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Just one computer in a tool box? Check out this.

Incidentally, here's the actual paper, the one referred to from the guy's own web site (minimal), published in Phys. Lett. A... Gravitational Field of Circulating Light Beams.

Beware; it's a little drier than the Boston Globe would like to make it...

I say the actual paper; in fact, this particular paper naturally doesn't make any suggestions of the "Hey, look, this research gives me a way to go back in time and save my father from the evils of cigarettes" type - if it did, it would never have made it into any serious journals. Mallett mentions two papers on his site, one on Bose-Einstein condensation and dark matter, one on this...

He has done other work - this , for example, not to mention work on Hawking radiation and probably a bunch of other stuff. His newest one is apparently "Gravitational Perturbations of a Radiating Spacetime", which looks relevant, not to mention full of terrifying maths. "The principal aim of our study is to understand how gravitational waves are scattered by a background radiating spacetime".

I don't care what the article says. Time travel using this method is simply not possible for a number of reasons. First off, the amount of energy in standard desktop lasers is far too weak to create the necessary effects. Yes, rotating objects or energy currents can have wierd effects on spacetime, even up to the possability of creating closed timelike curves, but it requires neutron star densities, and huge amounts of energy. Secondly, even if he did create the device, he could only (and this is according to the rules of general relativity) go back as far as the time machine's creation. He would still be locked out of the past. Lastly, a discovery like this you would think would be associated with all sorts of pre-print papers. I can only find one from him on the Lanl preprint server .

Of course, my real question is whether the purported alternative to black holes, viz. gravastars (Gravitational Condensate Stars; described here, with an associated /. story here), would do the same thing. It's my understanding that a gravastar would appear (almost?) identical to a black hole from the outside, and so ought to be able to produce this kind of phenomenon, but is it so? Would a star collapsing into a gravastar produce a gamma-ray burst? (I assume that, since they are different from black holes, the details of their formation would be different, as well--perhaps different enough to upset the whole thing.)

The laser-based system hopes to eventually bounce the signals off mirrors on satelites, sending keys anywhere in the world. (For a price... good for diplomats and military I suppose.)

The fiber systems are still in need of a repeater-like device before they can get more significant distances.

My recommendation is: those who are uncertain of their HTML coding abiliities should stick to plain-text and simply give the URLs:

• NASA BPP, proposal summaries (not sure if that was the intended link -- but you can search NASA yourself I suppose>)
• LLNL: Condensed Matter, abstract
• AntiGravity Research Conference
• Ning Lees Research (actually "Skeggs & Ning Li on Gravitational Modification")
• Nasa pumps 600k into research and has had tests
• AEI: John Hutchinson's Theories
• Japanese Anti-Gravity Experiment

That's all I have to contribute. Despite all the debate, "build your own UFO" looks like a fun thing to distract myself with some weekend.

We do have anti gravity.Scientists call it super conductivity. Super Conductivity
A technology NASA has right now which is called gravity shield. NASA only spent 600k on research, but the military could have spent hundreds of millions researching this.

QuoteIn response to the propulsion challenges specified by NASA's Breakthrough Propulsion Physics (BPP) program, the NASA Marshall Space Flight Center proposes to empirically explore the possibility of iinducing gravity modification through Josephson junction effects in magnetized, high-Tc superconducting oxides. Our technical goal is to critically test emerging physical concepts and provide rigorous empirical confirmation (or refutation) of anomalous effects related to the manipulation of gravity by magnetized type-II superconductors. Because the current empirical evidence for gravity modification is anecdotal, we propose, as a first step, to design, construct, and meticulously carry out a discriminating experiment. Our approach is unique in that we will construct an extremely sensitive torsional gravity balance to measure gravity modification effects by radio-frequency-pumped type-II superconductor test masses. Analysis indicates that an effective change in mass of less than 1 percent would be readily detectable by state-of-the-art differential capacitance transducers. The entire project is to be completed in 12 months. If uncontested positive effects can be detected, it would seem to imply a fundamentally new method for creating motion without propellant. This goes directly to the heart of BPP goal 1 which has the stated aim of reducing or eliminating the need for mass ejection from spacecraft propulsion systems."

This was in 1999. Its 2002. That was NASA, a government entity, so if NASA has anti gravity, the military has it too.

