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And before you point out - correctly - that with a sufficiently large energy input we could indeed synthesize all the components that make up "dirt" out of hydrogen, you haven't solved the problem.

Very interesting stuff because The Travelling Salesman Problem is NP-Hard. Perhaps, you were looking for http://physicsweb.org/articles/news/6/3/11/

Wait! You just said that folks at Oak Ridge have repeated experiements "which resulted in a nuclear reaction taking place."

This may be true (not just that he said it, but that they did it), but I would NOT call what they did "cold fusion."

Now you're saying you don't know if cold fusion is real. Which is it? If there's a repeatable experiment, then it's real.

The Oak Ridge claim is of a device that creates very high temperature in a very small space for a very small amount of time, but perhaps enough to support some form of "traditional" hot fusion. It may superficially resemble the "cold fusion" experiment in that they both use a flask of water on a lab bench, but they are very different. Cold fusion claims that fusion can happen at or near room temperature, the Oak Ridge experment does not. Here's the link (for the third time in this discussion, and only the second time by me):

http://physicsweb.org/articles/world/15/4/8

If there's not, then we continue our long twenty year wait of skepticism...

and no, it isn't just taking place in people's basements. folks at Oak Ridge and the russian academy of science have both repeated experiments involving ultrasound ...

I first read about this (sonoluminescence - putting ultrasound into specially prepared water in a spherical beaker causes a small bubble in it to emit light) in the February, 1995 issue of Scientific American. In the column The Amateur Scientist, it tells how to do it. It is quite an interesting phenomenon with no good explanation of what causes it. It had been known decades earlier, but only recently had a method been developed to consistently generate it.

In the last year or two I read an online science article that speculates the light is caused by the bubble becoming so highly compressed and reaching such a high temperature (apparently during the peaks of the ultrasonic wave - the frequency is tuned to the resonant frequency of the beaker, which then focuses all the acoustic energy into a point in the center) that for a brief moment nuclear reactions take place. But last I read this is yet to be verified.

After writing the above (I'd rather just correct it than rewrite it) I did some online research: Nuclear reactions are NOT suspected as the source of light, but it is believed that the setups to make sonoluminescence can momentarily achieve the temperature (a million degrees) and pressure required for fusion.

Here are two relevant links:

http://en.wikipedia.org/wiki/Sonoluminescence Wiki article on Sonoluminescence
http://physicsweb.org/articles/world/15/4/8 "Bubble Fusion" claim at Oak Ridge

It's nothing like the Pons and Fleischmann style cold fusion and has NO relation to it.

I have always been fascinated by them that they have so many incredible applications and multiwalled carbon nanotubes is just one of its many possible ways of using it.

Does anyone know more about this?

Does anyone know more about this?

http://www.research.ibm.com/quantuminfo/teleportat ion/

http://physicsweb.org/articles/news/8/6/10

IMO the core issue here may not be energy production; it's energy storage. Hydrocarbon-based fuels hold more energy than any other form of medium that we know of (eg lightweight batteries, hydrogen, ethanol (does that count as a hydrocarbon?)). All those mediums could be regenerated by adding energy to the end products, but they have limitations. They are either tricky to handle or don't hold enough energy. And up to this point, we don't have the ability to put energy into a system to generate hydrocarbon fuels easily. (And really those fuels are just mediums containing solar energy from long ago.)

However there is the possibility of at least generating CH4 via inorganic means. It's possible to take CO/CO2 from the atmosphere and generate CH4 from an industrial process; all of this could be powered via solar/hydro power. It would seem that if this was feasible, CH4 could be designated as a renewable fuel. Maybe vast amounts of CH4 could spur the faster adoption of fuel-celled cars... Maybe Halliburton and the Sierra Club may end up in a giant group hug over this... Maybe...

I would counter a few of your underlying assumptions with the following references - note that electron tunneling pathways affect protein folding dynamics and that quantum interference plays a critical role in photosynthesis. See also Zeilinger's biomolecule matter-wave interference experiments.

