Time dialation question

I think we've all read the standard example where an astronaut leaves earth travelling at nearly the speed of light for a year, then comes back and is many years in the future. However, I'm having difficulty understanding one specific part of this story. From what I understand, it's perfectly OK from the point of view of the astronaut to say that the *earth* is moving away from him at nearly the speed of light. So wouldn't that imply that from his POV, it is the *earth* that is time-traveling into the future? So from the earths POV, the astronaut is traveling into the future, but from the astronaut's POV the earth is traveling into the future. So what determines which point of view "wins" when the earth and the astronaut come back together? Archived source: https://web.archive.org/web/20101205113622/http://www.spacetimeandtheuniverse.com/general-physics/4193-time-dialation-question.html