"Overwhelming" Evidence For Magnetic Monopoles 256
Thorfinn.au sends along big physics news: magnetic monopoles have been detected at low temperatures in "Dirac strings" within a single crystal of Dysprosium Titanate. Two papers are being published today in the journal Science and two more on arXiv.org, as yet unpublished, provide further evidence. "Theoretical work had shown that monopoles probably exist, and they have been measured indirectly. But the Science papers are the first direct experiments to record the monopole's effects on the spin-ice material. The papers use neutrons to detect atoms in the crystal aligned into long daisy chains. These daisy chains tie each north and south monopole together. Known as 'Dirac strings,' the chains, as well as the existence of monopoles, were predicted in the 1930s by the British theoretical physicist Paul Dirac. Heat measurements in one paper also support the monopole argument. The two, as yet unpublished, papers on arXiv add to the evidence. The first provides additional observations, and the second uses a new technique to determine the magnetic charge of each monopole to be 4.6x10-13 joules per tesla metre. All together, the evidence for magnetic monopoles 'is now overwhelming,' says Steve Bramwell, a materials scientist at University College London and author on one of the Science papers and one of the arXiv papers."
"I maintain nonetheless..." (Score:3, Insightful)
"...that yin-yang dualism can be overcome. With sufficient enlightenment we can give substance to any distinction: mind without body, north without south, pleasure without pain. Remember, enlightenment is a function of willpower, not of physical strength."
-- Chairman Sheng-ji Yang, Essays on Mind and Matter
So, can haz magtube now plz?
Re:a magnetic monopole is like a one-sided coin: (Score:5, Insightful)
Re:pepetium mobiles?? (Score:3, Insightful)
> is it possible to create pepetium mobiles now?
No. The existence of magnetic monopoles does not imply perpetual motion.
Interesting, but... (Score:2, Insightful)
Re:a magnetic monopole is like a one-sided coin: (Score:4, Insightful)
I think the stupidity is yours. Magnets are not just atoms lined up, atoms themselves have magnetic poles. In fact, the components of atoms (such as electrons) have magnetic poles as well.
It's perfectly conceivable to think of a point source of just North or South where the field lines radiate outwards in all directions. They would arc toward the nearest magnetic pole of opposite polarity. The diagrams are simple to draw and have been accepted by just giants in the field as Dirac for eighty years. The only question is: do they actually occur?
Re:lo, you have defeated me (Score:5, Insightful)
I was attempting to point out that electric charge also has field lines but that they do not have two sides like a coin, the entire point of the discovery of a magnetic monopole is that it doesn't have two sides in the way that all the other magnetic dipoles we are used to have.
Re:Analogy (Score:1, Insightful)
I have no idea of what new uses this could be put to, or even if macroscopic-sized monopoles could be created.
Re:Not really useful (Score:3, Insightful)
After filtering out your sarcasm, I must say you are completely correct. How dare AC ask for further explanatino of the topic? The Scientists know everything, so nobody else needs to know anything! If The Scientists say its a monopole, that should be all you need to know, so go back to your video games.
I didn't study enough physics to know much about monopoles. The physics majors I knew told us of a lot of things you could prove, if you knew that a monopole existed. (I never asked, and they never elaborated.) That being the case, what constitutes a monopole probably has a lot more to do with setting up the conditions for those proofs, and a lot less to do with what seems (to the AC, myself, or anyone else) to be the intuitive meaning.
That being the case, it would be nice if someone who knows that they're talking about were to provide more explanation. Instead all we get is noidentity mocking an AC for asking what is really a pretty reasonable question.
Re:pepetium mobiles?? (Score:2, Insightful)
This is why I agree with the others that laugh at this article with it's ridiculous claim that monopoles exist. A monopole connecting to another monopole is called a dipole, no matter how long the connection or what kind of item it is.
Re:lo, you have defeated me (Score:5, Insightful)
I'm sorry, but you're going to have to provide your credentials if you want me to accept that you know more about magnetism than four separate physics research teams, two with articles in Science and two more with draft articles on arXiv.org, all of which show evidence of the existence of magnetic monopoles.
Christ, not to mention Paul fucking Dirac.
circletimessquare, you have one again exceeded yourself at demonstrating your truly incredible arrogance and stupidity.
Re:how does a magnetic field line just stop somewh (Score:3, Insightful)
How does an electric field line just stop somewhere?
Re:lo, you have defeated me (Score:4, Insightful)
Brace yourselves for the onslaught (Score:4, Insightful)
Re:i cannot conceive of the possibility (Score:2, Insightful)
The equations for magnetism are similar to the equations for electricity, apart from an extra equation which states that there are no magnetic monopole. That equation comes from empirical evidence and can be removed without breaking anything. As a proof, electricity doesn't have that extra equation and works just fine.
