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New Pictures of Dwarf Planet Ceres, which Could Hold Alien Life Options
Daemon
Posted: Sunday, June 14, 2015 5:00:00 AM
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New Pictures of Dwarf Planet Ceres, which Could Hold Alien Life

The closest pictures ever taken of the dwarf planet Ceres show that its surface is so peppered with crater marks that it looks like a giant golf ball. Ceres, the largest body in the asteroid belt between Mars and Jupiter, is being observed by the ... More...
Cliona Chee
Posted: Sunday, June 14, 2015 12:19:02 AM

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Joined: 6/12/2015
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Location: Kuala Selangor, Selangor, Malaysia
Maybe there'll be one day that the astronomers can reach there.
Congratulations! Humans are really improving!

Quote:
“You can't even stand without risking to fall.”
― Nick Vujicic, Life Without Limits
JUSTIN Excellence
Posted: Sunday, June 14, 2015 8:32:58 AM

Rank: Advanced Member

Joined: 6/25/2014
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Location: Veinau, Baden-Wuerttemberg Region, Germany
One of the most exciting questions for mankind is whether we are alone in the universe. That intelligent nonhuman beings exist was commonly believed in prehistoric times as well as in antiquity. Creatures such as giants, centaurs, angels, and fairies were essential and universally accepted parts of Greek, Jewish, and Germanic mythologies. Although no fossil traces of such beings have ever been found, most of us firmly believe that nonhuman intelligent beings do indeed exist. This conviction is derived from the staggering size of the universe with roughly 100 billion times 100 billion (1022) stars, which makes it inconceivable that we could be the only intelligent society in the universe. Indeed, modern science has shown that since the Copernican revolution all attempts to define our position as an exceptional one in the universe have failed dismally. But if other intelligent civilizations do exist, how can we find them?

Now... Ceres, the largest body in the asteroid belt between Mars and Jupiter, is being observed by the spacecraft -- NASA’s Dawn which arrived in the Spring. Scientists have previously spotted plumes of water vapour gushing from the asteroid raising hopes that it could harbour primitive forms of alien life beneath on the surface, or beneath its crust.



Quote:
The most complicated machines are made from words.
Jacques Lacan


According to Ernst Haeckel, “any detailed hypothesis whatever concerning the origin of life must, as yet, be considered worthless, because up till now we have no satisfactory information concerning the extremely peculiar conditions which prevailed on the surface of the earth at the time when the first organisms developed” (Haeckel 1866). Erwin Schrödinger (1943) also expressed pessimism regarding the chances of understanding life. In the same vein: “Life is like consciousness. If you think you can explain what it is, you got it all wrong” (Shaw 2002). Niels Bohr interpreted life as a fundamental property of matter analogous to certain quantum properties, to be taken as given, and thus allowing little if any logical scrutiny (Bohr 1933): :

Quote:
‘The existence of life must be considered as an elementary fact that cannot be explained, but must be taken as a starting point in biology, in a similar way as the quantum of action, which appears as an irrational element from the point of view of classical mechanical physics, taken together with the existence of elementary particles, forms the foundation of atomic physics.’


The modern day belief is that the origin of life may be unclear but that it is not an impossible problem. Overwhelmed by life’s incredible complexity, some scientists prefer to consider definitions of life as uninteresting, or even doubt the scientific need for them, or the chances of ever finding, a satisfactory definition for life. But if we cannot describe life on Earth, how will we be able to understand life as a general concept. That represents biological and nonbiological life, terrestrial and extraterrestrial life, material and cybernetic life.

Four major questions are generally formulated in exploratory astrobiology, the origin of life and artificial life:

• Is life a unique thing, or is it a unique collection of common features?

• Is the origin of life mere probability, or is it the result of some special circumstances?

• Is life a physical necessity?

• Is it possible to formulate a representation of life on Earth in a way that will address life elsewhere?

