Composition determined by spectra Mass information about inner structure, external appearance, future evolution Observe gravitational influence on nearby objects If you know distance between two objects, use Newton's Laws to calculate the masses.
(Composition; determined; by spectra Mass information about inner structure, external appearance, future evolution) (Composition determined by spectra Mass information about inner structure, external appearance, future evolution; Observe; gravitational influence on nearby objects) (you; know; distance between two objects) (you; use; Newton's Laws; to calculate the masses)
Composition Composition determined by spectra Mass information about inner structure, external appearance, future evolution you you
determined Observe know use
by spectra Mass information about inner structure, external appearance, future evolution
gravitational influence on nearby objects
distance between two objects
Newton's Laws to calculate the masses