Since people first looked up at the stars, they dreamed of traveling amongst them. Not knowing what they were or what it all meant, there was always a sense of longing to explore the glittering abyss of space. And as imaginations raced, they were quickened and informed by advances in science and an understanding of the world around us. Soon, science fiction was born, and within that a subcategory of these fanciful tales of epic battles and ships piloting the galaxy; it was called “space opera,” and it’s the basis for some of pop culture’s most sustaining works of the 20th century. “Star Trek,” “Star Wars,” Frank Herbert’s “Dune” series and Isaac Asimov’s “Foundation” works all explored different facets of the wonders held in the cosmos. As people prepare to re-enter the cosmic fray with the latest massive space opera, James Gunn’s “Guardians of the Galaxy Vol. 2,” it seems a fitting time to look at what a space opera is and how a centuries-old subgenre is still captivating audiences’ imaginations.

For all of its pervasive appearances throughout the years, the definition of space opera is an oddly elusive one. It certainly is a subset of science fiction, taking place in a reality closely related to our own, albeit with interplanetary travel and usually alien species interacting in some ways. The term was first coined back in 1941, a play on the derisive parlance “horse opera” used for melodramatic westerns. However, space opera stories appeared as early as 1854, depicting people navigating strange new worlds with unheard of technology and encountering different life forms in an adventure with space travel as the backdrop.

But that vague definition lends itself to many permutations; opposed to the hard sci-fi grounded in current or theoretical science and applications, space opera usually doesn’t bother so much with the technical details, but it can. Think of “Star Wars” and “Star Trek” – both are space operas, and both have faster than light travel and advanced technology, but the latter is usually concerned with the practical ways the technology works and finding scientific resolutions to solve their problems, while the former will simply shrug and say “the Force?” There’s lots of room to maneuver within the niche place of space opera, but it does tend to have some staples.

Impossible ships fueled by some as-yet-to-be-discovered machinery (what was once referred to as “unobtainium” before James Cameron co-opted it for his own space opera, “Avatar“) are the main staple. They travel between different worlds in a shorter manner of time than it would normally take using current spacefaring technology; in “Guardians of the Galaxy,” Peter Quill’s the Milano ship goes to the edges of the galaxy in a few minutes on screen as opposed to taking generations to reach. Sometimes these ships are for merchants/trade (like in “Firefly”/”Serenity”), sometimes they are for military purposes (much of the “Battlestar Galactica” fleet), and sometimes they are a mixture of all of the above (“Star Wars” and “Star Trek” again). But the central idea remains the same: species have learned how to traverse the cosmos in a way that doesn’t impede narrative immediacy and allows for encountering these different planets with various ecosystems, societies and perhaps even creatures on them.

Within space operas lies the ability to tell a whole host of stories, all with an adventure element that propels the action. There can be action stories (“Guardians of the Galaxy”), or political allegories (“The Expanse” books and TV show), metanarratives on individuality (John Scalzi’s novel “Redshirts”), scary tales transplanting our fears into the galactic background (“Alien” franchise) or even comedies (“Futurama”). As long as the story incorporates space travel in some manner, has some manner of melodrama and adventure, and isn’t earthbound for a large portion of the narrative, then it can be coded as a “space opera.” For example, Luc Besson’s upcoming “Valerian and The City of a Thousand Planets” is most assuredly a space opera, but is his film “The Fifth Element” one? A lot of it just takes place on a future earth, but there are excursions to another planet and even a few dogfights between spaceships in the starry plains.

Spectacle (especially in film and comics) absolutely sells the idea and makes people marvel at the possibilities of the human imagination and what could be encountered in space. That’s why so many space operas push boundaries in F/X and some of the most memorable aspects of them are specific shots or creature designs. But spectacle will always be outdone by the next generation of artists and technology; CGI in particular has aged terribly in the 30-plus years that it has been heavily employed in film. And something can look great, but if there’s no real story at its core, something to bridge the gap between the fantastic and the mundane (our world), then it ultimately will be forgotten.

Because space opera is such a malleable subgenre that is capable of multitudes of other stories, the most important element ultimately becomes the characters. Spock, Han Solo, Groot, Leeloo, Bender and a whole host of other space opera characters have become ingrained in our culture due to the strong work in creating them (using familiar archetypes) and gifting them with memorable dialogue that becomes nerdy shorthand within the indoor kid set. Space operas ask audiences to swallow a lot of stuff as given, like interstellar travel, weird alien monsters, universal language translators, ridiculous weaponry, among many others. The only way those fantastic aspects can be accepted, incorporated and not a sticking point for viewers is if there are characters we like or fascinate us that we’re willing to follow, no matter what gobbledygook is being spewed about Dilithium crystals or hyperdrives or wormhole technology. If the audience likes these characters or are interested enough in them in some grounding fashion, then they are willing to sidestep all of the nitpicky elements and go along for the cosmic ride.

That’s what makes “Guardians of the Galaxy” such a quintessential space opera. It has a vast array of different ships zooming between planets, populated by a mind boggling menagerie of different alien races, engaged in an adventure pitting good versus evil…but all while having brilliant characters holding audiences’ hands and reassuring them that this is a fun time. Even the soundtrack, made up of ’70s and ’80s classics, acts as a sonic bridge between the familiar and the fantastic that allows audiences to go along for the ride. James Gunn crafted an excellent entry in the giant space opera canon, and it looks like he’ll be doing the same again with his sequel. With “Star Wars: The Last Jedi,” “Valerian” and other films, novels, videogames and comics all due just this year, the subgenre will continue to thrive. As long as people look up to the sky, no matter what planet they’re standing upon, and wonder “what if,” there will always be a place for space operas in our culture.