Believe me, if you've seen the code that runs that site, it's impressive it runs as well as it does. Try to imagine 900M static binaries that take almost an hour to link because of some tiny little code change, because they can't be fucked to make their deployment system deal with dynamic libraries reasonably.
negative mass also implies negative energy according to E=mc^2. I guess that will have to change as well. I want to see how that plays out with nuclear reactions.
That would be how we know it isn't true. Antimatter is already well known to have positive inertial mass/energy.
So if it falls up then General relativity is wrong (or at least has severe problems) and if this is because it has negative mass then something is very wrong with many theories not just GR...?
Well, if it falls up, the equivalence principle is wrong, so general relativity fails, but would likely turn out to be the limit of some other theory. If it has negative mass (generates a repulsive gravitational field), then general relativity is wrong in that gravitational and inertial mass would not necessarily be the same. We *know* antimatter has positive intertial mass.
I suppose you have an alternative that is also consistent with all the observed instances of gravitation and meets your personal criteria for not being 'bunk'? Would you care to enlighten us? Why the heck is this drivel +1 Insightful anyway?
But how does antimatter react to curved spacetime (could it 'roll uphill')...
That's what the experiment in the article is testing. Does antimatter react the same way to an external gravitational field as normal matter, or oppositely?
It'd be Big News if it turned out to be oppositely, though. General relativity describes gravitation in terms of space-time curvature; particles under the influence of gravity alone move along geodesics which only depend on their initial position and velocity. There isn't any way to accomodate different particles feeling gravitation differently in that framework. There are generalizations like Einstein-Cartan gravity to accomodate spin, but that just allows the connection to have an antisymmetric part, and doesn't change the fact that there's only one curvature for every particle to feel. The key axiom of GR is the equivalence principle, which states that, locally, there is no observable difference between gravity an accelerated reference frame. This requires that gravity accelerate every particle by the same amount, independent of any other particle-specific variables.
Put briefly, this has never been tested before, but it'd be a very big surprise if antimatter behaved any differently from normal matter, and would throw most current theories of gravitation out the window. It'd be like a modern-day Michelson-Morley experiment.
and how does antimatter (with mass) curve spacetime? (could it 'outdent' rather than 'indent' it)
That's a different question, and one that would be far more difficult to test. You'd need to gain a few dozen orders of magnitude of precision in measuring these things, or assemble a macroscopic chunk of antimatter somehow.
It'd also be a big surprise for a different reason. This is essentially treating antimatter as having negative mass and thus producing a repulsive gravitational effect. There's no deep reason why this would be mathematically inconsistent with GR, although it would have wacky consequences like perhaps the possibility of stable wormholes and FTL. In technical terms, it violates the weak energy condition. It's also unlikely for a different reason: conservation of momentum in GR requires inertial mass and gravitational mass to be equal, so for antimatter to produce a repulsive gravitational field like this would also require it to have negative intertial mass. It would respond oppositely to ordinary, non-gravitational forces, a positronium atom would have *negative* net mass (the electron and positron masses cancel, and the binding energy makes it negative), and a whole host of other consequences that would be readily observable but haven't been seen. Further, in quantum field theory having negative mass particles would create problems with vacuum stability.
So, both of these are possible in the sense that the experiment hasn't been done yet, so we don't know for sure they aren't true, but either one would invalidate huge swaths of physics and definitely qualify as Big News.
Yeah. Now if I could just find one of those ATI cards with a 64-bit/66 MHz PCI interface and usable open drivers able to do dual DVI-D outputs at 2048x1536 each, I'd be happy...
I've got a 12-processor Sun E4500 that I want to put some graphics boards in and use as a workstation, and I've been having an annoying time finding anything that fits in a PCI slot, has proper open source drivers, and has dual DVI-D outputs. The closest I seem to be able to get is the Matrox G550, but that can only do up to 1280x1024 for DVI-D. This looked perfect, even if I'd have to spend my free time for the next n months writing Verilog for it, until I noticed this.
That's right, you need a closed Windows-only tool to synthesize and download logic for the FPGA. Bleh.:(
Eh? Don't tell me you're of the "Rehabilitation Not Punishment!" mindset:) If you're saying that I don't have a right to demand retribution for the acts committed against me, then you're attempting to invalidate the entire western judicial system. That's a bit ambitious for a slashdot discussion!
Well, yeah, too ambitious to go into here, so I'm not really going to. I certain would invalidate the entire western judicial system, though, because punishment or 'rehabilitation' both depend on the idea that it's legitimate to use force against someone in response to prior wrongful acts, when doing so would only add to the total amount of coercion in the world, rather than preemptively in anticipation of future acts.
I dunno. I'm a fan of the "It Takes a Village..." line of thought. If I had children, I'd certainly want to be informed of something like that, so why would I turn a blind eye to it when it's someone elses kids?
Because other people's children are not their property or that of a 'village' to enforce (rather than advise) such standards on, and further the 'It Takes a Village' presumes universal agreement on how to raise one's children and thus tends to promote conformity to increasingly coercive parenting through soical pressure and shaming of dissenters.
