An Astrobiologist is a person who studies the possibility of life beyond Earth. Astrobiologists try to understand how life originates and how life can survive in many different types of environments. This often involves the study of extreme life right here on Earth. They study different planets and moons to see if conditions there might support life. Some astrobiologist are involved in projects which seach for radio signals from intelligent life in the universe, while others look for places where the simplest forms of life may exist. An astrobiologist has to be an expert in biology as well as in astronomy.