Do magnetic monopoles exist?

[PhysicistIN]

A magnetic monopole is a hypothetical particle in particle physics. It is a magnet with only one magnetic pole (a north pole without a south pole or vice versa). We know that when a magnet is divided in to two parts,both of them will have a north pole and a south pole, instead of forming monopole. In more technical terms,a magnetic monopole would have a net magnetic charge. But such particles have never been observed and recent searches have still not found any. But the grand unified theory and super string theory predicts their existance

[rpenner]

I'm skeptical of the claim that string theory, if it models the physics of the universe, requires monopoles to exist. Experimentally, if they exist, they are quite rare and the only two reported sightings of them have been retracted or written off as probable equipment glitches.

[Walter L. Wagner]

The 'Price event' of 1975 was discovered before strangelet theory was developed. The event was of a particle that passed through a balloon stack of Lexan polycarbonate, leaving tracks in over 32 sheets stacked on top of each other. Analysis of the track showed an event of almost uniform ionization as it passed through the stack, and exited at the bottom side. The computed charge was very close to 137. It appeared to be a likely magnetic monopole track. However, a very massive strangelet of similar charge would have also produced a similar track due to relatively little slowing.

The charge of the particle interacts with the electrons of the polycarbonate, causing ionization damage and loss of kinetic energy of the particle, hence they will slow. Electrically charged particles increase their ionization rate as they slow, allowing for identification of the electric charge. Magnetic charge should not increase ionization as the particle slows.

Because of the intriguing evidence, searches are planned for the LHC to detect possible creation of magnetic monopoles, as well as possible creation of strangelets. The possible danger of strangelet creation is being set aside.

[pluto2]

Because of the intriguing evidence, searches are planned for the LHC to detect possible creation of magnetic monopoles, as well as possible creation of strangelets. The possible danger of strangelet creation is being set aside.

Proton-decaying magnetic monopoles pose no danger to the Earth. That is because cosmic rays rule out any form of danger. And btw we have never observed a proton decay.

Cosmic rays collide with the Earth's atmosphere at unparalleled number of times, and many with energies exceeding millions of times if not tens of millions of times than what the LHC can ever hope to achieve. If the LHC produces magnetic monopoles then that will also mean that cosmic rays have been producing monopoles for billions of years.

Remember all the vast number of planets and the stars they have collided with for billions of years and yet they still exist. The Sun's gravity is 28 times that of the Earth and with the escape velocity approaching 55 times that of the Earth, with 109 times the diameter of Earth, yet the Sun is still shining.

Don't forget that there are stars far more massive than the Sun (approaching 100 times the mass of the Sun, and many with the diameter of hundreds of times that of the Sun).

The LHC is no comparison to the cosmic rays, it is a microscopic toy when compared to the nature's most powerful accelerators.

[Billy T]

Perhaps but as small black holes:

At least 10 years ago a Cornell magazine I get, told that some science students had been given real money accounts to invest a year earlier and that a large fraction of those who did switched out of engineering college to go into more business oriented program of study. That made me so mad that I decided to write a cosmic horror story, Dark Visitor, DV, which was really a introductory physic book in disguise – hoping to get some pre-law, business majors etc. to wonder if it was true, if it could be true, that the Northern Hemisphere, NH, would soon be thrown into a permanent ice age by the impulse of the DV passing thru solar system 12 AU from Earth. (Changing Earth´s eccentricity slightly to made NH´s summers cooler and winters slightly warmer* with massive “spring snows” all winter long, that did not completely melt in the following colder summers. - All ports useless in a few decades as ocean levels fell, etc. I.e., if true they were not going to become rich, but dead as even Miami permanently iced over. Albedo much lower, etc.)

One of the chapters describes four or five things the DV could be. One was a very dense collection of N & S monopoles. (Theory predicts each may be thousands of times more massive than the proton.) So even though small (< a solar mass) they would have collapsed into a black holes with zero visibility and could change the earth´s orbit, which is “just on the edge” of an ice age already. I noted that unlike magnetic dipole´s inverse cube at best mutual attraction, the mutual attraction the monopoles is isotopic and inverse square so most formed during the big bang have collected together by now to form these small black holes – why no monopoles have been definitely found.

