If you want the answer to these and similar questions, try reading "The Physics of Star Trek" - see link below. Be forewarned that most of the discussions in the book show that it is impossible to do all the things you see in Star Trek. Since the arguments are based only on the current knowledge of physics, I like to believe that there is lots of undiscovered physics out there that not only makes it possible, but makes it feasible. It's a pretty good read.
http://www.amazon.com/exec/obidos/tg...99854?v=glance
Slick