Domain: lanl.gov
Stories and comments across the archive that link to lanl.gov.
Comments · 816
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Re:Not Reviewed Yet
I think you missed the point. Their paper has been submitted for peer-review. You can even get it at the XXX place (postscript required) and read it if you want to. The paper is not published yet, but big results like this do not come out of your nostril on a whim. People in the physics community knows about what you are doing and wait for your results. Getting it to the public (and the rest of the world) as early as you can is part of your job else NSF will ask you what they hell are you doing with our money.
So, yeah, you can come up with your nostril theory. And yeah, if you want to get it published, submit it to a journal. Better, you can put it up on the LANL XXX archive site .In fact, you will see once in a while a crazy theory like this appearing there. But don't cry mommy if people laugh at you. -
Re:Not Reviewed Yet
That's fine. If you areconfident in y our results and your results are sufficiently groudbreaking that itdeserves to be told to Joe Public who funds it in the first plac.
You can get the articles (not-reviewed) from the XXX server and decide for yourself how good they are. -
More Information
A quick search of the Fermilab site found some more specifics than in the Washington Post article: a press release, the paper itself: A Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering, and some slides [PDF] from a Fermilab seminar.
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Re:Another day...Science freely admits that it doesn't know what
cause the big bang.
True, but science has made lots of thories as
to why it happened. Including:
1. Time began at the big bang sigularity.
2. Richard Tollman's repeating big bang and
big crunch oscillating universe. Now invalidated
by Entropy consideration.
3. The Ekpyrotic hypothesis. The big bang was caused by a collision between two empty 3+time dimensional in a 4+time dimension
space.
3. A cyclic universe version of the above, ok with entropy
4. Baby universes bud a universe into a new
big bang from the insides of black holes, Lee Smolin.
5. Stephen Hawking No boundary hypothesis.
6. Timeless 4d space, tunnels into spacetime
Of couse we have little chances of proving these
thories at present. However they can make subtle
difference to astrophysics for example to fluctionas in the cosmic background radition. Don't assumption because the isn't a accepted
theory at this point, that there never will be
one. -
Re:The future holds that...
I wonder when they look at quantum computers using light
Quantum computers using photons is a good idea because photons are very well insulated from noise and decoherence, however it is a bitch to make them interact with each other for the same reason, so gates like controlled nots will be next to impossible to implement.
There is, however, a non-deterministic QC based on linear optics where multi-qubit work gates 1/16th of the time or something. I don't expect it will ever be useful for doing real computing though
The paper is here. -
Re:It's the British spelling
Aluminium was the officially accepted spelling here in the US too, until 1925, see the
Los Alamos National Laboratory Periodic Table entry for Element 13
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I'm with Shieber
I'm with Shieber on this. Anyone interested in this competition should have read Lessons from a Restricted Turing Test and the answer in In response to lessons from a restricted Turing test (which I found unconvincing, but YMMV).
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Re:Scientists strike back
If they pull this off, hopefully others will follow the example.
Have you ever surfed to xxx.lanl.gov?
That's been an open forum for e-prints for at least 10 years, and most scientists get their e-prints from there, at least in the disciplines which are covered. The curious thing is they've no comparable features which allow editing. I don't know why this can't be organized over the net, since few editors actually live in a centralized place even now. Perhaps there hasn't been a large enough demand for "moderation" at Los Alamos.
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Background Information
This technology appears to be some I've read about previously (as far back as 98). You can see the Los Alamos press release or an ABC News article (with a pic). Both give a little more background and tech info on the cells.
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Re:Make them helium
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Re:Some people just don't get it...America isn't currrently producing nuclear and (if we believe our government, at least) toxic weapons.
Depends on how you define "producing".
http://www.lanl.gov/worldview/news/releases/archi
v e/98-037.shtml -
Re:A Clarification...The idea being that "somehow" the measurement apparatus is communicating its setup to the distant particle, even though it really can't. This is really disturbing, but probably doesn't have any better explanation than "that's just how it is."
