To see the various colors that make up starlight, astronomers can use a prism to separate the colors. Common elements like helium and calcium in the atmospheres of stars block certain colors of light, ...

Various physical mechanisms broaden the intrinsic absorption lines. The most important is that the random motions of the absorbing atoms cause “Doppler broadening.” Larger motions within the object, ...

Weymann and Wilcox 1 have recently claimed that there is no evidence that the true occurrence of absorption lines in quasi-stellar objects (QSOs) is a function of red-shift. Such a conclusion, if true ...

The basic principles of AAS can be expressed as follows. Firstly, all atoms or ions can absorb light at specific, unique wavelengths. When a sample containing copper (Cu) and nickel (Ni), for example, ...