Then there was the discovery of a monopole at U. Houston. They sent stacks
of lexan sheets up in a balloon, and detected the signature of an extremely
heavy particle which they claimed was a monopole. It was reported in the
NYTimes as big news. A grad student decided to just check a few things out,
and it seems they had mismeasured the thickness of the plates so their
monopole turned into a known heavy nucleus. As I recall the mismeasurement
was a 30% error.
As a professor once said in class "Engineers only have to do one thing
wrong, but physicists only have to be right once." Maybe monopoles change
the past to prevent their discovery?