size of orbit relative to the gravity well of participating bodies.
This contradicts your previous statements, but it is more or less correct, except that for the caveat about the irrelevance of m in the asymmetric case.
Comparably deep in each others gravity well to the one in which Mercury is
This is incorrect. In the case of Mercury and the sun, we have (G/c^2)(M/r)=3x10^-8. In the case where M is the mass of the supermassive black hole Sgr A*, and r is 1 kpc, (G/c^2)(M/r)=2x10^-10. Therefore the relativistic effects for the binary black holes are smaller by two orders of magnitude.
(nvm that for those black holes it can still go much further down).
The orbital radii for these binary black holes is estimated to be 1 kpc. It's true that you could get stronger relativistic effects if you made r smaller ("go much further down"), but in fact r is much bigger, even in proportion to M.
General relativity has been verified countless times, from the existence of black holes, to gravitational lensing, to even time dilation. General relativity effects are even needed to be compensated for in GPS clock calculations. Are there aspects of general relativity left to be tested?
Sure. Of course you have to distinguish between falsifying Newtonian mechanics and verifying general relativity. It only takes one observation to disprove a theory, but proving a theory correct is a whole different matter.
A good (but somewhat out of date) popular-level description of this kind of thing is "Was Einstein Right?" by Clifford Will.
Some examples of things that are still left to test about GR:
Nobody knows whether gravitational torsion exists. Einstein and Cartan played around with it as a way of making a GUT. String theory requires it to exist. The experimental evidence so far has put an upper limit on it.
There are various theories of gravity that are consistent with GR in a certain limit, but differ from it in ways that should be empirically detectable. Two examples are the Brans-Dicke theory and Oestvang's quasi-metric relativity. The selling points of the Brans-Dicke theory are that it's supposedly more "Machian" than GR, and at one time it was thought to reproduce certain solar-system measurements that GR couldn't reproduce, although that turned out to be wrong. Oestvang claims that he can reproduce the Pioneer anomaly. Even if they turn out to be wrong, it's important to have them as "test theories." If you don't have any alternative theoretical framework, then it's impossible to decide what experiments to do to test GR, and it's impossible to interpret results of experiments unambiguously. This is basically the reason that it's been impossible to test propagation of gravitational effects at c; we don't have a viable test theory that predicts that they don't propagate at c, so there's no way to interpret the results of experiments.
There are various open theoretical problems in classical GR (cosmic censorship, chronology protection conjecture), which may have some bearing on whether the theory is even self-consistent as a classical theory of gravity. There's a strong argument that if cosmic censorship fails, GR fails as a classical theory.
There are significant questions, which could be resolved by observation, about the extent to which quantum effects alter the classical picture of the formation and structure of black holes. See, e.g.: http://arxiv.org/abs/0902.0346
You mean like the free Acrobat Reader? No wait, that supports only PDFs. Really the main advantage of this e-reader is that unlike Kindle, it uses a full sized monitor AND your computer [...]
TFA tries very hard to highlight the main advantage of Blio over Kindle.
If you look at the very first screenshot in the article, it's a color illustration of a human skull from an anatomy textbook. This is an appplication that Kindle can't handle: illustrated textbooks.
Kindle is black and white, has a page that's relatively small, doesn't usually (ever?) include illustrations, and doesn't have proper formatting for math.
I think the main advantage of Blio over PDF is this: "Like all e-readers, Blio will adopt some form of DRM and proprietary formatting [...]" Well, that's only an advantage in the publisher's eyes, but they do seem to see it as crucial.
I can also imagine certain categories of books where Blio could do something useful for the reader that can't be done as well by PDF. Consider a public-domain edition of Gray's Anatomy. You can get it here in html format. Now suppose you want to read it on the bus, without carrying a full-size laptop computer with you. If the Blio software is done well, it might adapt itself better to an e-book reader than html or pdf.
