Progress and Prospection in Searching for Extraterrestrial Life

Astrobiology is the study of origin,evolution,distribution and future of life in the universe,with searching for extraterrestrial life as one of its most important content.Searching for extraterrestrial life,the most spectacular area in the international space exploration,may support another breakthrough point for solving origin,evolution and future of life on the Earth,including human beings.Accordingly,this paper integrates and discusses the methods of astronomy,space exploration and numerical simulations used in searching extraterrestrial life on terrestrial planets in and beyond the solar system and important discoveries:the discovery by the spacecrafts to Mars launched by NASA and ESA that the Mars soil shows a little alkaline and habitat for life,that the Europa(Jupiter's moon) could serve as a abode for life if it has a hot inner;and that the atmosphere of Titan(Saturn's moon) was similar to the primitive Earth's which leads to the hypothesis of bridge the step from chemical to biological evolution.The deep impact mission of Comet suggested it might ever feed organic materials and even organisms to the Earth.The radio astronomy shows thousands of terrestrial planets are distributed in our Galaxy.Probably,the suitable condition for life's occurrence and evolution exists beyond the Earth according the current exploration results and important discoveries.This lightens the prospect of searching extraterrestrial life.However,the limited understanding of life forms and exploration technology will make it very hard to find them out.