Slashdot Mirror

How do you get rid of nasty infections? Autoclave! Heat things up enough to smoke out all those nasty hoomins and things can get back to normal around here.

As for volcanos, it looks like the production of CO/CO2 in eruptions can have an effect on global warming. It turns out, however, that the ash/SO2 released into the atmosphere has a cooling effect. It also helps scatter sunlight, allowing for more robust tree growth which leads to more carbon being taken out of the atmosphere.

So, all we need to happen is for the Yellowstone (NetBSD) volcano to erupt (supposed to be violent enough to wipe out hoomanity) and fill the skys with enough ash and SO2 to bring on Fimbulwinter to slow down global warming. Or have a big rock smack into the Indian Ocean.

Here's a mirror of the article:

gnuse.cx

Enjoy!

Here's a link about the myth of flightless bumblebees. Yup, it's a myth.

The IOP did a salery survey of qualifications a couple of years back

http://physicsweb.org/article/world/14/10/9

Damn depressing considering with my Masters, Im bottom of the heap

There's an article with more information on using diamonds as superconductors. If the techniques for this hold with these artificial diamonds, we could be seeing a great leap forward in computing power within the next few years.

IANAPhysicist, but its recently been suggested here that quantum mechanics might allow us to extract energy in situations involving a single heat bath.

In fact, American workers are more productive per hour than their German and British counterparts.

Whoever modded the parent up got trolled hard.

However, if fuel cells were used to recharge the batteries, there would be significant reductions in emissions from the power-generation and transport industries.

Also, that appears to be a five year old letter to the magazine. A more recent article sums up all the alternatives for 'green' motoring. As another article from the same issue states, there are some countries where these alternatives make more sense - e.g. Iceland, rich in geothermal and hydroelectric energy, and with no fossil fuel reserves whatsoever.

One other thing to remember - you have a much higher concentration of voters in cities than in the countryside. Spreading that pollution thinly over a large area may look as bad to you as having it concentrated on busy roads, but to many of the people along the busy roads, not in their backyard is nearly as good as not at all.

However, if fuel cells were used to recharge the batteries, there would be significant reductions in emissions from the power-generation and transport industries.

Also, that appears to be a five year old letter to the magazine. A more recent article sums up all the alternatives for 'green' motoring. As another article from the same issue states, there are some countries where these alternatives make more sense - e.g. Iceland, rich in geothermal and hydroelectric energy, and with no fossil fuel reserves whatsoever.

One other thing to remember - you have a much higher concentration of voters in cities than in the countryside. Spreading that pollution thinly over a large area may look as bad to you as having it concentrated on busy roads, but to many of the people along the busy roads, not in their backyard is nearly as good as not at all.

Fuel cells are a critical technology because of their high efficiency and low impact," said Charles Chamberlin, co-director of the Schatz Energy Research Center at Humboldt State University.

I love this stuff. Fuel cells are going to save the planet!

Or maybe not ...

Transport systems currently produce more pollution than power stations, and alternative solutions were mentioned in the letters by Ian Hurley (April) and Cedric Lynch (May). If battery-powered electric vehicles were adopted, the need to recharge them using electricity from conventional power stations would produce about as much carbon dioxide as the vehicles that they replace. Emissions of sulphur dioxide would also rise by up to 85%.

Don't get me wrong, I would love to see fuel cells in mass production, cleaner air and water, etc.

But we are not there yet, and nothing is gained since yes, running the vehicle from a fuel cell will make the tree huggers happy, but manufacturing/charging fuel cells is very dirty.

Now invent a system to charge fuel cells by solar power and you can hire Bill Gates as your butler.

Once again, the story has been posted on physicsweb two days ago.

No ground breaking crypto solving or Beowulfs yet but some solid calculations going on.

This gives you a lot of faith in the kind of screening they do at the national weapons labs and at Homeland Security!

You can actually also get superfluid properties with garden variety helium-4. Below 2.2 K, liquid helium-4 undergoes a phase change to the (confusingly labelled) helium-II. Helium-II is currently believed to be a combination of superfluid and 'conventional' helium-4, so it can sneak out of containers, too. Here's a very brief blurb.

Also on Psychics Web

Quantum mechanics is a natural result of relativity. To say that relativity does not preclude quantum entanglement because it doesn not consider quantum phenomenon is absurd. It is because quantum entanglement cannot transmit information faster than light that it does not preclude it. Look it up. I agree that Einstein was wrong about deterministic reality. He never seemed to be able to accept the logical conclusions of quantum mechanics.

