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Interesting theory indeed. I have always been thinking - where do we come from? So maybe there are other lives in this universe that started the life here, on the Earth. They introduced a software (genetics) which controls the further evolution.
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Panspermia (Greek: πανσπερμία from πᾶς/πᾶν (pas/pan) "all") and σπέρμα (sperma) "seed") is the hypothesis that "seeds" of life exist already all over the Universe, that life on Earth may have originated through these "seeds", and that they may deliver or have delivered life to other habitable bodies.
The related but distinct idea of exogenesis (Gk. ἔξω (exo, outside) and γένεσις (genesis, origin)) is a more limited hypothesis that proposes life on Earth was transferred from elsewhere in the Universe but makes no prediction about how widespread it is. Because the term "panspermia" is more well-known, it tends to be used in reference to what should strictly speaking be called exogenesis.
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It is the hypothesis that "seeds" of life exist throughout the Universe, that life on Earth may have originated through these "seeds", and that they may deliver or have delivered life to other habitable bodies.
The first known mention of the idea was by the 5th century BC Greek philosopher Anaxagoras.
Sir Fred Hoyle and Chandra Wickramasinghe were important proponents of the hypothesis, who further contended that lifeforms continue to enter the Earth's atmosphere and may be responsible for epidemic outbreaks, new diseases, and possibly new genetic material that contributes to macroevolution.
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Panspermia -- Panspermia is a theory (more directly described as a hypothesis, as there is no compelling evidence yet available to support or contradict it) that suggests that the seeds of life are prevalent throughout the universe and life on Earth began by such seeds landing on Earth and propagating.
The theory has origins in the ideas of Anaxagoras, a Greek philosopher.
An important proponent of the theory was the British astronomer Sir Fred Hoyle.
There is some evidence to suggest that bacteria may be able to survive for very long periods of time even in deep space (and may therefore be the underlying mechanism behind Panspermia).
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Recent studies out of India have found bacteria at heights greater than 40 km in Earth's atmosphere where mixing from the lower atmosphere is unexpected, while Streptococcus mitus bacteria that had accidentily been taken to the moon on the Surveyor 3 spacecraft in 1967, could easily be revived after being taken back to earth 3 years later.
However, a consequence of panspermia is that life throughout the universe would have a surprisingly similar biochemistry, being derived from the same ancestral stock. So the high-altitude bacteria might be expected, whether of earth or extra-terrestrial origin, to have a biochemistry similar to terrestrial forms. This is not resolvable until life on another planet can have its chemistry analysed.
Another objection to Panspermia is that bacteria would not survive the immense heat and forces of an impact on earth; no conclusive conclusions (whether positive or negative) has been reached yet on this point.
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Of material definitely known to originate off-earth, analysis of the rock sample known as ALH84001, generally regarded as originating on Mars, suggest it contains artifacts that may have been caused by life forms. This is the only indication of extraterrestrial life to date and is still widely disputed.
Some have taken the theory as an answer to those arguing the improbability of the origin of life, in that wherever life first began, it spread throughout the universe by panspermia.
This theory has been explored in a number of works of science fiction, notably John Wyndham's book The Day of the Triffids, Jack Finney's Invasion of the Bodysnatchers (twice made into a film) and even the Dragonrider books of Anne McCaffrey.
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It is the hypothesis that life on Earth originated from microorganisms from outer space.