It's a shame that the History Channel presents a theory that was postulated some 25 years ago but has since been proved wrong or at least unnecessary by most scientists, without even mentioning that this theory is outdated and mostly abandoned.To begin with, the theory was based on a hypothesis that mass extinctions occur on regular 26-million year intervals. This is no longer believed to be true. In addition, recent analysis of data on outer solar system object orbital patterns suggest that Nemesis couldn't possibly exist. And several detailed astronomical surveys that should have detected Nemesis failed to do so.The History Channel should stick to facts, or at least mark unpopular hypotheses as such.