Slashdot Mirror
"Overwhelming" Evidence For Magnetic Monopoles
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 Two papers are being published today in the journal Science and two more on arXiv.org, as yet unpublished, provide further evidence.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 The two, as yet unpublished, papers on arXiv add to the evidence.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 think this is at least one of the Science articles to which the post (almost) refers.
It's only against the law to use your monopole to extort the market.
Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
Uncle Pennybags purchases Acme's Magnet making division to create magnetic monopoly.
Clearly we knew monopoles exist already since Microsoft is guilty of being one right?
2 stupid questions: - Can someone make a car analogy? - Are there any applications for it within our understanding of physics? When I hear of monopoles it's often in a bad context, and in combination with news about LHC creating blackholes and other Earth eating stuff. I don't think the LHC is a doomsday device but I don't really get magnetic monopoles.
They come in "pairs" huh. Sounds like the N S of a regular old fashioned magnet to me. If they could be separated ever then they really would be monopoles but otherwise how can you be sure its not just a regular magnet thats too small a scale to detect the flux coming from every angle around it?
"...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?
impossible
if you have a coin with one side, you can turn it over, and there's another side. you don't turn a coin over and there's a black hole of nonexistence. you cannot construct a coin with one side. there will always be another side to that coin. please don't talk to me about toruses: we're talking about an analogy to the concept of a monopole
there's no such thing as a monopole. whatever it is, will have another side. and on that other side, there's the magnetic field lines, going on their merry way. a magnet is just atoms lined up in a certain way. are you telling me you can have one-sided atoms?
this is some sort of stupidity here
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Surely if they are two monopoles tied by a dirac string then they actually make a dipole. I was under the impression a monopole would create a dirac string (a discontinuity in the field) that extends to infinity. Interestingly by allowing the dirac string to extend first in one direction, then in the other and joining the two resultant fields gives a fully continuous description of the monopole without the need for a dirac string.
I think what the summary is refering too is similar to the creation of a electron and hole pair in a semiconductor rather than a fundamental monopole particle. So they are in fact creating both poles but that inside the spin glass they are not confined with respect to each other so each one appears as a monopole in the material.
is it possible to create pepetium mobiles now? ;)
most of the the 'free energy' designs are based around non-existing monopoles, and tricks to 'emulate' monopoles.
Comment removed based on user account deletion
Isn't this just in time for the new season of the show Big Bang Theory, where Sheldon is on an expedition to find magnetic monopoles? :)
Wait, how will this affect me tonight when I roll a big fatty and watch TV?
I mean, if you're traveling, you wouldn't want your houses and hotels to go flying off the board, so the magnets would be pretty helpful. I'm just wondering if the Chance and Community Chest cards are magnetized too? And how do you deal with all the money? These questions need to be answered before we can truly say there is overwhelming evidence for magnetic Monopoly.
Quidquid latine dictum sit, altum sonatur.
I thought we were talking about a Slashdot question that only had the CowboyNeal answer as a choice.
All my coins are shaped like mobius strips.
The Klein bottle manufacturer guarantees unconditionally the following:
I have contacted them to notify them of this and to request a refund of my Klein bottle purchase. If you also have a Klein bottle I highly recommend doing the same!
That tells me nothing. How many beard seconds is that?
Its not, its just like electric charge only for magnetism.
Monopoles? Dirac Strings? Did I just wake up in Star Trek? If so, where the hell is my Uhura?
with a weapon i cannot possibly match: colossal fucking ignorance of the concept of magnetism
woe is me
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Data: "Magnetic monopoles have been detected at low temperatures in "Dirac strings" within a single crystal of Dysprosium Titanate"
Geordi: "If we generate a phase-inverted lepton pulse from the main deflector, we might be able to force a quantum pulse cascade which will counteract their effect!!!"
Can someone translate this into English for us non-Physics geeks? What exactly does this mean? Will it lead to new applications of magnets (the closest analogy I can come up with from this brief description)?
If you have a regular old magnet, it has North and South sides. The net force, or charge, between those two sides is zero.
A monopole would be North or South, but not both. It would have a positive net force, much like an electron.
