Re: Needing an answer
The most effective way to reach relativistic speeds in science fiction without invoking some kind of technomagic is by using some version of a Bussard ramjet or a light sail. Even if one used photon rockets and matter-antimatter, it would be difficult to attain any reasonable fractions of C with onboard propellant alone. Of course, technologically speaking, the other two options are no piece of cake either.
