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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Panspermia | 5/5 | https://en.wikipedia.org/wiki/Panspermia | reference | science, encyclopedia | 2026-05-05T03:09:26.597459+00:00 | kb-cron |
==== Counterarguments ==== In 1972, both abiogenesis and panspermia were seen as viable theories by different experts. Given this, Crick and Orgel argued that experimental evidence required to validate one theory over the other was lacking. That being said, evidence strongly in favor of abiogenesis over panspermia exists today, whereas evidence for panspermia, particularly directed panspermia, is decidedly lacking.
=== Origination and distribution of organic molecules: Pseudo-panspermia ===
Pseudo-panspermia is the well-supported hypothesis that many of the small organic molecules used for life originated in space, and were distributed to planetary surfaces. Life then emerged on Earth, and perhaps on other planets, by the processes of abiogenesis. Evidence for pseudo-panspermia includes the discovery of organic compounds such as sugars, amino acids, and nucleobases in meteorites and other extraterrestrial bodies, and the formation of similar compounds in the laboratory under outer space conditions. A prebiotic polyester system has been explored as an example.
== Hoaxes and speculations ==
=== Orgueil meteorite === On May 14, 1864, twenty fragments from a meteorite crashed into the French city of Orgueil. A separate fragment of the Orgueil meteorite (kept in a sealed glass jar since its discovery) was found in 1965 to have a seed capsule embedded in it, while the original glassy layer on the outside remained undisturbed. Despite great initial excitement, the seed was found to be that of a European Juncaceae or rush plant that had been glued into the fragment and camouflaged using coal dust. The outer "fusion layer" was in fact glue. While the perpetrator of this hoax is unknown, it is thought that they sought to influence the 19th-century debate on spontaneous generation—rather than panspermia—by demonstrating the transformation of inorganic to biological matter.
=== Oumuamua ===
In 2017, the Pan-STARRS telescope in Hawaii detected a reddish object with significant, periodic fluctiations in albedo, strongly suggestive of a slender, rotating object. Analysis of its orbit provided evidence that it was an interstellar object, originating from outside the Solar System, accelerating away from the Sun with the absence of the visible outgassing that usually explains the acceleration of asteroids. Astronomer Avi Loeb argues that there are no satisfying natural explanations for this acceleration, and proposes that Oumuamua may be a solar sail, which would be partial evidence for the feasibility of directed panspermia. This claim has been considered unlikely by other authors.
== See also == Abiogenesis – Life arising from non-living matter Astrobiology – Science concerned with life in the universe Cryptobiosis – Metabolic state of life List of microorganisms tested in outer space Planetary protection – Prevention of interplanetary biological contamination
== References ==
== Further reading ==
Crick, Francis (1981), Life, Its Origin and Nature, Simon & Schuster, ISBN 978-0-7088-2235-7 Hoyle, Fred (1983), The Intelligent Universe, London: Michael Joseph, Bibcode:1983inun.book.....H, ISBN 978-0-7181-2298-0
== External links == Cox, Brian. "Are we thinking about alien life all wrong?". BBC Ideas, video made by Pomona Pictures, 29 November 2021. Loeb, Abraham. "Did Life from Earth Escape the Solar System Eons Ago?". Scientific American, 4 November 2019 Loeb, Abraham. "Noah's Spaceship" Scientific American, 29 November 2020