Gravity can be manipulated provided you have enough energy to do so, in lab experiments we've shown anti gravity works

Examples
Nasa



Ning Lees Research
Nasa pumps 600k into research and has had tests
Theories

http://www.totse.com/en/fringe/gravity_anti_grav it y/antigrv1.html

As you see, theres many anti gravity experiments which have been done in labs, its its done in a lab, chances are the military has prototype aircraft based on it. With so many theories of how it can be done, do you actually think none of these theories were successful? If any of them were our government would classify it.

AFAIK, thermoacoustic refrigeration still does not beat conventional vapor compression systems for efficiency, but offers a very reliable, environmentally-friendly system with few moving parts. Vapor compression systems may be very reliable in your kitchen, but they prove unreliable in mobile applications subject to severe vibration and shock (e.g., military applications).

One leader in the field of thermoacoustic research is small business Clever Fellows Innovation Consortium (they performed some research for my cubicle neighbor last year). And if you're curious, there is a lot more information on the web; a Google search for "thermoacoustic refrigeration" yielded me 713 hits. Los Alamos National Laboratory has several resources on their thermoacoustics page.

Not so great. Heat pipes work BETTER than copper of similar volume, by a substantial factor. That's why they are used instead of copper for the kinds of applications you are talking about.

Weird but true.

More info here and here.

(Contrary to what the URL might suggest, this is *not* a porn site, but an article preprint server at Los Alamos National Labs)

The preprint of their article is available here if anyone wants to take a look.

Rr, stupid space in the link. Try here.

Perhaps it's an idea whose time has come, however. Or perhaps not. I wonder how different this is from some of the other file systems that the various OSS projects have been looking into, like the "private namespace" filesystems and whatnot. Example? (postscript file). I'm sure that running SQL servers off an SQL-like file system would be a great idea, but don't see how these new ideas would be an improvement upon the traditional one as far as executable files are concerned. If the C:\WINDOWS wasn't such a rat's nest in the first place, you probably wouldn't have to search all over the place for a missing driver file or dll. Directory caching for improving performance is nothing new.

Fine - you keep it in your bedroom ;)

Now, I didn't have time to research this properly, but a quick trip to google turned up this (from a study on alpha particle emissions from radon gas):

"Our observations negate pre-existing assumptions that alpha particles like those emitted by radon and radon progeny exert their genetic changes exclusively through direct traversals of cell nuclei," said project leader Bruce Lehnert of Cell and Molecular Biology (LS-4). "Accordingly, current dosimetry models upon which environmental standards for radon exposure are derived now require serious reconsideration. Our work suggests that even interactions of alpha particles with the fluids that line the lungs may lead to alterations in the DNA of nearby cells."

(And just so as not to be misunderstood by the idle reader, I've got nothing against nuclear rockets, just rockets with nukes).

A quick, back of a napkin calculation shows that a supernovae at around 3 light years would appear roughly as bright as the sun

They agree with you on that (Quote from the article, page 3) :
"At distances larger than a few pc, the only component of the SN emission capable of performing serious damage to the biosphere is the charged cosmic ray radiation [...] UV radiations [...] would produce level [...] smaller than the amount of similar radiations received from the sun"

In their scenario the SN would have occurred around 40 pc (~130 ly) from our solar system.

Their idea is that the cosmic ray may have "speed[ed] up the production of NO, which catalytically destroys large amount of ozone."

The actual damage to any life form would have actually then been caused by the radiations coming from the sun because of a lesser protection by the ozone layer.

Perhaps you should read the article (the scientific paper that is, not the CNN article) before dismissing it as "insultingly ludicrous."

The local bubble is thought to have formed approx. 10 million years ago, not 5-6 billion.

The paper also references works that show that the various subgroups which make up the Scorpius-Centaurus OB association, have produced plenty of supernova's in the past.

Please read the paper before dismissing the theory.

Seems like I've been reading about this for years. Glad to see it finally becoming reality.

Oh darn. So it's a Linux conspiracy to make BIOSes incompatible with Windows! I should have known that!

Linux BIOS

Think Linux Bios. This is slippery slope stuff here. If m$ can control the bios, all hell can break loose.

Any study like this one must be based on a database, which puts the main restriction to its scope. In this case, the database we have used is the Marvel Chronology Project (MCP), which, according to its creator, R. Chappell [7], catalogs every canonical appearance by every significant Marvel character. Thus, the "significant characters" represented by nodes in our network and the "significant appearances" that yield the links in it are, actually, nothing but those characters and appearances currently included in the MCP database.