As far as the often-touted FTL phenomenon is concerned you might want to read this. No thing has gone fster than light yet.

Three days ago

There is another story about this on PhysicsWeb. The story is short, but has some more technical details.

The team estimates that about 10 billion neutrons are produced, which corresponds to an energy output of about 4 mJ.

..robbed of her credit and too dead to fight the point: more details here

Posthumously slagging off the person who gifted him a Nobel about her dress sense, what a wanker!

Granted, they may have found a left-hand rule for electromagnetic radiation, but doesn't a material need to let light pass through it in order for its refractive index to mean anything? And last time i saw see-through copper, i was shrooming. ;-)
To me, what seems most interesting about this is that it has the properties of negative electric permittivity and permeability.
If i'm missing something, please explain, but how would a material made of "ordinary" copper rings and wires refract light? So, in response to a previous poster, personally, i really don't see smaller glasses in the future. The fact that it already works with microwaves though, is very neat.

Nah.

OK... your wish is my command. See this article, written by a University of Toronto physicist, that explains in simplespeak the concept of relativistic simultaneity. To wit:

More importantly, the relativistic notion of simultaneity makes it clear that no information can travel faster than light without throwing all our concepts of cause and effect into disarray. Relativity teaches us that if two space-time events are separated so that they cannot be connected by any signal travelling at c or less, then different observers will disagree as to which of the two events came first. Since most physicists still believe that cause needs to precede effect, we conclude that no information can be transmitted faster than the speed of light.

Nevertheless, velocities greater than c can be observed. Suppose a lighthouse illuminates a distant shore. The rotating lamp moves quite slowly, but the spot on the opposite shore travels at a far greater velocity. If the shore were far enough away, the spot could even move faster than light. However, this moving spot is not a single "thing". Each point along the coastline receives its own spot of light from the lighthouse, and any information travels from the lighthouse at c, rather than along the path of the moving spot. Such phenomena are described as the "motion of effects", and are not forbidden by relativity.

here, here, and here.

There are three types of neutrinos: electron, muon and tau, each having a different characteristic mass and energy spectrum. The experimentally measured flux of solar electron neutrinos based upon the solar nuclear fusion reactions turned out to be too low by ~50% based on the theoretical GUT and QED calculations. As a means of explaining the apparent discrepancy, it had been postulated that neutrinos are capable of "oscillating" between types over distance and time, thereby affecting the number of measured events (the experimental measurement being limited to certain energies). However, theory suggests that in order to oscillate, the neutrino must have mass.

Ingenious experiments now seem to confirm that what was once considered a massless particle does indeed have mass, albeit vanishingly small.

Since neutrinos are produced in stellar fusion reactions and supernova explosions, etc., in very great quantities (the flux here on Earth is estimated to be over 10^10/cm^2/sec), they would be expected to be in a higher density in the vicinity of galaxies, and thereby could account for a large part of the "missing matter" holding galaxies together.

I think this is what the NPR story was referring to ... but maybe not.

A couple of links:

Physics Web articleon neutrinos.
Super-Kamiokande at UC Irvine Neutrino page.
UniSci article on oscillation.
The confirmation of Solar Fusion by neutrino detection 2002 Nobel Prize press release.

the ferromagnetic NOT gate is a "completely new class of device" that could be made even smaller. The researchers have also created a 13-bit shift register by linking the devices together, and believe it should be possible to make a full set of logic gates using their technique

Do you think only the USA have schools? Or even the best ones in everything for that matter? Wake up and smell the coffee: USA isnt the center of the world, there are research labs everywhere out there , and each country has its own universities / schools / whatever. Check the physic breakthroughts and tell me how many of those were USA-exclusive. Keep going like that, and well see stuff like encryption being developed faster and better everywhere but within your borders. After all, it wasnt long ago that redhat had to place its security patches on foreign servers regarding encryption. Sorry, but it seems that your downfall is imminent. Osama may have triggered those events, but you are sinking under the weight of your people fear and your government paranoia.

But dont worry: here in Europe, we also are going through a major phase of political dumbness. Your not alone.

Then, Bell Lab's star physicist Hendrik Schön got caught after having published faulty data. That was fraud on purpose.

The whole thing sheds a bad, bad light on science. I wonder why I work so hard to get my PhD sooner or (most probably) later... I think I should switch to physics.

Ok, so you build this thing and put it into orbit. Now how do you get the power to Earth where it's needed? Presently, all wireless energy transference technology loses most of what it sends, so you might as well put the solar cell on the Earth's surface. It would make more power. Having a tethered array would be about the only way to do it. See Slashdot for more information.

