I am sorry, but while relatively well informed, your post is not right on the mark.
First of all, particles of energies higher than 10^20eV have been observed in several experiments since the first observation in Utah in 1991. Just google for ultra high energy cosmic rays (UHECRs) or "oh my god particle". The existence of these particles above the GZK cut-off is not really a disputed fact.
The study and theoretical understanding of these UHECRs are in fact becoming a sub-field of its own today, and I have seen it come up again and again in the last couple of years at conferences.
The point here is that the GZK cut-off only applies to particles originating _very_ far away (more than 50 mega parsecs), since an UHECR produced "locally" could reach us without having a significant change to interact with the cosmic microwave background. The current theoretical puzzlement thus does not have to do with the observation of particles violating some fundamental law, but is due to the fact that people do not know of any "local" source in our neighbourhood which could produce particles of such high energies. There is certainly no indication that this affects the SM, and certainly not the big bang theory.
Of course, as a particle physicist, I would *hope* that the effects are due to physics beyond the SM, but I would guess it is more likely that the answer is going to be that we do not understand all astrophysical objects as well as we had hoped.
It might have been an inherrent property of all particles (except the massless photon and gluon), but it turns out that the nature of the weak force (normally known from beta decays of nuclei) conflicts with this.
The real understanding of this problem requires knowledge of Quantum Field Theory, but the gist of the problem is as follows:
All known matter particles (fermions) as well as the particles that mediates the weak force (the W and Z) behaves in experiments as if they have masses. However, if they actually do have masses the theory breaks down (it becomes non-renormalizable, and gives non-sensical answers such as "that decay have a branching ratio of 500%". It becomes a bit like sports-commentators, I guess).
The proposed solution to this conundrum, and the one the LHC and ATLAS will try to verify, sounds kind of like a lawyer finding a legal loophole when you first hear it. In essence it is: "All particles are really massless, but some of them behaves as if they have mass". The way to accomplish this is by the so-called Higgs Mechanism, in which particles acquire masses the same way that a light-weight guy walking in a waist-high pool will feel as much or more difficulty walking as a really fat guy walking on dry ground: All particles move around in a soup of Higgs particles and thus acquire the appearance of being massive due to their interactions with this Higgs-soup.
I thought it was kind of cheesy back when I first heard about it, but later I realised that similar effects already are known to happen elsewhere in nature, which kind of makes it more acceptible (for instance, those familiar with the Meissner effect for superconductors might recall how the otherwise massless photon acquires the appearance of mass inside superconductors due to the presence of a soup of electronic cooper-pairs).
But we will have to see when the LHC starts!
ps. I am actually a member of the ATLAS collaboration. Go magnets!
Actually a less fancy version of this technique was already used on mars pathfinder where several images were taken of the same objective and then combined to obtain better resolution.
"Superresolution image processing is a computational method for improving image resolution by a factor of n[1/2] by combining n independent images. This technique was used on Pathfinder to obtain better resolved images of Martian surface features."
Your logic is fine, but you are overestimating the effect you mention if you really think that it "solves the mystery".
500 users out of 25000 means that you have at most taken the 2 percent highest performers out of the CPU pool. If we assume that those 2 percent have computers that are 5 times as powerful as the average computer, then we have lowered the average performance of the CPU pool by roughly 9%.
This 9% systematic effect will lower the reported performance superiority of around 5000% of the GPU vs. the CPU to something like 4500%. I.e. it doesnt change the result at all (which seems to be that GPUs kick ass for these applications).
I agree, it is rather funny. My favourite is so far:
/usr/src/linux/arch/sparc/kernel/ptrace.c: /* Fuck me gently with a chainsaw... */
But I also stumbled upon this little gem in/usr/src/linux/net/core/netfilter.c:
/* netfilter.c: look after the filters for various protocols. * Heavily influenced by the old firewall.c by David Bonn and Alan Cox. * * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any * way. *
Anyone knows if there is a story behind this comment? Is it a private joke on taco, or did he piss them off?