Of course, future computing architectures can incorporate these 'spooky' features.

Better just to zap it with a laser

"This drift meant that the craft were experiencing a constant acceleration directed towards the Sun"

This rules out dust or a higher density inter stellar medium which would affect the probes in a different way.

"This drift meant that the craft were experiencing a constant acceleration directed towards the Sun"

This rules out dust or a higher density inter stellar medium which would affect the probes in a different way.

It is called Pioneer Anomaly: there is a small but systematic departure from the expected motion of the spacecraft. Both of them move as if they were subject to a new, unknown force pointing towards the Sun. This force imparts the same constant acceleration, of about 10^-7 cm / s^-2. Read more: http://physicsweb.org/article/world/12/1/5 and http://physicsweb.org/article/world/17/9/3.

It is called Pioneer Anomaly: there is a small but systematic departure from the expected motion of the spacecraft. Both of them move as if they were subject to a new, unknown force pointing towards the Sun. This force imparts the same constant acceleration, of about 10^-7 cm / s^-2. Read more: http://physicsweb.org/article/world/12/1/5 and http://physicsweb.org/article/world/17/9/3.

This doesn't quite quench my thirst for information: does this mean the probes are still sending radio waves/signals, or just irradiating passively?
Article at physicsweb says:

When the craft were at distances of between 20 and 70 astronomical units, researchers found that the Doppler frequency of microwave signals that were bounced off the craft drifted at a small, constant rate

So, passive it seems.

An article at physicsweb.org says:

When the craft were at distances of between 20 and 70 astronomical units, researchers found that the Doppler frequency of microwave signals that were bounced off the craft drifted at a small, constant rate

Link to the Physics Web article: http://physicsweb.org/article/world/17/9/3

German lab wins linear collider contest

Particle physicists have chosen to base the proposed International Linear Collider on superconducting technology developed by an international collaboration centred on the DESY lab in Germany. The superconducting approach was chosen by an international panel ahead of a rival technology developed at Stanford in the US and the KEK lab in Japan. The eagerly-awaited decision was announced at the International Conference on High Energy Physics in Beijing today.

The 30-km-long International Linear Collider (ILC) will collide electrons and positrons together at energies of at least 500 billion electron volts. Particle physicists will use the ILC to make detailed studies of the Higgs boson and any other new particles, such as supersymmetric particles, that might be discovered at the Large Hadron Collider (LHC). It is envisaged that the ILC will turn on by around the middle of the next decade, about eight years after the start up of the LHC, which is currently being built at CERN in Geneva.

Is this the answer to God, the universe and all that?

Physicists plan £3bn experiment in a 20-mile long tunnel

They call it the God particle: a mysterious sub-atomic fragment that permeates the entire universe and explains how everything is the way it is. Nobody has ever seen the God particle; some say it doesn't exist but, in the ultimate leap of faith, physicists across the world are preparing to build one of the most ambitious and expensive science experiments the world has ever seen to try to find it.

ITER Impasse Illustrates Challenge of Site Selection

...indeed, site selection is often a thorny matter, even for scientific projects not as costly or international as ITER or the next-generation linear collider.

Quick back of the envelope: (+ irresponsible google searches)

• Their guess is that 150kg of Deuterium would run a 1000 MW reactor for a year. (google cache, unfortunatly. Searched for "kg deuterium world energy")
• Ratio of deuterium to hydrogen: 0.015% = 1.5 10^-4
• Total world energy consumption: 403 quadrillion btu/year = ~14 TeraWatts
• Mass ratio of hydrogen in water molecule: ~1/9 So:

  (9 kg water/kg hydrogen)*(14e12 Watts)*(150 kg D/reactor) / ((1.5e-4 D/H)*(1e9 W/reactor)*(1000 kg water/m^3)) =

  1.2 10^8 cubic meters of water processed per year.

  Which translates to a mere .1 cubic kilometers of water needed to be processed per year. Of course, it's late at night, and *my* math might be wrong.. :-)

First: Diesel is cheap because there is less demand than gasoline. Switch all the cars to diesel, and there go your savings. Poof.

