The Panspermia Theory: Did Life On Earth Come From Space?
Scientists know that certain microbes are capable of surviving space travel and conditions on other planets. The theory of panspermia postulates that life on Earth, and on other worlds, may have begun when it arrived on an asteroid, meteorite, or even a deliberately launched object. One proponent of directed panspermia was Francis Crick, who thought that aliens had sent life to Earth. Though panspermia has yet to be proven, some believe that evidence for life has already been found in Martian meteorites.
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Key Facts In This Video
A small percentage of meteorites that have impacted Earth came from Mars. (3:15)
Necropanspermia is the idea that organisms needn't be alive after traveling through space and arriving on Earth for their genetic material to influence the evolution of life. (5:34)
NASA has to meticulously examine its equipment so that it doesn't inadvertently carry microbes into space. (6:55)