―Raj Koothrappali, The Monster Isolation Rajesh Ramayan "Raj" Koothrappali (Hindi: राजेश रामायण कुथरापाली, Tamil: ராஜேஷ் ராமாயண கூத்ரப்பலி), Ph.D., is a main character in The Big Bang Theory. He is an astrophysicist and Howard Wolowitz 's best friend.