Understanding life is not just a theoretical exercise; it is a quest directly connected with its origin and has many practical applications. Future explorers of the outer space (either man or machine), challenged with facing life forms unlike anything on Earth, have to be `armed’ with accurate guidelines capable of discriminating the essence of life from its composition and from its physical appearance. Many things in nature might seem related to life, whereas they are simple natural phenomena or complex processes, and conversely, many things that may seem lifeless, might be alive or even dangerous (to us). The creation of artificial life (making fully fledged autonomous systems) cannot advance without understanding its general properties and the circumstances leading to life and supporting it. The assessment of successful early life simulations involves identifying specific and interconnected objectives derived from the essential attributes of life or from the logic behind its self-organization. Finally, anticipating the overall consequences of life on another planet will become an important part of mission planning for all extraterrestrial exploration and the terraforming of other planets.

Several approaches are commonly used to represent life: mechanistic– reductionist, dialectic–materialism, holism, and vitalism. The mechanistic–reductionist approaches interpret all life-related phenomena through physicochemical processes but explain little about the origin of life. The dialectic–materialism views describe the origin of life as a set of qualitative changes (jumps) driven by quantitative (gradual) accumulations. Holistic views interpret life as a collective property, while vitalist theories attribute life to a hidden (vital) force. Although these approaches might sound different from each other, it is not always easy to tell where one ends and the other begins. An extensive collection of definitions of life has been formulated using such approaches. Some definitions of life are subjective and depend upon an individual standpoint and religious subconscience, ranging from pure materialism to pure spiritualism. A committed materialist defines life in terms of matter and energy, denying the need for a spirit, while a pure spiritualist would only consider the reverse. Although some address major requirements of life, many definitions do not identify the essentials of life, while others focus heavily on features that are particular to the terrestrial type of life. A comprehensive interpretation of life must address issues and identify properties that are independent of its physical nature, otherwise the model becomes flawed with exceptions and liable to unanswerable criticism. A correct interpretation of life must address the essential properties of life, must be capable of relating them to the early history of life, and must help reveal the forces driving its emergence and evolution.



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Holistic and Mechanistic Definitions of Life

Two scientific approaches dominate modern theoretical debate about how life should be interpreted: holistic (as opposed to reductionist) and mechanistic (as opposed to vitalist). Holistic interpretations of life are function- and purpose-related descriptions. The classic example of holism is “nothing is alive in a cell except the whole of it”. In holism, life is viewed as a collective property. It was suggested that an appropriate approach to obtaining a holistic definition of life is to address questions such as:

• How are different forms of life at different levels of the vital hierarchy related to each other?

• Is there a gigantic hiatus or a phenomenological continuum between life and non-life?

• What is more important for life: the form, the shape or the composition?

• Are life and matter intrinsically related?

• Are life and mind intrinsically connected?

Holistic approaches show considerable limitations in experimental practicality because they often neglect the particular properties of living entities.

Reductionist interpretations of life try to demystify the explanation of some very complex activities otherwise thought by some to have a nonmaterial explanation. One of the paradigms of modern molecular evolution is that minimal life consists only of molecules and their mutual interactions. Despite the popularity of reductionism, many scholars agree upon the existence of some emergent properties of matter, i.e., properties that appear only at certain levels of complexity. The structure at each level of organization is made of the components of a lower level, but the lower levels cannot explain some of the qualities of a higher level. Thus, structures may be considered the subject of a reductionist approach while some properties cannot.

The mechanistic interpretations of life are pragmatic approaches. They describe living forms as complex machines, whose parts function in a thermodynamic direction that is somehow fortunate for the survival of the overall system. This need for thermodynamic justification feeds most mechanistic interpretations of life. Most mechanistic descriptions of life tend to explain it as a probabilistic paradigm. When this philosophy is taken to its extreme (i.e., interpreting the origin of life strictly as a collection of chance-like events . . . ), it fails to identify any meaning for life in general, to understand life as a concept or even to consider the need to look for attractors that might have ‘pushed’ life into physical existence. The purely mechanistic interpretations are closer to ‘not seeing the forest for the trees’ than any of the other approaches.

