FROM THE STARS TO THOUGHT
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SUMMARY: The nucleosynthesis of the chemical elements which make up the matter
of the universe in the stars is interpreted as an antientropic process,
made at the cost of the strong increase of cosmic entropy produced by
stellar radiation.
The
work outlines and discusses the hypothesis that the chemistry of carbon,
the main component of living organisms, started in the carbonaceous stars
with the formation of various hydrocarbons, among which acetylene. This
highly reactive compound then polymerised, forming linear, cyclic and
heterocyclic products, which were subsequently erupted in the interstellar
clouds. Given their special chemical optical and electrical properties,
two main functions were attributed to these materials, which are among the
most common in space: the first being the accumulation of chemical energy,
the other the storage of the three key elements: carbon, hydrogen and
nitrogen. It is also stressed how, with the aid of light, the biogenous
molecules were synthesised in the interstellar grains by scission and
combination, starting from these polymers. This second phase, partly in
space and partly on planets, is characterised by a further tendency
towards a reduction of local entropy, compensated by an increase of
planetary entropy and by solar irradiation.
This adventurous trip, from the Big
Bang to the human brain, through various theories and hypotheses,
shows how exceptional "life" is, within the general economy of
the universe and how wonderful "conscience" is, within the
economy of life itself.
Living matter tends to the greatest possible spread, and protects its own
genome by means of a complex digital system. The birth of manifold
organisms in such a short time makes evolution less casual, favouring more
coherent and coordinated events.
Life and human conscience oppose the general increase of cosmic entropy
with a steady growth of organisation and information. In some way, we find
what matter loses at cosmic level in the human brain, as a splendid
virtual reversed image of our surroundings.
PREFACTION: Has the Universe always existed or did it start with a Big Bang? How
were life and matter formed? Is man the only evolved being? What are
thought and consciousness and where are they located?
Essential
questions, like these have always troubled men's minds. According to
modern science, living phenomena can be explained on the basis of simple
chemical, physical and biological laws and the properties of living
material can be attributed to a tendency of systems towards complexity and
self-organisation.
The
current work tries to bring an original contribution to this fascinating
problem.
1. DISTANT AND UNCERTAIN ORIGINS, PRECARIOUS FUTURE [2]
"
Wayfarer, your footsteps are
the way, and nothing more;
wayfarer there is no way,
the way is made with movement.
With movement one makes the way
and turning one's
glance back
one sees is the path to which
one will never return, to tread.
Wayfarer, there is no way,
but wakes in the sea"
Antonio Machado
Questions
about the origins of life, of man, of the earth and the universe existed
in ancient cultures and sometimes they were so persistent as to become
obsessive.
As many solutions were proposed as there were civilisations, even
extending to more abstract concepts (space, time, good, evil, etc). A
series of theories, hypotheses, and beliefs have succeeded each other over
the centuries, culminating in two great visions, those known as
Creationism and as Darwinism [3] According to Kant, instead, man must
limit himself to respectful contemplation and admiration of the Creation,
given that the necessary rational presuppositions for giving life to a
credible interpretation either of the origin or of the development of the
universe are missing.
On the other hand, the fact itself of asking the eternal question does
nothing but conceal fear and the need for protection: feeling near a
supreme Entity is reassuring especially when one is employed in a
relentless struggle for life.
Right from the start, the Creator was conceived with a human resemblance
and as a being able to give life and form to all things. The Creation has
been imagined as originating at times from an egg, at times from a flower
or a foaming wave of the sea; at times balanced on the wings of a bird or
accompanied by the thunderous rumbling of drums; other times as the
sweetest music.
These ancient representations seem to flourish once again in modern
science: the thunder of the Creation is now called Big
Bang (Urknall), while the
recently discovered “Music of the Sun” [4] calls to mind the ancient
harmonies springing from the depths of the cosmos.
The success gathered by evolutionary theory is due to scientific and
sociological factors and its roots come from the empiricism typical of the
modern era. This is based in on objective facts, on the revelations of
controlled experiments and on the more recent developments of biochemistry
and genetics, which have brought about the discovery of a mechanism for
the transmission of the common hereditary base of all living beings which
are coherent with the hypotheses of Darwin (1859) and which makes them
credible. Besides, the possibility of rationally explaining the
development of life found fertile terrain in the enlightened type of
borgeous society and also in that of Marxist-Leninist leanings of the last
century.
***
With
the end of the sparring match between evolutionists and creativists [5,6],
lay and religious culture in the West today appears to be inclined towards
accepting the rational scheme of the theory of evolution, while the so
called “state of life” or what we intend by life, continues to resist
the various attempts of physical or philosophical definition.
According to the most respected accepted version, “life” is “a
common state of material present on the surface of the earth and in the
oceans, formed by the complex combination of four principle elements
(carbon, hydrogen, oxygen and nitrogen) as well as sulphur, phosphorous
and traces of others [7].
It
seems easier to define some fundamental characteristics which distinguish
living creatures. We may present them as the following axioms:
1.
Living creatures are generated only and always from other living
creatures.
2.
They have a defined and constant form;
3.
They are made up of fundamental units (cells), affine for structure and
function;
4.
They possess the property of building and maintaining themselves at the
expense of the chemical substances and energy, which they obtain from the
environment;
5.
They maintain continuous relationship with the external world and are able
to react to determined stimuli;
6.
Each species safeguards its genetic information;
7.
They are not perennial, given that each individual is destined to
disappear at the end of a predetermined life cycle (biological clock);
8.
They tend to the maximum possible spread [8];
9.
They are thermo-sensitive and life is only possible in a very restricted
range of temperatures.
The
safeguarding of genetic information (point 6) allows conservation of the
information despite a general increase of chaos (entropy), thanks to a
complex digital system, like that of the chromosomes. This, unlike that of
our electronic technologies, based on two alternatives 1 and 0, adopts
four: A,G,C,T (Adenine, Guanine, Cytosine and Thymine), which represent
the letters of a living digital language. This language has demonstrated a
surprising capacity for conserving the hereditary characteristics of the
single species with accuracy and of defending them from the most varied
external agents.
