I know I'm dealing in hypotheticals, but say I get my PhD in Nuclear Engineering, and I decide to start a business or go to work for a private company for say 5-10 years. If down the road I decided I wanted to try and become a professor, would I still be eligible for post-doc positions in order to get published and bring my knowledge of current literature up to date? Because as I am looking at it right now, it seems like if a person wants any chance of becoming a tenure track professor, the only time they are going to be able to try and take that chance is directly after their PhD when their publications are fresh and they are knowledgeable about current literature so they can be hired for post-docs. If there is any gap, even a few years, you could be basically rendered obsolete and all the work you put into your PhD would no longer be applicable in the academic world, although maybe you could find a job in industry. Sooo my question is basically, if you don't try to go down the road of getting the tenure track directly after finishing your PhD, will you lose the chance to become a professor forever?