Science fiction is the imagination of a world that is different from our own. It often employs a plethora of everyday objects, interactions, habits, and occurrences in order to juxtapose this new and imagined world. Sometimes, these rudimentary happenings themselves are reimagined as often occurs in dystopian fiction.
Technology plays a central role in much of science fiction and I anticipate that science fiction will become more popular because of this. We are more intertwined and dependent upon our technology now than ever before. As technology continues to advance and take up more and more space in our daily lives, it seems possible that it will take up more and more space in our fiction.
War of the Worlds is an interesting example to use when attempting to define science fiction because the whole arc of the story, the catalyst, is a creative answer to the age old question are we alone in this universe? For many centuries and even to this day, the majority of answers to this question fell somewhere along these lines:
humans are not alone in this universe (because there is a present and loving God or gods who manipulate our fortunes etc.
or
humans are alone in this universe

Science fiction and War of the Worlds especially explores the gray area between these two answers. When confronted with somewhat stark answers to a meaningful question, science fiction tends to offer up a third (or fourth or fifth) creative and imaginative possibility by stretching the facts of the known world. A story like War of the Worlds imagines that humans are not alone in this universe and that there are other sentient beings living on other planets. They come down to Earth and try to take over due to the same sort of self-preservation ideologies that control human beings. This kind of creative answer to this age old question is emblematic of the possibilities of science fiction