If you follow science news on the Internet at all closely, you will have seen recent discussion of the possibility of faster-than-light travel dependent on some actual implementation of Star Trek's warp drive (here, for example).
The conclusion of such speculation seems to be that without expending the entire mass energy of the universe, faster-than-light travel is impossible. This, however, is a complete misunderstanding. To travel faster than light, for example on a mission to the planetary system of our nearest neighboring star, Alpha Centauri, all you need do is set off at an acceleration of 1 g, or 9.8 meters per second per second -- which is the acceleration due to gravity at the Earth's surface, and just keep going.
After one year at an acceleration of 1 g you will find yourself about one half light year from earth and your current velocity will be 1 C, or 299 792 458 meters per second. After another year, you will be travelling at 2 C.
If you are planning to stop and turn for home when you reach Alpha Centauri, which is at a distance of 4.367 light years from Earth, this is the time you'd better be thinking of turning your rocket ship around and using your 1 g thrust motor to slow you down to a standstill relative to the Earth by the time you reach Alpha Centauri.
Altogether, the trip will have taken you around four years—four years, that is, by the clock on board your space ship, or as measured by the biological processes of aging you have experience during the trip.
To the folks back home, however, the trip will have taken a vastly greater amount of time. Indeed, by the time you get back home, your children if any, and grandchildren, will have long since died, and indeed human civilization itself may have passed away. Thus, if you are space travel enthusiast, you should be careful about what you wish for.
Related:
Nick Herbert: Faster Than Light: Superluminal Loopholes in Physics
