List of astrophysicists

Because astrophysics is a very broad subject
astrophysicists apply concepts and methods from many disciplines of physics
Classical mechanics
Electromagnetism
Statistical mechanics
Thermodynamics
Quantum mechanics
Nuclear and particle physics
And atomic and molecular physics .

The astronomer (also mathematician, physicist and philosopher) turned the new observational tool toward the heavens, where he discovered the four primary moons of Jupiter (now known as the Galilean moons), as well as the rings of Saturn