Sci-fi uses the images that sf - starting with H.G. Wells - made familiar: space travel, aliens, galactic wars and federations, time machines, et cetera, taking them literally, not caring if they are possible or even plausible. It has no interest in or relation to real science or technology. It's fantasy in space suits. Spectacle. Wizards with lasers. Kids with ray guns. I've written both, but I have to say I respect science fiction enough that I wince when people call it sci-fi.
Ursula K. Le GuinIf one believes that words are acts, as I do, then one must hold writers responsible for what their words do.
Ursula K. Le GuinA panda walks into a tea room and ordered a salad and ate it. Then it pulled out a pistol, shot the man in the next table dead, and walked out. Everyone rushed after it, shouting "Stop! Stop! Why did you do that?" "Becuase I am a panda," said the panda. "That's what pandas do. If you don't believe me, look in the dictionary." So they looked in the dictionary and sure enough they found Panda: Racoon-like animal of Asia. Eats shoots and leaves.
Ursula K. Le Guin