Abstract
Titan is the largest satellite of Saturn, and has dense (ca. 1,500 hPa) atmosphere mainly composed of nitrogen and methane. In addition to various organic compounds, aerosol is found in the atmosphere. It is suggested that the aerosol was made of complex organic compounds, which was formed from Titan atmosphere by such energies as ultraviolet light, high-energy electrons (discharges) and cosmic rays. Voyager and Cassini missions partly revealed the nature of the aerosol. A wide variety of laboratory simulation experiments have been conducted by using a gas mixture of nitrogen and methane, and the resulting solid products are often referred as “Titan tholins”. The present paper reviews these observations and simulation experiments on the Titan aerosol, and discusses its relevance to origins of life.