Not a typewriter
Let me wiki that for you: Magnetic charge
Magnetic charges fired in a customised photon torpedo were used in Voyager S96E10 to defeat the dudes with forehead that looked like vulva.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
and not continue on its way around to the other side of a magnet?
i like the equations, it makes you look authoritative. next time i try to convince someone the planet earth is actually a flat disc, i'll throw in some equations
a magnetic monopole is a physical impossibility. point of simple fact
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
... run Linux?
They have units of ampere*meter instead of ampere*second. Don't listen to this "joules per tesla metre" non-sense.
Think of them as different causes of motion. Magnetic charges cause motion in magnetic materials and electric charges cause motion in other electrically charged materials. They are supposed to be linked in someway. Same goes for the "colour" charges of the strong force. And to generalize further, physicists hope to find a link to gravity which also causes motion (in all materials).
...therefore, God exists.
Magnetic monopoly has existed for years, guys, come on with these stories! jeez.
http://cgi.ebay.co.uk/Monopoly-Magnetic-Pocket-Edition-Boxed_W0QQitemZ280392141950QQcmdZViewItemQQimsxZ20090902?IMSfp=TL090902157001r16643
How does an electric field line just stop somewhere?
We all know what to do, but we don't know how to get re-elected once we have done it
i thought they were talking about www.poloniasingles.com/
if you don't know what a magnetic field line is, what can one say to you?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Now I've scanned one of the papers I see that they're not detecting the sort of magnetic monopole I was thinking of (i.e. a new sub-atomic particle)
Instead they've detected the equivalent of a charged molecule.
They give an analogy of the disassociation of water into H3O+ and OH-. They claim to have done the same thing with magnets - ending up with a disassociated north and south pole.
So their work doesn't appear to give any clue to the mass of a magnetic monopole particle. But AFAICT they have still created a type of magnetic monopole, exactly the same way as a proton is an electric monopole even though it has an internal structure.
Tim.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
(Disclosure: I'm a physicist)
You could just as well ask: "how can an electric field line just stop somewhere?", and thereby conclude that there can be no such thing as an "electric monopole" (a positively- or negatively-charged particle). As long as the universe has no net electric or magnetic charge, all lines will terminate somewhere. If the universe did have a net charge the point is subtle, but that's irrelevant: the paper talks above pairs of opposite-pole monopoles created together, like a particle and its antiparticle. So this argument doesn't hold water.
Monopoles aren't impossible in principle (it would just be an extra term in Maxwell's equations) and are predicted in some theories, but fundamental-particle monopoles have never been observed. The summaries of this paper are confusing a lot of people: the authors are describing a crystal system with excitations that look like monopoles. They are NOT describing discovery of a new fundamental particle, but rather a new kind of solid-state phenomenon.
By having a non-zero divergence. Just like Gauss' law divergence D = rho (charge density), we have divergence B = rho_m (density of magnetic monopoles).
These are not the magnetic monopoles you're looking for.
"and not continue on its way around to the other side of a magnet?"
Yes! That's why it's called 'monopole'. It behaves like electric charge, but with respect to magnetic field. For example, moving monopoles create _electric fields_ with closed lines.
And impossibility of monopoles is not a fact. In fact, (pun intended) it's long been known that monopoles can exist within the framework of classic electrodynamics.
An interesting fact: existence of even one monopole in the Universe forces _all_ electric charges to be quantized. But all electric charges ARE quantized.
The whole crowd of people selling devices that use Zero Point Energy and magnetic suspension perpetual motion machines and people who write hundred page manuscripts in purple ink arguing why the Second Law of Thermodynamics must be repealed are going to come out of the wood work now.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Having read at least one of the arxiv articles, it is clear to me that the authors have NOT detected magnetic monopoles, and don't actually claim that they have. They claim that a certain type of ordering in a very specific crystal at very low temperatures BEHAVES AS IF it was a magnetic monopole - it's an analogy at best. The energy required to trigger the effect is minute, so they can "see" lots of MMAs (magnetic monopole analogs [my terminology]), and hence study what would happen if lots of REAL MMs existed in some other situation. They confirm that setting up Maxwell's equations to include a monopole shows the same sorts of behavior as what they see. But a real, isolated magnetic monopole? Not this time......
What are the practical implications/applications of monopoles?
I'm not dissing the theoretical impact. I'm just curious if anyone has a use in mind for them.
a magnetic monopole is a physical impossibility. point of simple fact
A monopole is just one end of a very, very, very long dipole - the other end is lost in space so to speak.
i read somewhere that magenetic monopoles can be used to convert protons directly into energy, as per e = mc^2. can anyone clarify what this new discovery means for this concept. it would be the ultimate energy source, i would presume.
