Final answer:
The major conclusion from the study of line spectra is that absorption and emission of energy by electrons are quantized, leading to characteristic line spectra for elements which help in identifying their composition in celestial bodies.
Step-by-step explanation:
One of the major conclusions made from the study of line spectra of various elements is that the absorption and emission of energy are quantized. This means that electrons in an atom can only occupy certain allowed energy levels and can only gain or lose energy in fixed amounts when transitioning between these levels. This quantization leads to the presence of specific lines in an emission or absorption spectrum, which are characteristic of different elements. When an electron in an excited state returns to the ground state or transitions to a lower energy excited state, it emits a photon corresponding to the energy difference between these levels, resulting in an emission line. Conversely, absorption lines occur when electrons absorb photons and move to higher energy levels.
The study of these spectra is crucial for astronomers because it allows them to identify the composition of distant celestial bodies, such as stars and interstellar gas clouds, by comparing the observed line spectra with those obtained from known elements on Earth. For example, the discovery of helium in the solar spectrum before it was found on Earth was facilitated by the study of spectral lines.