TFA says, "Kurzweil and knfb are working with Google to try to make their extensive catalog of printed materials available for Blio."
Google is not in the same market as kindle. Amazon sells a relatively small number of recent, profitable books, each of which has to be formatted for the kindle. Google has a gigantic archive of old, public-domain books, none of which is a profitable item in and of itself, but which, aggregated, make something that google might be able to profit from. There is no way that google is going to bring out special e-book editions of all those books.
I still have the impression you think I was embracing alternative theories of gravity...oh well.
No, I pointed out that you'd misunderstood those alternative theories of gravity.
But as for Mercury; well, the fact stands that even with all other factors, with tiny mass of the planet, we were seeing it in different orbit than it "should" be [...]
Both in your original post and in this one, you seem to be displaying a misconception that the mass of the object is what matters. That's incorrect. What makes a black hole a black hole isn't its mass, it's the fact that the mass is compressed into such a small space. When an ordinary, main-sequence star collapses into a black hole, it actually loses mass in the process. Likewise the mass of Mercury is completely irrelevant to the discussion. You seem to think that Mercury's small mass reduces the relativistic effect on its orbit. That's incorrect. The relativistic precession of Mercury's perihelion is 43 seconds of arc. If Mercury's mass was half what it is, or double what it is, the precession would still be 43 seconds of arc.
Never mind even that this effect would be only slightly stronger - it's there. Newton isn't the choreographer.
Similarly, you could analyze the motion of two human bodies doing a literal waltz, and say that Newton isn't the choreographer. You'd be absolutely right. There would be relativistic effects on the motion of their bodies. That would be absolutely irrelevant, however, because the effects would be too small to measure compared to other effects that you couldn't even quantify, like air currents. Similarly, the relativistic effects on the orbits of these black holes are far too small to measure. The gamma factor for an object moving at 100 km/s is 1.00000006. The difference from 1, which is 5x10^-8, quantifies the size of the relativistic effects. If you take a look at the paper, they weren't even able to resolve the black holes well enough to determine their distances from one another. That means that their orbits are not known at all, much less to a precision of parts per billion. Also, if we assume that their order-of-magnitude estimate of 1 kpc for the orbital separation is roughly correct, each one is swimming in the gravitational field of a whole bunch of other densely packed stars near the galactic core. That effect, which is impossible to measure or calculate with any precision, is going to completely swamp the relativistic effect.
The relativistic effects on the GPS onboard clock due to its relative motion to the GPS receiver would result in the position calculation being shifted by 7 miles per day if it were not corrected for.
Sure. The error in locating yourself on the earth's surface equals the time error multiplied by the speed of light. Since the speed of light is big, the technique is extremely sensitive to tiny time errors.
Slashdot Mirror
That may be an exaggeration, but I kind of agree. I've been using ubuntu since Edgy, steadily upgrading, and am now using Karmic. Starting with Jaunty, and now continuing with Karmic, I've been having multiple serious problems with sound. Karmic is also causing me several problems where they changed something and made sure it worked with Gnome, but it doesn't work properly with other WMs: 1, 2.
I'm basically on board with McGovern, but some of the particulars stuck out to me as half-baked: "Add Washington's propping up of dictatorial, repressive regimes in order to secure continuing access to oil and natural gas -- widely (and accurately) seen as one of the main reasons for the invasion of Iraq and Afghanistan." I think it's true that the US props up dictatorial, repressive regimes in the Middle East and southern Asia (Kuwait, Pahlavi's Iran, ...). I think it's true that we would never have gone to war in Kuwait/Iraq in 1991, Afghanistan in 2001, or Iraq in 2003, if this hadn't been an oil-producing region. This is clearest in the case of Kuwait, and also reasonably clear in the 2003 Iraq invasion, since the WMD pretext was obviously bogus. The least clear one is Afghanistan, which really did have at least some reasonable justification in the immediate aftermath of the 9/11 attacks -- although if the region had never had oil, it would have made more sense to invade Saudi Arabia, from which 15 of the 19 9/11 terrorists originated.
