So let me get this straight. This "dark matter" stuff exerts enough gravitational energy to keep the Universe from expanding forever but: It never seems to hit Earth even though Earth has it's own gravity. Somehow in all the billions of years Earth has been in existence they can't scrap ANY of the stuff off of ANYTHING. It's totally invisible except for it's gravitational influence. It emits no energy of any kind even when it's heated to millions and millions of degrees around stars and stuff. The dark matter theory has as much validity as AGW.
Wanna buy some Dark Matter Credits?