Science fiction fandom is like a group of friends who really like stories about space adventures, time travel, lasers, and robots. They love talking about these stories, watching movies or TV shows about them, and reading books about them.
Just like how some kids really love superheroes and talk about them all the time and pretend to be one, people who are in science fiction fandom love thinking about what it would be like to travel to other planets or meet aliens.
These fans also like to dress up as characters from their favorite science fiction stories, play pretend games or video games about them, and go to big events with other fans to share their love and excitement for these stories.
In short, science fiction fandom is a group of people who get really excited and passionate about imaginary worlds and the characters who live in them.