I am from India. I have done B.Sc in electronics, M.Sc in electronics, M.Tech in nanoelectronics and currently have four years of research experiences in nanoelectronics. But now I want to shift from this career and get a Ph.D in astrophysics from the universities in USA. Can anyone tell me is this allowed? I have no prior degree in physics but have grown a deep love for astrophysics over the past few years and now am ready to take up GRE and spend the rest of my life doing researches in astrophysics.But my only concern is whether I would be allowed by the universities to do so since I had done my graduation in electronics and not in physics. Please suggest me.