Science Fiction or Fantasy?

Someone posed the question recently as to whether my book Timecrack was a sci-fi or fantasy story? A good question, as apparently there is some confusion as to where the division lies. A quick answer might be that it falls into a category sometimes called science fantasy.
The answer might be a little simplistic as a great deal of discussion has taken place about the two genres, each with their own history of development. Both traditions go back a long way, but fantasy can probably claim to be the oldest when one thinks of the many religious stories and myths surviving from the earliest human settlements: the ancient Mesopotamian, Minoan, Egyptian civilisations, and so on.
From what I can gather, science fiction’s beginnings can be traced back to a more recent date. In the seventeenth century (1638), The Man in the Moone by Francis Godwin was published posthumously. How successful the work was, I don’t know, but Godwin seems to have been a man much influenced by developments in astronomy, and a man ahead of his time. Much more recently, over 200 years later, the Oxford English Dictionary noted the use of the term “Science-Fiction” (in 1851) in William Wilson’s A Little Earnest Book Upon a Great Old Subject.
For me, science fantasy began in the Forties when my aunt in Canada started sending me comics, featuring Superman, Batman, Captain Marvel and the many other characters that would stimulate my young imagination. Needless to say, my interest and fascination with the subject grew from there, until many years later I decided to write the Timecrack series.
There is a great deal more information on the subject, and something you may want to check out for yourself. But someone has written that science fiction investigates and entertains the reader with what is possible, while the world of fantasy explores the impossible. I think that about sums it up for me.