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
i don't see how it is possible to disassociate the particle and continue that relationship with the environment. if the magnetic field line begins with a particle, but doesn't end anywhere associated with that particle, i don't see how it can continue to exist, since it cannot begin and never end
wouldn't a monopole just start moving and never stop until it exits the universe?
the argument against a monopole seems to me to be the same argument against a perpetual motion machine
a monopole IS a perpetual motion machine: a failure in human logic, nothing real
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I've been reading for decades about the search for subatomic-particle-type monopoles, and all the wondrous things one could do with them. This sounds more like some kind of group phenomenon, an emulation of a monopole, if you will. Sort of like holes in a semiconductor, which behave in some ways like positive "things", but are actually just the absence of an electron in a lattice.
I'm guessing that these aren't the kind of "real" monopoles that would let us build super-powerful motors, or compact proton disintegrators, or whatnot. On the other hand, even though the semiconductor folks can't isolate and sell bucketloads of holes, they do turn out to be quite useful.
I'm glad you provided the episode number, because the description didn't narrow it down much.
If you were blocking sigs, you wouldn't have to read this.
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?
appeal to authority rather than appeal to logic and reason
if einstein said the sky is green, the sky must be green, because einstein says so
pfffffft
dirac thought monopoles could exist? than dirac is wrong
because a magnetic field is something that begins and ends with a particle. it does not begin at a particle and never end. such a particle would begin moving and never stop: a perpetual motion machine
in fact, much like the idea of a perpetual motion machine, a monopole is simply a failure in logic and reason, not anything real
any belief in the existence of magnetic monopoles is an inability to understand what a magnetic field is conceptually
i am apparently getting a lot of flak here in the comments about the impossibility of a monopole
either i am insane, or a lot of people don't understand what a magnetic field is
i don't fucking get it: a magnetic field starts and begins with the same point in space. it does not start at a point and not end: that's not a magnetic field. such a field could exert no force, as its not grounded in anything
in what way is anything i just said wrong?
so i must be insane, or the whole lot of you are ignorant of what a magnetic field is
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
From one of the articles:
They've managed to create the microscopic equivalent of a long skinny magnet or a long bendy solenoid: a set of dipoles aligned end-to-end, which acts just like a string with two "monopoles" at the ends.
While this is an interesting microscopic state of matter, from the "discovering monopoles" point of view it doesn't seem fundamentally different than the macroscopic description of magnet "poles" that has been well understood for over a century (and observed for a lot longer than that). I call hype.
If a thing is not diminished by being shared, it is not rightly owned if it is only owned & not shared. S. Augustine
That it not entirely correct.
Magnetic monopoles have been observed.
The problem is that most student are told that magnetic monopoles haven't been observed,
and very few student check to see if that is correct.
Check out chapter 5 in
http://www.scribd.com/doc/4445/quaternionic-electrodynamics
for references to the articles.
i am not going pedantically explain why electricty is not magnetism, its like describing why a whale is not an elephant
so why is talking about electricity suppose to have any bearing on the existence of a monopole or not?
many people here have disputed my claim that a monopole is a logical impossibility by pointing out that an electric field doesn't have to begin and end at the same point
well no shit. but electricity is NOT magnetism
if i said that it is impossible for a whale to live on land, and you replied "well, elephants live on land, so why not whales?" would that make any sense?
so why the hell is everyone saying that any conceptually true about electricity is supposed to be useful in our understanding of the nature of magnetism?
magnetism begins at a particle, loops around, and ends at the same particle
beginning and ending of the concept of magnetism
this is simply what magentism IS
magnetic fields do not begin at a particle, and just keep going out forever. that's not magnetism. such a particle would just begin moving and exit the known universe: a perpetual motion machine, a failure in human logical reasoning abilities, nothing real
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
This mentality is a good example of what Joel Spolsky calls fire and motion. You just keep moving, keep publishing, keep innovating, and your opponent is so busy trying to catch up or deal with your earlier work that you gain huge momentum. Sometimes unstoppable momentum. People just can't deal with the information overload.