European scientists have carried out the first experiments on antimatter.
Wrong. They've been experimenting with antimatter for years. I think Carl Anderson's 1930s work was the first. This isn't even the first experiment with antihydrogen, or cold antihydrogen, for that matter.

Researchers in Geneva, Switzerland, have been able to trap and control anti-hydrogen atoms in a chamber at a sufficiently low temperature to begin studying their physics in detail.
Wrong. They haven't trapped it. Nor can they study the physics in detail yet.

Now they say they can store these fragile objects for study as well, allowing them to conduct simple experiments.
Wrong. They can't trap them, much less store them for any length of time.

By measuring the strength of the electric field, they hope to tell how tightly an anti-atom is held together and shed light on the differences between normal matter and antimatter that might explain why the Universe exists in its present form.
Not quite. They are able to tell how tightly these particular positrons are bound to their antiprotons, which reveals what quantum state the antihydrogens are in; this doesn't tell you anything about the properties of antihydrogen.

Cern physicist Jerry Gabrielse...
And, um, it's Gerry Gabrielse.

Much better articles available here, here, and here.

The original Physics world Article is at
http://physicsweb.org/article/world/15/9/2

One of the contributors described watching small plastic bags circulating in wind pockets, commenting that "sometimes there's so much beauty in the world, I just can't take it".

Regarding phase velocity vs. group velocity, both phase velocity and group velocity can exceed c - see Superluminal, second paragraph. Group velocities exceeding c have been done for decades - for a bit of a history, see No thing goes faster than light.

The innovation in this case seems to be that it's doable with cheap equipment, and over fairly long distances.

http://scienceworld.wolfram.com/physics/Superlumin al.html
http://www.weburbia.com/physics/FTL.html
http://physicsweb.org/article/world/13/9/3

The thing that really seems interesting about this is that they're doing this with cheap equipment, which will make experimenting with this a lot easier.

Can anyone explain how this would be used to increase subluminal transmission of electrical signals, as mentioned in the article? This whole group velocity thing has always seemed like a bit of an illusion to me, and none of the explanations I've seen has really clarified how it's anything more than that.

They create mumbo-jumbo terms like "electromagnetic vacuum", that sound plausible to the average sucker investor that never bothered to take a high-school physics class, but are nothing but a bunch of crap.

http://physicsweb.org/article/world/15/9/6

From another /. article earlier today. It explains the electromagnetic vacuum (a.k.a. vacuum fluctuations).

Didn't we have a story about how skeptical scientists were about these results.

Experimental proof that the "laws" of thermodynamics are half baked.

I've been "trolling" you for ages with the "the laws of thermodynamics are empirical laws" and here's another nail in their coffin.
To paraphrase Fort : "It spindizzies when it's spindizzy time".

Carbon nanotubes - tiny rolled sheets of graphite - have a host of unusual electronic and mechanical properties, which are the focus of research in Ajayan's group. During an experiment, de la Guardia tried to photograph single-walled nanotubes using a conventional flash, which has a spectrum similar to that of sunlight, but without the ultraviolet light.

Ajayan's team - which included researchers working in Mexico, France and UK - repeated this process on single- and multiwalled nanotubes. After packing samples of nanotubes to different densities, they exposed them to light pulses with a range of intensities and recorded the results on video. They later used an electron microscope to inspect the remains of the nanotubes.

Immediately after a flash, the researchers found that 'hot spots' appeared on the single-walled nanotubes and then spread through the sample until it was completely burnt. Samples packed to higher densities needed a more powerful flash to ignite them because the samples contained less oxygen, which supports combustion. The multiwalled nanotubes did not burn at all.

I've been arguing that physics exams, on the other hand, is a major problem for critical thinking. I even had an article in the journal "Physics World" about it.

I've been arguing that physics exams, on the other hand, is a major problem for critical thinking. I even had an article in the journal "Physics World" about it.

Discaimer: IANAP

But here is my understanding of black hole radiation or Hawking Radiation:

First of all, you must understand quantum tunneling. This is a principle in which particles have a certain probability that they will bypass, or "tunnel" though a barrier and reappear on the other side. Sometimes the particles tunnel at much faster than the speed of light. The thicker the barrier the less chance there is of the particle to tunnel. Tunneling doesn't only occur with microscopic distances. There have been experiments of photons tunneling up to a foot. (BTW, quantum tunneling has been observed experimentally.)

This does relate to black holes. In quantum physics, virtual particle-antiparticle pairs are produced from the Zero-Point Energy background all the time. They just annihilate eachother very quickly.

