Abstract : It now seems unlikely that extraterrestrial living organisms could have reached the earth either as spores driven by the radiation pressure from another star or as living organisms embedded in a meteorite. As an alternative to these nineteenth-century mechanisms, we have considered Directed Panspermia, the theory that organisms were deliberately transmitted to the earth by intelligent beings on another planet. (…)
Introduction : It was not until the middle of the nineteenth century that Pasteur and Tyndall completed the demonstration that spontaneous generation is not occurring on the Earth nowadays. Darwin and a number of other biologists concluded that life must have evolved here long ago when conditions were more favorable. A number of scientists, however, drew a quite different conclusion. They supposed that if life does not evolve from terrestrial nonliving matter nowadays, it may never have done so. Hence, they argued, life reached the earth as an “infection” from another planet (Oparin, 1957) …
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Directed Panspermiaby F. Crick, Lab. of Molecular Biology, Cambridge, England
& L. E. Orgel, Salk Institute for Biological Studies, San Diego, CA, USA.
(Received June 22, 1972; revised December 20, 1972)
Reprinted from Icarus, 19, 341-346 (1973)