For 30 years, physicists have believed that the universe is made up of tiny vibrating dimensional strings which only they are clever enough to understand. A fine idea, except it turns out not even they are clever enough after all. Nevertheless, they persist in this belief because the mathematics is beautiful. Likewise, many physicists persist in their belief in magnetic monopoles because the concept is beautiful, or some other such rubbish. Look! It even makes Maxwell's equations symmetric. So what? What's so important about having symmetric equations. Unsymmetrical ones are so much more interesting!
There's only one arbiter in physics, and science in general. It isn't a "flurry of papers". It isn't "beauty" or "symmetry" or "elegance" or "coolness". It isn't how many people agree with your viewpoint. It isn't how many journalists you can get to print words like "overwhealming evidence" in headlines. It isn't how much "supporting (online) material" you can find to back you.
The one, only, and final arbiter is the experiment. An honest to gods experiment. It finds things. It separates truth from fiction. You can try to twist the meaning of the result this way and that, throw back the grenade and carry on with your fire and motion, but in the end the results of all those experiments will finally weigh down your dishonesty and halt your advance.
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.
Modern science, and worst of all physics, is in a deplorable state. Cargo cult scientists,frauds, charlatans, fakes, and deluded true believers(Yes I'm serious about that last link) have saturated certainly the media circuit, but I fear many physics departments as well. Sensationalism and media attention are now as never before, deciding what the "consensus"* in science should be. It's disheartening to see the world lose its faith in the method of observation, hypothesis, experiment and above all skepticism that has served it so well for so many centuries.
P.S.
*Before the cranks jump in; No, I do not in fact, doubt the reality of anthropogenic climate change.
May the Maths Be with you!
and you've been so consistently for years now. Congrats, I guess. Shithead.
a magnetic field begins at one side of a particle, loops around, and ends at the other end of a particle
thats simply a conceptual description of magnetism
a magnetic field does not begin at a particle, issue forth, and never end
thats simply a failure to understand what magnetism is conceptually
if a magnetic field line emanated from a particle, it would interact with the magnetic field lines in its environment, begin to move, and simply never stop moving. because it could never reach equilibrium: its a monopole. it would exit the known universe. it has magnetic field lines sticking out one side of it with no apparent end, which is a logical absurdity
no magnetic field can be created without the other side of that particle/ bar magnet/ planetary core bearing the anchor of that magnetic field
am i insane? is everyone here stupid?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Years later, a doctor will tell me that I have an I.Q. of 48, and am what some people call "mentally retarded".
IAAP and I did do my PhD on this stuff, but it is a while ago now...
The Dirac string is not real, but is really just a failure of the coordinate system. Coordinate systems are always failing: just stand at the North Pole and ask which direction is South. All directions are, and the coordinate system is broken at that point. That's fine, it works everywhere else and we jsut remember to be careful in the rare cases where we are asking for directions at the North Pole. There is no fundamental breakdown of space and/or time going on, it's just because we chose to impose a silly coordinate system onto the physical world. The fact the it breaks down at the North and South poles is also a red herring - we just chose to make the polar axis the same as the axis of rotation of the earth.
The coordinate system used to simultaneously describe electric and magnetic charges is also broken, and the Dirac string is really just a way of fixing up this breakage. We imagine that one unit of magnetic flux arrived through a very narrow tube at the monopole and then spewed out in all directions (think toddlers or teenagers at this point). The tube is not real, it is just a way of patching up the failure of the coordinate system. In the same way that the Poles as points of failure is our choice, the direction that the tube arrives at the monopole is also an artifact of how we set up the coordinate system.
We can change the direction that the tube arrives at the monopole from transparently using what is technically known as a gauge transformation, but let's not worry about that here.
The tube is not real, so we must not be able to detect it. This leads to the concept of quantisation of electric charge. Normally, if you take a tube carrying g units of magnetic flux and then take an electrically charged particle round it in a circle, the wavefunction of the charged particle will change by a complex phase exp(i.theta) where theta is proportional to the product of q (its electric charge) and g. You can detect this phase using a quantum-mechanical interference experiment, if you feel the urge. If the Dirac string is to remain physically unobservable, no interference effects must be seen so the phase rotation must be a multiple of 2.pi, because exp(i.2.pi)=1.
So, we know if there is one magnetic monopole anywhere in the universe then q.g = 2.pi.n (where n is some integer) so that the Dirac string (a mathematical fix for a choice of broken coordinate systems) remains just a theoretical trick and not observable physics. We must then have that the electric charge of every particle in the universe is some integer multiple of e = 2.pi/g, where g is the magnetic charge of that monopole.
