13 juli 2015

Life emerging out of cooling stardust: an hypothesis

It’s no doubt that all material we know here on mother earth, once existed as stardust, as a glowing bust of material from dying stars. Huge amounts of superhot glowing material, probably at least for the most part as plasma, i.e. a cloud of nuclei of atoms and electrons unbound to each other. In the celestial empty room the plasma will cool down, resulting in electrons finding their shells in the atoms resulting in ions which will interact with each other; chemical reactions in the opposite way from what they do in our normal world; cooling down is the driving force.


Realize how incredibly powerful and complex this process will have been; a cloud of many worlds big; all possible atoms in the most reactive, still virgin state, waiting to cool down to become ready for any possible chemical reaction and to start forming molecules. And in the way they did, the first tiny roots of the tree of life were formed!


Stuart Kauffman, the big authority on complexity depicted in his inspiring book “At home in the universe”, how autocatalytic systems inevitably emerge in a complex reactive mixture. Autocatalytic systems will catalyze their own formation as long as enough energy and substrate are there. Now, what is more energetic and what is more complex than a glowing piece of stardust on the edge of chaos; converting from a plasma to a super-reactive chemical mixture of all possible atoms, driven by the force of cooling down; a peculiar form of chemistry, completely reverse from what we are used to in our contemporary world, where heating, or at least extra energy is necessary to induce chemical reactions.


The exact way this process happened is a matter of speculation; the cooling process most probably started at the outsides of the cloud, flames, pieces that were thrown out and fell back. Autocatalytic systems formed themselves inevitably, they resolved when reheated,  they combined, competed, resoluted, died out and sometimes “froze”.


How long these processes endured, thousands, millions, maybe billions of years is not essential; the autocatalytic systems were formed and developed themselves whereas they behaved as, in essence became, dissipative structures, dissipating the inner heat of the cooling plasma cloud.


Ilya Prigogine, the auctor intellectualis of dissipative systems and energy-rich chaos described in his book “Order out of chaos” (1980) how dissipative structures develop, become more complex, combine with each other to form more complex dissipative structures. Surely this would not have developed differently in the cooling cloud of virginal atoms as they completed their electron shells, reacting with each other, forming molecules which katalyze each others formation, resulting in autocatalytic systems, becoming dissipative structures themselves.
Looking at the biochemical chart with the Krebs cycle in the middle, the chemical parallel strikes me; a huge, highly complex but ordered system of chemical reactions resulting in the formation of its own components, the katalysts, enzymes in this case.


The start of “natural history”, the old name of biology, is here, being anorganic in the beginning, becoming more and more organic, i.e. carbonic because of the rich possibilities of the carbon atom to form diverse molecules with different properties; the end result being primitive organisms. It is my conviction that the development of the dissipative structures inevitably resembled the process of evolution of living animals here on earth; most part died out during the process and only the “fitting ones” survived, resulting in the architecture of the first primitive biologic organism(s) when the cooling process of the plasma had continued sufficiently. From then on evolution could take place in the way we think to know, with the archaebacteria as our primitive ancestors.


Anywhere, independently of this creative process the planets have formed, lumps of material around a star, in case of “our” planetary system, the sun. So far the sun did not or did hardly play a role in the development of the primitive chemical pre-life dissipative structures or primitive organisms; they existed anywhere in the cooling cloud where the circumstances made their existence possible, not to say inevitable.
On our mother earth, the only planet in our solar system where life exploded in a unique variety and complexity, it was the sun that was able to take over the energy supply that is necessary for dissipative structures to survive and to develop on the surface of the earth. And what happened is that the porphyrine molecule was not only able to play its role in the energy transfer but in the uptake of solar light energy as well, being the motor of life on the surface of the earth as we know it now.
Under the surface of the earth life could only go on using other sources of energy; chemoautotrophic organisms as still exist in the black smokers deep down in the oceans.


Evidence for the hypothesis
  • So far it is difficult to explain why life started to develop so fast after the earth was formed. This hypothesis states that the precursors of life were formed long before planets were formed themselves by a cooling process of superheat plasma from “stardust”;
  • It’s hardly possible if not a matter of a “thought experiment” to imagine a chemical process on the edge of chaos, where an immense cloud of nuclear plasma, with concentration varieties, pressure varieties etcetera cools down and starts its chemical life by cooling. But molecules will be formed and interactions will influence the reaction equilibria negatively or positively, inevitably resulting in autocatalysis;
  • The experiment of Urey and Miller has proved that aminoacids and nucleic bases are formed under extreme experimental conditions. In material from outer space, i.e. in meteorites, aminoacids were detected as well. These observations mean that these essential chemical components for life form a natural outcome of the chemical processes under extreme conditions, even in cooling stardust;
  • As “living fossils” out of the anorganic, i.e. non-pure biochemical phase of precursor life processes, a few anorganic components have remained in contemporary organisms; Zn, I and Se are essential for the living body albeit in only one or a few places in the biochemical “chart”.
  • A certain part of the earth crust consists of minerals, being inorganic, with an ordered crystalline structure and a circumscript chemical composition. In my hypothesis these minerals are part of the outcome of the autocatalytic processes that were “frozen” during any stadium of the cooling process of the stardust, any time of temperature during the formation of the earth.
  • Apatite, being a mineral in geology is known in biology as well; according to my hypothesis the formation of this mineral represents a catalytic process that has been taken up in the biogenesis and plays its role in calcium metabolism.
  • Stephen J. Gould stated in one of his books that bacteria are the main inhabitants of the world and for sure he is right; he states a layer of 1 meter of bacteria could cover the surface of the earth; in any sample so far collected deep under the soil, for instance in oil samples, bacteria were observed, most of them with completely unknown properties. So life does not need to be exclusively a matter of the surface of the earth as was thought so far, but of the planet as a whole. In accordance to my hypothesis I would like to state that extremophiles are the ancestors of organisms living under less extreme conditions and not the other way around.


Finally
I realize the impact of this hypothesis, I realize the huge gaps in the theoretical construct that is presented here. Consider it as a rough carbon sketch that is worth to be taken seriously, because it explains the incredibly rapid development of life proliferation on the early planet earth. It is in agreement with the theoretical constructs of Stuart Kauffman and Ilya Prigogine, the most important specialists in complexity and order. And it is in accordance with the origin of the material that everything exists of; the 92 natural types of atoms.


Contemplation
The origin of life remains one of the mysterious questions in science; today, and it has been as long as people realize they are part of the universe, sitting around a fire and looking to the stars and feeling the heat of the sun on their skins. From where are we? Religion has been an attempt to answer these questions. Anthropocentric worldviews have been paramount for a long time. Then the movements of the planets were discovered and more and more became known about the universe: stars, galaxies etcetera.
The intriguing question remained: how did life start?


The Urey Miller experiments showed the likelyhood of aminoacid to formation under primitive earth conditions; the hot soup theory has influenced the thinking of the scientific world. But the development of a living organism just from a mix of aminoacids and nucleic bases is as probable as an aeroplane being constructed out of a pile of accessories; an ordening process is necessary!
Therefore I thought back in the history of the earth, leaving the anthropocentric, geocentric and heliocentric views that influenced me so far. Doing this while applying the immense theories of Stuart Kauffman and Ilya Prigogine I came to the present hypothesis. It does not pretend to give the exact answer on questions as how bacteria developed, but it does to how life formation processes started from “nothing” but the glowing cloud of stardust.
Together with Stuart Kauffman I would like to end saying: “At home in the universe”.


Freising, May 1st, 2015
Dr. Evert H. van Elven

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