Unfortunately, now it is too late to increase the number of science and engineering students - the orient has overtaken the US in these critical areas.

* The mainly oceanic SH is also hotter when closer to the sun with greatly increased evaporation - supplying the mass of water that falls as a hundred feet of snow in the NH´s milder, wet winters.

[Fraggle Rocker]

Unfortunately, now it is too late to increase the number of science and engineering students - the orient has overtaken the US in these critical areas.

We're turning out plenty of fine graduates. The problem is that our merda-for-brains government keeps sending them back to the countries they came from, instead of letting them join our own labor force.

So all we end up with are the so-called "business majors" who can't make change for a dollar without a POS terminal but think they can run a bank. I.e., the people who invented the subprime mortgage.

[machaon]

I remember reading an interview in FEB1984 OMNI magazine with the scientist who actually discovered monopoles. So yeah, they have been known for a while.

[wellwisher]

Say you had a bar magnet with its field set up with its north and south pole. We then place a half-sphere shell around the bottom half of the magnetic, to shield the south pole from sight.

The magnetic field is still set up inside the half-shell, since the shell is away from the bottom of the magnet. However, from a distance we will only be able to see the north pole with our instruments due to shielding. Will this look like a monopole and could you use that to test how monopoles behave?

[Billy T]

Say you had a bar magnet with its field set up with its north and south pole. We then place a half-sphere shell around the bottom half of the magnetic, to shield the south pole from sight.

The magnetic field is still set up inside the half-shell, since the shell is away from the bottom of the magnet. However, from a distance we will only be able to see the north pole with our instruments due to shielding. Will this look like a monopole and could you use that to test how monopoles behave?

While you can drastically modify the magnetic field of a bar magnet with high permability material placed near it you will not "open any field lines" i.e. they will all still be closed loops.

The field lines from a monopole diverge radially. Are "open"

There have been a few observations that could be explainded as due to a magnetic monopole, but no magnetic monopole is available. They would be a permananet particle, like electrons or protons and very valuable as particles to accelerate. - Certainly one could be sold for many millions of dollars as if one were available it could be repeatedly used in better acceleartor costing only a few percent of what a proton or electron accelerator costs.

[rpenner]

I remember reading an interview in FEB1984 OMNI magazine with the scientist who actually discovered monopoles. So yeah, they have been known for a while.

Was the interviewee Blas Cabrera?

http://en.wikipedia.org/wiki/Blas_Cabrera
http://prl.aps.org/abstract/PRL/v48/i20/p1378_1
http://www.theory.caltech.edu/~presk...-monopoles.pdf

How is it possible to justify a lengthy review of the physics of the magnetic monopole when nobody has ever seen one? In spite of the unfortunate lack ofavorable experimental evidence, there are sound theoretical reasons for believing that the magnetic monopole must exist. The case for its existence is surely as strong as the case for any other undiscovered particle. Moreover, as of this writing (early 1984), it is not certain that nobody has ever seen one. What seems certain is that nobody has ever seen two.

At this time, Blas Cabrera's 1982 event has been classified as a weird event and not as an unambiguous detection of a magnetic monopole. It seems remarkable that the methodology has failed to reproduce the detection event and the estimates of flux rates dropped three orders in magnitude in less than a decade.

http://prl.aps.org/abstract/PRL/v64/i8/p835_1
http://www.springerlink.com/content/7x3u6kgnh54gjrn7/

Cabrera was either extremely lucky to have the event happen on his watch, or a victim of apparatus malfunction. On the basis of the 2002 experiment, an experiment roughly one million times more sensitive than Cabrera's 1981-1982 experimental run, we are still awaiting empirical classification of the nature of the magnetic monopole -- it could be that it doesn't actually exist.