Astrobiology is the study of life in outer space. The field of astrobiology looks for conditions necessary for life, such as liquid water or a similar substitute, a good temperature, or the presence of oxygen.

Some possible places to find life in the solar system are Europa,Ganymede, moons of Jupiter, or Titan and Enceladus, both moons of Saturn. Some of these places may have liquid water, or, in the case of Titan, hydrocarbons that could support a different type of life. They may be too cold to support life on their surfaces, but if they have liquid water, the water must be warm enough to support life. Astrobiologists suggest that there may be a liquid water ocean under their surfaces.