Vitalism is an ancient belief that living entities exist due to a mysterious force called the ‘vital force’, ‘perfecting principle’, ‘entelechy’, or ‘mneme’. Although modern science generally dismisses this stand, vitalism has never been scientifically demonstrated as erroneous. However, vitalism has fallen behind in the ranks of approaches to describe the origin of life because of its non-scientific belief in a transcendental principle. On the other hand, because modern science is still unable to provide an articulate model for the origins of life, vitalistic ideas still surface now and then. After all, vitalists can always claim that they said nothing more than ‘the force(s) behind life is (are) unknown’, and on this issue they are perfectly right. Vitalists would be wrong only if they claimed that the situation would remain so forever. Finding a physical attractor for life would actually provide some reconciliation between modern science and the old-fashioned vitalism.



Generalist vs. Minimalist Definitions of Life

Although the need to represent life in a simultaneously broad and detailed manner seems obvious, some descriptions of life use a conceptual generalization to an excessive degree. These descriptions either use an obscure language with disguised meanings and thus become eclectic to any non-specialist, or else they render themselves useless by providing insufficient information to discriminate life from non-life. They sometimes even go beyond what life actually is. Notable examples are:

• “Life is a historical process of anagenetic organizational relays”

• “Any system that creates, maintains and/or modifies dissymmetry is alive”

The minimalist approach considers that life can and must be defined on the least amount of information (necessary and sufficient) to distinguish it from inanimate matter. This approach was defended as an attempt to avoid dogmatic assumptions and arbitrary requirements about life. However, the products of this approach are not by design meant to explain how and why life emerged. Although sometimes praised as being intellectually challenging, minimalist approaches are often irrelevant or unable to convey true illumination. They do not make life clearer to whoever or whatever (observer or instrument) has already experienced life, nor are they insightful to whoever (or whatever) has never seen life before.

It has been claimed that a minimalist description of life would also implicitly address the problem of its essence. According to such an interpretation, a minimal and sufficient dictionary-type description of an object or a phenomenon (such as growing crystals, fire, clocks, hurricanes, wars or religious cults) must implicitly explain the forces and circumstances behind their emergence. A theoretical attempt has been made to describe life through the definition of a minimum unit of life. Apart from using the word ‘minimalist’, this interpretation reaches far beyond the dogma of a minimalist type of definition. It is rather an attempt to find a generalist interpretation of a minimal unit. The objection here is that the individual level of existence might not be enough to fully explain the meaning of life in general (at the supra-individual level). Life as an overall phenomenon has a considerable bearing on the understanding of its essence. Explaining life requires both individual and collective attributes. Generalist approaches to life are nevertheless valuable tools because of their built-in tendency to ignore the composition of individual life forms and address general concepts. They are the closest to a non-Earth-centric interpretation of life.



Cybernetic Definitions of Life

Cybernetic definitions of life are a product of the belief that it is possible to derive a definition of life from computer simulations, thus describing life entirely as a cybernetic ‘thing’. Yet caution must be exercised when using them. Statements such as “a living individual is as a network of inferior negative feedbacks (regulatory mechanisms) subordinated to (being at the service of) a superior positive feedback (potential of expansion)” are so unconstrained that many otherwise lifeless ‘things’ can fit the profile and be considered alive. Examples are not only plasmids and viruses but also the development of cloud systems, liquids at boiling point, fire, fluid vortices, magmatic extrusions, or uplifts associated with plate tectonics. Many of these ‘things’ display some form of intrinsic expansive tendency and use some form of regulatory feedback to adjust themselves to the tolerance limits of their available space and resources, thus apparently ‘avoiding’ functional collapse. If such things are alive, why not so consider other things such as the capital market, art, religion, or other phenomena related to the field of psychosociology such as the dispersion of news, lies, and gossip? They all display regulatory mechanisms at lower levels supporting the need for an expansion.

