Exobiology or astrobiology

A multidisciplinary science which has as its study field the factors and processes playing a part in the appearance and evolution of life, and determining its frequency in the Universe. Conditions favourable for life depend on a planet’s distance from its star, the heat released by the latter (for each star there is calculated around it a habitable zone where water can exist in a liquid state), or on the presence of oceans or an atmosphere. Exobiology can also take an interest in other heavenly bodies, such as comets, rich in ice water and organic molecules.