No, I think this paper by Prof. David Deutsch (expert on quantum computing) gives a better explanation:
All information in quantum systems is, notwithstanding Bell's theorem, localised. Measuring or otherwise interacting with a quantum system S has no effect [my emphasis] on distant systems from which S is dynamically isolated, even if they are entangled with S. Using the Heisenberg picture to analyse quantum information processing makes this locality explicit, and reveals that under some circumstances (in particular, in Einstein-Podolski-Rosen experiments and in quantum teleportation) quantum information is transmitted through 'classical' (i.e. decoherent) information channels.
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Xarchives Mirror of the paper [maths here]
There is a mirror of the paper here at the arXiv.org e-Print archive. 11 pages of pdf fun can be found:
HERE
Have fun! -
Re:Clarification...?Can anybody shed light on this? How would this experiment lead to a teleporter??
Well, this will get us into some of the most dangerous neighborhoods of quantum mechanics, but I'll see what I can do.
The quantum entanglement of two particles means that (just as you say) the behavior of one particle becomes perfectly correlated with the behavior of another. In the classic example case, two photons are generated with opposite polarizations. If you can transmit them a distance apart without any interference, then the photons will remain entangled, and a measurement of the polarization of one photon will have immediate implications for the polarization of the other.
Although this is very useful for quantum cryptography, please note that it will NOT allow you to transmit information any faster than the speed of light. To take the cryptographic example, it allows you to generate a safe one-time pad, known to both sides and to no one else, but you still have to transmit your actual message separately.
How can quantum entanglement be used for something like teleportation? Well, let us agree first that if I can produce a perfect quantum replica of a distant system, that is equivalent to teleporting the system. Any given electron (for example) is indistinguishable (in a very deep sense) from every other electron in the universe. So for teleportation all we need to do is reproduce a quantum state. You might say it's more akin to a quantum xerox machine than to most people's classical idea of teleportation.
Okay, so here's how it works: take your two quantum-entangled photons, and instead of simply measuring the polarization of the one nearby, get it to interact with a "target photon" that you want to teleport. If you set things up properly, and observe the outcome very carefully, then the interaction of the two photons on your end will cause the entangled photon - an arbitrary distance away - to enter a new state which is perfectly correlated with the state that your target photon had. Then, once you tell your distant collaborator about the exact outcome of the photon interaction on your side, your collaborator will be able to apply that knowledge to her entangled photon, and produce an exact quantum replica of your original target photon. Voila! Teleportation.
Note again that no faster-than-light communication is enabled by this. You still have to communicate a regular light-speed message between collaborators to get this to work. The actual experiment was carried out several years ago and is old hat by now. The current experiment improves upon previous efforts by entangling so many more (trillions!) particles.
The quantum entanglement of so many particles makes the actual teleportation of a similar number feasible, but one final note - even trillions of particles is many orders of magnitude less than the 10^27 or so particles in your average Starship Captain.
-Renard
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Decoherencedecoherence. Quantum dots don't seem to be very promising in this respect, as the minimum time to complete some elementary operation in them is about 10^-6 sec. while the average time to decoherence is about 10^-3 sec. (from Adriano Barenco "Quantum Physics and Computers," Contemp. Phys. 37, 375 (1996). (quant-ph/9612014). Meaning you can probably do about a thousand basic operations before decoherence makes any potential answers worthless. So what if you can pack billions of these quantum dots on a single semiconductor wafer if decoherence prevents you from getting any form of useful results because decoherence destroys any superpositions you have of your entangled quantum states before you can do anything useful. More promising so far have been nuclear magnetic resonance systems (which can take as much as several hours before decoherence sets in, only trouble is making basic operations with NMR systems takes a relatively long time too) or ion traps (if only it weren't so difficult to actually create and isolate large numbers of trapped single ions!).
Maybe the Purdue group will be able to shield their quantum dots from decoherence better than previous research on such objects has done so far. But as far as I know there is no getting around this; the best anyone can do is compute everything and read out your results before decoherence sets in.
This is not such a big breakthrough, folks. Hold onto your hats. If they can show that they can do operations much more quickly than old methods of dealing with quantum dots, or they can keep decoherence at bay longer than anyone expected, that would be the big breakthrough.
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Re:What total FUD.
like the parent thread, this comment is also off topic, Mod away!
> 30s from POWER ON to completely logged in.
30 seconds to boot Windows, but how long to boot linux on the same hardware? Is there a significant difference? Don't get me wrong, I don't want to start a flamewar. I think it's great for consumers that boot times are coming down because most "non-techies" don't leave their computers on 24/7, and it makes the computing experience much more enjoyable when you don't have to wait long.
