0 someone who studies astrophysics (= the study of stars and other objects in space using physical laws) :
The director of the planetarium is a well-known and popular astrophysicist.
Theoretical astrophysicists work with equations and computer simulations and don't usually get involved in spacecraft design.
She is a distinguished astrophysicist known for her work on dark matter.
I was surprised to find myself face to face with renowned astrophysicist Stephen Hawking.
Most astrophysicists have accepted the idea that the cosmos was born from a kind of explosion.
He was regarded as one of the very best particle astrophysicists in the world.