Hello friends! Let me start by saying that being a part of this community has been helpful beyond measure throughout my graduate career-thanks for always being so awesome.
I chose to apply to the school which I'm currently attending because of the intriguing work of the lone professor in my area of interest. I came and visited the school, got to sit down and talk with my potential adviser for 45 minutes, loved him and his work, loved the department, etc., and decided to attend. The catch: my adviser was selected for a prestigious research fellowship at (one of) the most influential math institutes in the world (not at the school I'm attending, to say the least...) for the 2014-2015 school year. Great! Meeting with him when I visited, he indicated that this was probably not an issue with regards to our working together-pure math requires pen and paper and not much else so (to a greater degree than for laboratory sciences) the distance really isn't a huge issue, and that he would be back in a year's time anyway. We've been having meetings over skype twice a week since the first week of school. Not only is he a "big shot," but he's completely humble, patient, and an excellent teacher. Everything you would want in an adviser.
Now...every time I mention to someone in the department that I'm working with this particular professor they say something to the effect of "Oh, he's great isn't he! We absolutely love him. We sure hope he's gonna stay with us..." That last sentence.
Now, I should make it clear that he has never indicated to me that he's planning on leaving. He just got his tenure last year. When we talked in April he talked about how the "two body problem-academic edition" influenced his decision to take a position at my current institution, spouse hire, etc. So I've never had much of a cause to allow this comment from people in the department to worry me.
Until now. When we were on the phone on Monday, we were talking about "life stuff" (as opposed to "maths stuff"), and he mentioned the fact that in January, his wife and children were relocating to his location. His wife had a teaching job lined up at the university nearby, and his children were starting school there! Now, he didn't say what sort of duration this new living arrangement would have, and in the moment I didn't think to ask. In fact I didn't realize the implications of what he said until later...
My question to you is...what do you make of this information? I feel that it would be wise for me to ask him directly what his plans are, but haven't had the courage. I also feel as though it's in my best interest to make an excellent impression on him as quickly as possible. How would you frame this conversation? What specifically would you ask? Should I wait until I've had more of a chance to impress upon him my drive and intelligence, or should I try to clarify as soon as possible?
My great apologies for the length, and my great thanks in advance for your advice!