Ok, so replace "shoplifting" with "smoking", or "drinking". There are plenty of activities which are criminalized in western society, yet aren't "wrong" per-say. In such a case I would certainly want the parents of the child to be aware of these acts - especially if they asked about it - but would not want such heavy-handed punishment inflicted on the child.
I'm not inclined to endorse that sort of retributive and paternalistic system of ethics. IMHO, the shoplifting thing would be justifiable as defense of your property but not in terms of seeking punishment or revenge against the child in question. Since in the smoking/drinking example there is no question of defending anything, I do not think I would make any particular response.
Your original statement - that any actions which result in negative consequences are evil - was fatally flawed.
Not my statement and not one I would be inclined to agree with. I'm with you about intent mattering rather than consequences.
But the Prime Directive is perfectly bloody stupid idea in the land of make-believe which is used as a universal excuse to stand aside and help alien states do horrible things to their slaves^Hcitizens. I would expect it to be even worse applied in real life.
Only if you knew they would react that way, but the analogy fails regardless. You have a perfectly legitimate right to stop people from shoplifting in your store, whereas this guy didn't do anything wrong.
Why not just outlaw internet use for those under 18?
Why not just go all the way and lock them all in prison? It'd just be for their own good, and then we could stop from... *gasp*... having sex!
Or maybe you could just try to think a little and realize that teenagers have been fucking each other as long as there's been a human race and it has conspicuously failed to bring about the end of the world thus far. What kind of lives do you think these kids are having that stopping them from using the Internet or from having sex would have a remotely positive impact? Do you *want* to raise a generation of sexually repressed, ignorant Bush-voting lackwits?
-- Andrea, who would never have survived adolescence without the Internet, has been living on her own since she started college at 16, and somehow still managed to stay a virgin until her twenties.
Slashdot Mirror
With Amazon, this isn't really shocking at all. I'm soooo glad I don't work there any more.
So, because some loser can set up a few records in a completely different domain, this is supposed to somehow have some effect on Amazon's DNS?
Believe me, if you've seen the code that runs that site, it's impressive it runs as well as it does. Try to imagine 900M static binaries that take almost an hour to link because of some tiny little code change, because they can't be fucked to make their deployment system deal with dynamic libraries reasonably.
Marry ME!!!!!!!!!!!!!!!!!!!! Lord that was a pleasure to read :)
Uh, sorry, but I'm about as lesbian as it gets. :)
No, the geodesic equation is second-order. If you follow a geodesic backwards in time you get the same geodesic.
negative mass also implies negative energy according to E=mc^2. I guess that will have to change as well. I want to see how that plays out with nuclear reactions.
That would be how we know it isn't true. Antimatter is already well known to have positive inertial mass/energy.
So if it falls up then General relativity is wrong (or at least has severe problems) and if this is because it has negative mass then something is very wrong with many theories not just GR ...?
Well, if it falls up, the equivalence principle is wrong, so general relativity fails, but would likely turn out to be the limit of some other theory. If it has negative mass (generates a repulsive gravitational field), then general relativity is wrong in that gravitational and inertial mass would not necessarily be the same. We *know* antimatter has positive intertial mass.
I suppose you have an alternative that is also consistent with all the observed instances of gravitation and meets your personal criteria for not being 'bunk'? Would you care to enlighten us? Why the heck is this drivel +1 Insightful anyway?
But how does antimatter react to curved spacetime (could it 'roll uphill')...
That's what the experiment in the article is testing. Does antimatter react the same way to an external gravitational field as normal matter, or oppositely?
It'd be Big News if it turned out to be oppositely, though. General relativity describes gravitation in terms of space-time curvature; particles under the influence of gravity alone move along geodesics which only depend on their initial position and velocity. There isn't any way to accomodate different particles feeling gravitation differently in that framework. There are generalizations like Einstein-Cartan gravity to accomodate spin, but that just allows the connection to have an antisymmetric part, and doesn't change the fact that there's only one curvature for every particle to feel. The key axiom of GR is the equivalence principle, which states that, locally, there is no observable difference between gravity an accelerated reference frame. This requires that gravity accelerate every particle by the same amount, independent of any other particle-specific variables.
Put briefly, this has never been tested before, but it'd be a very big surprise if antimatter behaved any differently from normal matter, and would throw most current theories of gravitation out the window. It'd be like a modern-day Michelson-Morley experiment.
and how does antimatter (with mass) curve spacetime? (could it 'outdent' rather than 'indent' it)
That's a different question, and one that would be far more difficult to test. You'd need to gain a few dozen orders of magnitude of precision in measuring these things, or assemble a macroscopic chunk of antimatter somehow.
