In the new movie "Upside Down," Jim Sturgess and Kirsten Dunst are would-be lovers kept apart by -- wait for it -- different gravitational fields. Their unique dilemma ups the stakes on the ordinary obstacles, like mere feuding families, which Romeo and Juliet had to contend with.

For a lot of cinematic duos, being with the one you love is damn near impossible, especially if one (or both) of you aren't even human. "It's complicated" doesn't begin to cover some of the issues these movie lovers have faced when even time and space conspire to keep them apart. Some of them managed to make it work, while others faced a huge sacrifice or had to give up on love all together.

Below, we've rounded up 10 star-crossed lovers from sci-fi movies, who tried to make a go of it against all obstacles.

RELATED: Jim Sturgess on Kissing Upside Down and Acting With a Hangover

categories Movies