In many previous comments, people call on professionals to answer questions about specific fields, like physicists, neuroscientists, economists, or computer scientists. There are many people in all these professions on this site willing to respond to questions, but most of the time none of them happen to read that comment.
As a way to fix this, I propose that people well-educated in certain fields volunteer to make an "Ask an X" post where they list their credentials and specialties, and anyone can ask questions about that field. Obviously, this would also be a good place to have a discussion between professionals in that field.
Another possibility is to ask people who don't mind being asked random questions to volunteer to be part of a list that can be posted to the wiki. Then, people could just PM that person directly.