tag:blogger.com,1999:blog-25327006.post1580235640272132641..comments2024-01-02T10:55:10.607-06:00Comments on Angry Astronomer: Book Review - The Eerie SilenceJon Voiseyhttp://www.blogger.com/profile/11550625188837528980noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-25327006.post-86959971992109964642010-07-11T15:56:50.031-05:002010-07-11T15:56:50.031-05:00Davies suggests that we look for forms of life on ...<i>Davies suggests that we look for forms of life on Earth that don't use the same base pairs (or amino acids) that life as we know does. Or life that has an opposite "handedness" (chirality) to it.</i><br /><br />While I see what he is suggesting, I think his suggestions are way too narrow to point toward a secondary origin of life.<br /><br />Some "non-conventional" nucleic acid base pairs are very common in terrestrial life, including inosine, which shows up as a "wobble" pair in transcribing mRNA codon triplets using tRNA (this occurs in humans!). Known microbial life has all sorts of weird bastardizations to the conventional genetic inheritance model, some so much so that you can't always easily move a gene from one organism to another and assume it will be properly transcribed in the new host. This is a common technical problem in restriction cloning.<br /><br />Also, "backwards" D-amino acids are commonly used in some microbes, including the well-known pentapetide cross-link present in gram-positive bacteria peptidyl glycan which is the target of the antibiotic penicillin.<br /><br />Because known life already demonstrates these qualities, a new life form that shows these qualities is not necessarily the result of a parallel but separate genesis.<br /><br />If he wants to convince me of a separate genesis, I would expect to see a demonstrated naturally occurring genetic algorithm involving unfamiliar, possibly unrelated chemistry. This means possibly a fundamentally different scheme of containing and passing heritable information-- genes not made of DNA, if you will. Heck, some viruses package genes exlusively in RNA and some biological phenomena are known that have a non-genetic inheritance-like pattern, including prions-- and these are both products of our genesis of life.<br /><br />Gotta forgive the guy, though. I think he just has no idea how far he's got to go in order to get to the true primitive, progenator life... which may not exist on our world any more and maybe has not existed for billions of years. What arose first may well have been wiped out completely by the more highly evolved, more competitive forms that came later, or maybe even was destroyed by its own biproducts (Oxygen, for instance). I expect that his specialty is telescopes and radio signals rather than actually breaking free of the paradigmatic (and highly restricted, possibly exclusively terrestrial) view of what life actually is.viggennoreply@blogger.comtag:blogger.com,1999:blog-25327006.post-3516017237551003312010-07-08T23:07:15.952-05:002010-07-08T23:07:15.952-05:00Jon,
As a mbr of the Planetary Society, just got...Jon,<br /> As a mbr of the Planetary Society, just got a ltr to help contribute to fund a revolutionized "Optical SETI" because 'there might be a 'Galactic Club' out there.<br /> Well, I must agree the technology might improve astronomical science research and/or make some new discoveries, but I am quite skeptical that there's some "Galactic ET Club" out there. Geeze, we have a really difficult time with just Homo sapiens "intelligence" on Spaceship Earth.<br /> By the way, the sun, moon, stars do not "come up/go down" or "rise/set". Earth's rotation brings them into view/sight and out of view when the horizon "clipses" them (R. Buckminster Fuller). We're still too earth=centric.Chet Twarognoreply@blogger.com