von Bloh Werner, Franck Siegfried, Bounama Christine, Schellnhuber Hans-Joachim
Potsdam Institute for Climate Impact Research (PIK), P.O. Box 60 12 03, D-14412 Potsdam, Germany.
Orig Life Evol Biosph. 2003 Apr;33(2):219-31. doi: 10.1023/a:1024627326871.
New discoveries have fuelled the ongoing discussion of panspermia, i.e. the transport of life from one planet to another within the solar system (interplanetary panspermia) or even between different planetary systems (interstellar panspermia). The main factor for the probability of interstellar panspermia is the average density of stellar systems containing habitable planets. The combination of recent results for the formation rate of Earth-like planets with our estimations of extrasolar habitable zones allows us to determine the number of habitable planets in the Milky Way over cosmological time scales. We find that there was a maximum number of habitable planets around the time of Earth's origin. If at all, interstellar panspermia was most probable at that time and may have kick-started life on our planet.
新的发现推动了关于泛种论的持续讨论，即生命在太阳系内从一个行星传输到另一个行星（行星际泛种论），甚至在不同行星系统之间（恒星际泛种论）。恒星际泛种论可能性的主要因素是包含宜居行星的恒星系统的平均密度。类地行星形成率的最新结果与我们对太阳系外宜居带的估计相结合，使我们能够确定宇宙时间尺度上银河系中宜居行星的数量。我们发现，在地球形成时期前后，宜居行星的数量最多。如果存在恒星际泛种论的话，那么在那个时候最有可能发生，并且可能在我们的星球上启动了生命。