But how can McGovern say that "one of the main reasons for the invasion of Iraq and Afghanistan" was "to secure continuing access to oil and natural gas?" This doesn't make any sense. Saddam Hussein was exporting oil before we invaded in 2003. The invasion devastated oil production. And Afghanistan has never been a big oil producer.
I think it would be more accurate to say that we went to war in Kuwait in 1991 in order to stabilize the Middle East oil producing region, and we went to war in Afghanistan in 2001 and Iraq in 2003 as knee-jerk reactions to the 9/11 attacks (which is pretty pathetic, because the whole purpose of terrorism is basically to cause a knee-jerk reaction).
He makes a big deal out of how nobody admits that one of the main motivations for terrorist attacks on the US is anger about Israel. This is undeniably true. The problem is, what the heck can we do about it now? We tried to hand democracy and territory to the Palestinians on a silver platter, and they messed up. Is there some obvious solution to the Israel problem that I'm missing?
Take a look at the paper I linked to. They grow and reproduce in the same sense that crystals evolve. They don't evolve.
Well, I use xpdf and evince on linux, and they work fine for me. However, I had an interesting experience getting people to switch away from AR on windows. I teach at a community college, we were trying to whip the software on the student computer lab machines into shape, and I was the faculty guy who was supposed to be the liason to IT to get this done. I suggested ditching AR and switching to Foxit. Everybody seemed okay with it. Then we switch, and all of a sudden people are complaining about goofy bugs in Foxit, like fonts showing up in rainbow colors. They were extremely upset, and guess who they blamed?
I can also see how a lot of people could look at the options on linux and decide they wanted AR. Xpdf is fast as hell, which is why I like it, but it's a throwback to 1996. Evince is very slow on certain types of files (with lots of big bitmaps in them), and it's also very bare-bones.
People in publishing really do use some of the fancy features in AR. For example, it can tell you all kinds of data about your file to help you figure out whether it's likely to work properly on someone else's printer. There are tools on linux that can do that (e.g., pdffonts), but they're command-line tools, and a lot of people only know GUIs.
The reason for all the security bugs in AR is javascript, which you can just turn off. The reason javascript is in AR is because it's used for forms that you fill in. This is not a completely stupid thing to want. What's the alternative -- tell everyone they have to open a Word file in order to fill out a form? That would be *much* worse in terms of standards and interoperability, and probably no better in terms of security.
I didn't mean to claim that no good science was done at NASA. I do claim that they have two specific areas where they have problems: Breakthrough Propulsion Physics, and crewed spaceflight. If it was just the BPP thing you could dismiss it as an aberration. But they also have all these outrageous claims they make that the crewed spaceflight program is justified by all the good science it does, and that is just totally false. I have the greatest respect for the science they're doing with uncrewed probes.
There are lots of varieties of bad science. The BPP thing is the kind of bad science that doesn't risk making any testable predictions. In a normal scientific research environment, you have a lot of ways of discrediting incorrect work. Peer reviewers can point out its flaws, so that it doesn't get accepted by peer-reviewed journals. Federally funded labs undergo periodic peer review to evaluate whether they are healthy enough to deserve continued funding. BPP and science related to crewed spaceflight are insulated from these pressures, because they have a gravy train of money from congress that's motivated by nationalism rather than by science.
What makes me very dubious about these claims is that the structures are so small that they'd have to be nanobacteria, and yet the so-called "nanobacteria" on Earth turn out to be non-living.
No. One does not have to accept an extraordinary scientific claim just because one does not yet have another explanation. There is lots of data on UFOs. For some of this data, there is no reasonable alternative explanation. That doesn't mean that I have to start believing in UFOs. It just means that UFOlogy is a field where the data are all a big pile of doggy doo. Science has many subfields in which the state of the art is so terrible that reputable people don't want to get involved, and no progress is being made. Two good examples that spring to mind are nanobacteria and IQ testing.
