So, I have a Ph.D. in computer science and a lot of programming experience in industry, but I would like to be working on condensed matter physics instead. To that end, I'll be getting an M.S. in physics next spring... but my question is, then what? My advisor in the M.S. program tells me that I should be looking for a post-doc... he says that I already have a Ph.D., so there is evidence I can do research, the M.S. shows that I have physics knowledge, and I have a few papers in collaboration with my advisor that show I can do research in physics. I'm not really convinced though... I don't feel that I have enough physics knowledge in general, and even with the M.S., I'm not convinced that I would be competitive for physics post-doc positions. On the other hand, applying to physics Ph.D. programs at my age seems like madness. Suggestions, comments, and/or ridicule would be welcome.