Second: I am skeptical of both biodiesel and ethanol from argiculture. I do not believe either produces a net energy gain once ALL factors of production have been accounted for - this includes gas for the equipment to harvest, energy used in processing and refining, oil and energy used in the creation of fertilizers, etc etc etc ad nauseam. Biodiesel lowers the amount of waste in that you can recover energy from that which would have otherwise been thrown away. It is not an energy source. (although; I am welcome to be proven wrong)

The depressing problem is NOTHING comes even CLOSE to oil. Oil is basically free energy lying there to be scooped off/out of the ground. Or, at least, it was - the energy profit from a barrel of oil is falling. It's that energy profit - e.g. quantity energy you get from burning that is greater than the energy that it took to extract the oil.

I highly recommend spending some time on the peakoil.net site and look at WHO it is sounding the alarm bells; there are going to be rough times ahead. There does not appear to be ANYTHING even close.

We need to look at fusion and other nuclear energy sources, and we need to look seriously at other crazy ideas, like extracting energy from the vacuum itself. The question is if viable alternatives are going to arise in time.

Every car out there already has a "hydrogen bomb" under the hood. Contained in some cases by a fragile piece of rubber tubing. You do know gasoline is a "hydrocarbon", right?

I should know better than to feed trolls, however I could not resist. Coaxial, you you know that the superconducting supercollider was cancelled by the Clinton administration, don't you?

I'm too lame to have a sig.

I find this quote interesting...

[Dark matter] is thought to come from a variety of heavy particles that rarely interact with regular matter and can pass through conventional objects unseen.

That sounds like another phenomena of a less scientific nature... ghosts! In some belief systems spirits or souls are more massive or dense then normal matter as well.

If this were true, I would suggest the reason that this experiment didn't find any "dark matter" is because there wasn't any in the vicinity, because the organization and distribution of this dark matter is neither even nor random.

Astronomers believe this arises from the gravitational effect of 'halos' of dark matter around spiral galaxies. (source)

Together, these two results suggest, to me anyway, that dark matter could really be more advanced civilizations or intelligences that we know nothing about.

I think the answer to the dark matter problem and the quantum theory of gravity is one in the same. Our description of gravity is wrong. It has recently been discovered that dark matter is 'missing' from three elliptic galaxies. One would think that on the scale of something as big as a galaxy and with WIMPs being so massive that you ought to detect some quite major effect..

Add that to the fact that the universe's acceleration is getting quicker rather than slowing down and I think we have a strong case for our description of gravity being incorrect.

Simon.

check this: laser can be used as source of entangled photons

For those (like myself) who have little idea about spintronics, Wikipedia has a general article that seemed to explain it to me quite well. Of course, I'm not a physicist so I have no idea whether or not it's accurate although I'm tempted to find out more from the referenced article. PhysicsWeb has more of the same. Apparently this will have far-reaching implications on RAM and cable bandwidth.

Nope, he was cremated. However, his brain could be spinning in its jar

Remember, this was the man that came up with some of the most complicated theories in modern physics,

... except that he plagiarized Dirac's works...

He used 'geddonken' experiments,

Gedankenexperimente, i.e. though experiments.

Bizarre, I've never heard this angle. Most references I find are related to claims in Galison's book "Einstein's Clocks, Poincaré's Maps: Empires of Time ". Everyone else seems to regard this as a bit apocryphal. Still interesting, though.

From the linked book review:

The young Einstein was not, of course, employed in the academic world but in the Swiss Patent Office. And Switzerland, as we know, was a centre of invention and innovation in clock technologies. The patent office at Bern was a clearing-house for new timing technologies, and Einstein's job afforded him a veritable grandstand seat from which to become acquainted with new electro-technological advances.

Given that you have worked on this project, would you care to comment on the other projects such as SUMO and LATOR which also aim to test Einstein's relativity?

I thought all you had to do to get fusion (though not break-even yet, I think) is shake some heavy acetone.

