宜居环境与地外生命

Habitable planetary environments and extraterrestrial life

到2005年人们发现了150颗左右的行星,但不知道任何宜居系外行星的存在,对太阳系其他地方是否适宜地球生命也不太清楚,因此在Science创刊125周年专辑中重点强调了利用射电波段"聆听"地外智能生命所发出的信号.从更广义的角度来讲,人们关心地外生命是否存在;而这正与Science 125个科学问题中的第56个问题"太阳系的其他星球上现在和过去是否存在生命"相符合.在这篇解读中主要围绕以下4个方面讨论:(1)非碳基生命;(2)太阳系天体的宜居性;(3)太阳系外天体的宜居性;(4)发现宜居环境和地外生物的展望.

Arguably one of the most important discoveries in the history of human being is the detection of a planet orbiting a main sequence star beyond the solar system. By the time Science celebrated its 125 th anniversary, ~150 exoplanets have been discovered. However, there was no known habitable exoplanet. Neither was it clear whether there is habitable environment in the solar system beyond the Earth. Thus the possibility to ＂listen＂ to radio signals emitted by extraterrestrial intelligence was a focus of the 11 th science question ＂Are we alone in the universe？＂. We equally care about the 56 th question ＂Is/Was there life elsewhere in the solar system？＂. In this essay we discuss the following 4 aspects：（1） non-carbon-based life;（2） habitability of solar system planets/moons;（3） habitability of exoplanets;（4） prospects of detecting habitable environments and extraterrestrial life.