It's said that any sufficiently advanced technology is indistinguishable from magic. Likewise, we could say that any sufficiently advanced species is indistinguishable from divinity. Erich von Daniken theorized in CHARIOTS OF THE GODS and other books that classical myths were based on visits from alien astronauts who constructed ancient artifacts that, to von Daniken, seemed too advanced for Earth technology of the time. In STAR TREK, deities from Terran mythology were sometimes revealed to be super-powerful aliens, as when the Enterprise crew encountered Apollo on a distant planet.
Many science fiction and fantasy authors, accordingly, have transmuted beings from myth and legend into aliens of sorts. Atlantis, a favorite motif for storytellers who want to invoke the concept of long-lost advanced science, is the ultimate source of magic and wisdom in Marion Zimmer Bradley's Avalon series (posthumously continued by Diana L. Paxson). Julie Kenner's Aphrodite series features superheroes who get their powers from the Greek gods. Classical deities and demons populate the complex mythos underlying Sherrilyn Kenyon's Dark Hunter stories. Angela Knight draws upon Arthurian legends in creating her witches and vampires and their other-dimensional home, the Mageverse.
When an author creatively crosses over -- or blurs -- the lines between myth, legend, fantasy, and science fiction, how much can traditional characters and motifs from the cultural group-mind be changed without risking loss of the archetypal elements that make them resonate as strongly with the contemporary audience as they have with people of past eras?
Incidentally, I'll be one of the Jewels of the Quill October spotlight authors. Stop by www.JewelsoftheQuill.com anytime in October and find out how to win a free book.