Missing Time Discrepancy

Rating: Null/10 (29 March 2006)

It seems to me the premise of the missing time (Jody Foster apparently traveled several minutes through space) is backwards. I have always heard that time on earth remains constant, but slows down or is non-existent in space. Hence, if she was traveling space for several minutes (as the white noise on her tape recording suggests), wouldn't earth time be far greater? Aside from this discrepancy, I think the movie is great. If my information about time and space is incorrect, please help me understand this issue better. It is hard for me to appreciate the movie fully until I resolve this, what I consider to be a fundamental problem.