Now if a particle-antiparticle pair are created just inside the event horizon of a black hole, there is a probability that one of the particles will tunnel out of the black hole and escape into space. Since the particles can't annihilate each other, they become real. In order not to violate thermodynamics, the new matter created is balanced out by the loss of some energy of the black hole. In this way, the black hole radiates energy.

Now this effect is negligible for large black holes, such as supermassive ones at galactic centers, or ones created from a collapsed star. But for small black holes, like quantum black holes that are about the mass of an asteroid, or very tiny quantum black holes made up of only a few particles, this effect is very important. (these asteroid sized quantum black holes may have produced at the big bang. No evidence for them exists. We're pretty sure the smaller quantum sized ones are created all the time by natural processes. There is an accelerator planned that will be able to produce them.)

Smaller black holes radiate much faster than large ones. As I said earlier, particles have a greater probability of tunneling across a thin barrier. A large black hole has a slower drop-off in the amount of gravity as you go farther away from it. That means that the particle has to tunnel a long ways to be able to get away from the black hole. This means that there is almost no energy escaping. The hawking radiation of a 30 solar mass black hole is 10-32 of a watt.

Now for small black holes, this is different. The particles have a greater possibility of escaping by tunneling because they have to tunnel a shorter distance to escape. An asteriod-mass quantum black hole created at the beginning of the universe would be finally exploding right about now. For a small quantum black hole, they last only a tiny fraction of a second.

Lastly, if we can figure out how to produce largish quantum black holes, with masses at least on the order of micrograms, our energy problems would be solved. You see, when black holes explode, only pure energy, not matter, is realeased. I don't know how that would be done. The yet-to-be-built Relativistic Heavy Ion Collider should produce quantum black holes. We should be able to detect the energy produced when the explode.

Anyway, here is an excellent article on artificial black holes. Here is one on Hawking Radiation. I am giving you the Google Cache because the original page has a DoubleClick cookie on it.

We are assuming that there is a sea under Europa's Ice Sheet, aren't we? Do we have any proof that there is a sea underneith?

They have also set a lower limit on the ice thickness, giving scientists an idea of the minimum depth such robots would have to dig.

BTW, for those wondering, the Spiderman bit in the headline of the NSU story: Reality Check foils Spider-Man, I think refers to a previous reporting of this study which labeled Spider-man as most connected.

At least, I think it does.

i found this and it's a little bit more detailed. What I want to know now is how much some of this stuff will cost and how do we sort out which little bubbles are O2 and H. wouldn't the whole thing just start fizzing like an alka-seltzer when you drop it in?

We should just use solar panels to generate hydrogen from sea water....

I predict that within 30 minutes, there will be at least two confused posts saying that we should just use solar panels to generate electricity to "crack" the hydrogen from sea water.

...except that, instead of using electrical conversion followed by electrolysis they will use photocatalysis, as described in this Physics World Article, which talks about the implications of a paper published in Nature.

The jist of it, for the link weary, is that by the use of a cunning contrived semiconductor it is possible to arrange the band-gap to be higher that the reduction potential of H2, which allows the production of H2 from the H+ ions that are always present in water.

Early days yet (efficiency is 0.66%, compared with an break-even of 4%), and lifetimes are unknown at the moment. But using solar panels to generate hydrogen should not be rejected out of hand just because the energetics are unfavourable with one particular type of solar cell.

This is one thing that has gone VERY wrong with academia in the past 30 years. Instead of teaching facts, and critical thinking skills, schools, colleges, universities by and large teach WHAT to think.

I agree about that. However, teaching critical thinking is all about changing the world, so I agree about the original quote as well, and I think there is no conflict at all with teaching critical thinking and being in the changing-the-world business. On the contrary, being in the changing-the-world business means teaching critical thinking.

Actually, I think you (and I, I think.... :-) ) would agree very much with the basic points of the person cited.

stephen hawking seems to buy into the anthropic principle, too! it's all way over my head, but i like how he introduces it: "One can make the Anthropic Principle precise, by using Bayes statistics. . ." :)

PhysicsWeb has this story providing additional detail about the accident, and their recovery plans.

• Here is a not-too-technical report on buckyballs, their properties, etc.

• Pretty pictures!!!

• According to
• this article, buckyballs hold the record for highest-temperature superconductor.

• A report (fairly technical) on research into building buckballs...

• And
• here's a report on single buckyball transistors.

Another place to read about this (complete with MPEGs of the self-healing crack) is at The PhysicsWeb.