While each movie strives to introduce its own questions and theories during its course, most, if not all, tend to reuse some ideas. This leads to the idea of tropes, or a common theme or action that is reused across a given genre.
When it comes to Sci-Fi movies, there are a series of tropes that have been widely recognized as part of the genre and in most cases, are accepted without it feeling like the movie has been done before. While some tropes in this genre may seem similar, a lot of them are very different but still use the same basic principles.
The Chosen One
The Chosen One is one of, if not the most used trope in not just Sci-Fi movies, but in most movies across various genres. The concept simply follows the belief that there is one singular person who can be a savior, whether it be to kill the unkillable or end the war that's been waging for centuries.
The Kylo Ren and Rey. While this may be overused, it's one of the few that may never get old.
Time
Time, as a whole, is a very common topic for Sci-Fi movies to touch due to its very complex nature and the various theories that stem from the concept. One of the most commonly used is the idea of time traveling, with popular franchises such as Terminator and Back To The Future using the idea to shape their plots.
Another time-related trope is the idea of a time-loop, where the main character is set to repeat the same day over and over until they make the right change. Happy Death Day used the concept and the escape was the main character finding her killer.
Post-Apocalyptic
A common trope in a lot of Sci-Fi movies sees the main character living in a new, post-apocalyptic world. Sometimes the main character will be part of a group of survivors and sometimes they are alone and traveling the wasteland.
One recent and popular example of this is Love and Monsters, which sees the main character leave his hidden development and travel in the open to find his old girlfriend. The world, which is now abandoned and covered in overgrown plants, has roaming monster bugs and animals that caused this apocalypse and forced people underground and in hiding.
World-Stealing Aliens
Aliens have been in Sci-Fi movies for as long as they have been made, thus causing multiple different tropes within this broader trope. One of the newer takes on Aliens in Sci-Fi movies focuses on aliens wanting to take Earth as a new home.
This can be for a variety of reasons; the alien's home planet was destroyed, the aliens are rouge and looking to settle, or they are just looking to expand. One popular take is the movie The Darkest Hour which saw aliens, in the form of balls of light, try to eradicate humans and take over.
World-Killing Aliens
Sometimes, Aliens long for a new place to settle, and sometimes they are looking to take out their aggression on the “weaker life forms.” This common trope, which can be seen in movies such as Independence Day, typically has scientists discover an incoming alien vessel.
Usually, they will try and approach it peacefully, only to be met with War of the Worlds.
Wormholes
Space travel is an essential building block for most Sci-Fi movies due to people knowing very little about the vast majority of space. While scientists are making new discoveries every day, there is still plenty left unknown or theorized, one being the use of Wormholes.
A popular theory, a wormhole can be used to travel a vast distance in space in a matter of seconds, thus simplifying space travel and making it possible without the need for cryogenic sleep. One of the most popular uses of this concept is future version of humans leave a wormhole for past humans.
Artificial Intelligence
Artificial Intelligence is a Sci-Fi movie trope that is slowly becoming more and more of a reality with technological advances every day. In Sci-Fi movies, typically, artificial intelligence is used to better assists humans in their everyday tasks. Sometimes it’ll come in the form of a phone or program, but typically it’s used in robots.
While at first everything is ok, slowly the AI becomes more self-aware and eventually decides humans should no longer have freedom. A recent use of this concept was in Ex Machina.
Dystopian Government
Dystopian governments are typically set up in the aftermath of an apocalypse where a certain group, typically elites, rise up and lead. In most cases, these governments will take advantage of the poor and weak, typically by hoarding an essential, while living in some form of Luxury.
Priest, which sees the world overtaken by vampires and the churches taking charge of the world by offering protection inside of their walled cities.
Alien Ancestors
The idea that Aliens either live beside or came before humans has been a common theory both in and out of movies. The idea is simply that Aliens helped shaped ancient civilizations and helped build them up.
One recent movie that explored the idea was Alien franchise. The movie saw the main characters find cave drawings depicting the ancient aliens and follow them as they travel to their home planet. However, things don't go as planned and they actually land in a testing spot for the original creator's weapon.
Space Pirates
With the comparison of space travel to ocean travel, a lot of Sci-Fi movies expand upon that idea with the inclusion of space pirates. While they may not look like the typical pirate, the idea follows a single person or group traveling through space and looking for a hidden treasure or looting and pillaging.
