A BIT OF BIOPHYSICS
Prior to my lecture on exobiology, we should review some biological concepts that are very important for the comprehension of the exobiology since the last century. I will start with the operational definition of life:
From the viewpoint of Biophysics, life is a state of the energy in some quasi-stable systems determined by a series of intervals that delay the spontaneous dispersion of the internal energy of those quasi-stable systems toward more potential microstates.
Let’s stop a little to explain in passing some statements contained in the definition of life:
An operational definition is a description of a variable, a term, or an object in terms of the specific process or the set of corroboration assessments used to determine its existence and quantity. The properties described by an operational definition should be publicly accessible so that one or more persons –other than the person that defined the concept- can measure it or test it independently at will, for themselves.
An operational definition is generally designed to model a conceptual definition, to be precise, by using words and concepts to describe a variable.
Phase Space is the space at which all the possible states of a system are represented. The phase space is produced by the general positions and their corresponding conjugated moments.
A conjugated moment derives from the difference between the kinetic energy and the potential energy in relation to an integral coordinate.
Delaying is not the same as revert; although revert could cause a delay, it is not the behavior of processes or states in nature. Many authors say that life involves a violation of the second law of thermodynamics, or that it follows trajectories against entropy, which is not factual. The referred law indicates that the energy always flows from a space or system with a high density of energy toward another space or system with a lower density of energy, which is precisely how life occurs. The Universe has a higher density of energy than that of the biosystems. If it were not thus, then life would not be possible.
The confusion was originated when some properties associated with the entropy were subordinated like alternatives to explain biotic features; for example, order, complexity, etc. However, to acquire order or to be more complex, the biosystem should transfer disorder toward the Universe and it has to take complexity from the Universe. Seen in this way, there is not any violation at the second principle of thermodynamics, every time that the biosystems are more disordered than the Universe and its disorder flows from the most disorderly system (the biosystems) toward the less disorderly system (the Universe). The major order of the Universe -as a whole- in contrast with any of its components, is specified by the theory of the energy density of the Higgs’ fields.
Given that life implies a state of the energy, it is precise that we know what energy is. Energy is the capability to do work, that is to say, a function of the quantifiable properties of a provided system.
Another term used in the conceptualization of life, essentially important for its formulation, is Quantum Energy. The term refers to the sum of the kinetic energy and the potential energy in a particle, which can be fermions or bosons.
The quantum energy (to be precise, the energy contained by a particle or a quantum) is proportional to the frequency of the electromagnetic radiation at which that particle of energy corresponds.
The formula to obtain the value of the Energy quantum is E = h f, where E is the quantum energy of a photon, h is the constant of Planck (6.626 X 10e-34 J.s) and f is the frequency of vibration of the radiant energy.
In the operational definition of life I used the concept of internal energy: internal energy of a system is the energy associated to the movement of the molecules in a thermodynamic system, that is to say, the energy subordinated to the temperature of such system. In an energy transfer, the internal energy of a biosystem is the energy that has already been transferred through the real or imaginary limits of that system (toward the inside of that system). For example, a multicellular biont has an external protector cover that isolates it partially from the environment. Each cell of a multicellular biont has a membrane or a wall that constitutes its real limits. There are organelles, as mitochondria, chloroplasts, etc. into each cell that have their own membranes as real limits, etc.
In the definition of internal energy I avoided to mention the words “disorderly”, “random” and “chaos” in relation to the molecular movement because the movements at a mesoscopic level are determined by microscopic fundamental laws that can be formally described by the mathematical notions of natural phenomena; therefore, the molecular movements are not chaotic, disordered or accidental. A small variation in the initial conditions can produce a change in the displacement of the particles, whether that we perceive or not that microscopic oscillation or the law that governs it.
What we call quantum state is the position, movement and energy density that follow a wave trajectory in discrete magnitudes or quanta. In this case, we refer to particles -like the fermions and the bosons- that establish the function of distribution of the energy in the intervals of delay in the spontaneous transfer of that energy.
The fermions are particles that have an intrinsic angular momentum that, calculated in units of Spin, is equal to an odd number from a fraction (1/2 or 0.5, 3/2 or 1.5, etc.) and that obey at the Exclusion Principle of Pauli. The fermions cannot coexist in the same position. Fermions are particles that comprise matter; for example, electrons, quarks, leptons, protons, neutrons, etc.
On the other hand, the bosons are particles whose angular momentum is always a whole number (0, 1, 2, 3, etc...), then, they do not obey the Exclusion Principle of Pauli and can coexist in the same position. For example, photons, gluons, particles w- and w+, gravitons, etc.
Angular Moment of Spin refers to the presence of angular momentum in an elementary quantized particle and not to a rotational movement. The magnitude of the spin of a quantized particle is obtained by the relation,
L = ħ √s (s + 1)
Where ħ is the Reduced Planck’s constant [ħ = h/2π = 1.054572 x 10-27 g-cm2/s] and s is an integral or a non negative half-integral.
h = 6.6260693 x 10-34 J.s
p = 3.1415926535897932384626433832795
Energy Density is the quantity of energy stored in a given system, or in a spatial region expressed per mass or volume units. For example, the liquid Hydrogen has an energy density of 120 MJoules per kilogram. The glucose has 17 MJoules per kilogram, etc.
A spontaneous process is that in which the energy always is dispersed toward more potential microstates. By this, when I talk about life, I am referring to no-spontaneous processes. For a spontaneous process to occur, it is not required the aggregation of energy of the environment, but of the transfer of energy toward the environment (exergonic process). In contrast, the life processes are endergonic, that is to say, processes that requires of the input of energy from the environment, or no-spontaneous processes.
In the definition of life I also introduced the concept of interval. An interval is a subset of states situated amid an initial state and a final state.
Finally, the quantum state of the energy in a biotic system is established by the flow of fermions and bosons that possess a quasi-stable density of energy during the transfer and storage of the energy through limited periods of time. For example, in the process of Transquantum Thermal Biotransfer of photosynthesis we study the positions, density and movements of the internal energy of a boson (photon) and of the fermions (electrons and protons) implied in the successive biotransfer of the energy freed by that boson. In the Transquantum Thermal Biotransfer of fermentation we study the density and the movements of the internal energy of the fermions, etc.
When we examine particles of matter, or with mass, we can only study a kind of particle, a given position or a given movement at once. Similarly, on studying the functions at some stage in the transfer and storage of the energy we can only study a function at one time. Once we have completed the study of each particle and each function, we integrate immediately the whole set to formulate the complete process.
CHARACTERISTIC OF LIVING BEINGS:
For astrobiologists, it is very important to distinguish between living and inert beings. The following are the characteristic differentials of living beings:
- The living beings are thermodynamic systems that have an organized molecular structure. This refers exclusively to the organization of macrostructures.
Biology and Chemistry, as opposed to Physics, do not admit ideological contexts: Or the biological phenomena are real, or they have been invented, thus of simple.
The biologists cannot go by there saying that such or which thing by being mathematically possible compulsorily exists (like the 27 dimensions of the strings hypothesis and the inter-dimensional worm holes).
For biologists, the land of speculations is well distinguishable and the biologists specify what is speculative and what it is not. By this, there are not lots of entropies in biology, but only the observable and quantifiable entropy, that is, the entropy that denotes the functions of macroscopic sets determined (the functions) by subsets of microscopic states of particles. What occurs in biosystems is a delay in the diffusion or dispersion of their internal energy; however, that internal energy never flows from fields of lower density toward fields of a higher density; on the contrary, the flow of the internal energy always happens strictly under the second law of thermodynamics.
Order and complexity are figured in macroscopic systems because at the microscopic level the entropy has a value of zero. When we consider the order of a macroscopic system and we consider its microscopic order, we find that there is not a border line among macroscopic and microscopic, between order and disorder and between complex and simple, by which, we clear up that the level of observable complexity in a macroscopic system obeys to a microscopic assemblage of variables with a level of complexity of zero, explicitly, for a volume of one (of the particles), an entropy of zero.
As much as we integrate the data toward a macroscopic level, we discover that the entropy acquires a value distinct from zero and that it will never adopt negative, but always positive values. Consequently, the entropy of the macroscopic system (to which we call complex) will have always a higher value of entropy than that of the microscopic system (to which we call simple) that was the condition that determined to the complex system. Thus, we find that the complexity and the simplicity are merely forms of mind fallacy presumptions, not what the nature exhibits, independently of the knowledge or ignorance that we have on the causal laws. If the complexity were a concept contextual to entropy, then the phase space at the microscopic level would be more complex than the phase space of the macroscopic system derived from the functions of the same microscopic level; thus, all would give an inverse turn, so the macroscopic system would be more disordered than the microscopic system from which it proceeds.
Objectively, the internal energy of the macroscopic set will occupy a higher number of microstates than the subset of microscopic initial states that determined all the positions of the macroscopic set. It clearly shows that the order and the complexity are anthropogenic concepts that belong to philosophical perceptions not related to real nature. In nature, the macroscopic systems always derive from microscopic variables, be that we have or not knowledge about them. By this, the theorist biologists propose that the order and the complexity be discarded as differential characteristics of living beings. We propose that the biologists must manage organization as one of the characteristics of the living beings, instead order and complexity.
Some years ago, someone asked me what would be of the Universe if there were not intelligent beings capable of perceiving it. I answered that the Universe would exist just as it is at present, independently of the existence of perceptive living beings.
- The living beings capture energy from the environment to temporarily maintain a density of their internal activation energy the more stable possible. That is, that the living beings perform no-spontaneous transfers of energy.
- The living beings reproduce once the conditions are favorable.
- The living beings suffer molecular variations that do not enlarge the number of available microstates. This refers to the process of molecular evolution.
Why we do not opt only for one of them, for example, reproduction?
Because there are inert beings that reproduce, grow and evolve; for example, prions. The mechanism of reproduction of the prions is highly singular. It seems to be a purely electrodynamic process.
Prions are particles of proteins that are produced in normal form by the cells. When those particles change its form molecular integral become prions infectious (Pr = protein; i = infectious) and accumulate in the cytosol, provoking the disqualification of the disqualification of information in the cell that produced them or that contains them. In the Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease, and other forms of degenerative brain diseases, the prions can originate in a different species to the host species. For example, the BSE can affect sheep, goats, deer, cats, hogs, frogs, horses and humans.
Obviously, prions are inert particles that are able to self-replicate. However, their replication takes place through a mechanism alike molecular resonance… Something comparable to the transfer of electromagnetic energy towards a water medium. When an abnormal prion enters in contact with normal cell prions, the particles in movement and not electrically charged of the infectious prion modify the structure of the normal cell proteomic particles to make them become into exact replicas of the infectious prion.
THE EVOLUTION OF INTELLIGENCE IS NOT AN ERGODIC PROCESS, BUT A STOCHASTIC SYSTEM.
When I talk about the evolution of intelligence as a process I apply contextual notions related to the laws of thermodynamics, for example, equilibrium and stability of the evolving systems.
The evolution of the intelligence obeys to morphological changes and these, at the same time, to disparities in the expression of genes due to variations in the conditions of the environment; then, the evolution of the intelligence is not a process that conforms to ergodic laws, that is to say, that the evolution of the intelligence does not adopt closed patterns that be independent of morphological initial conditions. However, the evolution of the intelligence is under stochastic laws because it exhibits states whose order and trajectory are algebraically unpredictable.
The evolution of the intelligence is an irreversible process because the natural initial conditions that caused the development of the function vary at a microscopic level, in such way that they occupy new feasible configurations. Irreversibility refers to a process -or to the formulation of a process- of which we cannot draw all the real possible intervals or trajectories. Nevertheless, it reveals our ignorance about the initial conditions that can give rise to a specific macroscopic function and not to a chaotic behavior of the macroscopic variables.
In the evolutionary process of living beings, the trajectories do not occupy all the microstates which are defined by the autocatalytic proteins and the sequences of nucleotides in the genetic material. The evolutionary configurations could always be promoted by small variations in the initial conditions that are not lost with time; then, the macroscopic morphological configurations of the living organisms will always be subject to initial conditions that determined the evolution of the biont from which they proceeded.
By which I have said in the previous paragraphs, we should be very careful in the emission of hypotheses, statements and theories to avoid the fallacy of the mind projection to do not think that some "complex" systems do not obey to deterministic laws.
Sydney Brenner, of the Institute Salk, has said that the complex biosystems are feasible only if it is feasible that the evolution can produce them. Facilitated Variation is the flexible organization of the processes that permit the change through the growth and the new molecular configurations.
Since I am talking about configurations, something very important for astrobiologists is that through three recognizable cosmic horizons occurred phase transitions from low energy density configurations to high energy density configurations without passing for intermediate states:
1. The origin of the Universe.
2. The origin of the solar system.
3. The origin of the life.
Whenever we deal with the theme of differences between living and inert beings, we say that in the biosystems the operator is internal and that the activator could be external or internal; in the meantime, we ratify that in inert beings the operator and the activator are external. It means that in the biosystems the energy flows from an initial state to a final state through operators situated inside the biosystem that acts through a cycle of transformations of potential energy to kinetic energy, to chemical energy, to electrical energy, etc. When I say that in the biotic processes the operator is internal I am referring exclusively to the no-spontaneous transfer of the internal energy of the biosystem.
In Quantum Mechanics, the angular momentum of the quantum is conserved like operator; that is, like a system that acts modifying to another system. If the operator is into the system, it is called an internal operator; on the other hand, if the operator is outside the system, it is called an external operator. Examples of internal operators at the microscopic level are the protons and the electrons, at the mesoscopic level the enzymes and the intermediate products are good examples of internal operators in living beings. An example of external activator in the transquantum biotransfer of Energy of photosynthesis is a photon. The subsequent quantum transferors through the photosynthesis process are internal operators and activators.
In the quantum state that defines life, the operators are always internal and the density of energy distributed by quanta varies according to the system that we are studying. A quantum is the minimum and indivisible entity that a specific magnitude can take in a physical system; for example, the minimum quantity of light is the photon.
The differences between inert and living beings belong to biophysics discipline. Otherwise, it would be not easy for the astrobiologists to distinguish between inert and living. The differential characteristics of living beings are:
1. The delay in the diffusion of the internal energy of the biosystem is caused by a no-spontaneous electrochemical gradient.
2. The living beings can establish autonomously a series of intervals that retard locally the spontaneous setting up of the thermal equilibrium.
DEFINITION OF EXOBIOLOGY
From the biophysical background explained in the previous paragraphs, we can obtain a conceptual definition of Exobiology. Exobiology is a term derived from three Greek roots Έξω= extension; external, outside; Βίος = life and Λόγος = science, treatise, discourse. From here, the concept takes the following form:
Astrobiology is a biological science that studies the origin and the existence of living beings in the Universe, besides Earth.
SYNONYMS OF EXOBIOLOGY:
The synonyms of Exobiology are diverse; however, the synonyms were structured in relation to the most important sciences implied in its development, Astronomy and Biology:
Astrobiology is the best term to design this science. The word is composed by three Greek words: Άστρου (a'stron) = Star, constellation, sky; Βίος (bi'os) = Life: and Λόγος (lo'gos) = Science, treatise.
Xenobiology is not a synonym of Exobiology because it is an uncertain term that refers to the study of bizarre beings distinct to humans; besides, if we consider the source of the word, Xenobiology is not a scientific notion because it means “biology of the foreigners”. To be a foreigner, it must be from other place and be living among us, got it? This is why the expression has been adopted joyfully by the alienologists because it refers exactly to intelligent extraterrestrial beings distinct to humans, so in molecular structures as in the energy dynamics that, in both models, infringe the fundamental laws. In contrast, the notion is linked to extraterrestrial beings whose existence is, until now, unreal.
By its extraction, Cosmobiology has been rejected like an adequate term or a synonym of Exobiology because it refers to astrological forgery. Cosmobiology derives from three Greek roots, κόσμός, cosmos = sky, world, universe; βίος = life; λόγος = science, study, treatise.
OBJECTIVES OF EXOBIOLOGY:
The efforts of the exobiology direct to the search of:
a. The origin and evolution of the Universe.
b. The origin and evolution of living beings on Earth.
c. The distribution of living beings in the known Universe.
d. The existence of living beings on other worlds besides Earth.
If this is not science, then, tell me what is science? There will be a time, not too far, when we will be able to explore many extrasolar planets in search of living beings. Now, we are engaged on futilities, like wars and divorces.
At the conclusion of my conference about the Origin of Life, a journalist questioned me on the uselessness of the exobiology. I replied that it was a knowledge that we cannot omit because it could permit us to do projections about the existence of the living beings on Earth. She insisted on asking "what’s for?”. I simply answered with the words of Dr. Leon M. Lederman:
Scientist is a person "who cares deeply and passionately for truth and clarification, for the liberating experience of finding order and beauty in a chaotic jumble of natural events". (Leon M. Lederman, 2001).
SCIENCES ON SUPPORT OF EXOBIOLOGY:
The exobiology is a biological science that is supported by other factual disciplines, for example, Physics, Chemistry, Geology, astrophysics, Astronomy, paleontology, Cosmology, Molecular Biology, Mathematics, etc. Why the astrobiology relates to Physics and Chemistry? Let’s see the reasons:
Why to Physics?
a. Because life can be reduced to well-known thermal phenomena.
b. Because the living beings obtain, store and manipulate the energy of the cosmos.
c. Because we can formulate the densities, positions and movements of the energy usable by living beings.
Why to Chemistry?
a. Because the biosystems are molecular systems.
b. Because the synthesis of living beings derived from the inorganic synthesis of simple and complex biomolecules.
c. Because the life of an organism is maintained and continued through chemical processes.
VIEWPOINTS ON EXOBIOLOGY/ASTROBIOLOGY:
1. Simplistic Posture: the living synthesis of beings depends only of water, carbon, energy and time. If we have the ingredients, we will have life.
This position denies the complexity of the primary abiogenesis. For a simplistic person, the fact that the abiogenesis do not occur today does not obey to a related situation to the development of the stellar systems, but to a pure twist of fate. It ignores the oscillations of the systems in the Higgs’ fields through the origin of the stars and the essential complexity of creating living beings in Vitro simply from those four factors. Happily, simplistic people are not biologists; at least, I do not know a simplistic biologist.
2. The Exclusivist Posture: the Universe is hostile for living beings because their origin is an event that occurred only in the Earth.
I hope that you have noted the mention of the word event; this is the favorite word of exclusivists because it connotes an intelligent or intentional program out from the physicochemical forces, specifically, the occurrence of an indeterminate state that would occur only by a miracle. For exclusivists, the Earth and the living beings were created in a sole planet, suddenly and once in the Universe. The Exclusivist believes that we have not found Earth-like planets merely because they do not exist, and not because we pay for our inadequate technology.
3. Relativist Posture: The synthesis of living beings can happen in any form on any place of the Universe.
Some biologists, I among them, identify relativism like Feyerabendism. The Feyerabendism is the ideology of the "All can happen", that is, that all is possible whenever someone have conceived it like an idea. From Feyerabendism the model of life based on any of the diverse elements of the Periodic Table was born; for example, the life based on Silicon.
4. Reductionist Posture: The synthesis of living beings depends on factors consistent with the fundamental laws of the Universe and can occur in any part of the Universe where the suitable conditions for the emergence of living beings take place.
It is not that I am a positivist scientist, but the reductionist posture is the best attached to the observation of the Cosmos and to the organized experimentation. More significant is the fact that it takes into account the present knowledge on the fundamental laws and on operational theories. Besides, any theory derived from this appreciation would be susceptible to exhaustive revisions, every time that the instruments to test any of those hypotheses or theories exist at hand.
Then, consistent with science, the Earth would not be the unique place in the Universe where there are living beings. For example, in the icy surface of Europe, a moon of Jupiter, we have observed large fractures that have been produced by constant thaws followed by sudden freezes of the tepid water that surges from under the thick icy cap. This makes us to think that there is a sea of liquid water below the frozen layer. Perhaps, many living forms stay alive and evolve in that environment.
PROBABILITIES ON THE EXISTENCE OF LIVING BEINGS IN THE UNIVERSE, OUT FROM EARTH:
We should take into account that, although the process is deterministic, the Abiogenesis is not predictable; thus, the estimations will always be highly speculative.
The number of stars in the Milky Way is from 200 to 400 billion stars. Besides, there are approximately 500 billion galaxies in the Universe. If each galaxy had from 200 to 400 billion stars, then there would be from 20 to 200 trillion stars in the observable Universe. If each star were encircled by 10 planets, then there would be from 500 to 2000 trillion planets in the Universe. A quantity very low from the trillions that the actor Sam Neill claims in a program of Discovery Channel about Life in the Universe.
It would seem that the probabilities of the presence of Earth-like planets in the universe, inhabited by intelligent beings, would be very high. However, we do not have the most minimum evidence about their existence. We have not found a single extrasolar planet alike Earth.
N = Ns fp ne fl fi fc fL
N = probabilities on existence of communicating civilizations in Milky Way galaxy.
Ns = approximate number of stars in the Milky Way galaxy.
fp = fraction of stars that I think have planets around them.
ne = number of planets per star that I guess are ecologically able to sustain life
fl = fraction of those planets where I think life evolves
fi = fraction of fl where I think intelligent life evolves
fc = fraction of fi that I think can communicate
fL = fraction of time during which I think culture survive.
Do not forget that it is a guesswork. Considering the inserted series are tentative, you can substitute the numbers as you wish (in proportion to the command of your imagination).
Although the formula of Frank Drake has had a broad diffusion like the "Formula of Life", actually, it has had a modest acceptance in the scientific neighborhood. It is a factorial progression based on unreal and unpredictable quantities. The problem of the formula is that it is not usable to emit hypothesis because it contains units that can never be verified. It has permitted that the applications of the formula had been related to simplistic or pseudoscientific arguments.
a. The thermodynamic laws operate in the known Universe.
b. The macroscopic laws can appear to be indeterminist by our ignorance about the microscopic fundamental laws.
c. The particles are the same in the whole Universe.
From the statements on the previous clauses, we infer that:
A) The living forms in the entire Universe should depend on liquid water.
B) Life in the known Universe should be experienced by structures made with Carbon.
WHY FROM WATER?
1. Water is available in the entire observable Universe.
2. Water is a thermoregulator for the atmosphere and into the bodies of living systems by the next properties:
- Its specific heat, that is to say the quantity of heat needed to increase the temperature of one gram of a substance in one degree Celsius. For water, it is one calorie.
- Its boiling point, which consists of the change of phase of a substance from a liquid phase to a gas phase. We need to apply 540 calories to evaporate one gram of water.
- Its solidification point, that is to say, the heat we have to extract so that a substance changes from the liquid phase to a solid phase.
3. Water is the universal solvent.
WHY FROM CARBON?
A) It is an abundant element in the Universe.
B) It is available for living beings like carbon dioxide in the atmosphere and in water, and like carbonates in soil.
C) It is the most versatile element to form compounds.
D) The compounds formed by Carbon are very stable.
WHY NOT FROM SILICON?
A. It has an atomic weight higher than Carbon (CAW = 12.01115; SiAW = 28.0855).
B. It does not possess the extensive versatility that the Carbon to form compounds.
C. The compounds formed by Silicon are unstable.
D. The SiO2 is a solid (Quartz, silicate), it is not a gas as the CO2.
The CaSiO3 (Calcium Silicate), the chemical equivalent of CaCO3 (Calcium Carbonate), would be inadequate for the oviparous because:
1. It Blocks the flow of heat, which would be a great impediment for the incubation of eggs. The CaSiO3 has been used in industrial ovens as a thermal isolator.
2. It has a heterogeneous texture by which the membranes and the chalaza would not be able to adhere firmly to the interior surface of the eggshell.
3. It tends to fracture easily. By this, it could not contain the low density albumin.
4. It is easy to be broken. A light longitudinal or transversal pressure would be enough to break a silicon egg.
5. It cannot be dissolved in water. Chickens would have serious impediments to rip an eggshell made with CaSiO3.
6. If it is left in humid environments through extended periods, the CaSiO3 is degraded into amorphous silica and dissolvable-in-water salts of calcium. This defect causes that this substance be inadequate to form support and protective structures.
7. Carbon is 3.5 times more abundant than silicon by tons; but at the atomic level, Carbon is 12.5 more abundant than silicon.
CONDITIONS FOR THE EMERGENCE OF LIFE ANYWHERE
A THREE-DIMENSIONAL SPACE- Living systems (biosystems) need a field in the Universe containing a space with three dimensions, longitude, width and deepness.
TIME- Living systems need a field in the Universe that includes available microstates to which their internal energy can be transferred and from which they can obtain energy. The measurement of the flow of energy toward more available microstates is what makes perceptible the dimension of time. Time flow is constant, although it appeared to be changeable from the human perspective.
A SOURCE OF ENERGY- Living beings must receive a stable and continuous supply of energy from a star. Earth receives a continuous and stable tide of energy from a G2V star (the Sun); besides, Earth is positioned at a suitable distance from the Sun (the Earth is placed at 1 AU far from the Sun), not too near as to be scorched by the intense solar radiation (as Mercury and Venus), neither too far as to be frozen in the cold sidereal space (as the outer planets like Mars, Jupiter, Saturn, etc.). The source of energy may not be necessarily a star. The planet that shelters living forms can be itself the source of that energy needed for life.
We think that the G class stars (yellow-white, with nuclear fusion reactions of Hydrogen and effective temperatures of 5300-6000 K. G Class are Sun-like stars) that belong to the main sequence (V or dwarf) are the most possible stars to have planets with optimal conditions for the origin and evolution of living beings. The Sun is a star of class G2V (surface effective temperature of 5800 K):
The star Alpha Centauri is also a G2V star. This makes it to be a star very similar to the Sun. It is an accessible candidate for exploration through our instruments because it is relatively near to our Solar System (4.36 light years from here). There is only a problem that darkens the scene: it has a star companion, this is to say that the system is a double star. Its companion is a dwarf of the class K1V (5300 K). If there were in that system a planet with intelligent living beings, they would see our Sun as a star of first magnitude near the constellations of Perseus and Cassiopeia. Our Sun would be their sidereal point of reference…
For stars to be included into the appropriate parameters for generating and maintaining living beings, astrobiologists record the physic characteristic of the stars, like size, electromagnetic spectrum, brightness, temperature, rotation, nuclear stability and metallicity.
Very hot or very cold stars should not be excluded from the catalogue because they may have planets that could be orbiting at such distance that they would not experience the pounding of high amounts of cosmic radiation. The problem found by some scientists that compels them to exclude hot stars from the habitable stars catalogue is that hot stars extinguish faster than the stars of low or medium temperature; however, most biologists think that the usual life of a star is not a critical impediment for the emergency of life on any of its planets. It is possible that the living beings have emerged in a world with the appropriate conditions and that they have continued their evolution through hundreds of millions of years, whenever the star that provided the energy had remained active and steady through that period.
An understandable example comes from the history of life on Earth where, although the biodiversity scaled through 3.3 billion years, the highest point of biodiversity occurred in the course of 500 million years (at the Paleocene). Thus, any star of F, G and perhaps K classes, which had habitable planets -in a system where the fundamental abiogenesis may have occurred- and that still were active and steady at this time, will be a suitable star for our list of habitable stars.
A STEADY AXIS OF ROTATION- The planet should have a stable axis of rotation. Earth has a big Moon that controls its spinning. The Sun and the Moon control the rotary motion and the orbital trajectory of Earth. However, even when this factor has been greatly important for living beings on Earth, it could be not obligatory for life forms on other planets. There are zones between the hemisphere that always faces to sun and the hemisphere that never faces to sun called twilight zones; life may flourish at twilight zones on planets without a big satellite as well as at planets with a stable axis of rotation.
A MAGNETIC FIELD- The planet that would hold living beings must have a protective field shield against massive particle's radiance during solar electromagnetic storms. Earth has an efficient magnetic field shield.
A PROTECTIVE ATMOSPHERE- The planet which would give shelter to living forms must have a protective atmosphere against cosmic radiation. Earth has an ozone layer, but it could be also dense clouds of dust and water vapor.
WATER- Living beings have to be formed in environments rich on water. This is certain because water has unique physicochemical qualities.
For example water molecules are disintegrated during the photosynthesis process, freeing oxygen atoms and electrons.
Water acts as a thermoregulator for climate and living systems:
Thanks to the water the climate of the Earth is maintained stable. Water works also as a thermoregulator in living systems, especially in endothermic animals.
It is possible because of the specific heat of water (specific heat is the heat in calories necessary to elevate the temperature of one gram of a substance in one degree Celsius), which for water is one calorie. In biological terms it means that before an elevation of the temperature in the surrounding environment, the temperature of a mass of water will rise with greater slowness than the temperature of other materials. Equally, if the surrounding temperature diminishes, the temperature of that mass of water will diminish with more slowness than that of other materials. Thus, this thermal property of water permits that the aquatic organisms live relatively placidly in an environment with a stable temperature.
Evaporation is the change of the physical phase of a substance from a liquid phase to a gaseous phase. We need 540 calories to evaporate a gram of water. At this point water boils (point of boiling). This means that we have to rise the temperature at 100°C to do water boils. When evaporates from the surface of the skin or from the surface of the leaves of a plant, the water molecules hold large quantities of heat. This feature works in the organisms like a cooling system.
Another advantage of water is its melting point. The extraction of heat from a substance changes it from a liquid phase to a solid phase. The temperature at which a substance changes from a liquid phase to a solid phase is called the melting point. To change the water physical phase from liquid to solid we have to diminish the surrounding temperature at 0°C. The change of one gram of ice to liquid water requires a supply of 79.7 calories. When water melts, the same amount of heat is released to the environment. This allows that the environmental temperature does not decrease to the point of annihilate all the life on the planet through winters.
Besides, water is a universal solvent. Almost all substances essential to sustain the living forms can be dissolved in water. Besides of being accessible for living beings, water acts as the best vehicle for food transporting so in the external environment as in the internal environment of all known organisms.
CARBON- Carbon is available for living beings mainly in the form of atmospheric carbon dioxide. It can be also found in carbonates in the soils. The Carbon has six electrons in its first level of energy and four in the second level of energy, sharing electrons with other elements in four covalent bonds (tetravalent), which makes it the most flexible element to form compounds (organic compounds, because they have Carbon in their skeletons) For example, Silicon atoms have also four electrons in its outer shell, but Silicon is heavier than Carbon (Silicon's atomic weight is 28.0855, instead, Carbon's atomic weight is 12); because of it, Silicon cannot offer the versatility presented by Carbon. The skeletons formed by Carbon atoms can vary in length and array (linear and ring structures of the same compound). Until now we have not found life systems based on other elements.
AGGLOMERATIVE SUBSTRATES- Substructures that facilitate the accumulation and chemical interaction of substances; for example, grains of Calcium Phosphate, Calcium Carbonate, Silicon Carbide, Graphite, Fullerenes (allotropic form of Carbon) and Iron Sulfur, which can contain icy water into their fissures and holes.
Recently, the scientists of NASA and ESA discovered that the Calcium Carbonate can be synthesized in the interstellar and interplanetary media without the presence of water (Cooper et all, 2001). This put in doubt the affirmations that the small carbonated globules found on Mars have originated in deposits of water. It is more probable that those Carbonates have been placed on the planet by a continuous and prolonged precipitation of dust from the Martian planetary cloud and from the Interstellar Medium, just as it occurred and continues occurring until now on Earth. The fractals of Calcium Carbonate in the planetary nebula would be suitable for the synthesis of biopolymers.
CONDENSER AGENTS- Substances that promote the abiotic synthesis of biomolecules, from simple biomolecules to complex biomolecules. For example, the HCN (Hydrogen Cyanide) and the C2H2 (Acetylene). These compounds abound in the early interplanetary media and both have been tested artificially as condenser agents. The evidence indicates that the bio-polymerization of proteins and carbohydrates was facilitated by these agents and through reactions promoted mainly by high energy bosons.
Fractals are granules of cosmic dust. I call those grains “fractals” because they fuse to form other greater bodies during the genesis of stellar systems. The fractals can be from few microns to several meters large. It seems that the fractals worked like dividing walls and protective agents in the abiotic synthesis of biological polymers in the terrestrial planetary nebula. Fractals could work in a similar way by:
a. Shielding the biomolecules against cosmic radiation of high energy density.
b. As agglomerative substrates that “dehydrated” the niches wherein the synthesis of polymers occurred by the action of light and heat on the globules contained by water into the holes and fissures of dust grains, helping to the polymerization of simple molecules to form larger biomolecules. Many fractals contained drops of water which suffered regular phase transitions from liquid to solid and vice versa. Those fractals, or dust granules, could also function like agglomerative substrates.
All our observations on the abiotic synthesis of biological polymers point to the previous conclusions.
The ozone has become necessary and indispensable for the living beings on Earth; however, not only the ozone functions like a protector of living beings against the Cosmic Radiation. Dust and water vapor also act like shields against Cosmic Radiation. Remember from the theory on the origin of life that when living beings emerged on Earth there was not an ozone layer and that the first bionts had to be protected against the cosmic radiation, composed mainly by wide streams of X-rays, emitted by an incipient Sun.
The fractals with frozen water trapped in their holes and fissures can act like shields against cosmic radiation. The protoplanetary disks are constituted by fractals of diverse dimensions and by heterogeneous substances that can act like protective screens.
The fractals or granules of forsterite or magnesium silicate are Olivines produced at very high temperatures. This indicates that the comet Wild-2 -from where we have obtained fractals of olivine- was formed in a zone very close to the Sun or at a very hot place out from our solar system, at temperatures near or over 1000 K. In this class of comets there could not have been synthesized complex organic compounds. It is more feasible than the biomolecules have been synthesized in the environment of planetary nebulas.
The grains of silicon carbide ejected by supernovas could have acted like agglomerative substrates wherein the biomolecules and the microspheres with lipidic membranes could have been synthesized. Those fractals have also holes and fissures that could have been filled with water and fundamental substances that would build biopolymers.
Also the sidereal porous fractals, as the type Porous Chondrites formed by silicates, which molecular structure is not altered by heat, water and the chemical reactions that occur among simple molecules, could have acted like agglomerative substrates for the formation of biomolecules. It has been confirmed experimentally that some biomolecules, like ribose and amino acids, were synthesized in porous fractals. Later, the polymerization into the holes of the granules there could happen.
The question is whether those processes that occurred during the gestation of our Solar System could be frequent events in the whole Universe.
At least, we know that the chronicle of life on Earth shows a sequence of events strictly connected to the physical and chemical universal laws. So, the life on Earth is not unique and it has not derived from events given by accident. (Christian de Duve; 2006)
The occurrence of life on Earth has been determined by the Universal physical laws; consequently, the life on other worlds of our Cosmos cannot be microstructurally very different to the terrestrial life.
If there were a possibility of existence of other biotic configurations, these would exist now on Earth because the Fundamental Laws operate in the whole Universe and the particles and their properties are the same in the whole Universe.
How would it be the first discovered extraterrestrial organism? We could speculate a great deal on the probable appearance of the extraterrestrial living beings whenever we had taken into account the conditions of the probable environments of other planets. For example, we can conjecture on the homeostatic systems of an organism living on a planet with a more or less dense atmosphere than the terrestrial atmosphere, or under a gravity force greater or lesser than the terrestrial gravity force, under a sulfurous atmosphere, etc. However, the astrobiologists have verified that the probabilities to find extraterrestrial intelligent organisms are extremely low. The signal "Wow!” registered by SETI in 1951, was an electromagnetic oscillation reemitted or bounced back by a fragment of spatial waste.
However, we can almost be sure that apparently the life can only be experienced by systems built with organic compounds (those built with Carbon), and that the biosystems living on other worlds should be similar to the terrestrial biosystems; at least, on microscopic structure and thermodynamic qualities, although their macroscopic appearance be totally different to the terrestrial organisms.
OPEN EXTRATERRESTRIAL ENVIRONMENTAL CONDITIONS:
How could be the prevailing environmental conditions in a world where there are living forms?
There are organisms that live in highly hostile environments for most terrestrial species; for example, Sulfolobus solfataricus, which tolerates sulfurous environments with acidity at pH 3.5 and temperatures at 90 C. Recently, it was discovered that the cooler effect of the cytosol of Sulfolobus solfataricus is due thanks to a protein (enzyme) called Alcohol Dehydrogenase.
Throughout the last 15 years, the astrobiologists have centered their attention on extremophiles. That obeys to the inhospitable environmental conditions exhibited by the planets at the scope of our technology which would be lethal for almost all the terrestrial living beings. Perhaps, some day we will find an Earth-like planet on where we will find not only extremophile prokaryotes, but also protists, plants and animals.
What the extremophiles are? Extremophiles are organisms that live in extreme environments that would be deadly for the greater part of the terrestrial living beings; for example:
A. Thermophiles: Resistant to high temperatures (Pyrococcus lives in water at 113° C).
B. Psychrophiles: Resistant to very low temperatures (Cryotendolithotrophus lives in water at -15° C).
C. Acidophiles: Resistant to acidic environments (pH 0).
D. Alkalophiles: Resistant to alkaline environments (pH 9-11).
E. Xerophiles: Organisms that live in waterless environments.
F. Halophiles: Organisms that live in hypersaline environments (some halophiles tolerate environments with a 30% of salinity).
G. Deinococcus survives after being exposed to 500 thousand rads; besides, it tolerates high levels of UV light and radioactivity at the same time.
The human beings are not extremophiles because we live in the middle part situated between the extremes of the environmental variables. The extremophiles live in those extremes.
However, the planets that could shelter extremophiles must have environments with the following features:
A) The conditions of the biosphere should be heterogeneous.
B) There must be sectors with conditions that permit the spontaneous synthesis, the molecular stability and the thermal activation of biomolecules.
C) Under these two conditions, the extraterrestrial biosphere must have the next physical characteristics:
- The climatic variability must occur into the ideal patrons for the survival of bionts.
- It should possess the basic nutrients, sufficient for the subsistence of bionts.
- It should maintain protective units against intense oscillations of the flow of energy from the source (a star, a planet core, etc.).
- The fluctuations of the chemical surroundings should not be extreme or abrupt.
Albert Lou, of the School of Medicine in Harvard, has proposed that the repair of the DNA is the singular resource of the extremophiles; however, the restoration of the DNA through ubiquitins occurs also in no extremophiles organisms. It is more feasible that the tolerance to extreme environments be a morphological adaptation of the proteins quaternary structure as a chemical response to the change in the surroundings, which is independent of the genetic material. That is to say that, for the DNA to be repaired, it must be functional proteins that can feasibly determine the restoration of the DNA.
TYPICAL CRITICISMS (ANTISCIENCE) AGAINST EXOBIOLOGY:
Some censors say that the extremophiles could have adapted to the hostile environments millions of years after the emergence of the first biotic forms. Of course! I agree, although it could also have been the opposite. Remember that the conditions considered today like deadly conditions were the prevailing optimum conditions for the occurrence of abiogenesis, and that the modern extremophiles can be the offspring of the survivors of those times.
They also argue that the possible extraterrestrial biosystems could follow evolutionary trajectories different to the trajectories followed by the terrestrial biosystems. Yes! Those probable extraterrestrial organisms could follow evolutionary trajectories different to the evolutionary trajectories of the terrestrial living forms, but hooked on the set of potential trajectories in the cosmos, not in a set of trajectories invented by us.
The detractors noisily express that to think that all the biotical structures in the Universe are based on Carbon and Water is dogmatic and restrictive, and that the exobiologists should be open-minded towards the opinion of others. Yea, we hold an open-mind, but only toward things that are adjusted to the behavior of nature. Our duty is to reject every vestige of ideological pseudoscience. One thing is how nature behaves and another very different thing is what we know about that behavior. Our ignorance or our erudition do not influence in facts of nature.
They also say that any extraterrestrial thermodynamic system which grow, reproduce, obtain energy and evolve would be alive, although it was not made of carbon. If this were enough to catalogue beings as being alive, we should restate all the science of Biology and crystallography. All the materials that did this would be considered like living beings, although they were crystals of cobalt chloride, copper sulfate or they were… prions.
The anti-exobiologists adduce that any living form in the universe would possess complex molecular structures, and that there would be no reason to be similar to the terrestrial bionts. Well, there are cosmic molecular structures more complex than the living beings and they are not alive; for example, the Earth, an asteroid, Jupiter, the Sun, etc.
Some detractors of Exobiology have told me that it seems that the exobiologists do not bear in mind the evolution when they are only seeking for primitive microorganisms on Mars. The reason to seek only for microorganisms on Mars is because it is a planet that has been vastly explored on which we have not observed multicellular living forms as those macroscopic bionts on Earth. There is not moss, lichens, grass, trees, insects, snails, worms, fungus, etc. We look for primitive microorganisms because we know that the favorable conditions for the evolution of multicellular organisms ceased some four billion years ago on Mars.
The concise answer of science is that the chronicle of life on Earth refers to facts strictly connected to the cosmic Physics and Chemistry. Then, life on Earth is not unique neither it is dominated by eventuality, but life has been determined by the fundamental laws of the Universe; consequently, the microscopic structures of the living beings in the Cosmos cannot be different to the microstructures of the terrestrial living organisms. If the existence of other biotic configurations were possible, these would exist now on Earth.
The emergency of living beings on Earth is not special and we assume that it is not unique. We unquestionably know that the emergence of life on our planet obeyed to the universal physicochemical laws and that it occurred simply because it had to occur like a natural and basic process, as well as it has to occur at any place of the Universe where the conditions that propitiated its development on Earth restage. This it is not a matter of conjectures, but of scientific knowledge that we have found out from nature.
Many detractors say that exobiology is not a science because it does not have a real object of study. Those antiscientific people do not have idea about what they claim because the living beings on Earth are creatures of the Universe, open to be studied because we have them here. Earth is a tiny part of the Universe, and astrobiologists are qualified to study the life at any nearby segment from the Universe.
Earth is the primary closer horizon from the Universe to be studied. Now we are doing it also on Mars and on Saturn’s satellites. This makes that exobiologists have a supply of subjects to examine, as any another factual science. Besides, exobiologists do not tell tales, but they are dedicated to seek for other worlds in the Universe where we could find living beings.
Perhaps the detractors wish that the exobiologists have an extraterrestrial organism into a flask for being considered like scientists? Well, we do not have an extraterrestrial organism into a flask, but we have at hand lots of terrestrial species alive to be studied like beings of the Universe, or Earth is not part of the Cosmos?
Exobiologists do not have to usurp the labor of biologists -given that astrobiology is a branch of biology, it is valid that exobiologists study the Earth’s life; so, exobiologists, or astrobiologists, study the origin and evolution of the living beings on Earth to make possible the understanding of their main occupation, which is based on looking for habitable planets and living beings in the whole Universe.
METHODS FOR DETECTING BIOMOLECULES IN EXTRATERRESTRIAL ENVIRONMENTS:
After the prior explanations let's try to answer the following question, how to look for chemicals needed by the living beings in other locations of the Universe?
We can look for chemicals needed by the bionts through the following techniques:
A) Through Indirect Observation. For example, through infrared radiation telescopes, radio-telescopes, space telescopes, etc.
B) Through indirect observation by robotized probes carrying specialized laboratories to the planets or other sidereal bodies to be investigated; for example, Spirit, Viking, Opportunity, Mars Explorer, etc.
RECENT FINDINGS THROUGH INDIRECT OBSERVATION:
The spectrum of the star HH46-IR of the nebula IC1396 in the constellation of Cepheus, made by the infrared telescope Spitzer, reveals the existence of methane, water, carbon dioxide, silicates and methanol. From this same images of that star we obtained images captured by different devices used for astronomical observation, for example the image of high energy density X-radiation and the image of the low energy density X-radiation were obtained with the telescope Chandra; the optic image with visible light was obtained with the Hubble Space Telescope and the infrared image was obtained with the Spitzer Infrared Space telescope.
In Antenna galaxy, which actually consists of two colliding galaxies, scientists have detected sulfurous compounds, carbonates, water and heavy elements, like iron and magnesium.
In Orion Nebula we detected large volumes of water.
Scientists have detected Polycyclic Aromatic Carbohydrates, water, methane and oxygen in the Horse Head Nebula. They found Glyceraldehydes in the most brilliant zones.
Supernovas are sidereal deposits of carbonates. We have detected large quantities of oxygen, water and sulfurous compounds in remnants of supernovas.
The findings achieved from the mission Huygens-Cassini on Titan, a satellite of Saturn, confirm one of the predictions of my theory about the ringed planetary cloud. The theory explains the presence of methane, acetylene and ethanol of abiotic origin in abundant quantities in the external sidereal bodies (external bodies are those which orbit more distantly from the Sun than Earth).
From photographs of stellar systems in gestation we can observe the disks of materials that will build planets. Astronomers are performing many spectrometric Studies to know the prevailing elements during the formation of those systems. The incipient star systems are comparable to huge centrifuges in which the simple compounds, like water and glycolaldehyde, are arranged in concentric orbiting rings around the stars and arranged thus according to their orbital angular momentum, to their quantum states and to the mass density of each system.
In the South Pole Martian, the European Space Agency (ESA) has verified the existence of frozen water in relatively small quantities. The largest mass of the ice is frozen carbon dioxide.
HOW TO DISTINGUISH LIVING FORMS ON SIDEREAL OR EXTRATERRESTRIAL BODIES:
How will it be the first living forms that we will find on other worlds, and how will we be able to know that they are alive? The procedure is not minuscule. We had the best example on the great debate provoked by the Martian meteorite Allen Hills found in the Antarctic on August 4th, 2001. The famous image of a microscopic structure found in the Martian meteorite Allen Hills-0804001 (ALH-0804001) is the fossil of a living being or is it an inorganic artifact?
Suppositions used as evidence in favor on that it was the fossil of a Martian microorganism:
A) Presence of Polycyclic Aromatic Hydrocarbons similar to those found around terrestrial fossils.
B) Presence of globules of carbonated minerals, which had cores of manganese or iron covered by carbonates, ferrous sulfate, magnetite and pyrites, around the main concretion of the Martian meteorite.
C) Presence of ovoid microspheres close to the concretion of the meteorite with diameters from 20 to 100 nanometers, which were considered by scientists of NASA like fossils of primitive martian bacteria.
Contextual facts against the hypothesis of the microfossil of the meteorite ALH-084001 (inconsistencies in each one of the above clauses):
A) There could be that the Polycyclic Aromatic Hydrocarbons were wastes of terrestrial organisms adhered to the Martian rock.
B) The minerals can form globules by spontaneous non-biological processes. We have found globules of non-biological origin in other meteorites.
C) The identification of the ovoid spheres like nanobacterias has decidedly been criticized by most scientists, so inside as outside from NASA, because the promoters of the idea turned to the ideology of Feyerabend ("All is possible", which consists of the inclusion of incoherent elements into an acceptable theory in which those elements are incompatible; for example, to deduce that not because we have not seen a dragons it means that dragons do not exist, or as saying that in this immense Universe the laws are not fixed neither universal and that any imaginable thing is possible). The smallest organism found on Earth is an archaeobacterium called Nanoarchaeum equitans that lives like an obliged symbionts on another archaeobacterium called Ignicoccus. Nanoarchaeum equitans is 400 nm (0.000000400 m) in diameter. 1 nm = 10e-9 m = 0.000000001 m.
Latterly of the speech on this theme, a person asked if living beings could be smaller than archaeobacteria. It is not easy to have hold the horses in public when you have to confront a pseudoscientific ideology; however, I did it there and I got the disgust from the people that were attending my conference. I said on that occasion that: The molecular biologists consider that the smallest package of molecular structures needed to support the efficient management of the energy would not fit in a volume smaller than 210 nm. The mitochondrial granules are from 30 to 50 nm in diameter each. The mitochondrial DNA and RNA molecules are 15 nm large each. Every one complete molecule of ATP Synthase is 10 nm in diameter each one, and there are hundreds of them in just one mitochondria. Considering all the molecules of carbohydrates, lipids and proteins fundamental for the independent cell metabolism, the tiniest matter package to experience life must be from 210 to 250 nm in diameter.
Bacteria are slightly larger that mitochondria (from 1000 to 4000 nm long and from 200 to 1000 nm wide, this is, 0.04 µm3). Archaeobacteria are a bit smaller than mitochondria; for example, Nanoarchaeum equitans is 400 nm in diameter. This thermophile lives like an obligatory symbiont on another thermophile called Ignicoccus. Both were discovered in hydrothermal fumaroles in Iceland.
More evidence against the hypothesis of the Martian fossil in the meteorite ALH-0804001:
A) It is possible to synthesize in vitro abiotic sediments identical to those that were found in the Martian meteorite through non-biological processes.
B) The age of the meteorite is 4.5 billion years. However, the concretions in the meteorite are 4 billion years old, which implies a probable emergency of living beings on a planet that no longer could maintain living organisms. According to the studies of David Shuster and Benjamín Weiss, Mars has always been an icy and aggressive for life planet. They completed their studies of many Martian meteorites, finding that Mars had been frozen by the last 4.1 billion years, just only 400 million years after the concretion of the red planet. This has been confirmed by other investigators.
C) The Polycyclic Aromatic Hydrocarbons of the Martian meteorite have been found in other meteorites, where they were synthesized by means of non-biological processes.
Finally, Robert E. Kopp III, of the University of Chicago, has shown experimentally that the organic concretions of the meteorite ALH-084001 are in reality residues of terrestrial bacteria living in Antarctic. Sorry by your disappointment!
In the meteorite MIL-03346 some NASA’s engineers found micro-tunnels that were similar to the microtunnels left by the terrestrial bacilli when they die and disintegrate. By this reason, those engineers of NASA published that those microtunnels could be the “coffins” of Martian bacteria. However, the biologists of NASA meticulously examined the microtunnels and they found that:
A) The transversal diameters of the microtunnels in the meteorite are extremely small (20 nm), so tiny as to not be compartments left by bacilli after their disintegration.
B) Geologists found identical structures in terrestrial volcanic rocks of Antarctic formed by non-biological processes.
C) Rather than the meteorite ALH-084001, the meteorite MIL-03346 did not present traces of organic substances, by which the idea of Martian bacilli was immediately discarded.
We have seen that it is not easy to identify beings living out there; then, how will we be sure at other planets if we cannot be there to confirm it physically? The modern astrobiology has proposed the following methods to verify the presence of living beings in other worlds out from Earth:
a. Finding products derived from living beings; for example, methane, sulphydric Acid, waxes, cellulose, milk, excrements, etc.
b. Observation of alterations of the environs by the activities of living beings; for example roads made by the step of the individuals (as by ants walking on grass), holes on soils or rocks surrounded by materials modified by the activities of living organisms (as the holes made by moles, snakes, ants, etc.).
c. Observation of structures that unmistakably can be identified like structures of biological origin as exoskeletons, hair, vegetal fibers, etc.
d. Cultures in adequate nutritious media by robotic portable microbiological laboratories (like the Viking ships).
e. Bringing them here.
What a hard task! Isn’t it? We have seen how we have failed in our intents to identify secondary products as derived from living organisms, such as the methane on Mars. Besides, we have seen how the geomorphologic phenomena can definitely be deceitful, as the sedimentary layers of Mars and the bacteria on the Moon. The space laboratories have failed on providing us satisfactory data, feasible to distinguish between biological and non-biological processes; for example, the data sent by the rovers Spirit and Opportunity on Mars. To bring here the living beings from other planets is currently not possible because it is expensive and extremely complicated.
OTHER ACTUALLY EFFICIENT METHODS OF INVESTIGATION:
The Proton Motive Force (PMF) is an observable expression of the thermal state of life. On account of this, I have proposed at diverse forums that the only approach -dependable and observable- to find living beings everywhere is the Proton Motive Force.
The PMF is an electrochemical potential formed by the fluctuations in the electrodynamic fields that allows the fermiones to displace toward one or another side of biomembranes. Those electrodynamic fluctuations obey to variations in the magnetic fields of the biomembranes provoked by transportable charged-particles.
The biotic phase is a configuration of the energy released when a proton goes through a biomembrane. The density of that free energy varies from 5 to 12 Kcal/mol. The fluctuations in the electrodynamic field produce an electrochemical gradient in biomembranes equal to 220 mV (0.22 V). One photon transports a quantity of energy close to 52 Kcal/mol.
Is this process spontaneous or no-spontaneous? It is necessarily a no-spontaneous process because a spontaneous process would happen directly with the diffusion of the internal energy of the system. In the biotic phase, the energy is incorporated from the environment.
Through experiments separating the molecules of ATP Synthase from the mitochondrial membranes, scientists have found that the molecules continue working, but inversely, that is, producing ADP instead ATP. This means that the molecules that were separated from their respective membranes operate spontaneously, that is, removing internal energy, not acquiring energy from the environment. In general, this means that to act no-spontaneously, the molecule must be attached to a biomembrane that experience an electrochemical potential and that, besides, the process in the complete system definitely is a no-spontaneous process.
Another important related element is that all the living beings have ATP Synthase -with inconsequential variations, from which I have assumed that the ATP Synthase is a molecule that has persisted since the autosynthesis of the microspheres that would develop into protobionts. Indeed, in the past I had been a bit discrete with this assertion, because some years ago I thought that the ATP Synthase appeared in protobionts. But now, I have found that this knowledge permits us to answer the problem about which appeared first, the microspheres agglutinated into capsules made of simple biomembranes or the microspheres agglutinated into capsules made of bilayered biomembranes, and that, by this reason, they survived like quasi-stable biosystems.
Well, at last we have found something exclusive of the living beings; now, how can we detect this “something” on other worlds? Easier than seeking for carbonates that can be synthesized by abiotic spontaneous processes:
We can detect life on other planets by means of the identification of products unmistakably implied in the PMF; for example, ATP Synthase, ADP (Adenosine Diphosphate), ATP (Adenosine Triphosphate), NADP (Nicotinamide Adenine Dinucleotide Phosphate), FAD (Flavin Adenine Dinucleotide), C Cytochrome, L-Aspartyl-4-Phosphate, etc.
A continuous and prolonged monitoring of the concentrations of the products is required, thus we can recognize fluctuations that would be unmistakable indicators of biological activity, which would require the use of probes that can be maintained functioning uninterruptedly at least along three years.
Dr. Constantinos Mavroidis of NASA has designed a midget spatial ship that functions with lithium batteries, which can be maintained stable and functional along 10 years, without interruptions. The ship would cheapen enormously the costs of the interplanetary exploration.
The mimetic bionanorobots into phospholipidic microspheres could be inserted into likely extraterrestrial structures to detect natural bioelectric activity. The nanorobots would be attached one to another to form a wide web that could cover extensive areas of the planetary land. It would not be left a millimeter of soil without an examination.
We can also use nanorobots transporting chemical sensors for the detection of the compounds implied in the Proton Motive Force.
The nanorobots could carry potentiometers with ultra-microelectrodes for biomembranes, which would detect and identify the membrane potential in cells of the purposed extraterrestrial living beings, although we do not be there to see them physically.
Another method for the detection and unmistakable identification of biotic compounds is the Spectrometry of Masses by Ionization and Agglutination of Electroatomization into a Vacuum Chamber. This device of spectrometry permits to carry out direct analyses of any substratum without a preliminary separation of the materials that we are going to analyze. The device sprays a specific ionizer solvent toward the substratum that is analyzed. The ions separated from the substratum are trapped by a vacuum chamber that directs them toward a small mass spectrometer for their identification.
Both devices, the Mass Spectrometer by Ionization and Agglutination in a Vacuum Chamber, and the potentiometers with ultra-microelectrodes for Biomembranes have been tested successfully.
But… If we find microorganisms on Mars, how could we know if they are local microorganisms or if they are terrestrial microorganisms that were taken there by one of our probes? We will never know, unless we can examine the genomes of those microorganisms; however, it is an impossible to achieve task with the current spatial technology.
UP TO DATE EXPERIMENTATION:
Currently, the astrobiological experimentation is focused on the following aspects:
a. The modeling of the early conditions of the terrestrial reductive atmosphere which data we have known through the paleontology and geological observation.
b. The synthesis of prebiotic molecules and other organized structures through abiotic procedures.
c. The Experimentation with diverse factors that could activate the synthesis of prebiotic molecules in the primal terrestrial atmosphere and that can be applied to the observation of other stellar systems.
d. Trials with diverse electrodynamic fields to recognize stellar systems where the synthesis of biotic compounds may be occurring currently.
In astrobiological experimentation the investigator must abstain to get involved in the processes to avoid the effect of "external operator".
A lamentable example of this fault is when it was achieved the synthesis of Ribozymes in vitro, the procedure was acknowledged like an abiotic synthesis of Ribonucleoproteins. However, in the description of the methodology, we found many processes that had not occurred without the intervention of the investigator; for example, the frequent alterations of the substratum each time that the experiment did not followed the desired trajectory. Finally, we found out that the chemical environment where the Ribozymes were spontaneously synthesized required of the external help of buffers, polymerases, nitrogenous bases, proteins, ribose and phosphates in proportions very far from the magnitudes observed in nature.
Then again, the abiotic synthesis of polypeptides has not been what we had expected because the chains of amino acids abiotically obtained in laboratory are you chiralic mixtures (stereochemical asymmetry) of L-proteinoids and D-proteinoids, with hydrolytic function, so that they could not build stable secondary structures like the ß-plates and α-helixes. Besides, we had to apply temperatures of 200° C that would do improbable the autosynthesis of other biological polymers, which do not remain stable at so high temperatures, and that necessarily would have to be formed in the same environment where the autocatalytic proteins were spontaneously synthesized.
The most suitable experimentation is the experimentation that has been centered on the synthesis of complex polymers into particles of dust in microgravity conditions and by the action of light and UV radiation. In this kind of experimentation, we simulate the conditions of the primitive terrestrial planetary cloud and the solar radiation with an acceptable realism, compatible with astronomical observations.
For example, Allamandola and colleagues completed the autosynthesis of microspheres with membranes under conditions of microgravity and coldness similar to that of the primitive terrestrial nebula. Consecutively, Perry A. Gerakines and colleagues, of the Department of Physics of the University of Alabama, have created organic molecules from frozen mixtures (at 20-100 K) by radiation with protons with an energy density of 0.8 MeV and by photolysis with UV radiation with an energy density of 6-10 eV.
Scientists of NASA have created complex macromolecules under conditions of microgravity. They affirm that it is simpler to create complex molecules under conditions of microgravity than under the influence of the terrestrial gravity.
EXOBIOLOGICAL, OR ASTROBIOLOGICAL, PROJECTS:
The Division of Astrobiology at NASA, now with a new director, will investigate places with perennial springs on Earth, which would permit us to know the frequency and distribution of microbiota. This would aid us to discover places with liquid water on other worlds.
We will try with microglobules synthesized by abiotic means to find the factor that could favor the sudden and discontinued transition in the microspheres, from a low energy density configuration to a high energy density configuration, without passing by intermediate configurations. It will continue the exploration for Earth-like extrasolar planets.
Besides, we will extend the study of the possible prebiotic photochemistry of the primitive Earth to verify the conditions in reductive atmospheres of other planets or sidereal bodies where living beings could be emerging.
For the next 25 years, the astrobiological investigation will be focused on relatively-nearby sidereal bodies, as Mars, Venus, Enceladus, Titan and Europe.
SETI will insist in its perspective to register signals of radio-communication emitted by extraterrestrial cultures, with a new director, with financial records trimmed to 50% and with thousands of users of the SETI program struggling for being the winners of the great prize by detecting the first radio-signal from an astral civilization.
ARE WE ALONE?
Until now, we know that we are alone at this side of the Cosmos. Nevertheless, may be we are not the unique "alone" living beings in the Cosmos. Perhaps, at this time, on a sidereal body barely heated by a small star, or on a world illuminated by a binary or a multiple star system, someone is asking itself (him, her or both) the same thing.
If the humanity takes care of the own humanity, attends his non-human brothers, those that barely think or that do not think, and takes care of the non-living things, the future of Astrobiology is promissory… whenever we explore what we have to explore, on feasible places to be explored.
New Braunfels, TX.
27 of July of 2006
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Resources on Exobiology/Astrobiology in the Web:
University of Hawaii. Astrobiology Winter School. Honolulu, Hi. Winter courses organized by NASA. Preference to graduate students (bachelors).
Northern Arizona University. This forum supports education and research in astrobiology at NAU. These activities take place through the Northern Arizona Astrobiology Club, coursework in astrobiology (AST 183 and AST 184L), and various research activities in the College of Engineering and Science. Registrar at http://www.astrobio.nau.edu/phpBB/profile.php?mode=register
Stockholm University. Astrobiology Graduate School. Students will be formally allocated to Physics, Geology and Geochemistry or Molecular Biology.
Cardiff University. Cardiff, England. Postgraduates. International Costs: £ 10, 950.00. Apply at:
Carnegie Institution of Washington. High School courses. Sponsored by NASA.
NASA Academy at Ames. Canceled by short funds.