Suggest some reading
A master's student in physics? At what uni? Did you ask your professors? Did you look for past PF threads discussing similar questions? (In the most recent, several of us mentioned Matt Visser as a leading researcher who is deeply involved in several of the most intriguing areas of research in gravitation physics.)
An excellent reference for advanced students is http://relativity.livingreviews.org/, a website which offers many authoritative and generally excellent review papers.