But regarding your "I think 99.95% is about as close to dead-on-balls-accurate as it gets with our current knowledge of the universe", allow me to take this opportunity to point out that Quantum Electrodynamics (the extension of electromagnitism and quantum mechanics into a quantum field theory) surely is the most accurate theory we have today.
In some circumstances its predictions have been verified to an astounding 14-15 decimal places! (Thats something crazy like 99.9999999999995%).
Of course, the day we combine quantum field theory with Einsteins general theory of relativity, that will be quite something. I for one hope it happens in my lifetime (and plan to go on a month-long rampage of drinking, dancing & singing bad karaoke in the streets if it happens).
> Too bad he's not involving himself figuring out how to make 50% efficient solar panels.. > with him on the darpa team, they could probably be making these panels for $1.00 within > 3 years. Good luck to him though.
One could always hope, but so far he has only proven that he is extremely good at absorbing and using existing knowledge.
Whether he will also be able to come up with new insight and fresh solutions remains to be seen. One can always hope of course!
(Noticed how I tried really hard to avoid the word "innovate"... and failed in the end of course).
Observing particles moving at 99.9% c is not so amazing as it sounds. First of all we routinely accelerate matter to great speeds for use in particle physics experiments (in places such as CERN, SLAC, FermiLab, Brookhaven, etc.).
As an example, the LEP accelerator at CERN which was used in the period 1989-2000, acceleratod electrons to about 99.9999999977% c.
But even outside the laboratories we have previously observed even larger speeds. The UHECR (ultra high energy cosmic rays) whose origin is still a mystery seems to consist of protons moving at speeds of 1-1^(-22) = 0.9999999999999999999999 c.
Furthermore, it might seem like we need absurd accuracies in our measurements to discern the numbers from each other. But we don't really - the speed of the particle is practically the same when 0.99c and 0.99999c are compared, but things like the momentum of the particle will still differ wildly. For the curious, the formula is: momentum = m*v/sqrt(1-(v/c)^2).
Why do you think that China is the most polluting economy? Of course having ~1 billion inhabitants it is going to be quite high up there, but the worlds most polluting economy must in all fairness said to be the US, where 4% of the worlds population produce 25% of the worlds greenhouse gases (according to this link)
Of course wikipedia tells us that China comes second.
True, and this makes it difficult for people who want to calculate protein folding or predict next weeks weather. But for particle physics computations we hardly need any communication between nodes at all. Rather, we need something simulated a huge amount of times (as in, "simulate this proton-proton collision 10 billion times") or "apply this fancy pattern recognition algorithm to each of these billions of events we took this week". Particle physics computations are to a large extent parallel in nature from the beginning.
The grid related problems faced in particle physics are of another nature, such as ensuring that the data is copied around the various grid facilities as needed and of ensuring that even if a given node fails to execute its job for some reason it is rerun elsewhere automatically - that sort of thing.
> There are no privilaged inertial frames, but the > Earth is not in an inertial frame. If it was, it > would be shooting off in a straight line at a > constant velocity.
Actually "straight line" is also undefined in this context. A frame of reference attached to the earth, is indeed not an intertial frame. But the way to see this is because the laws of Newton are invalid if expressed in the coordinates of such a frame (even in the unrelativistic limit).
OK, I dont usually do "me to" posts, but Hell Yeah, its ridiculous the number of hours I spent on those. I can even today remember the sound+graphics of the exploding bananas.
> What about those of us who want to try the OS out > before we pay for it? Some of us would like to > make sure the OS works 100% on our systems before > shelling out cash. Sidenote: I've paid for RedHat > and Debian CD's and paid for Mandrake, I'm just > saying though..
Well, you will have to use your hunch, or wait a couple of weeks (...oh the humanity!).
But they are creating artifical scarcity by limiting the release of the ISO's to a few who paid money. They are depriving me of access to the information (ISO's) because I do not want to join the "club" and pay a fee.. How is this OK? Information wants to be free!
Newsflash: Information is not sentient and doesn't want anything. Repeating something ad nauseum doesn't make it true. Not even if RMS thinks so.
