Differences between writing sci-fi and writing fantasy?

Well, fantasy is, as my friend so eloquently puts it, made up shit.  Sci-Fi is also made up shit, but it’s made up based on a thing, an idea or hypothesis or theory, that has happened or could maybe one day happen some time in the future, possibly.  AI or contact with Aliens, for example – things that haven’t happened yet but could.  Or may not.

For me personally though there isn’t a huge amount of difference.  I write about things I enjoy and am interested in.  I love science, but I also love mythology and folklore and history which are all things you would typically research when writing a fantasy.  Even fantasy not set on another world.  JK Rowling for example didn’t really just make it all up as she went along – so much of that stuff is based on what were real beliefs, myths and legends.