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Again Monopoles

by John G. Cramer

Keywords: magnetic monopoles, superconductors, SQUID, cosmology, Big Bang
Science Fact Article published in the September-1983 issue of Analog Science Fiction & Fact Magazine;
©1983 and 2021 by John G. Cramer.
All rights reserved. No part may be reproduced in any form without
the explicit permission of the author.

A few years ago, physicists at U. C. Berkeley and the University of Houston called a well-attended press conference to announce that they had discovered a magnetic monopole. They reported that they had found a very special track in a stack of photographic emulsions and plastic sheets flown in a balloon over Nebraska , and asserted that this track “could only have been produced by a magnetic monopole or by an energetic nucleus with a nuclear charge greater than 137.” Since the nuclear charges of known nuclei go up only to I07 or so, they concluded that they had observed a magnetic monopole. This announcement was met with great excitement and some skepticism. The magnetic monopole is an object which has been sought for several decades, ever since Dirac pointed out the possibility of its existence and determined the basic unit of a monopole’s magnetic charge.

Unfortunately, the initial skepticism about the monopole’s “discovery” was well justified. It turned out that there were some problems with the Cal/Houston measurement, and it was later essentially declared “inoperative.” But the false alarm had an interesting result. It prompted the Dutch physicist Gerald t’Hooft to consider the possibility that monopoles might be produced by the Big Bang. What he found was that in the early stages of the Big Bang there are intense “Higgs” magnetic fields, which become very tangled. During the rapid expansion of the early universe they become “snarled,” leaving behind “clumps” of magnetic lines which are magnetic monopoles.

These primordial monopoles are very heavy, about 1016 times heavier than a hydrogen atom. Ever since t’Hooft’s discovery of this mechanism, cosmologists have been desperately seeking ways of “turning off” the production of such monopoles, but have found them to be essentially inescapable. Their presence represents a serious criticism of the Big Bang cosmology, for no such monopoles have ever been observed.

There are problems with detecting heavy monopoles: they are likely to move very slowly and will not produce much ionization in detectors. But their detection may have been accomplished. Professor Blas Cabrera of Stanford University recently constructed a “monopole trap” consisting of a loop of four turns of superconducting wire connected to a SQUID (Superconducting QUantum Interference Device) magnetometer capable of detecting extremely small magnetic fields. Cabrera reasoned that if a slow monopole passed through his detector, even if it were very massive and moved very slowly, it would necessarily “thread” its trailing lines of magnetic flux through the loop, and this would be registered by the SQUID.

After this device had been in operation continuously for 126 days, on St. Valentine's Day, February 14, 1982, the apparatus showed a flux change of exactly the right size to correspond to the passage of a magnetic monopole with one Dirac unit of magnetic charge through the loop.  So far, only one such event has been recorded.

There is an amusing sidelight to this result. Cabrera works at the Stanford laboratory of Professor William Fairbank, who has recently announced the observation of fractionally charged objects on superconducting niobium spheres (see “New Phenomena," Analog, February l983). The Dirac estimate of the size of a quantum monopole magnetic charge was based on the assumption that the electric charge on the electron is the minimum possible electric charge. Fairbank’s fractionally charged objects, if taken seriously, would indicate that the minimum electric charge is three times smaller. And this would make the monopole charge three times larger than the value which Cabrera has observed. Thus, if Dirac's calculation is applicable, these two remarkable results from the same laboratory, monopoles and fractional electric charges, cannot both be correct! Or is Nature even trickier than we thought?

John G. Cramer's 2016 nonfiction book (Amazon gives it 5 stars) describing his transactional interpretation of quantum mechanics, The Quantum Handshake - Entanglement, Nonlocality, and Transactions, (Springer, January-2016) is available online as a hardcover or eBook at: or

SF Novels by John Cramer:  Printed editions of John's hard SF novels Twistor and Einstein's Bridge are available from Amazon at and .  His new novel, Fermi's Question may be coming soon.

Alternate View Columns Online: Electronic reprints of 212 or more "The Alternate View" columns by John G. Cramer published in Analog between 1984 and the present are currently available online at: .

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