Personally I think it's because it's the easiest language to write fast code with for vector calculations. It's extremely easy to work with Fortran array proces

Personally I think it's because it's the easiest language to write fast code with for vector calculations. It's extremely easy to work with Fortran array processing and you don't have to worry about pointer aliasing and promising the compiler you won't do it like you do with C. Fortran makes it extremely easy to convert scientific calculations into array or vector based code that is about as optimized as the best C would be, but requiring much less domain knowledge. The downside is Fortran really sucks to work with if you need data structures that aren't array based. I'd much rather do non numeric, or work that needs more abstract data structures in C or C++.