I am very skeptical about extraordinary scientific claims coming from NASA. NASA has not succeeded in instituting a culture of proper scientific peer review. For instance, the Breakthrough Propulsion Physics Project does crank stuff, and has ties to characters like Harold Puthoff, who specializes in things like telepathic visits to Jupiter. In a way it's not surprising that NASA has problems with proper peer review. They're the handmaiden of Congress. Congress wants the crewed space program to be run as a national prestige project, but they also want to be able to give justifications for the crewed space program that don't sound like pure nationalism. Therefore they coax NASA into coming up with bogus scientific justifications for programs like the shuttle and the ISS. In a culture that's all based on puffing up bad or nonexistent scientific achievements, it's not surprising that they're susceptible to kookiness.
Extraordinary claims require extraordinary evidence. It is not sufficient to say that there is no alternative explanation for these structures in the meteorites, and therefore they must have arisen from living organisms. No geologist has ever been to Mars. We know far less about Mars's geological history than we do about the earth's. It's not at all surprising that we find geological samples where we can't explain how they were formed. That doesn't mean that we immediately have to leap to the conclusion that they were made by nanobacteria.
It would be very interesting to hear more details on this end of things. The entire blog entry was completely about search, but google is really in the ad business, not the search business.
From the blog, it sounds like they are probably no longer going to have employees or offices in China. That seems like it would put quite a crimp in their ability to do ad business there. The Chinese government will presumably start blocking lots of google servers, and this would seem to make it difficult for them continue to accept payments from Chinese advertisers, or to make sure that their ads get shown to Chinese consumers.
The impression I get is that for a Chinese person who's educated and technically sophisticated, and especially if his English is good, it's really not all that hard to get uncensored information in China. The Chinese government only really cares about the possibility that dissent will grow into a mass movement.
I know very few people who use USB keychain drives for this kind of thing. I teach physics lab courses, and when students need to bring home a spreadsheets or something, they just email it to themselves. I don't think the size limit is the main reason they don't use flash drives. One reason is that they don't know in advance that they're going to need one. The other is that email is less of a hassle.
If you're getting up into the amounts of data that can't go in an email attachment, then you probably need a full-fledged file synchronization utility like unison anyway. Unison is smart about recognizing data that haven't changed, and it also takes away the hassle and confusion that people experience with trying to keep straight all the different versions of files they have when they try to use a keychain drive for this. If you don't have a decent tool like this, then mirroring large amounts of data is likely to be slow, labor-intensive, and error-prone. TFA says:
Presumably the "Premier Edition" part means you'll have to pay. So for the majority of applications where you have this much data, Google will give you convenience or zero cost, but not both.
One exception I can think of is that this could be a nice, convenient way to make off-site backups of a certain amount of personal data (that novel you've been writing, ...) in case of fire or earthquake.
Yep. What you said. If they have these scanners at the airport the next time I fly, I want to make sure to ask for a pat-down rather than a scan, which I understand they're supposed to allow you to do according to the current rules. Can any slashdotters report on practical experiences at airports that use these things? Is there some kind of clear signage that lets you know that this is one of the airports that uses them, and that the door-frame you're about to step through is it? If enough people ask for the pat-down, it could actually be a very effective form of civil disobedience. The system is set up under the assumption that only a tiny number of passengers will ask for one.