Whether you consider the smallest unit of electric charge to be the charge on the electron or the charge on a free quark (one third of this) doesn't matter. We do observe that electric charge is quantised (i.e. integer multiples of some base amount) and magnetic monopoles as fundamental particles provide a relatively elegant solution as to why this is true.
A monopole is supposed to be an elementary particle with a magnetic charge. This is--as the abstract itself says--a "tractable analog" of a magnetic monopole.
There are a lot of things in solid state physics that "behave like" some kind of elementary particle but aren't: phonons, holes, etc. This is just another instance.
so i must be insane, or the whole lot of you are ignorant of what a magnetic field is
I'd like you to consider the possibility that it's neither of the above. I recognize your signature and remember you making many good posts in the past. I don't think you're crazy. I just think you don't understand the theory of electricity and magnetism very well.
Electric fields also begin and end at particles. And there are electric dipoles, just like there are magnetic dipoles. Why should magnetism only have dipoles and not monopoles like electricity?
Just as electric dipoles are made from positive and negative electric monopoles (charges), there is no reason magnetic dipoles can't be made from opposing magnetic monopoles. Electric monopoles are definitely MUCH easier to observe in nature, but that doesn't mean there are no magnetic dipoles.
Did you know that observers in different reference frames will disagree about the strength of electric and magnetic fields? Electric and magnetic fields vary (in a coordinated way) under Lorentz transforms. That is, what looks like a pure electric field to one observer might look like a combination of electric and magnetic fields to an observer in a different reference frame. Putting it differently, eletricity and magnetism are two aspects of a single force called, creatively enough, the electromagnetic force. That's a reason to believe that magnetic monopoles might exist.
Additionally, electric charge is observed to be quantized in nature. All free particles observed so far have charges that are integer multiples of the electron charge. Quarks are believed to have charges that are +/- 1/3 or 2/3 of the electron charge, but free quarks have not been directly observed, and in any case, even if the basic unit of charge quantization is 1/3 of the electron charge, charge is still quantized. And in the theory, the existence of magnetic monopoles automatically leads to charge quantization. That's a big reason many very smart folks with Ph.D.s in physics have been looking for magnetic monopoles for some time.
I remember a magnetic monopole detector that was sitting in a garage-like bay at HEP, the High Energy Physics group's building, at the University of Chicago in the late 1980s. I believe it was something Henry Frisch had set up really cheaply, so the risk was low, and the potential return enormous. Think of it as a low-budget HEP nerd experiment in Chicago. If you look at Professor Frisch's CV, you'll see that he's written a bunch of papers about magnetic mnopoles and their detection.
Only tangentially related: it has been 20 years, so I shouldn't have been surprised, but seeing Frisch's hair that white was a bit of a shock. Probably because of what it implies about my own age.
"It is nice to know that the computer understands the problem. But I would like to understand it too." --Eugene Wigner
a magnetic field begins at a particle/ bar magnet/ planetary core, loops around, and ends at the other end of the same particle/ bar magnet/ planetary core
does the magnetic field begin somewhere, issue forth without anchor?
what is such a thing? its not magnetism. its simply not the same thing conceptually. and its also impossible
make believe our planet had a monopole at its core. it would interact with the sun's magnetic field lines, and start moving along those lines, looking for equilibrium. but it wouldn't find it, because unlike a normal magnet, its a monopole
so our planet would loop around, move through the core of the sun, and whatever aspect of our planet that was still in existence as a monopole would still continue along those field lines, never stopping movement, just looping forever along a field line
thats a perpetual motion machine. thats a monopole. thats impossible
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
those flying cars you keep promising.
Table-ized A.I.
Wasn't she the secretary that James Bond always flirted with?
Years ago, I learned that magnetism was really just a way of accounting for the way electrostatic forces and special relativity interact. So, it will be interesting to see how they reconsile the discovery of monopoles with special relativity. I wonder if they are saying that some sort of monopole particle really exists. I'm skeptical of this. Or, perhaps they have discovered a condition where the mathematics work out nicely if you pretend a monompole exists, but really under the hood it's all relativity and electorstatic forces.
http://skepticsplay.blogspot.com/2007/12/relativity-electrostatics-magnetism.html
http://www.newton.dep.anl.gov/askasci/phy00/phy00993.htm
http://van.physics.illinois.edu/qa/listing.php?id=2358
As I have stated in response to circletimessquare elsewhere in this discussion, there are a few good reasons to believe magnetic monopoles might exist. I remember circletimessquare's sig, and remember him or her making good posts in the past, but it's clear that he or she does not understand electricity and magnetism very well.
