Spectroscopy is a tool that scientists typically use to determine the mass, structur and the temperature of stars or other objects within the observable universe.
In general, scientists take a spectrum of the object they observe using a spectrograph. It is based on the theory that the lines of absorption at a given wavelength are special for each element.
Hence, the correct answer is spectroscopy or spectrograph.
They are constantly contributing to the scientific community and
improving it. There are always new things to be discovered and they are
constantly doing just that?