This isn't really a correct interpretation. Although it's true that a slight deviation from 1/r2 in a force law will give you precession of perihelion like Mercury's, that isn't a correct way of understanding the GR effect that leads to the effect on Mercury. It has to do with the fact that GR describes gravity as a curvature of spacetime. For instance, if GR only predicted a deviation from 1/r2 on a background of flat spacetime, then you wouldn't get the geodetic effect, or frame-dragging, or black holes. In particular, if gravity was just a force with some r-dependence, then a black hole would simply be an object whose escape velocity was greater than c -- but you don't need to be going faster than c to get out of a gravity well. A nice way of understanding Mercury's perihelion precession is to imagine the more extreme case where Mercury's orbit took it inside the event horizon of a black hole. Then it would spend infinite time at perihelion, i.e., never come out. In the less extreme case of our actual solar system, GR makes Mercury spend just a little extra time near perihelion, so it covers more angle before coming back out.
But wait! TFA says: 'According to True Companion's Web site, [Roxxxy] "can carry on a discussion and expresses her love to you and be your loving friend. She can talk to you, listen to you and feel your touch."'
I want to go this trade show and ask them to let me test-drive Roxxxy's physical capabilities. And then I'll say, "Hang on, can you demo how she can express love for me and be my loving friend as well?" And see if the sales rep can get through the whole thing without laughing.
You're absolutely right about dual-licensing being one of the most important answers to the OP's question 'What does "Acquire" mean?'
But I disagree that this makes it harder to fork the project. You want to fork MySQL, you fork MySQL. Nobody's stopping you. People have forked it. The only thing is, if you fork it, you're not going to be able to dual-license it and make money from nos-OSS copies sold. Most OSS doesn't have this type of gravy train to support development. PostgreSQL is considered by many people to be better than MySQL, and it doesn't have a dual-licensing system.
When I try to think of projects that really need such an income stream, the ones that spring to mind are Firefox and Ubuntu. Firefox is a very large and complex project, it targets a rapidly changing set of standards, and it includes a lot of features that are needed by a small percentage of users. For instance, I'm really glad that it has good mathml support, but most users don't care about that. If they hadn't had their big revenue stream from search engine placement, maybe they wouldn't have implemented mathml, or wouldn't have done as good an implementation. Well, that would have been too bad, but it wouldn't be the end of the world. There are other browsers out there: galeon, konqueror. Same deal with Ubuntu. Ubuntu is, IMO, significantly better than other Linux desktop distros, and they probably wouldn't have been so good if they hadn't had money from Shuttleworth. But if Ubuntu disappeared tomorrow, I'd still be able to run Linux.
I didn't say that it did.
A Turing machine is of course a mathematical idealization. That doesn't mean that theorems about Turing machines don't tell us useful things. There's a mathematical theorem about mathematically ideal Turing machines that says that a Turing machine can't predict whether another Turing machine will halt. The real-world interpretation of this is that if real-world program A is written in something resembling a Turing-complete language (modulo the finite amount of memory, etc.), then in general it is not practical to write another such program, B, that can take programs like A as input and tell us anything useful about their behavior.
The difference is that it's at least theoretically possible for an automatic computer program to look at a PDF at determine how long it will take to print. That's not even theoretically possible in the case of a PostScript file (again, modulo issues like finite memory, which do not invalidate the result for all practical purposes).
If #1-3 came out the way we don't expect, then we would expect white dwarfs to be destroyed, based on solid theory.
See these two papers: http://arxiv.org/abs/0806.3414 http://arxiv.org/abs/0806.3381
I didn't claim anything about strangelets, just about microscopic black holes. You're also incorrect to refer to the final state of the earth in this scenario as dark matter.
Anyway, see this paper and this paper for a discussion of the possibility of strangelets. The basic arguments against this scenario are: (1) strangelets would be positively charged, so they would be electrically repelled by ordinary nuclei, and (2) the LHC would produce them in smaller numbers than RHIC, which is already in operation.
All security problems are easy to solve if you have users who are sophisticated about security, and motivated to put up with inconveniences. The real world isn't like that.
A proposal like this inevitably requires that the user understand something about the sandbox, and also requires that the user go through various hassles because of the sandbox. They're going to perceive it as a hassle, because the sandbox is going to prevent them from doing things they would otherwise have done. If they're unsophisticated and unmotivated, they'll just see it as something to work around.