The Reversal is coming!!! Well, in about 300,000 years, that is.

For those who aren't familiar with this physical phenomenon, the Earth's magnetic field reverses itself (changes polarity) every 300,000 years or so. Rather quick on a planetary time scale, huh?

There are lots of geophysicists interested in this field (paleomagnetism) because it requires some sophisticated modeling of how geodynamos work. Take a look: here for supercomputer modeling of the reversal

I'm not sure which to place my bets on first -- a) the Moon flying away from the Earth, b) the magnetic field reversing, or c) the Earth stopping its spin... Well, ok. It's b). But between a) and c)? I'm not so sure.

The answer is expression templates. Briefly, the result of an overloaded matrix operator is not a matrix, but an expression template specifying the parse tree of operations that need to be computed. The assignment operator is overloaded to take such an expression template and to perform the computations on the resulting object.

No temporary objects made, maximum efficiency, clear syntax (horrors in the library itself though).

I have personally seen it in several places , it's out there but the tech-guys often don't shout about it. I don't know why, whether it is internal pressure, or commercial pressure or interoperability between departments.

QinetiQ the UK's commercial wing of DERA (Defense Evaluation and Research Agency) produced this report: QinetiQ_OSS_rep.pdf. Which is the most pro-OSS report I've read.

The German Government support GnuPG and a few other security related projects.

And of course the NSA have SE-Linux, and have put money into research at the university of Utah.

LANL have some pretty serious Linux clustering.

It is nasty stuff, being chemically similar to calcium. It is therefore absorbed by the body and used in bones.

They took this into account.

If you look at the actual paper (pdf version here), the 9th page shows the formulas they used to calculate the result.

you did not give the right address xxx.lanl.gov, a much better address than arxiv.org. It is the same site but the xxx is just better.

How do "know* something is real that's never been demonstrated?

Zero-point energy has a very testable hypothesis: the Casimir effect. Which has been demonstrated. Check this article or this one .

There have been experimental demonstrations of the veracity of the Casimir Effect, in which two closely spaced parallel plates are driven toward each other by the pressurre created by the ZPF.

It still doesn't get around the laws of thermodynamics, however. Just becasue it's an exotic energy source doesn't mean the rules don't apply to it. It's just beloved by fringe free energy types becasue it involves the magic word 'quantum', and seems to spring from nowhere.

• NIST Center for Neutron Research
• Los Alamos Neutron Science Center, Los Alamos
• High Flux Isotope Reactor, Oak Ridge National Lab
• Advanced Photon Source, Argonne National Lab
• Advanced Light Source, Lawrence Berkley Lab

Quite true. At present String theory doesn't
even seem to be sciences best bet for a
quantum theory of gravity. A theory called
Loop Quantum Gravity, that describes space-time
as network of lines each labelled with a spin,
is rapidly become a much more promising theory.
String theory still requires a space-time for
strings to move in, where as LQG, describes how space time is built. There are already some great results in LQG, including the formula for the Entropy of a black hole, a description of a big bang at zero time, no not a singularity, at that time the universe has a finite but huge curvature equal to 256/(81 G h-bar)

Have a look at the review paper i mentioned above, its excitted
work.

Quite true. At present String theory doesn't
even seem to be sciences best bet for a
quantum theory of gravity. A theory called
Loop Quantum Gravity, that describes space-time
as network of lines each labelled with a spin,
is rapidly become a much more promising theory.
String theory still requires a space-time for
strings to move in, where as LQG, describes how space time is built. There are already some great results in LQG, including the formula for the Entropy of a black hole, a description of a big bang at zero time, no not a singularity, at that time the universe has a finite but huge curvature equal to 256/(81 G h-bar)

Have a look at the review paper i mentioned above, its excitted
work.

Andrew Glassner, "Quantum Computing, Part 1," IEEE Computer Graphics and Applications, July/August 2001, pp. 84 - 92.
A. Glassner, "Quantum Computing, Part 2," IEEE Computer Graphics and Applications, September/October 2001, pp. 86 - 95.
A. Sheane and E. Rieffel, "Beyond Bits: The Future of Quantum Information Processing," Computer, January 2000, pp. 38 - 45.