It would be really cool if Microsoft could come up with some sort of Flash-ROM boot loader to speed up boot times. I recently found This website featuring a linux system that boots in 3 seconds! Thats faster than my monitor!
Currently my main O.S. is Win2k, which I've been very happy with overall. I've had very few problems, and most of my system crashes are caused by power outages ;-)
On the other hand though, I've had poor support for some of my hardware. Like my ATI all-in-wonder TV tuner card. It works fine in Win9x, but the latest "beta" drivers released at ATI's website crash my computer everytime I load the Television software. I gave up.
Likewise, my old ISA FM-radio tuner card has the same problem. No support in Win2k. Frankly I'm a little worried about upgrading to XP for fear of losing further compatibility. It's a shame I can't somehow preview XP on my current hardware before I decide to purchase.
That is probably the biggest reason why I'm considering a switch to Linux. I already own a copy of VMWare so I'm hoping if I make the switch permanent, it will be less painful.
The other thing I think makes Unix cool enough to consider switching is shell scripting. I'm just a mechanical engineer, but I dig the ability to program simple scripts to automate tasks.
Something I've been dying to do is create a script to record my favorite morning radio show in the morning, convert the file to a compatible audio format, and then burn to audio CD, all before I even wake up! That's just one little project I've been wanting to take on, but I'm sure it would be much easier to do in Unix than windows.
Another task I plan on doing often is execute elaborite Finite element models using Matlab. To do this, it would be cool to be able to remotely log into a faster computer to execute code. That "PCAnywhere" feature of XP that you mentioned gives me the impression that I may be able to do that with XP.
XP does sound like it's come a long way from Win2k, but it will still be tough to decide to stick with Win2k, switch to XP, or switch to Linux. -
Linux Bios has been there, done that
Who needs LILO?
Check out the linuxbios home page
Cold Boot to single-user in under 3 seconds.
Yeah Baby! -
check it out
Not quite as fast, but still very cool
http://www.acl.lanl.gov/linuxbios/
The Dual Athelon setup sounds promising -
check it out
Not quite as fast, but still very cool
http://www.acl.lanl.gov/linuxbios/
The Dual Athelon setup sounds promising -
Re:.8 sec... SO?
Then I suggest you look into this page that is working on a Linux BIOS.
Enjoy. -
Re:Something similar?
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laboratory check; statistics; so what?The change they claim to have detected, based on astronomical measurements, is about 1 part in 10**15 per year. At the end of their paper, they compare with various other methods, and say that the upper limit from laboratory measurements, carried out over a time period of a few months, is 1 part in 10**14 per year. Presumably the lab experiments can be improved with enough funding and motivation --- either the technique can be improved, or they can just take data for years instead of months, or both. I don't really trust the purely astronomical method, although it's true that the resolution of the solar neutrino problem did turn out to involve new physics, not misunderstood astronomy.
You also have to realize they're only claiming a four-sigma result. Four sigma is very convincing if it's really four sigma, but experimentalists never really truly know their error bars that well --- four sigma could really be two sigma, which could be wrong.
And anyway, say they're right. So what? It would be interesting, but I don't think it revolutionizes physics. The link to string theory suggested in the NY Times article is kinda silly, since string theory would only have produced significant effects at times a zillionth of a second after the Big Bang. Also, it's not news that the fine structure constant isn't constant. In quantum field theory, coupling constants are not absolute constants; they have different values on different distance scales. So yes, it's surprising if atomic spectra have changed, but it doesn't bring all of physics to its knees.
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the paperThe paper is here.
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Seek-and-destroy
On http://xxx.lanl.gov/RobotsBeware.html:
Click here to initiate automated "seek-and-destroy" against your site.
Uh, what exactly is that supposed to do??? -
Insightful my ass! Read the damn article
Another glib, uninformed remark rated as Insightful -- two people who obviously didn't bother to read the article. Well that's the Internet for you.
To sum it up: They built this magic superconductor thingy in a vacuum chamber, charged it up and measured the effect at different distances on pendulums of various materials, weighing 10 to 50 grams, hung in a separate vacuum chamber see their rough drawing. When they fired up the superconductor, the pendulums swung away several inches.