Despite the great efforts Mandrake takes to only ship GPL'ed software and providing the results of their hard labor for free, some people will always complain.
Let me ask you this: What did YOU contribute to the open source world (or free software, since you are parrotting RMS). And if you did contribute anything significant, where can I download it (using bandwidth that YOU paid for). And where can I go and bitch and complain if it doesn't live up to my ethical standards?
> I have to wait for community written software in > the form of an ISO because I am poor? Isn't that > creating false scarcity? Information wants to be > "free". Charge for support, not our software.
The "support" in this case is that mandrake took the time to put all the bits and pieces together.
And not to be rude, but please dont make it sound like having to wait a few weeks for a cutting edge distribution is a great injustice. You still get it for FREE, even though mandrake put millions into it.
Slashdot Mirror
I am sorry, but while relatively well informed, your post is not right on the mark.
First of all, particles of energies higher than 10^20eV have been observed in several experiments since the first observation in Utah in 1991. Just google for ultra high energy cosmic rays (UHECRs) or "oh my god particle". The existence of these particles above the GZK cut-off is not really a disputed fact.
The study and theoretical understanding of these UHECRs are in fact becoming a sub-field of its own today, and I have seen it come up again and again in the last couple of years at conferences.
The point here is that the GZK cut-off only applies to particles originating _very_ far away (more than 50 mega parsecs), since an UHECR produced "locally" could reach us without having a significant change to interact with the cosmic microwave background. The current theoretical puzzlement thus does not have to do with the observation of particles violating some fundamental law, but is due to the fact that people do not know of any "local" source in our neighbourhood which could produce particles of such high energies. There is certainly no indication that this affects the SM, and certainly not the big bang theory.
Of course, as a particle physicist, I would *hope* that the effects are due to physics beyond the SM, but I would guess it is more likely that the answer is going to be that we do not understand all astrophysical objects as well as we had hoped.
It might have been an inherrent property of all particles (except the massless photon and gluon), but it turns out that the nature of the weak force (normally known from beta decays of nuclei) conflicts with this.
The real understanding of this problem requires knowledge of Quantum Field Theory, but the gist of the problem is as follows:
All known matter particles (fermions) as well as the particles that mediates the weak force (the W and Z) behaves in experiments as if they have masses. However, if they actually do have masses the theory breaks down (it becomes non-renormalizable, and gives non-sensical answers such as "that decay have a branching ratio of 500%". It becomes a bit like sports-commentators, I guess).
The proposed solution to this conundrum, and the one the LHC and ATLAS will try to verify, sounds kind of like a lawyer finding a legal loophole when you first hear it. In essence it is: "All particles are really massless, but some of them behaves as if they have mass". The way to accomplish this is by the so-called Higgs Mechanism, in which particles acquire masses the same way that a light-weight guy walking in a waist-high pool will feel as much or more difficulty walking as a really fat guy walking on dry ground: All particles move around in a soup of Higgs particles and thus acquire the appearance of being massive due to their interactions with this Higgs-soup.
I thought it was kind of cheesy back when I first heard about it, but later I realised that similar effects already are known to happen elsewhere in nature, which kind of makes it more acceptible (for instance, those familiar with the Meissner effect for superconductors might recall how the otherwise massless photon acquires the appearance of mass inside superconductors due to the presence of a soup of electronic cooper-pairs).
But we will have to see when the LHC starts!
ps. I am actually a member of the ATLAS collaboration. Go magnets!
Actually a less fancy version of this technique was already used on mars pathfinder where several images were taken of the same objective and then combined to obtain better resolution.
"Superresolution image processing is a computational method for improving image resolution by a factor of n[1/2] by combining n independent images. This technique was used on Pathfinder to obtain better resolved images of Martian surface features."
Taken from the abstract of this article:
Damn, I read that as "TV Really Might Cause Atheism".
How disappointing!
Your logic is fine, but you are overestimating the effect you mention if you really think that it "solves the mystery".
