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#39266 - 08/02/11 03:13 AM What odds on other life in space now,
Orac Offline
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#39275 - 08/02/11 01:16 PM Re: What odds on other life in space now, [Re: Orac]
redewenur Offline
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Registered: 02/14/07
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Ditto. Considering that:-

(a) there appear to be at least 10^18 stars in the observable part of the universe
http://www.esa.int/esaSC/SEM75BS1VED_index_0.html

(b) many complex carbon-containing molecules have been found in star formation regions http://en.wikipedia.org/wiki/List_of_interstellar_and_circumstellar_molecules

(c) "Impacts of small comets could also provide high local concentrations of organic material with enantiomeric excess as high as that found in Murchison, which is again higher than can be produced by any plausible Earth-based process. Thus, whether a very high enantiomeric excess is a prerequisite for the origin of life, or a very small effect is amplified in the process, the ultimate source is likely to be of extraterrestrial origin" http://biology.kenyon.edu/courses/biol113/2006-2007/Readings/cosmic%20amino%20acids.pdf

"More research found that some amino acids were present in enantiomeric excess, leading some to suspect terrestrial contamination...[however] In 1997 research showed that individual amino-acid enantiomers from Murchison were enriched in the nitrogen isotope 15N relative to their terrestrial counterparts, which confirmed an extraterrestrial source for an L-enantiomer excess in the Solar System. The list of organic materials identified in the meteorite was extended to polyols by 2001."
http://en.wikipedia.org/wiki/Murchison_meteorite

"The researchers say it [the Murchison meteorite] probably passed through primordial clouds in the early Solar System, picking up organic chemicals" http://news.bbc.co.uk/2/hi/8516319.stm

- I think it likely that there's been extraterrestrial carbon based life appearing and disappearing - much still extant - since the formation of second generation stars. These recent observations increase the prospect of finding life within a detectable range.

p.s. http://www.thefreedictionary.com/L-enantiomer
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#39277 - 08/02/11 10:23 PM Re: What odds on other life in space now, [Re: redewenur]
redewenur Offline
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Registered: 02/14/07
Posts: 1840
Error:

The estimate given is 10^22 to 10^24 stars, i.e. 10,000 to 1,000,000 times more than the 10^18 quoted. Still, either way, it's a lot, eh?..1,000,000,000,000,000,000,000,000...mind boggling.
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