The amount of movement varied with the mass of the pendulums, but not the distance or the materials (they mention metal, glass, ceramics, wood, rubber, plastic). Pendulums 6 meters and 150 meters away in a different building, separated by brick walls and an inch of steel, showed identical effects. Even with "trace amounts of iron" a magnetic effect would vary with the square of the distance. But what do I know?
Of course, perhaps I'm prejudiced against people who criticize research without bothering to read it (and moderators who hand out points like candy).
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Re:Magnetics?
My mistake for replying to a reply, rather than taking a quick glance at the article. Since this is being presented on xxx.lanl.gov, that means that he's basically putting out a preprint. I don't see it mentioned anywhere, but it may actually have been submitted for review somewhere.
I guess that the original poster (who made the remark about not submitting to peer review) is unfamiliar with the way that physicists do things these days. They now put articles that are still under review (or even very preliminary results that aren't ready for formal review yet) on preprint servers like xxx.lanl.gov so that people can read them ASAP with the understanding that they're still preliminary. The authors aren't avoiding review; they're just getting the news out quickly through normal channels.
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Re:Paramagnetism?The paper states that the pendula were contained in Faraday cages and shielded from UHF EM radiation. That was, in fact, one of my first thoughts as well.
It will be interesting to see what sort of response (if any!) this work gets from the experimental community. Although lanl is not peer-reviewed, many scientists read the articles (or at leat the abstracts) on a regular basis, and aren't afraid to write responses to papers they think are bogus.
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Re:Paramagnetism?The paper states that the pendula were contained in Faraday cages and shielded from UHF EM radiation. That was, in fact, one of my first thoughts as well.
It will be interesting to see what sort of response (if any!) this work gets from the experimental community. Although lanl is not peer-reviewed, many scientists read the articles (or at leat the abstracts) on a regular basis, and aren't afraid to write responses to papers they think are bogus.
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Re:Paramagnetism?The paper states that the pendula were contained in Faraday cages and shielded from UHF EM radiation. That was, in fact, one of my first thoughts as well.
It will be interesting to see what sort of response (if any!) this work gets from the experimental community. Although lanl is not peer-reviewed, many scientists read the articles (or at leat the abstracts) on a regular basis, and aren't afraid to write responses to papers they think are bogus.
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Re:Paramagnetism?The paper states that the pendula were contained in Faraday cages and shielded from UHF EM radiation. That was, in fact, one of my first thoughts as well.
It will be interesting to see what sort of response (if any!) this work gets from the experimental community. Although lanl is not peer-reviewed, many scientists read the articles (or at leat the abstracts) on a regular basis, and aren't afraid to write responses to papers they think are bogus.
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Re:Paramagnetism?The paper states that the pendula were contained in Faraday cages and shielded from UHF EM radiation. That was, in fact, one of my first thoughts as well.
It will be interesting to see what sort of response (if any!) this work gets from the experimental community. Although lanl is not peer-reviewed, many scientists read the articles (or at leat the abstracts) on a regular basis, and aren't afraid to write responses to papers they think are bogus.
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They are pots of gold
While I am sure journals aren't exactly pots of gold,
Actually, they are. North Holland, the scientific branch of Elsevier is responsible for a large art of the groups profits. As regards the costs: the non-profit American Physical Society publishes high quality titles that are two orders of magnitude cheaper than Elsevier and Kluwer, they charge only the actual const of printing and overhead.
What is more, because of the importance of their titles, they can charge exorbitant subscription fees. Libraries just can't afford to not subscribe. But they increase their fees by amounts of the order of 10% each year, forcing ibraries, with their fixed budget to drop some of the competing journals.
In some fields (e.g. physics) most actual communication of results already takes place through the so called 'preprint servers' e.g. xxx.lanl.gov. Publication in a paper journal only serves as an 'approval stamp', a year after the actual publication.
If someone were to add a peer review system to these preprint servers, you could do away with the paper titles altogether.
The system screws scientists in every way. The only reason it lasts is because of the reputation of the titles, which creates a vicious circle. Sooner or later scientist will have to break this circle.
If scientist don't wake up, I guess they don't deserve better.
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Re:slashdot/kuro5hin model?
