The spectroscopic analysis shows that the elements emit a set of characteristic wavelengths called atomic spectrum. Lighter elements have relatively simple spectra with a few characteristic spectral lines but for heavier atoms the spectra contain a large number of lines. Scattered radiations do contain faint radiations with frequencies greater as well as less than the incident frequency. This scattering effect is known as Raman Effect. According to big-bang theory the universe was dense; fire ball at the time of explosion. The luminous band of light scattering from horizon to horizon called Milky Way. Inter stellar medium means space between stars contains atoms & molecules of hydrogen (90%). The space between stars is mainly filled with hydrogen & other molecules as well as dust particles. The space between stars cannot be entirely empty. According to stellar evolution, Sun is formed by condensation of interstellar gas & dust, so also plants. Average distance of Mars from sun is 227 million km. Graduate and Senior undergraduate students in atomic and Space Physics, or engineering students, who intend to do research in Atomic and Space Physics should find this book useful.