-- Chuck Hards asked on 8/15 ---

I recall that there are 2 bio-chemical "paths" (lacking the proper term at the moment) that photo-synthesis can take here on earth. Was wondering if there are any botanists on the list who would speculate on the possibility of a form of photosynthesis that could work under the spectrum of a non-G type star? -- and 8/16 he speculated that - [W]hile ET species may share a common chemistry, they may have totally different sensory organs, or similar organs that operate at different wavelengths/frequencies.

There are three paths. I'm not a botanist. I. For the blue end of the visible spectrum - The terresterial plants that predominte our local Intermountain city-scape use chlorophyll-b to drive photosynthesis because chlorophyll-b absorbs light from the higher wavelength energy blue end of the spectrum - and reflects unused green light. Because blue light contains more energy, it can drive more efficient higher energy photochemical cycles - http://www.sirinet.net/~jgjohnso/modphotopigments.jpg in - http://www.sirinet.net/~jgjohnso/photosynthesis.html http://www.biologie.uni-hamburg.de/b-online/ge24/03.jpg in - http://www.biologie.uni-hamburg.de/b-online/e24/24.htm Note that absorbtion stops in the visible spectrum and does not occur in the ultra-violet. The limiting factor is uv light is too energetic - it can break down proteins and degrade photochemical processes. Groups of chorophyll-b driven plants are shown as items 1,2 and 3 in this spectral diagram - http://www.bio.mtu.edu/~mrgretz/bl4140_www/taiz_art/Illustrations/ch07/PP070... in - http://www.bio.mtu.edu/~mrgretz/bl4140_www/photosn1.htm II. For the green middle of the visible spectrum - Another group of plants - the red alage - http://tolweb.org/tree?group=Florideophyceae - use the less efficient carotenes to drive photosynthesis. Carotene photosynthesis utilizes the lower engery green portion of the spectrum, reflects unused red light, and is represented by item 4 in the spectral diagram - http://www.bio.mtu.edu/~mrgretz/bl4140_www/taiz_art/Illustrations/ch07/PP070... III. For the red end of the visible spectrum Also, within the green leafed plants that we are most familiar with in our daily lives - there are two photosysthesis systems - http://www.sirinet.net/~jgjohnso/photosynthesis.html http://en.wikipedia.org/wiki/Light_reaction (cyclic photosynthesis using photosystem I, non-cyclic photosynthesis using photosystem II an photosytem I). Photosystem II utilizes chlorophyll-b to absorb blue light. But Photosystem I utilizes chlorophyll-a to absorb red light at the far end of the spectrum. See the red side of the spectrum in - http://www.sirinet.net/~jgjohnso/modphotopigments.jpg http://www.biologie.uni-hamburg.de/b-online/ge24/03.jpg So, the color of the leaves of plants (not the flowers) can tell you about what wavelengths of light the plant _is not using_. This implies whether it is using chlorophyll-b based photosynthesis or carotene based photosynthesis. IV. Speculative astrobiology. One speculative thought experiment implied by these three photosynthetic pathways, that utilize three separate portions of visible spectrum, is the existance of alternative ecologies around G and M class stars. One thought experiment proposes that there is a habitable zone around red drawf stars - stellar class M4-M6. http://www.emse.fr/~yukna/researchers/reddwarf.htm Red drawf stars are among the most prevalent type of star in our Local Neighborhood of the Milky Way galaxy - the M class. Numerically, the M-class comprises about 80% of the stars on the main sequence. http://anzwers.org/free/universe/startype.html Wolf 424A-B, Gliese 752B and Wolf 359 are nearby red drawf stars. http://www.solstation.com/stars/wolf424.htm http://www.solstation.com/stars/wolf359.htm - but are also flare stars. Our Sun is rich in blue light - hence chlorophyll-b plants dominate in the ecology. Because our blue-light photosynthesis-based ecology produces autotrophic plants with a high energy content, Earth's ecology can support more trophic levels in a food chain that contains more active, complex predators. http://en.wikipedia.org/wiki/Trophic_level http://en.wikipedia.org/wiki/Food_chain If there is a planet is around the red-light dominated star Wolf 359, would the ecology of that planet be based on plants that use carotene and/or chlorophyll-a photosynthesis? If there is a carotene based ecology around Wolf 359, what how many trophic levels of ecological predation would it support? Would the most complex predator be a red algae-eating marine iguana? http://www.junglewalk.com/info/iguana-information.htm Because Wolf 359 is a flare star - could life on a hypothetical planet around the star adapt to flare distruptions? In conclusion Chuck, ET may have a 6-foot bulbous head and look like one of these - http://tolweb.org/tree/ToLimages/flortitle1a.100a.jpg - and want to "interwine" some tenancles with you, instead looking like one of these - http://www.avp-movie.com/ - and want to "have you over" for lunch. V. Targets for tonight? Since this is an astronomy listserv, if I would like to take my scope out tonight and look for a Gliese star of brighter than mag. 11-12 in the M4-M6 class - what would I look for? Barnard's Star - M4Ve? - Peace - Canopus56 Further reading - http://nai.arc.nasa.gov/ NASA Astrobiology Institute http://www.astrobio.net/ Astrobiology net http://astrobiology.arc.nasa.gov/ Astrobiology web at NASA http://en.wikipedia.org/wiki/Astrobiology Wikipedia entry on astrobiology __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

Quoting Chuck Hards <chuckhards@yahoo.com>:

I. Kurt, you never cease to amaze me. What do you do besides read textbooks and science Websites? I am again incredibly impressed at your range (and available study time!).

