Eng: Branch of astronomy...

天體物理學

Branch of astronomy concerned with the physical nature of stars, galaxies, interstellar clouds, and other objects, including their luminosities, temperatures, densities, and chemical composition

天體運行

branch of astronomy that deals with the motions and gravitational interactions of objects in outer space (The)

天體力學

branch of astronomy that deals with the motions and gravitational interactions of objects in outer space (The)