500 users out of 25000 means that you have at most taken the 2 percent highest performers out of the CPU pool. If we assume that those 2 percent have computers that are 5 times as powerful as the average computer, then we have lowered the average performance of the CPU pool by roughly 9%.
This 9% systematic effect will lower the reported performance superiority of around 5000% of the GPU vs. the CPU to something like 4500%. I.e. it doesnt change the result at all (which seems to be that GPUs kick ass for these applications).
I agree, it is rather funny. My favourite is so far:
: /* Fuck me gently with a chainsaw... */
/usr/src/linux/net/core/netfilter.c:
/* netfilter.c: look after the filters for various protocols.
/usr/src/linux/arch/sparc/kernel/ptrace.c
But I also stumbled upon this little gem in
* Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
*
* Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
* way.
*
Anyone knows if there is a story behind this comment? Is it a private joke on taco, or did he piss them off?
I agree - Einstein is the man.
But regarding your "I think 99.95% is about as close to dead-on-balls-accurate as it gets with our current knowledge of the universe", allow me to take this opportunity to point out that Quantum Electrodynamics (the extension of electromagnitism and quantum mechanics into a quantum field theory) surely is the most accurate theory we have today.
In some circumstances its predictions have been verified to an astounding 14-15 decimal places! (Thats something crazy like 99.9999999999995%).
Of course, the day we combine quantum field theory with Einsteins general theory of relativity, that will be quite something. I for one hope it happens in my lifetime (and plan to go on a month-long rampage of drinking, dancing & singing bad karaoke in the streets if it happens).
> Too bad he's not involving himself figuring out how to make 50% efficient solar panels..
> with him on the darpa team, they could probably be making these panels for $1.00 within
> 3 years. Good luck to him though.
One could always hope, but so far he has only proven that he is extremely good at absorbing and using existing knowledge.
Whether he will also be able to come up with new insight and fresh solutions remains to be seen. One can always hope of course!
(Noticed how I tried really hard to avoid the word "innovate"... and failed in the end of course).
Observing particles moving at 99.9% c is not so amazing as it sounds. First of all we routinely accelerate matter to great speeds for use in particle physics experiments (in places such as CERN, SLAC, FermiLab, Brookhaven, etc.).
As an example, the LEP accelerator at CERN which was used in the period 1989-2000, acceleratod electrons to about 99.9999999977% c.
But even outside the laboratories we have previously observed even larger speeds. The UHECR (ultra high energy cosmic rays) whose origin is still a mystery seems to consist of protons moving at speeds of 1-1^(-22) = 0.9999999999999999999999 c.
Furthermore, it might seem like we need absurd accuracies in our measurements to discern the numbers from each other. But we don't really - the speed of the particle is practically the same when 0.99c and 0.99999c are compared, but things like the momentum of the particle will still differ wildly. For the curious, the formula is: momentum = m*v/sqrt(1-(v/c)^2).
For your convenience here is a sorted list of people according to the votes they have gotten so far:
1 151 Torvalds
2 120 Turing
3 105 Stallman
4 101 Ritchie
5 101 Berners-Lee
6 78 Thompson
7 60 Stroustrup
8 52 Kernighan
9 47 Rossum
10 45 Oreilly
11 42 Joy
12 41 Hejlsberg
13 39 Gay
14 33 Fielding
15 30 Tanenbaum
16 30 Gosling
17 29 Booch
18 28 Pike
19 27 Brin
20 25 Cutler
21 23 Bricklin
22 19 Knopper
23 19 Fowler
24 18 Icaza
25 17 Bosworth
26 15 McClannahan
27 15 Frankston
28 14 Kapor
29 14 Bloch
30 12 Ferguson
31 12 Bray
32 8 Brand
33 6 Box
34 5 Patrick
35 5 Kertzman
36 5 Hillis
37 4 Winblad
38 4 Myhrvold
39 3 Paoli
40 2 Brilliant
Why do you think that China is the most polluting economy? Of course having ~1 billion inhabitants it is going to be quite high up there, but the worlds most polluting economy must in all fairness said to be the US, where 4% of the worlds population produce 25% of the worlds greenhouse gases (according to this link)
Of course wikipedia tells us that China comes second.
