Zoony is right that there is a vast difference between genuine scifi and fantasy. Of course scifi is fantasy because its a myth that someone creates but proper scifi has the 'what if' element which is not necessary in fantasy. Unfortunately the boundaries are being blurred from both sides. Most scifi published these days seems to be more fantasy than anything else so I don't bother. Another problem is that as we learn more about thy universe, some older scifi looses its realism. I don't in general read fantasy, Lord of the Rings being an exception, but I will watch films just to see how technically convincing they can be. Real, new, 'could happen,' scifi is a rarity these days so I have stopped looking.
Mike.X