I can say with pride that I lived in an era when men like Stephan Hawking lived amongst us.
1. I can possibly answer your first question. For Nobel in any of the science field your theories must be validated through an experiment where your theory can correctly predict the result of the said experiment, in a nutshell it should be verified by an actual experiment.
This is the reason why Einstein got his Nobel for photoelectric effect and not much celebrated his relativity theory.