Question

if u could travel at the speed of ligt without fuel, where would the energy required for the engine come from? is this possible?

Would gravity control be helpful?
Antimatter?
Warp-Drive?

I need help answering this question:-(

Answer 1

Would the magnatic sail be helpful?

Answer 2

Would this be right?
if I could travel at the speed of ligt without fuel, the energy would come from a plasma.