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Saturday, October 15, 2005

Astrobiology

I am currently looking through Nasa's Astrobiology magazine.
Astrobiology rests upon a remarkable confluence of science, technology, and popular culture. This historical juncture invites collaborative and indeed synergistic action on the part of scientists from virtually all disciplines and on the part of the public. Through astrobiology we learn about the boundary conditions surrounding our own existence. Discovering how life begins and develops, finding out whether life exists elsewhere, and determining our future on Earth and beyond will have a profound and fundamental effect on the human species. Astrobiology affects our views of the universe, our science, our culture, and ourselves–in short, every aspect of our existence.

1 Comments:

Blogger John Umana said...

Hi, I'd like to share my current thinking on the fundamental questions faced by astrobiologists:

(1) There is no other life in this sun system. Mars contains no life and never did -- notwithstanding that 70% of scientists polled believe that there is or was life on Mars at one time. Saturn's moon Titan contains no life and never did. No other planet or object, no comet, no asteroid in this sun system contains any form of life. Europa does not contain liquid seas under the ice. When NASA gets there after 2010 or so, we’ll see that there are no fishes swimming around. Only Earth in this sun system contains seas of liquid water at this time, though Mars once did have shallow seas as the rovers Spirit and Opportunity and the orbiters have established. Where did/does the water come from on Earth and (billions of years ago) on Mars? Volcanoes produce large amounts of water steam, and they are largely responsible for Earth's waters. Other released gases from volcanoes included carbon dioxide (CO2), sulfur dioxide (SO2), hydrochloric acid (HCl), hydrogen fluoride (HF), hydrogen sulfide (H2S), carbon monoxide (CO), molecular hydrogen gas (H2), NH3, methane (CH4), silicon tetrafluoride (SiF4), and minor amounts of nitrogen (N2) and argon (Ar). But no oxygen. … And no life. Plenty of hydrogen, however, is a great start. The name is derived from the Greek ‘hydro genes,’ meaning water forming. Though most of our planet's water came from steam emitted by volcanoes (ditto Mars when it had seas a few billion years ago), carbonaceous chondrites, among the most primitive objects in our sun system, contributed, as they contain water locked up in phyllosilicate minerals with the water content making up about 10% by weight of the meteorites.

(2) In my opinion, the Universe including our galaxy is teeming with life. All life throughout the vast cosmos is nucleotide, DNA-based. This is the structure of life throughout the universe.

(3) In my opinion, the Universe including our galaxy is teeming with intelligent life. The reason that SETI is not picking them up is that they are unlikely to be communicating by radio or any type of electromagnetic communication -- far too slow for the distances involved. There's got to be another way to communicate over interstellar distances.

(4) Extraterrestrial astronauts did not “seed” mankind or life on Earth. The theory of panspermia is way off the mark. No need to keep worrying about whether comets could have carried spores of life here; that's not what happened and the distances are too vast for a living spore to hitch a ride on a comet in any event. There is no life beyond Earth for a long, long ways.

(5) Darwin's/Wallace's theory of the evolutionary theory of common ancestry is proved conclusively by the convergence of the entire scientific and fossil record, including paleontology, molecular biology, genetics, mitochondrial DNA, Y-chromosome DNA, comparative anatomy and physiology, biogeography, geology and archaeology. Yet, I do not believe there was a single common ancestor RNA strand. Rather; there was differentiation right from the first period of emergence 3.9 Ga into what would become the plant and animal kingdoms (eukaryota), bacteria and archaea. Life on Earth does not share a common ancestor with life on other habitable worlds. Life emerged separately and independently on Earth.

(6) The Darwinian theory of "natural selection" as the mechanism for origin of the species is unsubstantiated, overly simplistic, and runs contrary to what is observed in modern microbiology. It is bad science as theory of emergence or origin of species, though natural selection is a true force of nature and accounts for microevolution, such phenomena as pesticide resistance of insects (e.g., the mosquitos that survive an application of a given pesticide eventually develop an immunity to it over time) or the resistance of bacteria to antibiotics. Natural selection (NS) is not the causative mechanism for the evolution of a single species on Earth or anywhere else, in my view. Rather, natural selection (a.k.a. CHANCE) leads to greater disorganization, entropy, not to more advanced structures. The neo-Darwinists are way, way off the mark as to the specific mechanism of evolution as microbiology is beginning to demonstrate. NS was Dr. Darwin's Wild Guess back in the 1800’s. But it is less interesting today with microbiology. Whatever the right answer is as to emergence and origin of species, it isn't NS.

(7) Life emerged on Earth independently of other habitable worlds – 3.9 billion years ago at the tail end of the Heavy Bombardment. In my view: At dawn one day 3.9 billion years ago, the sun rose, and there was no life. At dusk that day, Earth was life-bearing in several locations under the seas.

(8) Where/how first life emerged on Earth? Pick an area where the critical amino acids are found. Prep needed. Areas under the shallow seas at that time and areas where seas met rocky shore, protected from UV rays. (Black smokers come much later; emergence of life there was much more difficult.) Still massive comet strikes every few days, equivalent to thermonuclear blasts, sending massive seismic shock waves throughout mantle and core. Temperature out a balmy 200-300 degrees; more inhospitable as approach live volcanos. Pre-biotic Earth temperature range roughly -288 F to +260 F. At night, temperatures dropped sharply as on our moon. No free oxygen to speak of on Earth. No ozone screen 10-15 miles up in atmosphere to protect emergence of first life from lethal UV. Earth highly radioactive as remnant of solar nebula, creating enormous challenge to emergence of first RNA strand that emerged under the seas; no membrane at first; highly unstable molecule. Thin atmosphere of H2O, CO2, SO2, N2. Stark sunlight. Pristine earth. No blue sky. Orangy, whispy clouds occasionally high up. More like sunlight falling across face of moon or Mars. Because of gamma radiation, UV and wide temperature swings, only rapidly reproducing self-replicating helix strand possible, containing backup files for self-repair when damaged by radiation or UV -- until Earth cools off radioactively within the next few billion years (as of 4 Ga). That's the reason why there was no evolution beyond single cells until 1.2 Ga or so.
[rights reserved] Regards, John Umana

11:21 am  

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