Hi, I have a B.sc with first class honours, with a major in biochemistry and I want to do a phd in astrophysics. I have two years of undergrad physics and a good knowledge of vector calculus, DEs, linear algebra, etc. What are my chances of getting into a program? I know in america you guys have a standardised exam for grad school entry, but we don't have that here. Does it depend on finding a phd supervisor willing to take me?