Classical electric and magnetic fields vary in a coordinated way between different Lorentzian reference frames. So where one observer might only observe an electric field with no magnetic field, an observer in a different reference frame moving at a constant velocity with respect to the first observer's frame might see a combination of electric and magnetic fields. Electricity and magnetism are different aspects of a single force, believed to be one of the four "fundamental" forces. It is called, shockingly enough, the electromagnetic force. That's one reason to believe that since electric "monopoles" (charges) exist, magnetic monopoles might too.
There are electric dipoles, which are made of opposing electric "monopoles" (charges). Why couldn't magnetic dipoles also be made of opposing magnetic monopoles? That's another reason to believe magnetic monopoles might exist.
Dirac didn't just think magnetic monopoles might exist for no reason. He discovered in his calculations that the existence of magnetic monopoles would automatically lead to the quantization of electric charge. Since all electric charge observed in nature is quantized (in integer multiples of the electron charge for free particles and, we believe, in integer multiples of 1/3 of the electron charge if we include particles that are not observed "free"), we have yet another reason to believe there might be magnetic monopoles.
Very smart folks with Ph.D.s in physics have been looking for magnetic monopoles in creative ways for a very long time. In another post in this discussion, I mentioned Professor Henry Frisch of the University of Chicago. These people aren't just looking for magnetic monopoles to do something crazy. They're doing it because their deep understanding of the theory and the experimental data leads them to believe magnetic monopoles might exist.
"It is nice to know that the computer understands the problem. But I would like to understand it too." --Eugene Wigner
1. By softball sized foam ball at Hobby Lobby.
2. By a couple hundred small neodymium magnets online.
3. Get a hot glue gun and hot glue one pole facing towards the surface and the other pole away.
4. Glue more magnets to the entire surface of the foam ball is covered in magnets.
5. You now have your very own "Macro-Sized, Monopole analogue!"
Tsukasa: All I really want, is to be left alone...
Wake me when this gets to market.
God has the only monopole in the universe and it is currently floating over the N pole of a large planet sized Neodymium magnet he keeps on his desk.
He uses the magnet as a paperweight and once he got a new metal desk and needed Chuck Norris's help in moving his paperweight around. Chuck Norris then told the magnet to behave so God could move it and the magnet obeyed so now God doesn't have to keep asking Chuck Norris to move it all of the time for him.
Tsukasa: All I really want, is to be left alone...
IANAP (I am not a physicist), but perhaps it's some relation between magnetic and gravitational fields? Certainly gravity is related to mass, so perhaps there is some relation or parallelism in magnetic fields?
Hear, hear! Thank you for the appropriate and physically literate statement of what I would have liked to tell GP.
Disclosure? It isn't a disclosure, it's more of a disclaimer.
AFAIK you disclosure when you have a potential bias about the subject matter, and want to be honest about it. What you have here is bragging rights.
(Disclosure: I'm a physicist too)
entropy happens
These are simply sets of atoms that, together, act like monopoles. What has been discovered is not a single particle with one pole. It is a place inside a material that acts like a monopole. Real 'Dirac strings' connecting real monopoles are not long chains of molecules, these long chains of molecules simply act like Dirac strings. Please. This is the most misleading title and summary I've ever read here, and that is saying A LOT.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
""Overwhelming" Evidence"
"Theoretical work had shown that monopoles probably exist..."
Overwhelming Theory seems more appropriate when you look at it this way; Overwhelming evidence that monopoles may probably exist in theory. :)
Uhh, how about providing the theoretical groundwork not only for being able to reverse the polarity of the phase inducers (which is the answer to most of life's problems), but also for being able to reverse the polarity of the main deflector dish to fire a tachyon pulse? Generally speaking, it allows you to reverse polarity on things, thereby providing an extremely simple and elegant solution that somehow was never conceived before.
Well, sir, there's nothing on earth
Like a genuine,
Bona fide,
Crystalized,
Nano-sized,
Monopole!!
