I have a masters degree in Computer Science & Engineering (and currently employed in s/w industry in India), but have no degree in physics. For long, I've been interested in doing research in physics, especially in astronomy, astrophysics or in particle physics.
Are there good institutes or universities in EU, US or India which accept students without any degree in physics to PhD program in astronomy or astrophysics? If so, do they also offer financial assistance or some form of scholarship to such students to meet at least one's tuition fee expenses?
I checked with an institute in Germany that offers PhD in physics but I was told that a masters degree in physics is a mandatory prerequisite. Does this apply to all leading German institutes? What about other leading institutes in EU or in the US?
What are the pros and cons, if any, between doing PhD in US versus in EU, especially in the field of physics (in the subdomains I mentioned, if that too matters)?