It'd also be a big surprise for a different reason. This is essentially treating antimatter as having negative mass and thus producing a repulsive gravitational effect. There's no deep reason why this would be mathematically inconsistent with GR, although it would have wacky consequences like perhaps the possibility of stable wormholes and FTL. In technical terms, it violates the weak energy condition. It's also unlikely for a different reason: conservation of momentum in GR requires inertial mass and gravitational mass to be equal, so for antimatter to produce a repulsive gravitational field like this would also require it to have negative intertial mass. It would respond oppositely to ordinary, non-gravitational forces, a positronium atom would have *negative* net mass (the electron and positron masses cancel, and the binding energy makes it negative), and a whole host of other consequences that would be readily observable but haven't been seen. Further, in quantum field theory having negative mass particles would create problems with vacuum stability.
So, both of these are possible in the sense that the experiment hasn't been done yet, so we don't know for sure they aren't true, but either one would invalidate huge swaths of physics and definitely qualify as Big News.
Apparently, Perl's PRNG is the 6883rd smartest human on earth with an IQ of 101.36. Why do people pay attention to tests like this again?
You enjoy your x86 trash, and I'll stick with something civilized, okay?
Yeah. Now if I could just find one of those ATI cards with a 64-bit/66 MHz PCI interface and usable open drivers able to do dual DVI-D outputs at 2048x1536 each, I'd be happy...
I've got a 12-processor Sun E4500 that I want to put some graphics boards in and use as a workstation, and I've been having an annoying time finding anything that fits in a PCI slot, has proper open source drivers, and has dual DVI-D outputs. The closest I seem to be able to get is the Matrox G550, but that can only do up to 1280x1024 for DVI-D. This looked perfect, even if I'd have to spend my free time for the next n months writing Verilog for it, until I noticed this.
That's right, you need a closed Windows-only tool to synthesize and download logic for the FPGA. Bleh. :(
Eh? Don't tell me you're of the "Rehabilitation Not Punishment!" mindset :) If you're saying that I don't have a right to demand retribution for the acts committed against me, then you're attempting to invalidate the entire western judicial system. That's a bit ambitious for a slashdot discussion!
Well, yeah, too ambitious to go into here, so I'm not really going to. I certain would invalidate the entire western judicial system, though, because punishment or 'rehabilitation' both depend on the idea that it's legitimate to use force against someone in response to prior wrongful acts, when doing so would only add to the total amount of coercion in the world, rather than preemptively in anticipation of future acts.
I dunno. I'm a fan of the "It Takes a Village..." line of thought. If I had children, I'd certainly want to be informed of something like that, so why would I turn a blind eye to it when it's someone elses kids?
Because other people's children are not their property or that of a 'village' to enforce (rather than advise) such standards on, and further the 'It Takes a Village' presumes universal agreement on how to raise one's children and thus tends to promote conformity to increasingly coercive parenting through soical pressure and shaming of dissenters.
Ok, so replace "shoplifting" with "smoking", or "drinking". There are plenty of activities which are criminalized in western society, yet aren't "wrong" per-say. In such a case I would certainly want the parents of the child to be aware of these acts - especially if they asked about it - but would not want such heavy-handed punishment inflicted on the child.
I'm not inclined to endorse that sort of retributive and paternalistic system of ethics. IMHO, the shoplifting thing would be justifiable as defense of your property but not in terms of seeking punishment or revenge against the child in question. Since in the smoking/drinking example there is no question of defending anything, I do not think I would make any particular response.
Your original statement - that any actions which result in negative consequences are evil - was fatally flawed.
Not my statement and not one I would be inclined to agree with. I'm with you about intent mattering rather than consequences.
But the Prime Directive is perfectly bloody stupid idea in the land of make-believe which is used as a universal excuse to stand aside and help alien states do horrible things to their slaves^Hcitizens. I would expect it to be even worse applied in real life.
Only if you knew they would react that way, but the analogy fails regardless. You have a perfectly legitimate right to stop people from shoplifting in your store, whereas this guy didn't do anything wrong.
Best ... comment ... ever. :)
Pedoplex? He must have needed a lot of space for his kiddie porn collection. :)
Okay, you've got my 12 years of fvwm beat. :)
Lets say you are an evil terrorist hell-bent on infultrating the American military and wrecking havoc.
I think this would, in fact, make you not evil, but very very good.
Google seems to have an extra ! somewhere in their motto interpreter lately.
Why not just outlaw internet use for those under 18?
Why not just go all the way and lock them all in prison? It'd just be for their own good, and then we could stop from ... *gasp* ... having sex!
Or maybe you could just try to think a little and realize that teenagers have been fucking each other as long as there's been a human race and it has conspicuously failed to bring about the end of the world thus far. What kind of lives do you think these kids are having that stopping them from using the Internet or from having sex would have a remotely positive impact? Do you *want* to raise a generation of sexually repressed, ignorant Bush-voting lackwits?
-- Andrea, who would never have survived adolescence without the Internet, has been living on her own since she started college at 16, and somehow still managed to stay a virgin until her twenties.
Aw, little Susy sent out naked pictures to her friends? Great, let's educate her and her parents, ...
How about just minding your own business and not presuming it's your place to 'educate' everyone who doesn't do what you think they should do?
Since when is .il in Europe?