Not only that, but this isn't an optimal solution. A flash game has to be a Turing-complete program. A memo doesn't have to. The simple solution is just to stop embedding Turing-complete programming languages in file formats that don't require them. Adobe actually started by designing postscript as a Turing-complete language. That had some unfortunate consequences, since, e.g., you can't predict whether a program written in a Turing-complete language will halt, so in principle you can't predict whether a document will take forever to come out of the printer. The realized that that was a mistake, and when they designed pdf, they intentionally made it not Turing complete. Now we've come full circle, and they've added a Turing-complete language, javascript, back into pdf. That's just bad design. The solution for users is actually pretty easy: if you're using Adobe Reader, turn off javascript.
As a physicist, I'm not losing a lot of sleep over the LHC-ends-the-world scenario. However, I think you've overstated the case a little bit.
Here's what would have to happen for it to be the end of the world:
Evaluating the plausibility of these:
If you could assign probabilities to all of these, they'd be small probabilities. Multiplying all the small probabilities together, you get a very small probability, which is why physicists aren't worried about the end of the world. Nevertheless, it's not completely impossible.
If you want a relatively high-probability end-of-the-world scenario, I'll give you one. Pakistan and India have a nuclear war. Current attempts to model nuclear winter say that such an exchange might actually cause a nuclear winter. Agriculture breaks down world-wide. The human race becomes extinct.
This is irrelevant. The end-of-the-world scenario is one in which a stable black hole becomes gravitationally bound to the earth. You only need one of those, and then the earth is toast.
This is basically correct, except that with very high probability the products of LHC collisions are not quite at rest, they're moving at greater than the earth's escape velocity. The hypothetical danger would come from low-probability events in which black holes were produced at velocities less than escape velocity.
This is a relatively short and nontechnical paper that discusses this. See p. 7. For more detail, see this paper, pp. 16ff and 79ff.
First you have to assume that black holes could be produced at the LHC (which requires some nonstandard physics like extra dimensions), and also that they don't evaporate immediately due to Hawking radiation (which violates basic principles of quantum mechanics). Then you have a black hole that is typically produced at a velocity greater than the earth's escape velocity. If it happens to be emitted in the downward direction, it passes through the earth once without stopping, and therefore accretes a negligible amount of mass. However, the velocities are random, and some small number could be produced with velocities less than the earth's escape velocity. These would oscillate permanently in the earth's gravitational field. They would therefore have unlimited time to do low-probability accretion events, so even though the cross-section is small, they can end up accreting significant amounts of matter.
Your calculation underestimates the radius for capture. This is discussed on pp. 16ff of the second paper. The radius for capture depends on the dynamics. For instance, if you release an atom at rest with respect to the black hole, then it will be absorbed with 100% probability from any radius, because it will simply slowly accelerate toward it; the radius for capture is infinite. In reality you have nuclei that are bound into atoms, and the black hole is zooming past at high speed. The actual radius for capture is therefore bigger than the Schwarzschild radius, but smaller than infinity. They estimate it to be about 10^-16 m, which is small, but not as ridiculously small as the Schwarzschild radius. (Your Schwarzschild is wrong, because the mass isn't equal to the mass of the proton. It's more like a TeV.)
Here is the scientific paper.
No, that's incorrect. There are three quantities that could be relevant: the mass of the primary M, the mass of the satellite m, and the radius of the orbit r. Contrary to your previous statements, m is irrelevant for a highly asymmetric system like the sun and Mercury. What quantifies the strength of the gravitational effects is the unitless quantity (G/c^2)(M/r), where m is the mass of the primary, and r is the radius of the orbit.
This contradicts your previous statements, but it is more or less correct, except that for the caveat about the irrelevance of m in the asymmetric case.
