The conditions required for Earth-like life to emerge on a planetary body are thought to include the presence of liquid water, the availability of energy and the existence of organic material. There are situations when determining whether the above conditions exist on a planetary body is not possible without a detailed understanding of the radiative processes occurring in a planet's atmosphere. In this work, studies of the radiative flux and transfer within planetary atmospheres are carried out in order to elucidate whether certain planetary bodies may be habitable. The first section of this work quantifies the impinging X-ray flux on sub-Neptune sized planets in the Kepler spacecraft dataset to determine the conditions for such planets to be stripped of their primordial atmospheres, with implications for the stability of liquid water on their surfaces. In the second part, the absorption of light in the atmosphere of Saturn's largest moon Titan due to methane and other gases is modeled in order to understand how close to the surface one has to be to detect organic molecules of prebiotic relevance, including amino acids and nucleobases.