http://videogames.yahoo.com/events/plugged-in/the-real-science-of-halo-reach/1411159

It's definitely worth a visit.

i was hoping they would have done the plasma grenade cool read though

"Not only would a Dyson Sphere require titanic amounts of energy," said Dr. Kevin Grazier, the scientific advisor for Battlestar Galactica, "but finding the amount of mass that would yield a structure with sufficient structural integrity would prove challenging."

Dr, Michio Kaku has a show on Discovery Channel called "Sci Fi Science" where they talk about this stuff all the time. He's a "theoretical physicist and a science fiction fan". In one episode, "Building A New Solar System" he discussed building a Dyson Sphere around the sun. The amount of material it would take equaled roughly the mass of our entire solar system...unless you use graphene, a one-atom-thick planar sheet of bonded carbon atoms that are densely packed in a honeycomb crystal lattice. Not only would this material be thin enough to make it plausible, but it's super strong. It's one of the strongest materials measured.

I couldn't find the full episode, but here's the promo for it.