If you want more of a technical paper, check this out (its still an intro, but not for laymen):
V. Vedral and M. B. Plenio, "Basics of Quantum Computation," quant-ph/9802065, 1998. http://xxx.lanl.gov/format/quant-ph/9802065

As for IBM building the 7 qubit computer, Los Alamos did it a while back...
http://www.lanl.gov/worldview/news/releases/archiv e/00-041.shtml

Andrew Glassner, "Quantum Computing, Part 1," IEEE Computer Graphics and Applications, July/August 2001, pp. 84 - 92.
A. Glassner, "Quantum Computing, Part 2," IEEE Computer Graphics and Applications, September/October 2001, pp. 86 - 95.
A. Sheane and E. Rieffel, "Beyond Bits: The Future of Quantum Information Processing," Computer, January 2000, pp. 38 - 45.

If you want more of a technical paper, check this out (its still an intro, but not for laymen):
V. Vedral and M. B. Plenio, "Basics of Quantum Computation," quant-ph/9802065, 1998. http://xxx.lanl.gov/format/quant-ph/9802065

As for IBM building the 7 qubit computer, Los Alamos did it a while back...
http://www.lanl.gov/worldview/news/releases/archiv e/00-041.shtml

Nope, sorry, this is the only one I know of. But as someone else suggested, you might try looking around http://xxx.lanl.gov/. They may have something there. Good luck!

--GFish4

My brother found this for me not too long ago. The math involved can get rather intense, but I think it 's worth pointing out:

An Introduction to to Quantum Computing for Non-Physicists - Available in PDF, PostScript, and others.

If you do a google search, you probably can find it elsewhere, also.

--GFish4

even though we can factor 15 == 3*5, we are still far away from useful quantum computer applications. the problem is that the coherence time of the atoms is fairly short and only O(10^3) computations can be performed before the system is decoherent. there are many interesting (but rather technical) papers about this subject and how to build quantum computers with quantum dots or any other solid state devices. you can get a glimpse of what is going on at the front of physics at http://xxx.lanl.gov/. just search for quantum+computing...

This is being studied. Check e.g. here.

arctic parsed better than antarctic (a clumsy word) and i just presumed you had penguins in the northern hemisphere as well

- later i thought to check, realised my error and knew i'd be picked up by the slashdot crowd straight away

more on-topic, here's a link to the linuxbios homepage

I'm surprised nobody posted this link yet:

The Linux Bios Homepage

The neutron spectrometer doesn't have a very high energy resolution, but it can tell the difference between high energy and thermal/near thermal neutrons. By thermal neutrons, I mean that they have a kinetic energy of about 1/40 of an electron Volt per neutron. This is the same kinetic energy as a gas phase molecule at room temperature.

The detector has two components, a plastic (hydrogen rich) scintillator doped with the Boron-10 isotope, and a gamma ray detector. The Boron dopant has a large neutron capture cross section at thermal energies. When the Boron captures a thermal neutron, it decays via alpha emission to become Lithium-7. The excited Lithium nucleus then emits a gamma ray which is detected by a separate gamma detector. (Plastics are less efficient at detecting gamma rays than, say, semiconductor based dectectors because they have a lower number density of electrons. You detect gamma rays via electron/photon collisions. Hence, the more electrons per cubic centimeter, the more likely you are to observe a collision.)

Now if a high energy neutron enters the plastic scintillator, it rattles around briefly, colliding with the hydrogen in the plastic, until is slows down enough to be captured by a Boron nucleus. These collisions produce a broad photon pulse with a long tail in the plastic. A couple of microseconds later, the neutron is absorbed by Boron and produces an alpha particle and a gamma ray. (The alpha particle also produces a scintillation in the plastic.)

If a low energy neutron enters the detector, then it is captured by a Boron-10 nucleus almost immediately.

So you can distinguish the two types of neutrons by looking for the delay between the scintillations in the plastic detector and the gamma ray detector. If they occur simultaneously, then you saw a thermal neutron. If there is a significant time delay, then you saw a high energy neutron.

It's been a few years since I've worked with this sort of thing, but I believe I have the fundamentals basically correct.

To expand on this, I would say that if NP-complete problems were solved, we would quickly find PRACTICAL ways of using quantum mechanics to do cryptography. We already have it in labs (see this link). But I believe research would be more focused as Quantum computation would become necessary.

