I was about to come in and mention "Passengers" myself. It seems rather divisive among critics, but if you're a sci-fi buff like... basically everyone in here, you'll probably love it. It reminded me of "Mad Mad: Fury Road" in that it marketed itself as one thing but ended up shining for how much it was something else - in this case, they marketed it as a comedy/romance/adventure and in so doing duped everyone into watching a pretty good hard sci-fi piece (minus the magic engine and the energy shield, but those I can forgive this time).
Needless to say I was also a big fan of "Serenity," so now we've got that one covered ;P
I'd also recommend these:
- "Solaris" (I only saw the recent remake, so that one): A psychologist is sent to evaluate why everyone aboard a research station has either mysteriously died or gone insane, and in the process encounters what I judged to be a Matrioshka Brain.
- "Space Brothers": A businessman loses his job and decides to switch careers and become an astronaut, thus giving the audience a tour de force of the (very near future) nature of astronaut training and space exploration.
- "Arrival": Not what it looks like at all. Aliens arrive on Earth (duh), but in the process of decoding their language the protagonist comes to terms with some disturbing yet deeply empowering revelations about the nature of time.
- "Interstellar" (another obvious one for this crowd. I probably don't even need a description but meh, have one anyway): A mortal man must deal with the cruelly harsh consequences of General Relativity in his desperate effort to find a way to avert humanity's self-inflicted extinction. If nothing else, watch - or rather, listen to - this movie because its soundtrack is a thing of surreal beauty.
- "Battle Angel Alita": A defunct cyborg girl is resurrected by a curious scientist in a grungy cyberpunk dystopia, where she makes use of her unique skills to build a career as a champion of justice, climbing the ladder from vigilante to superheroine. Currently only available as a manga and OVA, but next year a blockbuster movie is planned under the direction of James Cameron and Robert Rodriguez.
- "BLAME!": Another cyberpunk world, in which a lone cyborg wanderer spends his life searching the bowels of a seemingly endless multilayered cityscape for a remnant of the original, unaltered humanity, with which he hopes to regain control of the feral robots controlling the city and thereby save what few people remain. Not an easy read due to its minimal dialogue, but worth the effort for the scale and macabre beauty of the setting. If you have too much trouble, a good alternate option is "Knights of Sidonia" by the same author, Tsutomu Nihei.
Formerly known as "parameciumkid."