Astrophysics is often associated with universities and advanced study; it's seen as scholarly. He's giving a lecture on astrophysics at the university next week.
Pro Tip 2/3
Complexity
The word suggests a complex, specialized field; it's not used for basic discussions about space. Astrophysics equations can be hard to solve without a strong math background.
Pro Tip 3/3
Research Oriented
Astrophysics commonly implies active research and discovery, not just learning known facts. She's published several papers in astrophysics journals.