I'm a bit confused by this (Score:4, Insightful)
Dirac's argument (and all the field-theoretic) arguments in favor of the existence of magnetic monopoles have had to do with an elementary particle exhibiting those characteristics. Sometimes this is phrased in the terms of a 0-dimensional topological defect, something that would be produced by certain kinds of symmetry breaking; and indeed one of the arguments in favor of cosmological inflation theories was the fact that we don't see fundamental-particle monopoles, and would expect to. Finding one of these guys would be amazing news.
What these experiements seem to have done, however, is detected the effect of what condensed matter physicists like to refer to as a quasi-particle, akin to the phonon, which is a different thing entirely.
Or am I missing something?
Re:Practical Impact? (Score:4, Insightful)
If they were real, physical, isolable monopoles, they might turn out to have some minor applications in energy production [washington.edu]. (Yeah, I linked the same article upthread; it's interesting enough to repeat.) The claim is that they would make protons (and neutrons) decay promptly. Of course, if these folks were seeing that kind of monopole, they would have noticed side effects, starting with a sudden inability to keep their samples below 1 K.
Re:i cannot conceive of the possibility (Score:3, Insightful)
a magnetic field is a relationship between a particle and its environment. it begins at the particle, it loops around, it ends on the other side of the particle
Mmm... can we say "begging the question"? You assume a magnetic field like must "[begin] at the particle" and "[end] on the other side of the particle", and then use that as proof that a field line must begin and end at a particle, thereby disproving the existence of magnetic monopoles.
Re:Not really useful (Score:2, Insightful)
Re:Analogy (Score:0, Insightful)
Now here's the part I'm going to take a thought to the n'th degree. Suppose you had enough of these monopoles in a balloon exerting enough force against the pressure from the outside of the balloon. Say our balloon is analogous to the universe and space/time. Now suppose the exertion outward is so great space/time is warped thus creating a white hole [wikipedia.org].
Not sure that would work but I'd be interested to hear form someone why that's crazy talk.
Re:Not really useful (Score:3, Insightful)
When we create protons and antiprotons, or electrons and positrons in an accelerator we always create them in equal numbers.
The universe is (conjectured to be) uncharged. So there are equal numbers of positive and negative charges.
But we still have the idea of an isolated charge and, if we get close enough to it we can see that the divergence of the electric field is non-zero. With electrostatics it's trivial to get a macroscopic volume where the divergence is non-zero.
These papers claim the same has been achieved with magnetism. In a box approximately 1nm on a side there is a north pole with no matching south pole. So there are magnetic field lines flowing out of the box with no matching field lines flowing in. Of course "over there" there is a south pole which has field lines flowing in without field lines flowing out.
Tim.
Re:what is magnetism, conceptually? (Score:1, Insightful)
make believe our planet had a net mass. it would interact with our sun's gravitational field lines, and keep moving orthogonal to those lines, looking for equilibrium. but it wouldn't find it, because unlike a normal mass-dipole, its a monopole
so our planet would loop around, move through mostly empty space, and whatever aspect of our planet that was still in existence as a monopole would still continue orthogonal to those field lines, never stopping movement, just looping forever orthogonal to a field line
thats a perpetual motion machine. thats mass. thats impossible bitches
Re:Is His Hubris Humerous? Hardly. (Score:3, Insightful)
There are no magnetic monopoles. You can try to separate north and south pole. You can even construct models of "magnetic charge" and dipoles if you like. But in the end, you can't get a north pole without having a corresponding south pole, very, very close by.
Interesting. It seems if you properly understood experimentalism, you would say, "No experiment has shown the existence of a magnetic monopole, but no experiment has shown that they must not exist."
You seem to be taking the approach that if an experiment does not show that A is true, then A must be false. Not only would a physicist criticize you (rightly) for this line of reasoning, so would any philosopher or logician.
Re:Not really useful (Score:1, Insightful)
There are many people having PhD in and holding research positions at well known university but would not like to talk publicly against well known entities. For one, I have a PhD in Physics too and yes, I have the same questions. This is not same as magnetic monopole but rather an effect that looks like a pair of monopoles. An electron equivalent of this would be a wave function in which there is finite probabilities at two locations separated by zero probability space. This looks like electron broken into pieces. But that is what it is, an electron looking like broken into pieces which not same as electron broken into pieces. What this paper describes is very similar. Two magnetic monopoles whose magnetic fields are not connected. These are very short range defects. You won't be able to play with these monopoles in any manner like electrons (e.g. CRT monitors).
Re:Missing Link (Score:2, Insightful)
I'm gonna be a big jerk right now. I'm pre-announcing it so you know I aware.
(All of the above snark is not aimed at the poster, but rather provided for entertainment purposes only. Like mind readers and strippers. Not to be taken seriously.)