No, no, no! If they read about something on a public forum, the original publisher could bring forward the date at which it was submitted as proof of prior art. There's no reason that publishing on a web site would be treated any differently than publishing in a book, provided that you could demonstrate a date of publication. In any case, if they really wanted to patent it, they could apply for the patent before submitting it. Hell, most physicists currently make their articles that are under review available on preprint servers (like http://xxx.lanl.gov and nobody's going around and stealing their ideas. The web was invented by physicists specifically to make it easy for them to make their work available before it was formally published on paper.
This is the key point that so many people are missing. We have very strong evidence that what the biologists are requesting would work becuause the physicists have already tried essentially the same thing and made it work. There's no good reason to think that the result would be any different in biology.
Karma below 50 again. Thanks Karma Kap.
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The crown jewel of publicly available resultsThe LANL preprint server. Despite the somewhat suggestive prefix, it is where a huge number of exciting new results in physics, engineering sciences, astronomy, and mathematics first see the light of day.
Of course, the obvious and oft-mentioned drawback of this kind of thing is the lack of peer review (hey, you get what you pay for), but it's really incredibly neat, and there are precedents for papers on this site being cited in accepted journals.
It is my opinion that peer review isn't necessarily all it's cracked up to be--lots of good papers never get seen because of politics or one really dense reviewer out of, say, ten, and lots of redundant and low-quality papers get published, often in conference proceedings. The journal system has to change. It's way out of hand.
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Re:common publishing practice
The shameful thing isn't that authors have to sign contracts - it's that in the case of scientific journals the authors aren't being compensated and the works that they essentially donate are being restricted.
In a real sense it's worse than that. Science simply doesn't work if the scientists never exhange their ideas; it's much like journalism in the sense that gathering the data is pointless unless it's disseminated in a timely fashion. This is true not only in the sense that publication is important to the authors careers (which it certainly is) but also in that the research doesn't do anyone any good unless the results are made public.
The publishers have figured out that the authors are eager to publish and they can get them to give up their rights in exchange for getting the work published. And then they can turn around and charge outrageous prices for the work because it's critical for other scientists to be able to read it. As long as most of the journals stick together and insist on those rules, the scientists have no choice; they must publish and they must read, so they have to accept the publishers' terms.
The net (and particularly the web) is putting a big kink in that. The physicists have already banded together and forced the publishers to accept that things have changed. Now it's the biologist's turn. If they can create something as powerful as xxx.lanl.gov, they can get somewhere.
Karma below 50 again. Thanks Karma Kap.
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Re:Big Science == Dangerous Science?
When RHIC was being designed a lot of possible disaster scenarios came up. A very serious study was done by some rather well-respected physicists, with the results in a paper that can be found here. They found that the possibility of a black hole forming was very small, and that all of the other disaster scenarios were also very unlikely.
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Quark/Gluon plasma
One of the main reasons that RHIC was developed was to study the quark-gluon plasma. Though there are more energetic acclerators (Fermilab's Tevatron, for example), RHIC is unique because it collides gold nuclei together instead of single atoms or leptons. Even so, most of a gold nucleus is empty space, so when they collide, the nuclei basically pass through each other, but at such a high energy that the bonds that hold the quarks together are temporarily broken, creating a very hot, dense quark-gluon plasma. (BTW, gluons are the carriers of the 'strong' force and hold quarks together to make hadrons such as protons and neutrons). This allows physicists to study the properties of very hot, dense matter, such as the stuff that existed shortly after the big bang, before the era where protons and neutrons were formed. A paper describing the potential physics of it can be found here.
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Re:Yeah, Right
Now we can at least look at a satellite image for the planet and see where the jet stream and fronts are heading.
Satellite images are all very well for short term forecasting, but long term climate forecasters don't really use them. The basic tools here are the mathematical equations of air/ocean flow/interaction, efficient numerical algorithms and supercomputers (ever wonder what the machines at Los Alamos have been doing since they stopped nuking the shit out of the New Mexico desert?)ObSlashdot: They also built a Beowulf cluster to do it with
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Re:Yeah, Right
Now we can at least look at a satellite image for the planet and see where the jet stream and fronts are heading.
