Magnetic monopole deficit hints that hunt is futile - New Scientist - New Scientist

Magnetic monopole deficit hints that hunt is futile: Unlike electric charges, which abound as individual positives and negatives, magnets seem always to have both a north and south end. Yet monopoles pop up in descriptions of the early universe and also help to explain why electric charges come in discrete "quanta". If monopoles actually exist, will we ever spot one?

Our best hope may be to capture a relic monopole from the early universe, but the likelihood of this depends on how many there are near us. The limit on the number of such high-speed relic monopoles that could inhabit the Milky Way without sapping its magnetic field is called the "Parker bound".

Now readings from ANITA, a balloon-borne neutrino telescope based in Antarctica that can also detect monopoles, suggest that the maximum is just 1/10,000th of the Parker bound for monopoles moving close to the speed of light, says David Besson at the University of Kansas, Lawrence, and colleagues.