According to a paper by the cosmologist Stephen Hawking in 1974, they would rapidly evaporate in a poof of radiation and elementary particles, and thus pose no threat. No one, though, has seen a black hole evaporate.So here is a person who is considered to be an expert on the subject, but who is comfortable enough with how the process works to consider that his theories might be wrong, although everything he knows about the known (i.e. experimental) facts of gravity, quantum mechanics, particle physics, astrophysics, etc. reassure him that he is most likely not. Ultimately, it's Wagner's self-generated certainty, based on purely negative evidence (e.g. "I might be right because you might be wrong"), that makes him the weaker party in this argument.
As a result, Mr. Wagner and Mr. Sancho contend in their complaint, black holes could really be stable, and a micro black hole created by the collider could grow, eventually swallowing the Earth.
But William Unruh, of the University of British Columbia, whose paper exploring the limits of Dr. Hawking’s radiation process was referenced on Mr. Wagner’s Web site, said they had missed his point. “Maybe physics really is so weird as to not have black holes evaporate,” he said. “But it would really, really have to be weird.”
And for the record, the "Cosmic rays" Wikipedia entry was started in 2002, but Wagner's "discovery" was only posted on January 13, 2008 by an unnamed author (which turns out to be a dialup connection in Honolulu - just 'nslookup 188.8.131.52'!), just in time for his re-entry into the blogosphere.