When I was a kid, I used to be enthralled by reruns of those Ray Harryhausen Sword and Sandal epics like Jason and the Argonauts and Sinbad, which featured a fearless hero embarking on a quest and fighting terrifying monsters. A decade later, I was equally enthralled when George Lucas' Star Wars hit the big screen, for very much the same reason. And it seemed to me that, other than triremes being replaced by spaceships, and swords by blasters or light sabers, there really wasn't much of a difference between these two.
More recently, this led me to develop the thesis that mythology and science fiction are really the same thing. That science fiction, especially in its most popular, epic literary and cinematic space opera format, is basically mythology and myth-making (mythopoesis, a wonderful word coined or popularised by J.R.R. Tolkien) for the present day. And conversely, classic myths and stories like Odyssey, Beowulf, 1001 Nights, and Monkey's Journey to the West were the scifi of their era.
The Space Opera sub-genre
While there are many sub-genres within science fiction, such as post-apocalyptic, alternate history, time travel, and so on, the one that is, I contend, most predominantly the modern mutation of myth-making (mythopoesis, to use the technical term coined J.R.R. Tolkien), is the classic, epic genre known as "space opera".
At its simplest, Space Opera could be defined as epic storytelling set in outer space or on alien planets, featuring heroic protagonists, high adventure, spaceships and other futuristic technology, interstellar battles, and the fate of the galaxy hanging in the balance. The term itself is a play on "soap opera" and "horse opera" (the latter referring to badly written Westerns). While originally associated with the pulp magazines of the late 1920s and 30s, and the Flash Gordon and Buck Rogers matinees (among the original inspirations for Star Wars), it also came to be associated with literary science fiction, beginning with E. E. "Doc" Smith's Skylark and Lensman series (still the source of many Star Trek and Star Wars tropes), and continued through with Asimov's Foundation series (1940s) and Frank Herbert's Dune (1950s) as the classic and most influential works. Just the book covers alone help define the genre, as shown by the two images above; a spaceship against a starfield, and mysterious figures on an alien landscape. Also of mention are the Perry Rhodan German science fiction series of novels (1961 onwards) and the French Valérian and Laureline comic series (1967 onwards, and now made into a movie by Luc Besson) by writer Pierre Christin and artist Jean-Claude Mézières. Although these defined Space Opera in German and French respectively, both would be closer in both quality and quantity to the work of E. E. Smith than to the more intelligent, thoughtful, and self-contained Asimov and Herbert works.
The list of space opera or possible space opera novels, movies, TV shows, anime, graphic novels, video games, and roleplaying games would be too large to mention here.
Science fiction as modern myth-making
While on the surface it may sometimes seem like mythology and science fiction, even Space Opera science fiction, have little to do with each other. One is based on legends and supernatural stories of the past about deities and miracles, the other about technological and social development along rational lines in the future.
But this turns out not to be the case. With the exception of the "hard science" sub-genre (see my essay), outer space science fiction is often as fantastical as any mythological story, and becomes increasingly more so the more that it pertains to the "scifi" or movie & TV version.
Certainly the roots of High Fantasy (as opposed to Science Fiction) in myth are obvious; Tolkien was a philologist who specialised in old English and Germanic languages, and the entire Middle Earth cosmology with its elves and dwarfs and earlier ages is taken over almost verbatim from Nordic mythology.
But the same can also be said about the type of cinematic, blockbuster Science Fiction (sometimes called "sci-fi") ushered in by Star Wars. George Lucas for example used mythographer Joseph Campbell's The Hero With a Thousand Faces as a blueprint for the Star Wars storyline. The same story also appears in the Wachowskis' The Matrix (see Star Wars Origins - Joseph Campbell and the Hero's Journey - http://www.moongadget.com/origins/myth.html )
What science fiction especially space operatic science fiction, high fantasy, and premodern mythology have in common is that they take place in strange and remote places, representative of the world of the imagination. Often there is a chosen one, a quest, a fellowship of companions that accompany and aid the hero, a villain to be vanquished, a prize to be won.
Take away the technological veneer, and epic science fiction has the same story and the same tropes as in the great adventure myths. Just as Odysseus and his men visit various islands and distant lands abnd face a huge cyclops, sirens, and other dangers, so starship captains travel to distant worlds and with their crew face all sorts of dangers. It wouldn't take much to adapt traditional stories of adventuring and myth making, such as Homer or Wu Cheng'en (author of Journey to the West), to a science fiction setting.
Myth and the Collective Unconscious
Why are these particular kinds of stories, featuring a heroic journey across strange lands or worlds, challenges and trials, and all manner of creatures and personalities, so popular and timeless?
Carl Gustav Jung was a Swiss psychologist and student of Freud who became fascinated by the way certain images and symbols appeared in the dreams and spontaneous fantasies of his patients. On researching these, he would discover the very same myths and symbols in ancient classical works or obscure alchemical texts.
Jung came to the conclusion that there is a common source of myth and meaning, that is universal and appears regardless of culture or historical period. He called this the Collective Unconscious, which he contrasted with the personal or individual unconscious described by Freud. The personalities that inhabit the Collective Unconscious he refferred to as Archetypes, and stated these were the same as what in previous times were called gods. It is these same archetypes that appear time and again, in stories and legends, in different guises but always with the same underlying structure.
Jung's students and followers further elaborated upon his ideas, and also presented them in easier to understand terms (Jung's works are very technical and obscure, with only one, Man and his Symbols, written for the layman).
Joseph Campbell studied how Freud and Jung used myth in psychology, and although he never met Jung, he was greatly influenced by him. Campbell's conception of myth was based on Jung's method of dream interpretation, which revolves around the use of symbols
Campbell's own mythography is more approachable than Jung's, and it is easy to see how Lucas could apply it to his own work. Nevertheless, it's not necessary to be familiar with Campbell or Jung, like Lucas or the Wachowskis, to write an archetypal story. The whole idea of the archetypes, and of a universal mythic consciousness, is that it's something that appears spontaneously. All one needs is the inspiration. The tackiest novels and movies can incorporate archetypal or mythic themes, even if they don't do it very well. While conversely a genius like JRR Tolkien didn't need to read his contemporaries Jung or Campbell at all, because like them he went straight to the source.
Although Tolkien wasn't a non-fiction writer like Jung or Campbell, his comperehensive worldbuilding and storytelling of Middle Earth are the exact literary equivalent. And like Jung he asserted an universal, objective, source of myth of legend, only he called it Faerie rather than "The Collective Unconscious"
What Jung, Campbell, and Tolkien are all saying is we have an intrinsic psychological need to believe in and experience myth and magic in our lives; that this is an intrinsic part of human nature. This being the case, it is certain that science fiction in some form or other will always be with us.