Cellularist vs. Genetic Definitions of Life

Cellularist and genetic definitions are descriptions based solely on experimental knowledge of life on Earth. Most classical interpretations of early life were either cellular or genetic. A ‘cellularist’ believes that the formation of a cell (a semi-permeable physical enclosure or a compartment) represents the relevant turning point toward life and that all other properties of life are consequent. In contrast, a ‘geneticist’ considers replication and variability as being the true starting points for life. In the last few years it has become more and more obvious that these two visions are not actually antagonistic to each other, but rather entangled, complementary and temporally connected. They are different facetes of the same thing. Although cellularist and genetic definitions of life are no longer much favoured, they are often used for teaching purposes.



Parametric Definitions of Life

Parametric (or criterion-based) definitions of life try to identify a list of the most relevant features of life. The most extreme (and most mistaken) parametric approach tries to identify one single feature of life as explaining everything including its origin. So far this attempt has proven fruitless and it is likely to remain so. One single step toward life is extremely unlikely. It is no different from viewing life as an extraterrestrial experiment, a miracle, alchemistry or magic. The philosophy of most criterion-based definitions is to gather the smallest bundle of features of life, features that in each author’s mind are the most striking, the easiest to perceive (or to measure) and the most comprehensive. The most popular parameters used in parametric definitions are replication, metabolism and evolution.

Despite their analytic appeal, parametric interpretations of life fail to discriminate between properties of life that are primeval or causal and properties of life that are derived (i.e., consequential and therefore subsequent). Some features from the physicochemical world such as electrical charge, the notion of spin from quantum mechanics, the electromagnetic force, mass and gravitation are considered more fundamental than others such as temperature, energy, viscosity, the strength of a chemical bond or the shape of a crystal. The latter are generally considered derived because they can be explained as consequences. Analogously, life also displays some features that are fundamental (either causal or phase transitions) and others that are derived (deterministic or emergent). This separation is not trivial, especially when early life is discussed. Although features such as energy balance, preservation of molecular and cellular architecture, metabolism, replication, reproduction, complexity, Darwinian evolution, homeostasy, motion, genetic blueprints, response to stimuli or intelligence are excellent discriminators for life, they are not primordial. These features are deterministic consequences of other preexisting circumstances, outcomes of the way living nature functions and are often not a confirmation that life is present.

Numerous lifeless physical realities display some life-analogous properties. Computer programs are capable of replication, fire is capable of growth, oceans have boundaries, the economy displays a means to achieve homeostasy, and the arts have an evolutionary history. Simply assembling such features indiscriminately, without regard for their type, meaning and interdependencies would be superficial. An endless plethora of overlapping combinations of parametric definitions of life can be (and have been) formulated. Although never completely wrong and usually not mutually inconsistent, they have no special merits in themselves and often tolerate each other. All these definitions are snapshots of the same multidimensional ‘thing’ we call life, viewed from different angles. The biggest caveat of the definitions of life that use exclusively derived properties is their inability to relate to the early history of life. This is because, instead of viewing life as a qualitative accretion punctuated by stepwise probabilistic novelties, a thing in harmony with its surrounding universe, parametric definitions contemplate life as a mere collection of unusual attributes, a spatiotemporal coincidence of remarkable properties. They tend to ignore the conditions and the factors that lead to these properties. A potential trap for a purely parametric description of life using exclusively derived properties is that of failing to recognize prelife forms as relevant. This applies especially when elaborate features such as hierarchical networking, oxidative phosphorylation, semi-conservative replication, or Darwinian evolution are used as criteria to formulate a definition for life.



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Material-Related Definitions of Life

Although “living organization is...characterized by a deep interrelation between form and materiality”, the universal properties of life are probably independent of its material nature. Despite the fact that life on Earth should only be used as one possible example of life, many descriptions of life are Earth-centric. The extension of this bias is also known as the ‘weak anthropic principle’ or the ‘anthropic cosmological principle’. The anthropic mentality implies that some very restrictive conditions are required for the existence of life, such as the particular properties of water at terrestrial temperatures, the properties of the carbon atom, or the critical events of phase transitions.

