Hello everybody. I am considering teaching myself physics in spare time, starting from college physics and multivariable calculus, to a level that I can understand most of the research papers on GR, QFT and cosmology. There are some obstacles that I can foresee: 1. I will certainly get stuck somewhere, especially on the advanced topics. When this happens, I may not find someone to help me out, and have to skip the part that I don't understand. If it happens frequently, I may not be able to proceed. 2. The exercises in advanced-level textbooks usually don't have answers. This means that my understanding will be based solely on the text (and perhaps also by *trying* to do the proof-type problems). 3. The textbooks available on the market may not be advanced/up-to-date enough, so that a self-learner cannot obtain sufficient knowledge to understand research papers by just studying textbooks. (I am not sure about this). I don't prefer to go back to school due to financial concerns, but I really don't want to self-study for many years, only to find myself stuck in a mud pool and can go nowhere. Do you think it is feasible to self-study physics to such an advanced level, for a person with average intelligence and can devote 2 hours per day for the next 20 years? or is there really no choice but to study in school? Could you give me some suggestions on how I can overcome the obstacles mentioned above?