Satellite images are all very well for short term forecasting, but long term climate forecasters don't really use them. The basic tools here are the mathematical equations of air/ocean flow/interaction, efficient numerical algorithms and supercomputers (ever wonder what the machines at Los Alamos have been doing since they stopped nuking the shit out of the New Mexico desert?)ObSlashdot: They also built a Beowulf cluster to do it with
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Re:Yeah, Right
Now we can at least look at a satellite image for the planet and see where the jet stream and fronts are heading.
Satellite images are all very well for short term forecasting, but long term climate forecasters don't really use them. The basic tools here are the mathematical equations of air/ocean flow/interaction, efficient numerical algorithms and supercomputers (ever wonder what the machines at Los Alamos have been doing since they stopped nuking the shit out of the New Mexico desert?)ObSlashdot: They also built a Beowulf cluster to do it with
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Not exactly "casting doubts"...
Speaking as a physics graduate student whose PhD thesis will be in cosmology, I would consider it a strong overstatement to say that this paper "casts doubts" on our theories of galaxy formation. The paper (available here) describes the possible effects that magnetic fields could have on inflation. Basically, the tension in cosmic magnetic field lines (which act like big rubber bands - the more you stretch the field line, the stronger the tension in it) tends to accelerate spatially closed regions and decelerate open regions. What's important about this is that even weak fields can have a very strong impact in an open universe, suppressing the acceleration phase of inflation. The addition of the magnetic terms to the FRW metric (which describes how the universe curves) causes makes the universe tend towards flatness in an effect which is potentially much stronger than the amount of matter and dark energy in the universe, to a degree.
However, it would be rather difficult to have a significant net magnetic field in the inflationary era. The universe was basically an incredibly hot, dense soup of plasma at this era and most importantly, is almost totally homogenous and isotropic (ie there are no preferred directions or places in the universe at this time) which would serve to keep magnetic fields somewhat local and randomized. The net result is that there probably weren't large-scale magnetic fields in the early universe.
All in all, it's a very interesting paper, and makes a very valid point - namely, that magnetic fields have the potential to be very influential in a cosmological model! However, it's important to realize that the author wasn't trying to say that the inflationary theory was wrong, just that in theory things could have turned out much, much differently.
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PreprintThe full paper is available at http://xxx.lanl.gov/abs/astro-ph/0012345
It's an interesting prospect, if instead of being an effect of the physically rather dubious "dark energy" (vacuum energy density), or the even more dubious "vacuum state tunneling" of inflation, the apparent flatness of space at large scales might be due to plain old magnetic fields.
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Re:The orbit explainedThe last detailed description of the "probable" orbit of Nemesis was something that might best be described as an attempt to draw a rose without lifting pen from paper. The real beauty of this proposed orbit for Nemesis was more its ability closely fit the very odd pattern that impacts seem to have. They seem to be getting spaced farther and farther apart, and not quite in tune with anything. But there is a real period there; or at least something that looks suspiciously like one. When one sees the impact data, it certainly doesn't look random. Sure, its not quite evenly spaced, but it certainly seems to have a pattern. To some extent, I would think rounding to the nearest million would probably be fine due to the scale of distances the objects travel, and the fair number of variables involved would introduce a fair amount of noise. On the surface it would certainly seem straigh forward enough. Create an fairly simple model of nemesis disturbing the oort cloud and throwing a bunch of rocks towards the sun, and inevitably earth, and compare it to a truly random set, or better yet run each 100 times, and see which looks more like the observed. (This idea is so terribly obvious, I'd be amazed if it hasn't been done.) This is where the elegance of Nemesis comes into it own. Those who would like to blame the oscillations of our solar system through the galactic plane have a fair amount of hand waving attached to their argument. Nemesis, other than the idea the sun might have an unknown companion star, doesn't really. In fact, some current ideas of star formation predict campanion stars to be quite common (hence the earlier link). The fact is since our sun is so unremarkable in an abundance of respects why should it be more remarkable in this? It certainly is an idea worth considering (not that you have denied this, but there are those who do), and it's elegance has quite an appeal. Then on top of it someone just happens to find a star that seems to have all the right properties and is arriving on time? It seems to me, that this might be one of those moments of serendipity.
