First of, you will not be able to learn all these things. Or maybe you will learn several of them, but you will only have a working knowledge of at most one or

First of, you will not be able to learn all these things. Or maybe you will learn several of them, but you will only have a working knowledge of at most one or two. Curiosity is good and take it as it is: understanding the concepts and open problems of other science fields. That is very enjoyable, but you will never be a scientist in every of those fields. Now assuming you do that aside your day job. You should remember what you wanted to achieve as a child, and achieve it or some of it. Me I wanted to understand Godel's proofs. So I bought books and currently studying them. Now that overlaps and interferes with my career goal, but that is a problem of my own :) I took a number of MOOCs and enjoyed them: they provide a frame to your learning and short term goals. You can also ask questions to human beings. The issue is they may drive you away from your core goals, since there are not interesting MOOCs on every subject.