I am in the final semester of my bachelors in Mechanical engineering, my aggregate %age is only 65. I am interested in studying physics, astronomy, I always wanted to, but I opted for engineering after my higher secondary(10+2) instead of bachelors in physics. Now I feel that it is too late to start doing what I am passionate about. I was quite depressed during last few years and could not concentrate on my studies.I have, I would not say excellent, but a fair grasp of my subjects. But something tells me that I should go for it. I am from India, the education system here is quite different than that of the U.S. and Europe, we do not have the concepts of major and minor in engineering, there are just subjects divided in 8 semesters. My problem is that my scores are not good enough for universities in the U.S., also I do not know anything about the admission process. I have visited several universities' websites and they all say something about recommendation letters from faculty who are acquainted with the my academic or research qualifications. Am I good enough to study masters in physics in U.S.. after bachelors in Mechanical engineering with average scores.I know there are a lot of good institutions in India like the IITs, but I want to move out on my own. I have heard about GRE, If I score good in this test, will it help?