It was a low-research day! The most productive moment came early in the morning, when I had a great discussion with Boris Leistedt (NYU) and Adrian Price-Whelan (Princeton) about the structure of my group meetings at CCA. We need to change them; we aren't hearing enough from young people, and we aren't checking in enough on projects in progress. They agreed to lead a discussion of this in both group meetings tomorrow, and to make format changes, implemented immediately. I have to learn that failing to do things right is only bad if we don't learn from it and try to do better.
Right after this conversation, Price-Whelan and I got in a short discussion about making kinematic age estimates for stars, using widely-separated, nearly co-moving pairs. I hypothesized that for any real co-moving pair, the separation event (the spatial position and time at which they were last co-spatial), will be better estimated than either the velocity or the separation, given (say) Gaia data.