People use these ancient trees to make some of the finest instruments in the world. Physics web has This Article
On "Science and the Stradivarius" A bit long unless your interested in what makes a fine musical instrument sound so...hmm....expensive.

To sum up...Ancient wood sounds Good.

So, this computer program has a large array of variables that represent the current state of the program. A small set of these variables represents the physical brain of some self-conscious individual.

The program starts out with an initial state, and at each iteration of the program it changes one variable based on a set of rules. Now you run the program, and after each step you store the entire array of variables. Run the program until the program "ends," i.e. the end of the simulated universe (let's just arbitrarily choose the end to simplify the experiment. The program runs for a finite number of "steps" for instance.).

OK, so now the program is done running, and you have a bunch of data that represents everything that ever happened in the universe, including everything that ever happened in the brain of the simulated individual. The question is: which represents OUR universe - the program when it's running, or the static data? You're saying that the static data cannot represent the universe, because the simulated individual would not percieve change - but what is the difference? If the individual's brain is represented by finite variables, then the brain cannot *really* tell what it's previous state was. The brain in any one "slice" of the universe contains information that "remembers" the previous states, but that "slice" exists independently, also. When the program is running, the brain has no connection with its "past" other than its own internal state. The state of the brain stored in the block of data is *identical* to the state of the brain when the program is running. What is the difference to the brain?

Of course, this is all assuming that a computer program is a good representation of the universe. Is our physical universe a state machine? Is it "running," or is it a merely a bunch of data? Is there even a way to tell the difference?

In my opinion, theories in physics are getting closer to representing the universe as a set of discrete data that's being acted upon by a set of rules. Check out loop quantum gravity for example. Pretty interesting.

1. Because it's possible
2. It's kinda cool (literally0
3. It keeps overclockers off the streets
4. It gives us something to do
5. It's just interesting
6. Performance!

7. Because liquid nitrogen is "so yesterday".

8. The angst of our inability to get a date is so great that we do not limit ourselves to one form of technology anymore.

9. We won't be happy until we force our CPUs into Bose-Einsten condensate so we can laugh in the face of the uncertainty principle and thereby squeeze another 3fps out of quake.

10. We want to have intelligent discussions with our computers like on the Starship Enterprise (see #8 above).

11. When our friends and family ask us to fix their computers, we'll be able to take care of their fridge and air conditioning too.

12. Human Cryogenics should not be limited to rich people and baseball players.

13. So we can have our own sperm bank, not so much for future generations but so future scientists can map our DNA to understand us.

14. Blue screen of death??? HAAAA!!! Blue screen of COLD!!!

Playboy for Thorne and Private Eye for Hawking, says here.

If they can use this to measure very small forces on very small objects, they might be able to construct some interesting tests of gravitational fields or of quintessence. We all think gravity changes with 1/r^2 and is irrespective of material composition, but do we really know that this rule works for ALL ranges of mass, distance, and material?

Inquiring physicists want to know and this innovation could help them know it.

Hmm, while I do admit that that would be nice there already is PhysicsWeb, BottomQuark, and the Physics Forums. If anyone else can add to this list please do!

There's a VERY detailed article about the whole thing over at Physics Web.

I'll let Weimann (researcher at JILA, Joint Institute for Laboratory Astrophysics, his group was the first to create a BEC) do my talking for me since I only have an overview understanding of the topic:

"Although superfluid helium exists in conditions much warmer than the Bose-Einstein condensate that the Colorado researchers made, it is widely considered a Bose-Einstein condensate, even though it is in a very different sort of system than Einstein was talking about."[1]

Additionally in a Bose condensed gas strong interactions in the fluid state are eliminated making the system easier to understand and measure its properties.[2, 3]

So while it may be arguable whether its a new state of matter, based on how different the state is from a superfluid state, it is important because it makes the study of these systems in detail possible by eliminating many confounding interactions.[2]

I'll let Weimann (researcher at JILA, Joint Institute for Laboratory Astrophysics, his group was the first to create a BEC) do my talking for me since I only have an overview understanding of the topic:

"Although superfluid helium exists in conditions much warmer than the Bose-Einstein condensate that the Colorado researchers made, it is widely considered a Bose-Einstein condensate, even though it is in a very different sort of system than Einstein was talking about."[1]

Additionally in a Bose condensed gas strong interactions in the fluid state are eliminated making the system easier to understand and measure its properties.[2, 3]

So while it may be arguable whether its a new state of matter, based on how different the state is from a superfluid state, it is important because it makes the study of these systems in detail possible by eliminating many confounding interactions.[2]

I'll let Weimann (researcher at JILA, Joint Institute for Laboratory Astrophysics, his group was the first to create a BEC) do my talking for me since I only have an overview understanding of the topic:

"Although superfluid helium exists in conditions much warmer than the Bose-Einstein condensate that the Colorado researchers made, it is widely considered a Bose-Einstein condensate, even though it is in a very different sort of system than Einstein was talking about."[1]

Additionally in a Bose condensed gas strong interactions in the fluid state are eliminated making the system easier to understand and measure its properties.[2, 3]

So while it may be arguable whether its a new state of matter, based on how different the state is from a superfluid state, it is important because it makes the study of these systems in detail possible by eliminating many confounding interactions.[2]

The article seems to highly stress the practical application of this new form of matter.

That is to say the least. It talks about superconductors for maglev trains etc. but in reality the new form of matter is a small blob of gas hanging trapped by lasers in a vacuum chamber. The only connection is that these studies may help us develop better theories about how superconductors work. (The current theories on high-temp superconductors are quite weak). A less popular introduction to Jins work is here, but it's not quite recent.

What are the safety and health issues involved in using this in 'practical applications'?

None. There are no practical applications yet, and when you look at the experiment it's just a submillimeter blob of potassium. The moment someone disturbs the experiment it will disintegrate and fill the vacuum chamber with very dilute potassium gas. Potassium can be dangerous, but there's a thousand times more in the bin they take it from, and I'm not worried about that at all.

Here's a link you can actually click on: http://physicsweb.org/article/world/15/4/7 Now come on show me the karma love ;)

clicky

Hubble's successor is launched in 2010 and any money is definitely better spent on the successor rather than the old Hubble.

The Standard Model of particles says there's no graviton, that's who! :)

You said:
"No, the graviton can very well have an anti-graviton and a photon an anti-photon. The argument against it would be that both things don't have a charge...well neutrinos don't have charges either, but they have anti-particles."

You're misunderstanding why Photons Gluons and presumably Gravitons, if they exist, do not have anti-photons, anti-gravitons etc. and are actually THEIR OWN ANTIPARTICLES. It is not because they have no charge, that's irrelevant, it's because they are Bosons which are particles with integer spin. The chargeless Neutrino and anti-Neutrino are Fermions which have non-integer spin. I would suggest a look at CERN's The Particle Adventure site if you want to learn a bit more about subatomic particles, it's a great site.

However, this being said, there is a very tiny chance you may still be partially right about gravitons (though it's not your fault :] )since we've never actually observed one and there are hints that the Standard Model may break soon (though it must be noted that it is the most sucessful theory at describing our universe ever devised). Then who knows what the superseding theory (supersymmetry? strings?) will say about quanta of gravity.

Disclaimer: IANAP but I do know a thing or two about physics (if there is a physicist here and I've made a mistake in my post please feel free to correct me, though I'm fairly certain the contents are accurate).

You said: "If you do something to one of your photons, it will simply destroy the entanglement" This is wrong!! rubidium does not take any energy away from light therefore the catastrophic chaotic cascading you refer to does not have a chance to occur. See a nicely written article here:> or ENS home, here

Might this hypothesis be tested by using the KamLAND anti-neutrino oscilation detector to see the antineutrinos emitted by the beta decays from the fission products produced by the core(just like it sees them from our fission reactors)? I wonder if anyone has thought of doing this yet.

light, not matter