Do daemons dream of electric sleep()?
Impossible magnet
On selfish pole
Burma Shave
Great post. I'm sorry I used up all my mod points.
Comment removed based on user account deletion
To be fair, TFA (Nature) wasn't much better. It never actually broaches the topic of molecular vs. particle monopoles which is kind of central to anyone not in the know understanding that this isn't the big deal everyone's been talking about for the last decade+
Yes, but don't go putting anyone's eye out with it.
There's nothing trollish here. At the least it's an honest counterarguement, and worth replying to rather than burying.
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
Exotics are always the best way to finance those hellbore cannons. Will will bring the Ur-Quan to their knee equivalents, yet!
A government is a body of people notably ungoverned - AC
The end of a good solenoid (long cylinder of wrapped wire with current flowing through it) is a good approximation to a magnetic monopole. A short fat solenoid isn't so different from a bar magnet â" it's a dipole field, all right. But the longer and thinner the solenoid is, the more its magnetic field looks like two well separated monopoles. The Dirac monopole is precisely the mathematical limit of an infinitely long, infinitely thin solenoid, whose ends are then true monopoles. The vanishingly thin solenoid running between them is the 'Dirac string'.
What seems to have been seen in this crystal is something like a quite thin, quite long solenoid. It's not a new elementary particle with a magnetic charge, and in a way it's no different from the long thin solenoid you could make in your basement and power with a D cell battery. But in another way it's actually very big news, maybe even almost as good as it sounds, because the point is that nobody sat down to engineer a tiny solenoid. These things form spontaneously, for reasons that probably have to do mainly with physics on much larger scales than the solenoid thickness. And if that's so, then saying they're not 'real' monopoles is a fairly irrelevant quibble, as far as modern physics is concerned.
That equation comes from empirical evidence and can be removed without breaking anything.
It would break the empirical evidence... And I think you mean extra "term".
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
A magnetic monopole would be attracted to one end of a magnet and repulsed by the other. So you could set up a wheel with identical magnetic monopoles on the edge and a magnet parallel to that edge, and the wheel would accelerate indefinitely. Unlike an electric motor no energy would be required, it would be better than a perpetual machine, it would be a free energy machine. This of course would violate conservation of energy, which for me indicates that an isolated monopole is impossible.
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
Citation Please
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
Not a bad book, but its discussion on magnetic monopoles is hardly conclusive.
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
Assuming you weren't being snarky, they're two sides of the same coin -- electromagnetic force, which is one of the four fundamental forces, along with the strong nuclear force, the weak nuclear force, and gravity. That's why you can generate an electromagnet by passing current through a wound wire, or generate electricity by passing a magnet along the same.
https://www.eff.org/https-everywhere
I guess Simon & Garfunkel got it wrong. The words of the prophets are written in e-mag textbooks.
The Science article is just as bad. The editors should have insisted that this article be entitled something like:
"Solid-State Analogs of Dirac Strings and Magnetic Monopoles in Spin Ice Dy2Ti2O7"
The existence of H3O+ and OH- shows that an electric monopole exists, even though it is not directly observed; you cannot construct these molecules/ions from dipoles only. Similarly, it looks like this experiment shows the existence of magnetic monopoles. To me that is more interesting than the details of the elementary monopole particle. For one thing, it explains (via Dirac's proof) why electric charge is quantized.
Escher was the first MC and Giger invented the HR department.
Are you serious? All this fuss about "fake" monopoles? Honest questions. I read one news article about this and it seemed they had found real particle monopoles. But then, I'm not a physicist.
Normally, all cars are diaxles. But these guys have created a stretch limo so long and stretchy that when a few dozen of them are wrapped around one another in a parking lot, and the front of one is sticking out, it looks like it's a free-standing monoaxle.
If there are independent monoaxle vehicles, then gasoline is a homogeneous liquid. Otherwise, according to Maxwell's equations, it's a bunch of tiny pebbles.
Shop as usual. And avoid panic buying.
Your Jedi mind tricks do not work on me!
There would be no net force once equilibrium was reached. The magnetic monopoles on the other side - the ones nearer to the unfavorable pole - would feel just as strong a repulsion trying to turn the wheel the other way, and no net motion would result.
I'm not a physicist either, but slashdot poster ajs is and he backs me up on this, so I think I read it right.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton