I have mixed emotions on this one. The ending was a bit too silly for me, and, perhaps it was my confusion, but the movie seemed to imply that time dilation would only be a problem if you landed on a planet-sounds like bullshit to me, as did frozen clouds that solid. Still, it's been a long time since a movie had scenes tense enough to make me hold my breath. And the lack of sound in the space scenes almost brought a tear to my eye. How long did it take Hollywood to get that right?