Science-fiction often proceeds science-fact. The latest one is the possibility that future events can affect the past, at least at the quantum level. As Doctor Who said, > Wibbly, wobbly, timey, wimey. Or perhaps a little more elegantly ... > "The future can affect the past, even though the past is a road

There was an interesting letter in this week's New Scientist about Dark Matter, that implies that it's existence is not open to question. The Letter > New Scientist has developed an annoying habit of declaring confidently that "Dark matter makes up 80 percent of the universe's matter ..." without qualification (for example,