A common downside consequence of this vision is to impose Earth-related physical and chemical limits on where life may exist in the Universe and even to establish theoretical habitable zones based on material composition. In a few cases particular types of molecule such as nucleic acids and proteins are used to describe life. As far as we know, life on Earth might be the only type of life in the entire Universe using proteins and nucleic acids. Not only do protein/DNA-centric visions put any other possible form of life out of scale, but they interfere with a fundamental goal in exobiology, which is to understand life as a general concept. On the basis of an Earth-centric ‘policy’, an extraterrestrial flying to Earth, its body made of tar, its blood liquid ammonia and breathing chlorine gas, should be treated no more than as a bag of chemicals, irrespective of how complex its technology, how efficient its metabolism, or how elaborate its mathematics and its music. The ‘Earth-centrist commission’ would declare the ‘extraterrestrial bag’ to be ‘a non-living thing’ because it did not have ribosomes or DNA and it was too much unlike us. They would then draw some fluid from it with a syringe, make a chemical analysis and put the ‘thing’ in a freezer. How does this differ from the Amazonian indians killing explorers simply because they were unlike anything they had ever seen before in the jungle?



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What is Needed to Explain Life?

“Definitions are usually like a fisherman’s net: too small to encompass Leviathan, but with a mesh too large to hold many of the denizens of the deep”. Contemplative visions such as “the mystery of life isn’t a problem to solve, but a reality to experience” (Herbert 1965), approach life as something that cannot be understood, considering the subject too magnificent for our tiny brains. This mentality denies the spirit of the scientific method, portraying scientists as lost beings, doomed to wander forever in seas of incertitude and jungles of paradox. Most scientists believe that even though we may not yet be up to the task, life and its origins remain decipherable natural phenomena. Although life appears very complex, it may be simple in its basic principles. The main objective in exobiology is to find a way to approach the Gordian knot of life? Without cause–effect events regulated by the laws of chemistry and physics, there can be no science of the origin of life. It appears obvious that one should start from simple physical principles and follow their causality until lifelike properties are achieved.

The most common approach used by modern science to explain the origin of life is molecular Darwinism. Chemical simulations may be able to tell us something about how life can accrete, but early life is so far from us in the past that we will never know its exact chemistry. When details are not available, what is left are the basic principles. Whatever pushed life into existence was not its material nature but the determinism of its very essence. Thus some properties of life in the Universe may be presented independently of its material basis. An appropriate theory of the origin of life should identify a general sequence of events, rather than trying to solve the abiotic genesis of its individual pieces, e.g., its particular molecules. Since the assemblage of life was stepwise and nonrandom, its description must also be hierarchical. In a hierarchical scenario, events of a different causal rank are presented in a connected web.

Both criterion-related descriptions and purpose-related descriptions of life must be used to outline the essence of life and to understand its universal properties. The criterion-based component of such an interpretation must focus more on fundamental features, covering both the emergence and the historical survival of life, addressing the causality of its derived properties, and allowing a numerical discrimination of the living state from lifeless physical realities. The purpose-related component of such an interpretation must shed light on the meaning of life (its purpose-like nature), and it must also address the question of whether some physical force(s) pushed or assisted life into existence, and eventually lead to the identification of the general and the minimal conditions required for the emergence of life. A correct interpretation of life should be minimal yet elaborate enough to discriminate life from non-life. It must address both modern life and early life, and must be scientifically sound and unambiguous, yet comprehensible to a person with a non-scientific training.

A definition of life cannot be so esoteric as to become hard to convey. In the present work, the aim has been to seek an interpretation of life which achieves the following:

• To describe life independently of any material, size or time frame considerations. This approach is based on the common assumption from cybernetics, artificial intelligence, computer and systems sciences and artificial life that “the material or energetic aspects of an organization do not affect its logical essence”

• To define the minimal conditions required for life to emerge, considering the constraints which formal operational requirements put on the material components

• To use criteria that are comprehensive (universal) enough and at the same time simple enough to apply to everything that may be alive.

• To address both material life and cybernetic life and ask whether life can be reduced to an intrinsically computational algorithm.

• To allow the identification of non-Earth-centric biosignatures that are measurable.

• To provide a set of tools that optimizes the possibility of finding life whenever present and minimizes the possibility of false positives.

• To generate a construct that can be related to the early history of life on Earth.

• To address the emergence of life as both a causal (deterministic) and a fortuitous (chance-like, probabilistic) ‘thing’.




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Outline of a Historical Reconstruction of Life

The origin of life is often separated into three main stages: geophysical, chemical, and biological. Geophysical and early geochemical evolution deal with the formation and evolution of our planet, the formation of minerals, rocks, water, oceans, dry land and atmosphere before life emerged. The geochemical evolution of Earth is a common starting point and framework for most origin-of-life theories. It has some relevance for astrobiology but it is almost useless in the field of artificial life. Chemical evolution is the best-explored segment of the history of early life. In the footsteps of Darwin and Oparin, most scientists believe that small organic molecules formed first through abiotic processes, that monomers subsequently emerged and were followed by polymers. Other features were added later, such as cellularization, molecular mechanisms and metabolism. The vast majority of early life simulation experiments (also called biomimetic studies) aim to clarify a number of precise chemical. Although life on Earth cannot be understood without investigating its particular chemistry, most scholars now agree that the existence of proteins, lipids and nucleic acids is not an absolute requirement for the living state in general.

The least explored, yet by far the most interesting part of the origin of life is the transition between lifelessness and life. Only a limited number of biomimetic experiments try to make the transition between chemistry and biology. The elaborate intricacies of life make it obvious that life cannot just pop out from randomness in a single swift step. Numerous physical and chemical steps were required for life to emerge. This study focuses on rules and patterns followed throughout the early accretion of life, on the various stages and types of primitive life, and on the ‘lifeward’ developments that were subsequent to abiotic geochemical evolution. Considering the transition: geophysical evolution −→ chemical evolution −→ biological evolution, this study is positioned somewhere between chemical evolution and biological evolution.

Although relevant for understanding the composition and functioning of life on Earth, prebiotic geophysical and chemical evolution on Earth goes beyond the scope of the present work because what is questioned here is how many of the properties of life can be understood independently of its material nature. No chemical details are discussed, and nor do we address the questions as to where and how the first radicals, amino acids, pentoses, amphipates or cofactors were formed. We are concerned instead with the overall consequences of their existence and to some extent the general circumstances surrounding their formation. All the changes that followed once a Darwinian-type evolution had emerged and all the events that are subsequent to the establishment of a planetary homeostasy fall beyond the scope of this study and they are in any case beautifully covered in several classical studies...



Dominant Models

There are three dominant models concerning the origin of life:

Phase separated systems (PSSs) or vesicles formed first, then enzymes were added, followed by genes in a third stage

Template synthesis (replication) was the first meaningful event, followed by metabolism and then by cells

Abiotic activity (proto-metabolism) emerged first, followed by cellularization and then molecular evolution in third place

The preeminence of metabolism over genetic mechanisms was also hypothesized. It is posited here that during the early evolution of life major features such as cellularization, metabolism or genetic mechanisms could not have been successive as they coevolved. None of them was primordial because none of them was dispensable. The hierarchical history of life is not a succession of its major topics but a presentation of their concerted upgrades. The history of early life was a stepwise (punctual) accretion of achievements which can now be represented artificially through some major issues such as energy, boundary, metabolism, order, information and handedness. Thus one should not ask what major issue came first (energy or information or metabolism) but rather what type of mechanism they were represented by in different evolutionary episodes. One should also explore the attractors (forces) that lead to the upgrade of one evolutionary state into another. When applying this knowledge to artificial life, a mathematical theory of these transitions is also required. Yet the focus of the present study has been purposefully narrowed down to the logic rather than the mathematics behind the transition toward life, in order to construct a theoretical basis for the deconvolution of the tree of early life. For in the absence of purpose, logic and meaning, mathematical models are indistinguishable from combinatorial games or from infinite kaleidoscopes.

A reconstruction of early life brings out some guidelines:

• The structure, the function and the origin of life are inseparable.

• A description of life must be more than a picture of the present. It must also reflect its early history, ranking its achievements, and it must be purpose-oriented.

• Despite some historical step-like phase transitions, the separation between life and non-life was not very sharp. Many ‘things’ in nature exist at the boundary between non-life and life. Thus the non-life/life distinction is somewhat loose, especially at the transition zone (the origin of life) and a variety of interpretations of where lifelessness ends and life begins may be tolerated.

• Although it was sometimes argued otherwise, ‘life’ and ‘living entities’ are not synonymous things, but display certain independent. This distinction is essential to understanding both. A description of early life evolution must discriminate between ‘units of life’ and ‘units of evolution’

• Although early life forms were simpler than their modern successors, their overall functional principles and their evolutionary tendencies were similar.

• The type of life on Earth (referred to as the ‘terrestrial type of life’) is only one possible type of life amongst many others equally possible.

• Although living entities in the Universe can be very ‘different’ from each other with respect to their material substrates, constructive details, size, density and metabolic rates, they must all share some common properties (the universal features of life).

• In contrast to a commonly held belief, the overall evolution of the biochemical network was not dominated by “a convenient import of clue components at critical moments out of a bountiful palette of external abiotically-made molecules.” Although the terrestrial type of life did start with a handful of very common organics of abiotic origin, the build-up of the internal molecular network proceeded through the development of a selective import and novel biosynthetic achievements, and self-directed itself toward a peculiar chemistry that was purposefully uncommon to the outer world. In order to draft their own destiny (achieving some level of self-maintenance and gaining some functional independence), living units must beget distinction from outside chemistry. They must purposefully display a compositional personality. Thus trying to identify abiotic conditions leading to complex molecules of life such as nucleic acids, chlorophyll or proteins may be a mistaken line of research, as these molecules may have developed completely within life itself.

•Because modern life is hierarchical and emerged hierarchically, it is preferable to center the description of early life on how various states transited into various other states, rather than to list all possible disjoint steady states.

• The origin of life was both probability and necessity. A gradual accretion of life, using stepwise (fundamental) phase transitions and their consequences (derived achievements) allows one to interpret its origins as both probabilistic (chance-like) and deterministic (causal).

• The overall properties of life did not evolve independently of each other. Instead they have coevolved. Rather than being a smooth transition, the accretion of life was a stepwise (punctual) addition of achievements belonging to all major features of life.

• The derived properties of life are consequential (deterministic), i.e., direct outcomes of defined circumstances. The fundamental phase transitions toward life are chance-like (probabilistic) events.

• The ‘technological achievements’ of life (either probabilistic or deterministic) were not added randomly but in a meaningful sequence that was progressive with respect to its overall efficiency.

• The driving forces behind all historical upgrades toward life (i.e., the agents that pushed life into physical existence) are somehow related to a unique purpose-like tendency. This ‘purpose-like aspect of life’ must have applied from the earliest, the smallest and the simplest individual (the protobiont), to the latest, the largest and the most complex supraindividual level (the biosphere). It must also exist in abiotic nature. It is posited here that the major driving force behind the early evolution of life is energy-related and not some form of molecular selfishness. Molecular selfishness is a mere byproduct, a consequence of the need for the propagation of the structural and functional consistency of living units, and it is not a major drive toward life.

• In order to avoid cyclic arguments resulting from the use of biological terms in the definition of life, one has to define life in purely physicochemical terminology.

The major issues needed to understand life as discussed here are: energy, boundary, metabolism, specificity and information. Handedness is interpreted as a particular case of specificity that is meaningful for a type of life based on polymers. Most of the achievements of life did not end their evolution after their emergence. Yet for graphical simplicity many of them will be illustrated as pop-out boxes in most figures.



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Conclusion

Life on Earth displays a remarkable constructive unity. All living organisms use the same genetic code. Proteins only contain twenty amino acids and they are the dominant catalysts, while phospholipids are present in all membranes. This unity is hard to explain if the concept of life is truly independent of its material composition. Could life have emerged only once anywhere in the Universe? Do life forms need to exchange genetic information,which eventually led to structural unification? Is it possible that any given habitat may host no more than one form of life? Are our experimental approaches making us miss other forms of life for places like dwarf planet Ceres?

These two characteristics of terrestrial life (solitude and constructive unity) complicate the understanding of what life is in a more general context and thus limit our ability to locate extraterrestrial life forms, because a false mentality may persist wherein life can only be constructed this way. The absence of other types of life to be used as examples impede the establishment of the general principles of life, and this often leads to difficulties in interpreting the meaning and the origin of some ‘things’ present on Earth such as viruses, prions, desert varnish, manganese nodules or nannobes. Such ambiguities ‘at home’ are warning signs for the potential pitfalls in identifying extraterrestrial (ET) life.

The properties of life most often emphasized in the literature are derived either from classical biology or from computer simulations. In the simplest case, a group of such properties can be additively assembled with or without a causal relationship among them. Even if ET forms of life may be chemical and polymeric, it is unnecessary (and potentially misleading) to expect them to be based on the same materials as the terrestrial type of life, i.e., the same 20 amino acids contained in proteins, the same ATP, the same four nitrogenous bases contained in DNA, RNA, and the same phospholipid membranes. While it seems unlikely that ET life forms would share identical mechanisms such as chemiosmotic energy transduction, DNA replication or ribosome-based translation, all forms of life (biological and nonbiological, terrestrial and extraterrestrial, material and cybernetic) must share some common properties and obey some common rules. Thus, the parameters depicting life must be selected in a way allowing the extension of the quest for life in the Universe beyond the reductionist search for a few particular molecules, for the chirality in amino acids, for DNA, and in general for any other terrestrial-life-related or Earthcentric fingerprints. These universal parameters should also provide tools to understand the early evolution of life and monitor progress in artificial life simulation experiments. Biological life displays many measurable properties such as respiration, C-assimilation, motion, handedness, chemical disequilibrium, heterogeneity, homeostasy, Darwinian evolution, isotope fractionation, or biomineralization which, although good indicators of life on Earth, are derived features. In order to understand life in general, to clarify its origin, to focus on the very moments that made a difference in its early history and comprehend life independently of its material substrate, its form, its size, its shape, its kinetic activity and its evolutionary level, non-derived parameters of life are also needed that have a broad yet well-defined physical meaning.

References:

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F. Herbert: Dune (Berkley Books, New York 1965)

B. Korzeniewski: Cybernetic formulation of the definition of life. J. Theor. Biol. 209, 275–286 (2001)

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FounDit
Posted: Sunday, June 14, 2015 10:02:48 AM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 14,279
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A very interesting read, Justin. Thanks.
ChristopherJohnson
Posted: Sunday, June 14, 2015 11:02:38 AM

Rank: Advanced Member

Joined: 3/27/2014
Posts: 2,471
Neurons: 1,996,564
Location: Tbilisi, T'bilisi, Georgia
Our solar system seems to be full of water - satellites of gas giants, planetoids, asteroids contain or consist mainly of water. So why do many scientists think that water on our planet was brought by comets or asteroids? Why our water cannot be of local origin? If Ceres has water of its own, why cannot our Mother Earth?
NeuroticHellFem
Posted: Sunday, June 14, 2015 5:58:14 PM

Rank: Advanced Member

Joined: 7/22/2014
Posts: 2,292
Neurons: 2,590,862
Location: Lilyfield, New South Wales, Australia
Is anyone else humming The War of the Worlds theme? Whistle

Fascinating story. I can't believe I was born before man walked on the moon & now we've got craft filming the galaxy. The asteroid belt has always held mystery for me.
ithink140
Posted: Wednesday, June 17, 2015 7:16:25 AM
Rank: Advanced Member

Joined: 3/4/2013
Posts: 2,453
Neurons: 17,922
‘New pictures of Dwarf Planet Ceres, which Could Hold alien Life’

Yes… and a Large White boar just flew past my window.
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