If someone could positively answer all of those questions, they would be pretty rich and pretty famous.
The only one that can be answered, maybe, is "How did the scientists figured it out?" There is a great documentary on 'Brilliant Minds' airing right now about Galileo, Newton, Einstein, and Hawking. It took a lot more than just them, but they talk alot about how their work was completed.
Believe it or not, the greatest minds worked mostly in their heads, had extreme abilities to focus and see in pictures. They figured out what we do know (think we know) by observing fundamental laws of nature. This can especially be said about Galileo and Newton. Einstein and Hawking probably did/do this in their head.
Black holes are real and are becoming better understood every day, but to explain them would require some theoretical comments.
I don't know man, read what you can and start small. Oh, and don't be afraid to challenge anything.