This is incorrect. In the case of Mercury and the sun, we have (G/c^2)(M/r)=3x10^-8. In the case where M is the mass of the supermassive black hole Sgr A*, and r is 1 kpc, (G/c^2)(M/r)=2x10^-10. Therefore the relativistic effects for the binary black holes are smaller by two orders of magnitude.
The orbital radii for these binary black holes is estimated to be 1 kpc. It's true that you could get stronger relativistic effects if you made r smaller ("go much further down"), but in fact r is much bigger, even in proportion to M.
Sure. Of course you have to distinguish between falsifying Newtonian mechanics and verifying general relativity. It only takes one observation to disprove a theory, but proving a theory correct is a whole different matter.
A good (but somewhat out of date) popular-level description of this kind of thing is "Was Einstein Right?" by Clifford Will.
Some examples of things that are still left to test about GR:
TFA tries very hard to highlight the main advantage of Blio over Kindle. If you look at the very first screenshot in the article, it's a color illustration of a human skull from an anatomy textbook. This is an appplication that Kindle can't handle: illustrated textbooks. Kindle is black and white, has a page that's relatively small, doesn't usually (ever?) include illustrations, and doesn't have proper formatting for math.
I think the main advantage of Blio over PDF is this: "Like all e-readers, Blio will adopt some form of DRM and proprietary formatting [...]" Well, that's only an advantage in the publisher's eyes, but they do seem to see it as crucial.
I can also imagine certain categories of books where Blio could do something useful for the reader that can't be done as well by PDF. Consider a public-domain edition of Gray's Anatomy. You can get it here in html format. Now suppose you want to read it on the bus, without carrying a full-size laptop computer with you. If the Blio software is done well, it might adapt itself better to an e-book reader than html or pdf.
TFA says, "Kurzweil and knfb are working with Google to try to make their extensive catalog of printed materials available for Blio." Google is not in the same market as kindle. Amazon sells a relatively small number of recent, profitable books, each of which has to be formatted for the kindle. Google has a gigantic archive of old, public-domain books, none of which is a profitable item in and of itself, but which, aggregated, make something that google might be able to profit from. There is no way that google is going to bring out special e-book editions of all those books.
No, I pointed out that you'd misunderstood those alternative theories of gravity.
Both in your original post and in this one, you seem to be displaying a misconception that the mass of the object is what matters. That's incorrect. What makes a black hole a black hole isn't its mass, it's the fact that the mass is compressed into such a small space. When an ordinary, main-sequence star collapses into a black hole, it actually loses mass in the process. Likewise the mass of Mercury is completely irrelevant to the discussion. You seem to think that Mercury's small mass reduces the relativistic effect on its orbit. That's incorrect. The relativistic precession of Mercury's perihelion is 43 seconds of arc. If Mercury's mass was half what it is, or double what it is, the precession would still be 43 seconds of arc.
Similarly, you could analyze the motion of two human bodies doing a literal waltz, and say that Newton isn't the choreographer. You'd be absolutely right. There would be relativistic effects on the motion of their bodies. That would be absolutely irrelevant, however, because the effects would be too small to measure compared to other effects that you couldn't even quantify, like air currents. Similarly, the relativistic effects on the orbits of these black holes are far too small to measure. The gamma factor for an object moving at 100 km/s is 1.00000006. The difference from 1, which is 5x10^-8, quantifies the size of the relativistic effects. If you take a look at the paper, they weren't even able to resolve the black holes well enough to determine their distances from one another. That means that their orbits are not known at all, much less to a precision of parts per billion. Also, if we assume that their order-of-magnitude estimate of 1 kpc for the orbital separation is roughly correct, each one is swimming in the gravitational field of a whole bunch of other densely packed stars near the galactic core. That effect, which is impossible to measure or calculate with any precision, is going to completely swamp the relativistic effect.
Sure. The error in locating yourself on the earth's surface equals the time error multiplied by the speed of light. Since the speed of light is big, the technique is extremely sensitive to tiny time errors.