With reguard to the paper you linked to. First off, it was a letter to the editor, which while not quite the same thing as a letter to the editor of say Discover, is a little bit differnet than a typical paper (In my experience). They typically reperesent an opposing or unrepresented view point. That said, the writer certainly has an interesting and legitimate point of veiw (ie the subjective choice of the researchers concerned with proving their points might create a pattern more agreeable with their arguments). I would argue that their conclusion, the period for mass extinctions is every 2.8 million years as opposed to ~28 million, is likewise flawed. They don't do a lot of justification for what they consider the threshold where a die off become a mass extinction. But the various researchers involved aren't looking for just any mass extinction, they're looking for a specific kind. One that kills nearly everything, everywhere caused by an extraterrestrial object. So while the periodic extinctions they find, may well have a greater significance, or stand out more than those chosen by proponants of the "galactic carousel" or Nemesis, but they really don't address the point of those proponants. Essentially they say, this period for our much larger set of mass extinctions is more statistically convincing, than this subset, which may not have a causal relation. When they do look at the impact crater data, they find that those who came before Muller, Alvarezet al introduced, unwittingly, a significant bias into the data. The writer interestingly implies in their conclusion that this introduction of human bias into the data has totally corrupted it and made it of nominal value. And like all letters to the editor, it's really just an excuse to bust out the asbestos skivvies and shout, "Flame On!"
The arduous task for future geological research is to determine more accurate (preferably non-integer) revised ages for impact craters to eliminate the "haman-signal", which may lead may then lead to a detection of real periodicity.
-- from the conclusion of The "human" statistics of terrestrial impact cratering rate in PDFThe individual who wrote the paper doesn't acctually test any of the models. He just tests the data, determines that it has been tainted to some degree, accidently, then takes his ball and goes home. Ok. But in the end that says very little about the merits of Nemesis, or one of its competitors "the galactic carousel" (our solar system moving in basically a sinusoidal manner through the galactic plane). Again, that's probably why its in the letters section. It's an interesting addition, but really says very little about these models, and more than anything admonishes people to remember where the data they're relying on came from. As long as I'm wandering, I'd just like to say, science journal flames are the best. It also goes to show that what journals print is at least in part determined by who the paper is sent to and if they agree with you. Fermi's paper to Nature on the nature of neutrino's gets regected because everyone knows neutrinos aren't real, they're a bookkeeping method. And I'm pretty sure Ponds and Fleishman(sp?) fired off at least one paper on cold fusion which got accepted. How you get a PhD in Chemistry without knowing about convection will forever escape me. Science journals are like every other human endevour, prone to human error. So while a paper submitted to a peer reviewed journal might garner more of my respect than say a newspaper article, on its face it garners no more than another paper. After all, have not both been peer reviewed? A short anecdote about data. One lab I did way back, hit exactly the predicted value, but the catch was it was +/- 50% of that value. Oops. I took the point of view that we coincidently hit the "book" value, but would could say little if anything due to the unreliability of the data. Turns out the TA's disagreed, while you might not want to build a bridge relying on such data, you can speak about probable trends. Its just one of those things that sticks with you.
As far as divine retribution goes, that was my lame play off Nemesis the Greek Goddess of just retribution. I'm not going to comment on the state of the art in 1 million AD, and I probably couldn't accurately predict 10 years ahead. But that said, it's not going to be one comet from the Oort cloud on an earth crossing trajectory. It will be many many heading towards the sun. Who knows, maybe thousands. This would certainly complicate matters a little. But still, I get your point
:).But if Nemesis does exist, I'll certainly offer it a toast, after all without it, we'd still be rodents foraging for seeds in the brush. Then there is the whole thing about being able to appreciate the vulnerability of yourself, your tribe, whatever with respect to the void, forces of chaos etc, predict the probable form of armeggedon, and quite another to be able to circle Judgement day on your calander.
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The orbit explained...the fairly complicated orbit of this star, too complicated for me to describe here...
According to the links, the star is in an highly excentric elliptical orbit. A pretty good image can also be seen on the space.com link you give. This means, the orbit should be similar to long-period comets. Some graphs showing the orbit of the Hale-Bopp comet can be seen here.
There are also some scientist who think the claimed 30 million year periodicity is not real, but a result of impact crater data rounded to nearest round millions of years. You can get the artcile by entering the number 9701104 in the field here. The paper has been published in an international refereed astronomical journal, Astronomy and Astrophysics
My personal opinion is that Nemesis is propably not lurking out there, but I think it would be worthwhile to check it.
