The science fiction genre remains difficult to define, as critics and proponents alike fail to agree on what constitutes science fiction. However, a few common characteristics categorize a work as "sci-fi":
Aliens are one of the central characteristics of the science-fiction genre. A sci-fi novel may deal with aliens coming to Earth, humans encountering aliens on space explorations or a number of other variations. Sometimes the aliens are friendly, while other works portray aliens as mortal enemies.
Space travel is a common element of sci-fi, regardless of whether or not it features contact with aliens. Space travel pops up in fiction over and over again as humans wonder whether or not they're alone in the universe, and what might happen if humans encounter other life forms.
In scientific theory, time travel is possible based on potential technologies utilizing scientific knowledge. In fiction, time travel poses many questions, including that of the time travel paradox, and it is a popular topic for science fiction, as protagonists can glimpse the future or change events in the past.
Futuristic Setting Or Alternate History
Even if there's no time travel involved, science fiction novels are often placed in a futuristic setting, while other sci-fi novels feature alternate histories. Whether moving forward or back in time, very few sci-fi novels are set in the present day.
Early science fiction writers and editors focused on the hard science of science fiction, and much of that incorporates the development of advanced technology, or creative ways to utilize existing technology. As the last century has seen big advances in technology, it's not difficult to imagine some traditional sci-fi technology that could be very real in the future.
Additionally, some science fiction writers have proven almost prophetic in predicting the rise of technology that didn't exist during their time-notably Jules Verne, although other writers have foreshadowed or outright predicted other pieces of technology.
One common theme of many science fiction novels is a dystopia set sometime in the future. Dystopia sci-fi themes are often used to explore current social issues, and they have very little to do with science, except dystopian fiction that revolves around technological mis-utilization. "Nineteen Eighty-Four" is a good example of a dystopian sci-fi story.
Exploration Of Popular Societal Or Cultural Issues
Much of sci-fi attempts to explore popular societal or cultural issues through a sci-fi setting. These issues range from class struggles to misuse of technology, and sci-fi gives voice to the concerns of the society in which they are conceived. Common social issues include a world destroyed by war; a world destroyed by overuse; a world in which the government controls everything; or a world in which genetic experimentation has gone terribly awry.
Science Fiction Follows Scientific Rules
Whether or not it utilizes hard science, science fiction novels follow scientific rules, to some degree. They may follow an extrapolation of scientific rules or unfamiliar scientific principles, but sci-fi sticks to certain rules nonetheless, as opposed to an arbitrary system of the author's devising.
Many sources say the "Father of Science Fiction" is Jules Verne. While Verne undoubtedly deserves credit as a pioneer in the genre, he isn't alone, and others deserve equal recognition.
Science fiction writings of the nineteen forties and fifties continue to prove their relevance despite the pursuit of many film goers for the novel gadgets of our day.
Despite the declining readership of science fiction magazines, there are more than ever.