Re: "They must know about each other," Lelli said.
I get a chuckle in that talking about visible matter and the dark matter is couched in anthropomorphism. :)
Alex
"There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge."
-- Isaac Asimov