II. How are you on picking stocks and investment funds? Even if you're _not_ a financial advisor- shouldn't make a difference, from what I've read here- we need to talk.

III. Will you run for club office? Better yet, Representative Buttars seat?

I thought we were through with online dating. ;) Just kidding...

With an intellect like his, he would need a lobotomy before he could qualify for public office. I am in awe . . . Michael W. Kwan Chances are high that one or more of the foregoing statements was intended as humor by an individual with little to no discernible sense of humor. No offense was intended to any person, animal, reglion, political party, spirit, race, ethinicity, gender, sexual orientation, plant, fungus or other as-of-yet-to-be-discovered form of life or death. If you find any statement to be offensive, I sincerely apologize and humbly beg for your forgiveness. -----Original Message----- From: utah-astronomy-bounces+mwkwan=sisna.com@mailman.xmission.com [mailto:utah-astronomy-bounces+mwkwan=sisna.com@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Tuesday, August 16, 2005 4:33 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Photosynthesis I. Kurt, you never cease to amaze me. What do you do besides read textbooks and science Websites? I am again incredibly impressed at your range (and available study time!). II. How are you on picking stocks and investment funds? Even if you're _not_ a financial advisor- shouldn't make a difference, from what I've read here- we need to talk. III. Will you run for club office? Better yet, Representative Buttars seat? --- Canopus56 <canopus56@yahoo.com> wrote:

There are three paths. I'm not a botanist.

I. For the blue end of the visible spectrum -

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--- Chuck Hards <chuckhards@yahoo.com> wrote: Thanks as always for your kind words.

II. How are you on picking stocks and investment funds? Even if you're _not_ a financial advisor- shouldn't make a difference, from what I've read here- we need to talk.

Now there's an idea - put Intelligent Design Theory to a useful purpose - a stock picking program that seeks out the intelligent CEO (who isn't an Enron-WorldCom type crook). - Canopus56 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

Dredged-up from the depths of memory I seem to recall that a sci-fi author in the '70's came up with an incredibly physically robust, long-lived intelligent alien species who lived on the outer hulls of their interstellar starships, and absorbed miniscule amounts of energy from starlight. Now there's photo-synthesis taken to the limit. Anyone remember who the author was? The name of the species? ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs

Quoting Canopus56 <canopus56@yahoo.com>:

Although seemingly off-topic, speculative science-fiction is one good way to hook young new-members into the hobby.

You'd have to get them to put down the remote first. You can do this by reeling a twinkie across the room between them and the PS2...

Chuck Hards wrote:

Science has little or nothing to do with Hogwarts...

Ah, but remember that astronomy is taught at Hogwarts and even has an astronomy tower. :-)

Thanks anyway, but I recalled both author and the name of the species. I'll refrain from posting in case anyone still wants to guess. You post waaaay too many sites for me to take the time to investigate, darnit! My total screen time is usually taken up by just these posts, time stolen from other activities. Your story is familiar! I was reading my dad's science fiction paperbacks at age 4 or 5, the astronomy interest came a few years later, about age 7 or 8. Both were spured by Star Trek and the space program. I got my first "real" telescope at age 9 or 10, circa 1968. --- Canopus56 <canopus56@yahoo.com> wrote:

--- Chuck Hards <chuckhards@yahoo.com> wrote:

...

<snip> I seem to recall that a sci-fi author in the '70's came up with an . . . intelligent alien species who lived on the outer hulls of their interstellar starships, and absorbed miniscule amounts of energy from starlight. <snip> Anyone remember who the author was? The name of the species?

What a listserv. Just after my eyesight returned after being temporarily blinded by visions of bowling ball meteorites and urine powered telescopes, we move onto "super-intelligent space barnacles." As another thread mentioned, these may be all symptoms of severe photon deficiency. -:)

I don't know the answer to your question, but maybe this link may help:

The Astronomy Society of the Pacific List titled: "Science Fiction Stories with Good Astronomy & Physics: A Topical Index"

http://www.astrosociety.org/education/resources/scifi.html

- see subtopic "Life Elsewhere (Plausible Examples)

http://www.astrosociety.org/education/resources/scifi04.html#life

The PASP "Good Astronomy & Physics: A Topical Index" bibliography is a sublist from the PASP's Astronomy Education Bibliographies Website - http://www.astrosociety.org/education/biblio.html PASP's Astronomy Education Bibliographies Website looks like a good resource for those interested in astronomy for public school presentations.

Although seemingly off-topic, speculative science-fiction is one good way to hook young new-members into the hobby. In the faded memory of my youth, I can no longer recall which came first astronomy or science-fiction, or whether my interest in them grew together.

- Canopus56

P.S. - And, as an aside for reference purposes, because it's a Utah listserv -

References to Mormons in science-fiction stories http://www.adherents.com/lit/sf_lds.html

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