True, and this makes it difficult for people who want to calculate protein folding or predict next weeks weather. But for particle physics computations we hardly need any communication between nodes at all. Rather, we need something simulated a huge amount of times (as in, "simulate this proton-proton collision 10 billion times") or "apply this fancy pattern recognition algorithm to each of these billions of events we took this week". Particle physics computations are to a large extent parallel in nature from the beginning.
The grid related problems faced in particle physics are of another nature, such as ensuring that the data is copied around the various grid facilities as needed and of ensuring that even if a given node fails to execute its job for some reason it is rerun elsewhere automatically - that sort of thing.
It appears you are right, a search on /. old stories on "mandrake" didn't turn up anything.
I probably read it at linux weekly news then or somewhere else...
It is an interesting interview, but it was published more than a month ago on may 12th.
/. back then).
(and I think it was also covered on
Mandrake doesnt use the "evil XFree". They use the ~4.3 XFree version without the new annoying license.
And they were one of the 4 (i think) linux companies that stood up and made a point of not using XFree 4.4 due to the new licences.
> There are no privilaged inertial frames, but the
> Earth is not in an inertial frame. If it was, it
> would be shooting off in a straight line at a
> constant velocity.
Actually "straight line" is also undefined in this context. A frame of reference attached to the earth, is indeed not an intertial frame. But the way to see this is because the laws of Newton are invalid if expressed in the coordinates of such a frame (even in the unrelativistic limit).
OK, I dont usually do "me to" posts, but Hell Yeah, its ridiculous the number of hours I spent on those. I can even today remember the sound+graphics of the exploding bananas.
>> However, Bruce Perens, a former Debian Project Leader and author of the Open Source Definition, wasn't as quick to compliment Red Hat.
In a public post, Perens wrote, "I have a large customer who... <<
The public post mentioned was actually this Slashdot comment here.
> What about those of us who want to try the OS out
> before we pay for it? Some of us would like to
> make sure the OS works 100% on our systems before
> shelling out cash. Sidenote: I've paid for RedHat
> and Debian CD's and paid for Mandrake, I'm just
> saying though..
Well, you will have to use your hunch, or wait a couple of weeks (...oh the humanity!).
Huh? I am a standard member and I am downloading the 3+1 cd's of 10.0 official just fine.
Please go back and check the links (official is a couple of lines below community on the mdk club torrent page).
Also, please double check these things before coming with these serious (and unfounded IMO) allegations.
Newsflash: Information is not sentient and doesn't want anything. Repeating something ad nauseum doesn't make it true. Not even if RMS thinks so.
Despite the great efforts Mandrake takes to only ship GPL'ed software and providing the results of their hard labor for free, some people will always complain.
Let me ask you this: What did YOU contribute to the open source world (or free software, since you are parrotting RMS). And if you did contribute anything significant, where can I download it (using bandwidth that YOU paid for). And where can I go and bitch and complain if it doesn't live up to my ethical standards?
> Is there any kind of objective review of these two ?
I think both of these two nice distro's beat each other in certain areas.
So which one is better will depend heavily on what you want to use it for.
Personally my needs are better satisfied by mandrake than by debian, but as stated YMMV.
> I have to wait for community written software in
> the form of an ISO because I am poor? Isn't that
> creating false scarcity? Information wants to be
> "free". Charge for support, not our software.
The "support" in this case is that mandrake took the time to put all the bits and pieces together.
And not to be rude, but please dont make it sound like having to wait a few weeks for a cutting edge distribution is a great injustice. You still get it for FREE, even though mandrake put millions into it.
Danish: "Ses vi den 17. april 2004?".
Just to nitpick: How much smaller than a proton is an electron?
Answer: we dont know, since the radius of an electron has so far been too small to be measured.
Unless you mean their masses of course - then we are talking a factor of 2000.