Divine retribution seems to be a million years away
I think that in one million year, out tech can stop the comets that this star might drop from the Oort cloud. Even with present tech, we get a good early warning. A 'killer comet' would probably be detected at least half a year before the possible impact. I'd be much more worried about the Near-Earth Asteroids - they may remain undetected until a few weeks before D-day.
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Why we need a lightweight browser
I say : As a maintenance tool for low end boxes.
(Such as, say, the old PPC I use as a gateway to the net. 3 years old, 180 MHz, 32 meg RAM.)
On such a machine, you need something to
- Browse local help pages;* **
- Search the web for code and rpms;
- Download these onto the machine.
* Bonus if it can read man and info pages, (like gnome-help-browser).
** Double bonus if it supports find string on page (unlike g-h-b).Skipstone is nice (uses gecko and fewer gnome libs than galeon), but I found it still memory hungry and a quite bit slower than g-h-b, or legacy Netscape for Mac on the same hardware.
(The one I tried compiled against Mozilla 0.9. Although there may be good progress since, I wonder if gecko may just not be lean enough... Moz 0.9.2 is still a big memory hog on my other machine -- like 50 meg after a little browsing, where legacy Netscape would stay around 30.)
Encompass uses gtkhtml instead. Can anyone comment on it? Will it do (1), (2) and (3) above? I still need to figure out exactly what dependencies it needs to compile. Anyway, it seems promising -- see this review and some more recent news.
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Re:If only you knew the complexity
We've got some nice machines down at Los Alamos National Laboratory - no SPs, just big Origins. (new toys coming soon...) There's a nice paper on the Los Alamos Coupled Climate Model floating around somewhere describing how the software systems are built from coupled submodels of things like sea-ice and land. Just my $0.02.
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Improvements...Using the floppy drive to boot the system is pathetic. There are several other options, any one of these would be a better, more reliable boot system:
- DiskOnChip (basically flash that looks like an IDE hard drive, usually used for embedded systems, hence the DIP package. Probably expensive.
- A small (8MB or smaller is fine) CompactFlash card. CompactFlash presents itself to the system as an IDE drive interface. So all you have to do is load a bootable filesystem on it.
- A network card that can boot from a LAN. 3Com cards (even the $30 ones) can do this. Many other cards can too. You'll need to figure out how to configure a BOOTP and TFTP servers on your Linux server to get this to work.
- Possibly the cheapest option (if your motherboard permits it) is to use LinuxBIOS to actually put a full Linux kernel into the flash memory already on your motherboard, replacing the BIOS. Presumably, you would build a kernel that supports your network card, so all you would have to do is pass the "root=/dev/nfs,nfsroot=serverip:/dir" option to the kernel at boot time.
Oh yeah, any of these would be faster than reading a kernel image from a floppy disk. Also the machine would be less vulnerable to tampering.
Cryptnotic
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Re:Is it just me or did the author make a mistake?Hi pclminion.
Thanks for the feedback.
You said:
There may, in truth, be a relationship between physical entropy and informational entropy but the relationship has not yet been discovered, as this article would lead us to believe. If it ever is discovered, the form of the relationship will certainly not be as simple as is stated here.
Well, I entirely ommitted Lloyd's calculation for this (as I said in the article). It's too technical to include in an article on a tech enthusiast site like Ars. It's quite followable, mind you, but technical enough that I didn't think it belonged in the article.I invite you to read Lloyd's paper for yourself, and examine his approach. If you find fault with his math and physics, well, congrats!
:) I'd suggest that you let Lloyd know about this, and certainly announce the results of your analysis here. An extra pair of eyes looking at Lloyd's fascinating ideas is good.Cheers,
-GeongeonSPAM@ISBADarstechnica.com
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OpenBIOS / LinuxBIOS
Unfortunately it looks like OpenBIOS hasn't updated in 14 months, and it's hard to tell if they ever actually achieved anything
...
The LinuxBIOS project (http://www.acl.lanl.gov/linuxbios/) looks more promising (originally covered in this slashdot article ... -
Re:apt?
I doubt it could be done, but it would be very cool. A truely awesome hack. I'd pitch in for some beer for whoever does it.
I wonder if any motherboard makers are thinking about LinuxBIOS...