Science fiction is cool because it allows heroes to do crazy stuff like bounce around on meteors, fire laser cannons, and make a difference in the world. It makes sense that people look up to these astro-good guys. Here are six of the best sci-fi heroes who always saved the day. May Green Lantern's light be with you, or whatever.

Luke Skywalker. The protagonist of the first three "Star Wars" movies is a classic, archetypal hero. He comes up from nothing, discovers his true potential as a crusader for justice, and saves the universe from evil. He also finds out that his dad is part of that evil, and he gets a cool robot hand in the same night. And he almost makes out with his sister. This is all basic Joseph Campbell-type stuff.

Space Ghost. He looks like Batman in space, but he's so much more than that. Okay, so he wasn't that much more than that, but he did save the day a lot, with the help of his sidekicks, Jan and Jace, their pet monkey Blip, and his Phantom Cruiser. His power bands and inviso-belt probably didn't hurt, either. When he retired from interstellar crime-fighting, he got a sweet gig as a talk show host. Let's see Skywalker carry a show for ten years.

Green Lantern. Another member of the "outer-space superhero" subset, Green Lantern's adventures were recently turned into a big screen movie starring Ryan Reynolds, but he's been dealing with threats both foreign and domestic in comic books and on TV for decades. He has a pretty cool power ring that can make anything he imagines real, but even with power like that he manages to bump into bad guys that can challenge him.

James Bond (in "Moonraker"). Agent 007 is usually confined to the surface of the Earth, but for one brief, shining movie, he made the journey to the stars and into the ranks of sci-fi heroes. Sure, it's generally considered the worst Bond movie (which is nonsense, there have been several worse ones), but how can that be when there are all those laser beams getting fired around? Sometimes you just have to accept the gift that you're given.

Samus Aran. The heroine of the "Metroid" series of games pretty much defines "sci-fi hero". She has an awesome power suit, a cool arm cannon, and a wicked spaceship-what more do you want? Although her occupation is technically listed as "bounty hunter", she actually spends a lot of time clearing areas of evil Space Pirates and other alien scum.

Iron Man. Not all sci-fi heroes have to travel to space. Take the metallic star of the "Iron Man" comics, TV shows, and movies. He's undoubtedly sci-fi; just look at him. But he tends to stay a little closer to the ground, unless he has to leave the atmosphere with The Avengers or something. The point is that he's always saving the day-isn't that what matters?