Perhaps for the first time in history of the Cosmos, we are facing the
capacity on the part of some molecular chains of perpetuating themselves,
safeguarding the information necessary for the formation of the successive
individuals, at the cost of energy captured from the surrounding
environment.
This is a sort of challenge to the universal tendency of increasing
disorder and entropy, which finds its maximum triumph in human beings and
in particular in the human mind, with its capability of rational
coordination and creative bursts and extending to the conquest of
self-consciousness.
Many biologists claim that the synthesis of life from inanimate matter
will be possible in the near future. At that point the axiom 1 would fall,
according to which living creatures always generate living creatures and
only living creatures and thus, the last frontier between the animate and
the inanimate worlds would also disappear. This ambitious objective has
not yet been reached, despite the fact that we know a lot about the
structure of the cells and that the “biochemical building blocks”
necessary for their assembly are readily available. Other scientists
consider the realisation of life in the test-tube an improbable event
because of the complexity of the living matter, which has only been
reached through an evolutive process of various hundreds of millions of
years. Wanting to repeat this process in the laboratory in a brief time
with the purely casual approach appears if not unrealistic, at least
improbable. The future of this question is uncertain and it is difficult
to predict how many years still remain for the classical axiom “Viventes
viventibus generantur” (Spallanzani, 1729-1799)[9]
From quarks to the galaxies and from bacteria to planetary ecosystems,
nature tends towards greater complexity and selforganisation: the atomic
particles become atoms and molecules: these become biomonomers and
polymers, and later protobions in pluricellular structures and organisms,
which in turn give rise to social and ecological systems (axiom 6) [10].
The birth in such a short time of all this plurality of organisms and
structures reduces the casuality of evolution and alters the possibility
of variation in favour of coordinated and coherent results, able to make
order prevail over chaos.
***
Even
before prehistory, an irresistible push to overcome every frontier
characterised all forms of life. The migration of animal species, with the
scope of exploring and conquering territory, expresses the tendency of
planetary expansion of living matter. It is clear that such a form of globalisation does not represent a purely
human and terrestrial phenomenon, but rather a universal biological law.
Evidence comes from the arrival of forms of primordial life on earth,
transported on the backs of meteorites and comets from the depths of the
cosmos.
The push towards globalisation is not absent in any living being, all the
less so for the vegetable world or that of microorganisms, from viruses to
bacteria, to fungi and protozoons. At times the spread has come
indirectly, through appropriate biological and atmospheric vectors: pollen
and seeds transported by the wind and insects, seeds in the form of
evanescent clouds (aerosols) or at the mercy of the wind, attached to dust
and sand.
The phenomenon then spread from the biological sphere to the cultural
sphere. Homo sapiens has been
the main instrument, through migrations, commerce, movements, spread of
knowledge and culture, thanks to science and technology [11]. The exchange
of written and spoken idioms, also the various attempts to overlay
dominant linguistic stock (Greek, Latin, English, Mandarin, Hindi, etc)
and supplant local languages, have effectively facilitated reciprocal
comprehension and cultural interchanges (crossfertilisation).
What happened in the past repeats itself in a modern key: today two of the
main motors of interchange and development are a common language (English)
and the freedom of movement of people, ideas, written and telematic
information.
In both biological and cultural evolution one finds movements in
a reverse sense with the formation of niches, isolated from the
evolutive trend and from the environmental context. In the biological
niches, life and development proceed slower, in small steps, and the
possibilities of interchange with the outside world are scarce (e.g. the
Galapagos islands). Analogously there are cultural niches, those of single
ethnic groups living an almost prehistoric life (e.g. Australian
Aborigines, Indios in Amazonia etc).
The sudden and unexpected collision of biological niches and the modern
world can be dangerous: it can create hygiene problems with at times
disastrous repercussions at a planetary level (ebola, hiv, aids etc) [12]
or politico-social problems which are not easy to solve.
For biology globalisation represents a completely unusual process but not
without serious risks, every time established equilibriums will be upset.
Innumerable plagues have afflicted mankind in the past [13]; others like
AIDS are devastating the world modern and still others are about to do so
(BSE, molecular diseases)[14,15]. These plagues are nothing but passing
accidents in the process of globalisation occurring on our planet.
Louis
Pasteur's phrase is ever more pertinent, coming as an admonishment: “Messieurs, c’est les microbes qui auront le dernier mot”.
2.
SUDDEN AWAKENING
"
All the efforts of all ages,
all the dedication,the
inspiration, the bright greatness of human genious,
are destined to end in the vast
death of the solar system, and the temple of
human conquests will be inexorably buried
under the detritus of a universe in ruins..."
Bertrand Russell
Distressed
by the thousand dangers of a
hostile environment, man has always looked for protection and security, to
the point of designing a model of the universe made in his own measures.
From Ptolomy and from the ancients we inherited a reassuring picture of a
static calm earth at the centre, caressed by the sun, watched over and
almost protected by the other planets; man trusted himself to Divine
Providence to the Last Judgement. Copernicus, Galileo and Newton brutally
awakened us from this idyllic dream, which had lasted millennia. All of a
sudden, we found ourselves in an earth pirouetting around the sun, and
joined with it in a flight across the universe, prey to black holes,
cosmic rays, asteroids and comets [16]. Today we know that the universe
tends to maximise dispersion and about thermal levelling (freezing) and
that it is it is the unexpected fruit of an immense catastrophe, the Big
Bang. Beyond our galaxy, which we had mistaken as an immutable
expression of eternal order, there are a succession of apocalyptic dramas
unknown to the ancients: asteroid and cosmic collisions, explosions,
births and deaths of stars and planets, encounters between giant galaxies.
The sun and the stars, whose friendly light guided trusting navigators and
merchants for centuries are nothing but bombs, hydrogen bombs, fed by
nuclear reactions, and all predestined to go out, some sooner, some later.
The unconscious fear of some universal judgement has given way to the
rational certainty of an inevitable end.
The universe, at one time all order and peace now appears to us in the
throws of gigantic nuclear manifestations. The blue of the sky, the site
of Olympus and of our ideals of highest perfection, is the theatre of
menacing novas and supernovas, of lethal radiations, of solar winds, of
incessant bombardments of dangerous ionised particles.
From interstellar space more or less visible flashes of light reach us
across dense clouds. formed by gas and cosmic dust. From these clouds,
which sooner or later will collapse into stars and planets, a confusion of
simple and complex organic composites are born. These are the building
blocks from which carbohydrates and proteins are formed, to be assembled
later into cells and living organisms [17].
We are taught that man was created in the resemblance of God as part of a
great celestial project, while we discover that we are the fruit of
chance: some millions of years ago a giant meteorite fell onto the earth
darkening the sun and provoking darkness and intense cold or that a
supernova exploded nearby inundating the earth with lethal radiation. The
cataclysm condemned the dinosaurs and a great part of the living species
to death, while it allowed the formation of a biological niche better
adapted for the mammals. From here, the hominids started and from them
came Homo Sapiens.
3.
DUST AND CINDERS OF THE STARS
"
Our destiny in indissolvably
linked to
that of the stars "
Paul Davies
Urged
by an inexhaustible curiosity, prehistoric man studied the nature around
him and, with wonder, observed the connections between various phenomena.
The firmament burning bright with shining stars in the clear nights
strongly attracted his attention. Alternating observations, adoration and
meditation, he began to put some aspects of the earth's climate, like
precipitation, temperature and the play of the tides, into relation with
movements of the constellations and with the systematic nearing of lunar
phases. Astrology and astronomy, the first the oldest among man's
inventions, were founded on a completely empirical basis. Considering the
lack of adequate instrumentation and the modest knowledge, one must
recognise that astronomy reached admirable levels of knowledge among
independent and distant populations like the Sumerians,
Assyro-Babilonesians, Egyptians, Greeks, Mayas, Aztecs, Incas, Chinese,
Indian Arab etc.
Later, cosmology would develop from astronomy
and pose problems of a more ample nature about the structure and
the future of the entire universe. Having outlived the speculative
approach, cosmology then developed into empirical science, thanks to the
innovation of technology and means of observation, like telescopes with a
wide spectrum, radio astronomy and spectroscopy [18].
"Once upon a time about 14 billion years ago, there was a terribly
dense incandescent ball and its huge explosion would give rise to the
origin of our universe, with its masses and galaxies, with stars, suns and
planets: and on at least one of these latter one day life appeared".
Thus Giulio Giorello summarised the theory of the Big Bang about the origin of life and the universe[19].
Opposed by many, appreciated by many, this theory today is more or less
universally accepted and has formed the basis for the development of new
hypotheses about life and its origins.
***
The
initial explosion interested space and time simultaneously , signalling
the start of all of physical reality. Through a progressive process of
expansion and cooling, the initial temperature of several millions of
degrees fell to 2.7°K of today. In the first instants elementary
particles like quarks formed from the radiation together with free
electrons which blocked the passage of photons: for this reason the
universe was not transparent and would have seemed totally dark to a
hypothetical external observer. A little after, that is at the end of the
first three minutes, the temperature had fallen to less than 3000°K
allowing the formation of hydrogen atoms, by combination of protons and
electrons, passing thus from the era of pure energy to that of matter. On
the basis of various experimental data, today it is believed that in all
the stars there is an uninterrupted process of nuclear fusion with the
conversion of hydrogen into helium and the emission of radiating energy.
This fusion energy can feed a star for billions of years in a remarkable
equilibrium between forces of gravity pressure and of radiation. When the
temperature of the star is sufficiently high the nucleus of helium melts
again forming first carbon and then oxygen, nitrogen, neon and other light
elements. For thermodynamic reasons the chain of spontaneous reactions
finishes in the stars with the formation of iron [20], while in a
supernova, where enormous quantities of energy are liberated in an
explosive form ,chemical elements heavier than iron, like gold, lead,
uranium, and so on, are formed. All these from the lightest to the
heaviest will then be projected into space from the explosion of the
supernova where they mix with the detritus of other older generations of
stars [21].
It is clear that this 2% of matter present in the cosmos and the stability
of the sun, able to burn with continuity and almost without alteration for
billions of years, have represented the two factors essential for the
birth of life.
This
2% of matter has furnished the elements and the molecules necessary for
the assembly of the bricks of life up until the first monoorganisms and
pluricellular organisms [22], while the sun has provided the energy to
feed this cascade of reactions, which needs an addition of external energy
to be able to evolve [23]. The energy necessary to form and break a
chemical bond is modest, amounting to only 1 electronvolt (eV) per atom or
electron [24]. The photons which reach us from the sun possess
energy of precisely this order of magnitude, and thus they are able
to set off and terminate all the chemical reactions appropriate for the
assembly of life, like for example photosynthesis [25]. The number of
photons present in the universe (from 100 million to 20 billion for every
nuclear particle) is able to produce whatsoever chemical reaction. The
organisation of inanimate matter into living matter is a complex process,
which proceeds through a series of chain reactions, passing to simple
composites to complex composites (cfr. Eigen's theory of hypercycles). To
realise a reaction with the formation or splitting of a chemical bond it
is necessary to satisfy some essential conditions like affinity,
concentration and temperature. This means that two composites react with
each other if they have an adequate reciprocal affinity and if the
temperature (energy activation) and
concentrations (kinetics) are sufficient to guarantee the trigger and
maintain the reaction [26].
The existence and creation of matter obey chemical laws and the more that
one goes up the scale of complexity the more are the restrictions to
respect and the fewer the degrees of freedom available.
Living matter is composed of four main elements: carbon, hydrogen, oxygen
and nitrogen. Among these the first has such an importance that we may
affirm that the chemistry of life
is the chemistry of carbon.
Among all the other possible elements, candidates for this role (e.g.
silicon) carbon has the advantage of the chemical and physical properties
of some of its derivatives:
For the oxidation of carbon one obtains carbon dioxide (C + O2
-> CO2) a gaseous substance soluble in water, easily recyclable and
which plays a fundamental role in the photosynthesis of plants and
therefore in all the vital processes. From another element which shows
many chemical analogues with carbon, silicon, by oxidation one obtains
silicon dioxide (Si + O2 ->
SiO2) the most widespread mineral on the earth, well known in its
crystalline form of quartz. Silicon dioxide is solid, insoluble, inert and
not easily recyclable. This difference of chemical physical properties
represents the main reason that living matter is made of carbon and not
silicon.
The metabolism of living matter leads to three end products: carbon
dioxide (CO2), water (H2O) and ammonia (NH3).
The first and last are gaseous while water is liquid but evaporates
easily: the three products can therefore easily mix in the atmosphere
facilitating their recycling in all the planet.
In
the last analysis it is this possibility of easy recycling that conditions
the existence of terrestrial life.
4.
THE COSMOS, DARK CASKET OF LIFE
“A universe populated by an
infinite number
of suns, around which rotate many planets,
populated by
creatures, with an intellect no
different from that of mankind. Such a countless
vastness of the cosmos will end up cancelling not
only the centrality of the earth, but also that
of man "
Giordano Bruno, 1548-1600
Space
is not empty as was once thought, but contains matter, distributed among
stars, planets nebulas and galaxies.
Most of this matter, composed of hydrogen (70%) and helium (28%) in a
gaseous state, formed following the Big
Bang fills space in a uniform fashion. Only a minimal part (2%)
constituted by cosmic dust is distributed randomly in interstellar space
or in an aggregated way among comets, meteorites, asteroids and planets.
The cosmic dust (ISM, interstellar media) is formed of ashes, erupted into
space by stars dead for a time: and these ashes give birth to new
generations of stars and planets [27]. In space various elements have been
identified, like oxygen, carbon, nitrogen, nickel, sulphur, silicon,
aluminium and iron as well as some hundred of so simple and complex
organic molecules (PAH from Polycyclic
Aromatic Hydrocarbons).
Current opinion claims that most of these derivatives of carbon have
formed in the interstellar grains through complex chemical reactions of
photosplitting and photosynthesis. The carbon and the hydrogen derive from
the photolysis of the PAH, the oxygen from photo demolition of iced water.
According to this hypothesis the key molecules for the synthesis of living
material derive from the PAH, which are in turn composed of chains
of carbon and hydrogen in policyclic hexagonal structures. This thesis is
given value by the spectroscopic identification of the PAH in space
[28] and by experimental simulations carried out in the chemical
laboratory on earth [29].
To arrive at the molecules for life one can therefore imagine a sequential
process, exemplified in eight main stages;
1.
Formation of carbon, hydrogen, oxygen and nitrogen by stellar
nucleosynthesis.
2.
Subsequent stellar synthesis, of aromatic hydrocarbons formed of carbon
and hydrogen (among which PAH), of water formed by hydrogen and oxygen (H2O)
and of ammonia formed by nitrogen and hydrogen (NH3).
3.
Expulsion of these substances into cosmic space.
4.
Photo splitting of the PAH into smaller fragments in the
interstellar grains.
6.
Transferral onto the earth of these simple organic molecules and their
more complex derivatives by comets and meteorites.
7.
Synthesis on earth of biomonomers and polymers from organic molecules of
cosmic origin.
8.
Evolutive assembly of these chemical structures into living material.
Regarding
this stimulating hypothesis, we express below some critical
considerations;
1.
The temperature of the interstellar grains varies according to their
ubication. Those near to active stars reach temperatures of thousands of
degrees, those far away temperatures near absolute zero. Temperature
represents a critical parameter in most chemical reactions. On the surface
of the hottest grains reactions of the gaseous phase could be favoured, in
the colder ones reactions in the solid phase.
2.
For the reactions of photosplitting and photosynthesis the exposure to
sources of radiating energy is fundamental. Also in this case there are in
nebulous zones more or less exposed and therefore zones adapt and not
adapt for photo-chemical reactions.
3.
The concentrations of the reagents in the grains are so low that the
probability of simultaneously and efficient meeting between two three or
more molecules are irrelevant. For this reason it is difficult to
understand how monomers and polymers, most of which contain the four key
elements; carbon, hydrogen, nitrogen and oxygen can form in these
conditions.
4.
These problems of a kinetic nature throw a veil of uncertainty over the
hypothesis that the PAH are key products necessary for the synthesis of
the so called building bricks of life and from which the other organic
molecules derive.
5.
It seems possible that part of the simple organic molecules like cyanidric
acid, acetylene, ethylene etc, derive from the stellar synthesis as well
as from photosplitting and combination of the PAH in interstellar grains.
6.
,Carbon is formed from hydrogen in carbonaceous stars. In nature this
element is found in four forms called allotropic: soot, graphite, diamond
and fullerenes. If other reactions do not occur later the carbon is then
erupted in the same state into the interstellar space, where, in fact, it
has been identified. Considering the great quantity of hydrogen present
and the high temperature, part of the carbon reacts with the hydrogen
giving rise to the simple highly reactive non-saturated hydrocarbons
(methynic and methylenic radicals, acetylene, ethylene etc). These
composites tend to stabilise reacting with themselves (dimerisation and
polymerisation) or with other affine molecules, initiating the birth of an
immense number of simple and complex organic molecules. According to this
scheme, all the organic composites present in the space and on earth, may
be considered substantially derived from methinic /methylenic radicals and
acetylene.
***
As
above mentioned, the PAH are binary carbon and hydrogen based
composites concatenated in hexagonal rings and may be considered polymers,
formed in the giant stars from acetylene and its derivatives. On earth
they are found in tars from the distillation of carbon and petroleum[30],
accompanied by analogous cyclics also containing one or more atoms of
oxygen, nitrogen or sulphur. The PAH are systems with complex structures,
and their chemical and biological properties, like stability, reactivity
and toxicity, vary greatly from compound to compound. It is enough to
think that benzopyrene, sadly known for its carcinogenicity (cigarette
smoke!) is in this class. The PAHs are spread in the interstellar
space, but are easily synthesised in the laboratory by the combustion of
acetylene [31]. This latter, present in space, can be prepared in the
laboratory from hydrogen and carbon at high temperatures. It is a very
reactive compound, formed from only two atoms of carbon and hydrogen (C2H2),
which tends to react with itself in a process called polymerisation,
giving rise to more stable structures, among which it is worth naming Acetylene
Black, an organic pigment and excellent electrical conductor.
In a previous work [2,32] we hypothesised the existence of this black
pigment in interstellar clouds, where it could play a relevant role in the
transferral of electrical charge, contributing to causing the dark colour.
It represents a "space warehouse" of carbon from which it is
possible to obtain by photolysis and photosynthesis chemical
fragments suitable for the synthesis of biogenic monomers.
The carbonaceous stars are rich in carbon, hydrogen and nitrogen. It is
easy to imagine how in the course of a stellar chemical reaction, and in
an analogous way to the formation of PAH, also the nitrogenated
heterocyclics are formed (cyclic compounds with a base of carbon, hydrogen
and nitrogen). In Halley's comet, the PUMA project has identified various
cyclic products belonging to this class and of fundamental importance for
the chemistry of life (pyrrol, pyridine, pyrimidine, imidazol, and perhaps
purine and adenine)[33].
Many of these compounds, as for example pyrrol and indol, tend to
polymerise in an analogous way to acetylene [34], forming black polymers,
which we have called PHB (Polycyclic
Heterocyclic Blacks).
The PHB are compact molecules, with which are transported
simultaneously ternary mixes of carbon, hydrogen and nitrogen. From these
modules it is possible to obtain, by photo disociation and combination,
nitrogenated and oxygenated organic molecules identical to those which
make up living organisms.
Polymers structurally similar to PHBs also exist on earth where
they have been amply studied. We know therefore that they are very
sensible to oxygen, light and LASER rays, the latter provoking a real
explosion of their structure [2,32].
For this reason it seems believable that in the interstellar grains the PHB
suffer similar reactions, with the formation of organic fragments
identical to those obtained in terrestrial laboratories.
***
Pushed
by scientific and technological progress, our cosmological vision has
modified and more and more often we advance the hypothesis of an
extraterrestrial birth of life. Today we know that there is matter in
space and that many of the molecules identified are also found on
earth. The non stellar nebulas are huge black dumps of cosmic garbage,
enormous accumulations of ashes, from which new stars and planets are born
and will be born: life, and ourselves, are in fact the ashes and dust of
the stars.
The
grains in which the interstellar dust is aggregated show some interesting
properties:
-
Optical: diffraction and absorption of electromagnetic and corpuscular
radiation;
-
Electrical: charge transfer and photoelectric effect;
-
Chemical: catalysts of photo chemical reactions, disassociation and
combinations.
The
grains behave like small space laboratories where delicate reactions
occur: complex materials like PAH and PHB are split into
fragments and these recombined into oxygenated and nitrogenated molecules.
Thus varied key organic compounds like alcohols, aldehydes, carboxylic
acids, amines, nitryls, aminoacids, phenols and other important functional
derivatives of carbon may form.
Living matter is formed of carbon, hydrogen, oxygen and nitrogen. To form
it is necessary that these elements meet in appropriate forms (for their
chemical affinity) in appropriate places and for relevant times. They come
from stellar synthesis and/or cosmic synthesis in simple and combined
forms.
Carbon, as carbon dust, fuligines, graphite, diamond, fullerines, carbon
monoxide and dioxide, methane, ethylene, acetylene, methynic radicals etc;
Hydrogen, as water
Oxygen, as water;
Nitrogen, as ammonia, nitrogen monoxide and dioxide; pure nitrogen.
The PAH and PHB are condensed forms of carbon/hydrogen and
carbon/hydrogen/nitrogen respectively. Packed into solid modules, these
elements are transferred from the stars to the nebulas without dispersion
(hydrogen and nitrogen, gasseous by nature, are trapped in the spaces of a
solid framework). The polymerisation of the acetylene serves a double
scope: compacting the key elements and accumulating chemical energy. In
the interstellar clouds, the polymers are split and their fragments
recombined with radical oxygenated and nitrogenated radicals coming from
water and ammonia ice.
The PHBs are good conductors, showing a pronounced photoelectric
effect (transformation of light into current) and play a role in the
evolution of the stellar clouds. In the cosmic chemical evolution, the PHBs
play a triple role, as:
- SUPPORT STRUCTURES: mechanical, electrical and optical properties
(charge transfer, diffraction and absorption of radiation, transformation
of light into electrical current);
- ACCUMULATORS: of chemical energy;
- SPACE WHAREHOUSES: of carbon, hydrogen, nitrogen in the form of compact
solid modules from which simple molecular fragments can be obtained (the
building blocks of biogenesis).
A similar role is played on earth by the various organic polymers,
highlighting the strict relationship between terrestrial and spatial
chemistry and the fact that a single architectonic principle seems to
organise living matter and interstellar matter.
The
reactions of space and the stars belong to chemical prehistory and are
partially comparable to those which we usually conduct in the terrestrial
laboratory. In the stars the reactions occur at very high temperatures and
pressures in a reducing environment, an ideal site for the reactions
between carbon, hydrogen and nitrogen. The oxygen instead, where it is
present will soon be captured by the hydrogen with the formation of water
[35].
The
chemistry of space occurs in the grains, at temperatures near to absolute
zero or locally higher according to the position, in solid systems under
the action of radiation in the presence of water and ammonia ice. In these
conditions the bonds must be split and reformed with precision, lacking
almost totally the thermic oscillations of the base [36]. In the hottest
zones reactions in the gaseous or absorbed phase prevail, nearer to
conditions on earth. Thus equilibrium reactions with the formation of
polyfunctional molecules (amminoacids, etc) could also be set off .
The chemistry of the biotic age, that of living matter, is more
sophisticated. It is the chemistry of enzymes and in an antiradical
function: it loves moderate temperatures like those of our bodies, a
watery environment, an atmosphere rich in oxygen, the most aggressive of
the elements present on our planet.
Notwithstanding the obvious differences between the three
"chemistries", stellar,
spatial and terrestrial they are governed by the same laws have the same
common principle: "NATURA ENIM
SIMPLEX EST".
5.
THE CURTAIN RISES
"
Science cannot explain the
final
mystery of nature.
And this is because, in the final analysis,
we ourselves are part of the mystery which
we are trying to explain "
Max Planck
According
to spectroscopic analysis the interstellar grains are composed of a
nucleus of silicon covered by a mantle of water and ammonia ice.
Trapped in these icecaps one finds complex organic structures deriving
from the polymerisation of reactive molecules erupted from the stars.
These materials undergo high energy cosmic radiation and are split and
recombined in the grains, which play a support role for the reactions in
the solid, gasseous and perhaps liquid phases, making selective splitting
and combinations on photosensitive molecular targets.
The fragmentation of the interstellar black matter leads to free radicals
able to capture oxygen from the molecules of iced water: thus new
oxygenated, nitrogenated and mixed compounds are born, key products for
the synthesis of monomers and polymers of a biological importance.
The stellar formation of various light and heavy chemical elements, the
first synthesis of organic matter and transformation of pure energy into
chemical energy, represents an antientropic phenomenon, an exception to
the general increase of entropy of the cosmos.
The elements tend in turn to transform into organised structures (simple
and complex molecules) obeying precise laws (affinity and valency). This
means that every single element can combine with elements for which it has
a certain affinity only in relation to preestablished (valency) ratios,
while the two parameters of affinity and valency will be determined by the
electronic structure of the single elements.
We may try to simplify this concept by two examples:
If we burn carbon (C) in an atmosphere of oxygen (O2) carbon monoxide and carbon dioxide (CO and CO2)
always form. This means that the carbon has an affinity for oxygen and
that it reacts with it always and only in the ratios 1:1 and 1:2. If we
make a spark in a mixture of hydrogen (H2) and oxygen (O2)
we will have an explosion with the formation of water (H2O).
This demonstrates that the two elements have a great affinity and that
they react in the proportions 2:1.
The laws of valency and of affinity have a universal validity, respecting
a global principle organising matter.
The chemistry of the stars and space shows up how the organisation of
matter passes through phases of major and minor complexity which alternate
in time:
à
stellar nuclear reaction à synthesis of elements à synthesis of molecules à polymers (PAH, PHB, acetylene black) à
splitting into fragments à recombination of fragments à
and so on.
From the simple to the complex, from the complex to the simple to return
to the complex with higher levels of organisation, according to a definite
antientropic process.
***
In
five hundred million years, the earth has been bombarded innumerable times
by small planets, asteroids, comets and other residue of the solar nebula.
The traces of these apocalyptic collisions are still obvious in the small
and large craters discovered in various regions [37]. Apart from the
material damage caused by this spatial "rain" it is more than
credible that with them organic molecules stored in the grains of the
interstellar clouds came to our planet. Thus a mixture of reagents ready
for further combinations came to be created on the terrestrial crust in
the marine and lake waters. On the earth in the prebiotic era chemical
reactions already sketched in space continued and others adequate for the
new environmental conditions developed. The temperature passed from almost
absolute zero to the mild terrestrial temperatures. The molecules no
longer frozen into grains became mobile and superactive, with a great
possibility of remixing in waters agitated by intense tides. The kinetic
possibility of encounters and collisions and reactions greatly increased.
The reaction means, now liquid and weakly acidic, favoured the dissolution
of basic substances (amines) and the reactions of addition and
condensation (e.g. aldehyde + nitryl -> aminoacid) while the reducing
environment safeguarded sensitive products (aldehydes, alcohols phenols
etc) from oxidation. The water screened the UV rays participating in the
reactions of hydrolysis and hydration. New possibilities of assembly into
complex structures were created at the solid/liquid and solid/gas
interfaces between dissolved and gasseous reagents with inorganic matrixes
(clay, pyrite) and organic matrixes(melanin).
The splitting of the water forms highly reactive oxygenated radicals
giving rise to reactions and new composites:
the age of oxygen started in this way.
In the new terrestrial environment the increased temperature stimulated
reactions previously blocked because of the lack of activating energy. A
myriad of metallic ions, free or bound to opportune matrices, filled the
marine environment and lakes: chemical catalysts were born which, in the
biotic era, would give headway to the enzymes.
The "prebiotic test-tube" became bigger and bigger, and now
embraced lakes, seas and oceans: the biological soup was ready to host
life.
The cosmic chemistry has imprinted the terrestrial world, shaping the
living world according to common architectonic principles.
Everywhere chemical reactions take place: the plants and certain bacteria
fix solar energy transforming it into chemical energy (photosynthesis);
other organisms decompose the living matter into simpler structures using
the energy contained in them. In every cell a succession of concatenated
chemical processes (reduction, oxidation, hydrolysis, synthesis etc) takes
place.
The
biochemical architecture of living beings is based on a few columns of
elements (carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorous etc)
but it ramifies into a multitude of molecular composites: binary on the
base of carbon and hydrogen (hydrocarbons); ternary with a base of carbon,
hydrogen and oxygen (carbohydrates, polysaccarides, fats etc); quaternary
with a base of carbon, hydrogen, oxygen and nitrogen (aminoacids,
polypeptides, proteins, nucleic acids, alkaloids, lipoproteins etc) and so
on.
Living beings possess unique characteristics like reproducibility and
specificity of their single structures, with a strict relationship between
the structures and the biological role.
The surprising variety of living forms and the individuality of the
various organisms can be traced to the individuality of some
macromolecules: the proteins. Yet these are nothing but the combinations
and permutations of a few aminoacids; always the same ones for various
millions of years.
In all organisms food is transformed into carbonanhydride, water and
ammonia through a few passages. Production and use of the energy from part
of the cells is based on the same mechanism in many animals from the
protozoons to mammals.
Various theories have been constructed about this incredible phenomenon of
life as attempts to unravel its mystery. We shall discuss a number of
these in the next chapters.
However, Newton's axiom always sounds relevant "Natura
enim simplex est".
6.
LIFE IN THE UNIVERSE
"
The world of the physical
sciences and the
world of the life sciences are still separated
today by an unexplored no-man's-land "
Mario Ageno [49]
Notwithstanding
the most recent conquests of biology life remains the great mystery of the
universe. In the general economy of science its origins and its function
are still the object of more or less bold hypotheses on the border of
science and religion.
In every age numerous scientists have tried to discover the laws which
regulate living beings, compared them with those of the inorganic world
and tried to use the laws of physics and chemistry to give a unitary
picture of their behaviour. But the many attempts were systematically
disappointing.
In a famous essay in 1940 Bergson [38] thus expressed this a sensation:
"all our analyses show us that life is an effort to go up the hill
which matter descends. Certainly, life which evolves on the surface of our
planet is attached to an organism which subjects it to the general laws of
inert matter. But everything happens as if life did everything possible to
free itself of these laws. It does not have the power of overturning the
direction of the physical changes which determine it, the principle of Carnot, but, if nothing else, it acts as a force which left by
itself would work in the opposite direction".
The same impression is found in the works of P. Lecompte du Nouy [39],
who, in the light of a careful and detailed analysis of evolution sees a
systematic tendency towards the development of the brain and consciousness
as a sign of a spiritual end in nature which manages to triumph over the
forces of matter.
The mathematician L. Fantappiè [40] formulated the theory in which he
claimed the existence of a class of phenomena for which time seems to run
in the inverse sense compared to the rest of matter. He called them they
are called syntropy the opposite of entropy and in the scope that animates
the action of the living sees a sort of cause which follows its own
effect, since in the living beings something manages to overturn the
normal course of time, contrasting with the general increase of disorder
in the inorganic world.
If for example one projects, parting from the last photogramme, a film
which records a vase falling one will have the disconcerting vision of
thousands of small fragments which recompose to build a vase: a scene
which calls to mind the budding of a flower. The projection of an
inanimate natural phenomenon appears as animated if seen according to the
inverted succession of time. One then is tempted to suspect that in life
one verifies something similar.
A theory which opens a scenario of intrinsic temporal symmetry,
reproposing the dualism of matter-spirit in a scientifically credible
form. Also a profound theologian like Teilhard de Chardin [41] finds
himself on a similar line of thought.
Other thinkers have deepened the relationship between nega-entropy (or
syntropy) and information even trying to link information with the
opposite of entropy mathematically. Among these we recall O. Costa De
Beauregard [42] who deepened the problem of information posing it in
relation to the probability criteria (or better of improbability) of the
theory of thermodynamics. Among others one should certainly mention
M. Eigen [43] for his brilliant work on the evolution of the
biological macromolecules.
In a special way another great scientist who has fully dealt with the
problem of negaentroopy tracing it to a general picture of entropy should
be recalled .
We refer to Ilya Prigogine [44,45] and his dissipating structures far from
the equilibrium which can have a sort of unnatural dynamic stability,
which makes them seem in practice as if provided with negaentropy. The
hypothesis which life can have found origin in the order deriving from a
fluctuation happening in an open system, like that of the surface of the
earth, continually radiated by the sun, seems daring but captivating.
If one accepts such a hypothesis one loses the sense of the thesis of
Monod which attributes the origin of life to chance, since instead, in
conditions far from equilibrium some reactions which are decidedly
improbable if taken in normal situations near to equilibrium become
suddenly necessary and systematic. These even present the characteristic
of accelerating the increase of entropy in the surrounding environment.
A common element of all these theories lies in their having attributed to
living matter an opposite current compared to the rest of the universe, in
a certain sense acting against the universal law of increasing entropy and
moving according to special laws in a context able to invert the passage
of time. The different theories attribute different origins to such a
phenomenon from the spiritual telefinalism of Lecompte Du Nouy to the
mathematical symmetries of Fantappie to the reductionism of Prigogine.
The recent discoveries in genetics show the importance of information in
explaining the mystery of life: the double helix is a digital code able to
self-replicate and to defend itself against attacks from the outside
external world. A sort of alien in the world of inert material which even
though it does not escape entropic laws, and is perhaps limited to the
thin layer of the surface of a particular planet like our earth , still
manages to give rise the life of flower, to generate a protozoon, a mammal
or even a man, up to forming a brain able to create works of art and to
ask questions about its own origins.
***
The
first components of matter are characterised by particles and their
respective antiparticles, which interact according to quantistic rules,
respecting some rigorous principles of conservation and of symmetry.
At this level time does not seem to present any preferential direction: if
one inverts its sense (t -> -t)
and contemporaneously changes the particles with the corresponding
antiparticles, the reactions remain identical to themselves. Time does not
present any particular preferred direction as if every antiparticle were
nothing other than the mirror image of the particle which corresponds to
it according to an almost perfect symmetry.