I don't think there will ever be an end to the problems we have to solve. There will always be one class of problems that are unsolved.

This introduction explains how the quantum channel is used by Alice and Bob to negotiate a key. Sure, you could eavesdrop, but having read the stream does not enable you to clone it in a way that would spoof Bob.

One of the named inventors on the patent, Butler Lampson, is a famed CS person who is noted in the Jargon File. Microsoft Research has all kinds of famous computer folk working there, including the inventor of Qsort, the author of VMS, the author of Turbo Pascal (now C#), and others.

Of course, this rights-management is all useless (as any informed antivirus software user can tell you) as long as users have the right to execute whatever code they want on their PCs. No software is safe from attack from an emulator. They'd have to make VMWare and Virtual PC illegal, and make flashing your computer's BIOS to a different BIOS illegal to actually have this work and stop any but the most casual practitioners.

Of course the way the legal system is acting as of late, that may not be too unrealistic a scenario :-(

I've quoted some problematic statements:

"Those scientists who spread anxiety in the eighties.." [ad hominem],
"Precise forecasts that prove correct are a sharp criterion for efficient science. The protagonists of global warming remain empty-handed in this respect in spite of great material and personal expense." [false and unscientific]
"All these predictions have turned out to be untenable. It is accepted that global temperature has risen by 0.5 C in the last hundred years. Yet during the last fifty years the temperature has remained approximately at the same level, even though 70% of the anthropgenic carbon dioxide contribution was injected into the atmosphere during this time. From 1940 to 1970 the temperature fell, and according to satellitite data available since 1979, which are in good accord with balloon data [27], the trend in the lower troposphere has remained at -0.06 C per decade." [misrepresentation of the data, see here]

And it's conclusion is almost gibberish:
"If we bear in mind that the correct forecasts based on the semiquantitative model of solar-terrestrial relations presented here are thinkable only if the sun's varying activity is a dominant factor in climate change, it seems difficult to resist the insight that once again an artificially constructed homocentric position is beginning to rock. A general survey of the given results indicates that climate variations are governed by the sun, not mankind." [artificially constructed homocentric position? solar-terrestrial relations?]

Plus, the graph you cite has been deprecated; the authors of the 1991 study state in a new, revised 1999 report (see below) that solar variation cannot account for the warming trend observed during the 1990s. Solar variation accounts for 50% of the warming, at best, and there is clear evidence of an anthropogenic component.

From the relevant section of one Global Warming FAQ:

Is the recent warming caused by changes in solar activity?

There is no doubt that solar variability plays an important role in global climate change. Interest in the relationship between solar activity and the current global warming was sparked by a paper from the Danish Meteorological Institute, published in 1991. This found that there was a close correlation between a particular parameter of solar activity and surface temperatures, and it is discussed on this page from Stanford. More recently, however, the DMI has published an update of their work, in which they reveal that the increase in temperatures since 1990 no longer correlates with solar activity. They call it 'The fingerprint of the anthropogenic greenhouse effect'. Dr Keller of the Los Alamos National Laboratory has also researched this phenomenon, and he describes the relationship in this lecture he gave in 1998.

The detailed causes of the recent warming trend have been investigated by the UK Meteorological Office using climate models, and are presented here. They found that about half of the warming is caused by solar variability but that, in the second half of the century, these effects have been countered by sulphate emissions from volcanoes (which act to cool the earth). The overall effect of all these natural causes (sun and volcanoes combined) has been quite small. Similarly, two recent studies of ocean temperatures have found that the observed increase is best explained by the effect of greenhouse gases.

The current science seems to support the hypothesis that man-made emmissions of greenhouse gases pose a threat to the stability of the climate.

The question is "What can we do about it?" Clearly, dramatic reduction in fossil fuel usage is in order. The move to renewable solar, wind, hydro, and nuclear power, must be accelerated. Cleaner forms of transportation, such as hybrid-electric and fully-electric cars, must be promoted. Energy efficienct homes and appliances can be implemented. The list goes on.

Let's act now, while there is still time to affect the future.

btw, this is a really cool site Wavelet Compression of Lightning Signatures.

t.

Check out Reginald Cahill and Process Physics: Papers Homepage

Oh really? Show me expression templates like in PETE or operator overloading like in Blitz++ for C. Yumm.

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.