From the simple structure of the hydrogen atom with its precise levels of
energy calculable using quantum mechanics to the dimensions of the
molecules regulated by the laws of chemistry, when we put together some
billions of molecules to obtain a grain of sand, we are no longer able to
follow the phenomenon, since it takes on an enormous number of
unpredictable parameters: the grain then becomes a small chaos, in which
we are not even able to predict the shape and the weight. Putting together
elements known singularly the characteristics of their groups eludes
us.
Quantity becomes the source of uncertainty and, together with such a
deficit of information, the entropy of the system increases and the
sparring of time becomes much clearer.
If one imagines a beach where a child has built a sandcastle, we are in
the presence of something (information) which has partially reduced the
entropy of the beach, giving it a well defined aspect. Neither does he
disappearance of the sandcastle by the work of the wind and of the tides
surprise us. We would be strongly impressed, instead,
if the sandcastle had appeared alone in the course of the night on
some deserted beach. A reduction of entropic disorder with the consequent
appearance of some information, no matter how insignificant it is,
immediately acquires the aspect of a prestigious event for which one is
induced to look for a cause.
Brian Green [50] proposes the following explanatory example:
"Even if you put your desk in
order, piled up with paper, diminishing its entropy in this way, the total
entropy, that of your body
plus that of the room will increase. To order your desk a certain
expenditure of energy is necessary, your body emanates heat, thereby
moving the molecules of the surrounding air: if we take into account all
these effects, the diminishment of entropy of the desk is amply
compensated by the total increase"
These
small banal examples tell us that we live in a world in which the loss of
information (increase of entropy) is completely natural but in which,
though, with every increase of information (reduction of disorder) there
must necessarily correspond an ordinating cause, information in some way
imported from elsewhere. A world where chaos does not make news, but where
order and organisation generate wonder, the sense of time being turned
constantly in the direction of an inexorable deterioration of the messages
with the consequent increase of confusion (background noise)[51].
In
our world every form of life has adopted digital information in the form
of the double helix, the same digital technique which we have rediscovered
to defend our electronic communications from disturbances which compromise
intelligibility. Life manages to reduce its own entropy consuming chemical
energy, like our information which feeds on electrical energy. But while a
diskette can conserve a message for an indefinite time, the genetic
patrimony of a living being is constrained to live in an organism which is
able to procure it the necessary energy for conserving and improving the
information of which it is a carrier, besides safeguarding the project of
self-assembly. It is thus that life has invented death with the annexed
instinct of reproduction.
Life
appears therefore, in the
light of modern science like extraordinary information but also a dramatic
challenge against the own planetary environment, which tends to alter the
contents. The reflection of Bergson which is quoted seems all the more
prophetic and the different theories outlined here each express an aspect
of the same truth, searching to identify the cause.
7.
ENTROPY AND IRREVERSIBILITY
"
The more I examine it in
detail,
the more I am convinced
that in some way
the universe must have known
we were coming "
Freeman Dyson
Unlike
the other forms of energy, heat, once passed from a hot body to a colder
one, would never manage to make the inverse passage spontaneously.
Research into the causes of such irreversibility has constituted a great
problem for scientists of all times. R. Clausius in 1865 made it the
object of a general law (the second law of thermodynamics) for which there
were excogitated two possible interpretations: the dynamic
which explains it in purely mechanical factors, as for example an
imperfect elasticity in the colliding molecules, which would then lose a
part of their kinetic energy in each collision. This theory was abandoned
by Bolzman himself, who declared himself in favour of a purely probabilistic
interpretation of the thermodynamic phenomenon: because of the high number
of molecules involved the
probability that the heat passes from a cold body to a hotter one would be
statistically impossible, like expecting that a billion playing cards
after reshuffling over and over again go back into order. The entropy of a
system, being linked to the thermodynamic probability cannot but increase
continually. In such a system the statistical laws in fact exclude the
possibility of passing spontaneously towards a less probable state and
such impossibility is expressed by stating that the entropy increases with
every irreversible transformation. Bolzmann, in the light of such an
exclusively probabilistic conviction was pushed into claiming that for the
universe as a whole it had no sense to speak about a direction of time. He
surmised that the knowledge of the time would never have allowed a
different interpretation of the irreversibility of the thermal phenomena.After
the event of Relativity and Quantum Mechanics the dynamic interpretation
of the second law can no longer be reasonably excluded: even a single
photon emitted or absorbed by a molecule of the system or the minimum but
inevitable quantistic indetermination in the energy equation of a
collision are sufficient to make the reversibility of a given phenomenon
impossible. Today we may confirm therefore that the irreversibility of a
system is not only something statistically improbable but comes from the
very nature of our universe, where time therefore presents itself in a
single well defined direction or, as one says, an "arrow"[52].
The old analogy of Ovid between time and the passing of a river comes back
as ever to being current and today Bolzmann could not claim that time in
the universe, taken as a whole, knows no direction.
Besides, the simple observation of a phenomenon is enough to introduce a
some quantistic perturbation which characterises it in an unrepeatible way
and each attempt to reduce to a minimum the disturbance of the phenomenon
due to the observer is made impossible by the principle of uncertainty
(quantistic theory). To the statistical irreversibility of the systems
there is therefore added a more general and structural one which ratifies
a growth of entropy for every isolated system. A reduction in entropy is
however obtainable locally only through the use of energy as in a
refrigerator or a heat pump in which, though, there is made an energv
greater increase in the
entropy of the environment. Modern physics can express the irreversibility
of a system as the reshuffling of a pack of cards, but on the part of a
player with dirty hands.
8.
MAN IN THE UNIVERSE
"
O nature, o spirit of man!
How inexpressible
are the analogies which link you! Even the smallest
atom doesn't agitate or live in matter without
having its good duplicate in the mind "
Herman Melville
According
to some thinkers [39,40,41] who have recognised in the coming of man an
extraordinary event even at a cosmic level, the strong development of the
brain represents something more important than a banal adaptive
hypertrophy |
