Published in "Life as we know it".
Cellular Origins, Life in Extreme Habitats and
Astrobiology, Springer, Dordrecht, The Netherlands, pp. 505-517.

DESTINIES OF THE UNIVERSE AND LIFE:
The final frontiers of cosmology and astrobiology (*)

JULIAN CHELA-FLORES
The Abdus Salam International Centre for Theoretical Physics
Strada Costiera 11; 34136 Trieste, Italy
and Instituto de Estudios Avanzados, Caracas 1015A, R.B.Venezuela

(*) The author wishes to dedicate his chapter to the memory of John Oro, a friend, a colleague and a teacher.

1. The intelligibility of the universe

Up to the present the intelligibility of the universe has been a topic restricted to philosophy and especially to the philosophy of religion. Amongst the various aspects of intelligibility we wish to highlight the destinies of the related phenomena of the origin and evolution of the universe (Sec. 2) and the subsequent emergence of life (Sec. 3). The arguments presented in this chapter argue in favor of bringing these fundamental topics within the frontier of astrobiology to encourage interdisciplinary interactions (Chela-Flores, 2001). Amongst the priorities of this new science, we should consider the search for other lines of biological evolution elsewhere in the universe, a search for what has been called 'a Second Genesis' (McKay, 2001). The main conclusions of such a study are likely to be relevant not only to astrobiology, but also to have implications in ethics and philosophy. Intelligible means the capability of being understood, or comprehended. Alternatively, intelligible can signify to be apprehensible by the intellect alone. A third aspect of intelligible, closer to the significance of the term in the context of the present work, is related to something that is beyond perception. An "intelligible universe" can be the starting point of a prolonged and systematic discussion amongst astrobiologists, as well as philosophers and theologians. The Belgian Nobel Laureate Christian de Duve, at the end of his recent review on the origin and evolution of life, asks himself the question "What does it all mean? Not only in science (de Duve, 2002), but also in philosophy (Davies, 2003) and in theology (Russell, 2001) the intelligibility of the universe raises questions that lie on the frontier between science and the humanities: often considerations on intelligibility return to the often quoted, but less frequently debated statement of Steven Weinberg, the American Physics Nobel Laureate (Weinberg, 1977):

"The more the universe seems comprehensible, the more it also seems pointless."

We begin this chapter by discussing, whether this quotation is on the same footing as the statements usually made in physics and
In other words, we should clarify whether the quoted statement reflects rather a specific philosophical trend, or attitude, characteristic of the first half of last century. Hence, if that were the case, the statement should not discourage the general dialogue at the frontier of science and religion discussed in this chapter. The common approach from both ends of the academic discourse to a Second Genesis should contribute, as we shall see below, to the progress of the philosophy of religion. Reciprocally, the questions raised in any field of the humanities arising from the discovery of a Second Genesis could, in turn, enrich the search for the place of humans in the universe.
The above quotation can be best understood in the context of a philosophical trend called Existentialism. Earlier doctrines (Rationalism, Empiricism and Idealism) arose from the increased scientific knowledge of the 17th and 18th centuries. They had maintained that the cosmos is a well determined ordered system, and hence comprehensible to all observers. In that framework there was no motivation for viewing the origin and evolution of the universe and life as being absurd, or pointless, a trend that was to arise some two hundred years later. On the other hand, the existentialists went beyond Rationalism that was represented, amongst others, by Benedict De Spinoza the Dutch-Jewish philosopher and foremost exponent of this 17th-century doctrine (Spinoza, 2002). The existentialists also went beyond Empiricism.
Another influential philosophical view stresses the central role of the ideal, or the spiritual, in the interpretation of experience. Known as Idealism, this philosophic doctrine, unlike Rationalism and Empiricism, maintains that the world, or reality, exists essentially as spirit or consciousness, that abstractions and laws are more fundamental in reality than sensory things. Rationalists, empiricists and idealists laid down solid bases on which to discuss questions related to the eventual destiny of life and of the universe. Rationalists and empiricists had argued that we could discover all natural universal laws by reason and experimentation, largely in agreement with the emergence of modern science with Copernicus, Galileo, Bruno, Digges, Newton and others.
A systematic idealist, Georg Hegel attempted to elaborate a comprehensive and systematic ontology from a logical starting point (Hegel, 1967). In other words, although differing somewhat from other idealists Hegel attempted to defend faith as being logical. This movement was influenced by the growth of science since the Enlightenment. The need was felt for a harmonious development of human culture. The bases of the philosophy of religion had to be extended to accommodate so much new revolutionary scientific knowledge. Faith in a Creator had to be seen in a new light. The Danish philosopher and religious writer Soren Kierkegaard opposed Hegel's views, particularly the concept that religious faith was logical; he explores the notion of the absurd: Abraham gets a reprieve from having to sacrifice Isaac, by virtue of the absurd (Kierkegaard, 1986). He further anticipates the still-to-come philosophical trend (Existentialism), insisting in a thesis opposite to Hegel's: humans suffer a deep anxiety (and hence need religion) because one has no certainties (Kierkegaard, 1981). In more modern terms we can paraphrase Kierkegaard and other pioneers of Existentialism by saying that life in the universe is pointless and absurd. To put it simply, according to Kierkegaard, life in the universe is not intelligible. Consequently, the questions of our destinies could not be incorporated as a frontier between astrobiology and the humanities that would encourage a fruitful dialogue.
A third relevant aspect of Existentialism came from the implications of the philosophy of Martin Heidegger (Heidegger, 1996), as interpreted by his close follower Jean Paul Sartre (1947). Heidegger formalized Existentialism on the basis of the work of Edmund Husserl, a German philosopher who had founded Phenomenology (Husserl, 1999). This earlier method of enquiry was applied to the description and analysis of consciousness through which philosophy attempts to gain the character of a strict science. Husserl's method is an effort to resolve the opposition between the emphasis on observation that is maintained by Empiricism, and on reason that is stressed by Rationalism. Against this background, Sartre maintained that Existentialism is an attempt to live logically in a universe that is ultimately absurd. Another eloquent supporter of this doctrine was the Literature Nobel Laureate Albert Camus. In the mid-twentieth century Camus, through writings addressed the isolation of man in what he considered to be an alien universe (Camus, 1991). At the end of this long line of intellectuals that were under the influence of Existentialism, in the above quotation Weinberg reflects a view of the universe to which he was constrained by the adopted philosophic trend that influenced his generation.
In the Existentialist view of the universe there still remains some hope for the concept of a meaningful universe, namely intelligibility of the universe could be approached with the hope of the eventual emergence of a future "theory of everything". In this proposed all-embracing future theory we would hopefully discover the fundamental laws of nature in terms of a set of equations (Weinberg, 1993). Then, all phenomena should follow from these equations (the hope being that chemistry and biology could also be deduced). This is an extreme form of Reductionism, not an inevitable choice, given the many insights of current progress in science as a whole. Since the Enlightenment the ever-increasing growth of science has encouraged Reductionism. The reductionist dream has been supported by preliminary sets of successful equations that have embodied general phenomena at the most disparate scales (both microscopic and macroscopic). Today we recognize such efforts by assigning the equations the surnames of their authors: Newton, Maxwell, Einstein, Schrödinger Dirac, Salam and Weinberg. We are still at a very early stage in the comprehension of life in the universe. When the open question of the intelligibility of the universe is posed in a wider cultural context, including the earth and life sciences, Reductionism's restricted view becomes more evident. This contrast between different views on the intelligibility of the universe illustrates the relevance of the frontier of astrobiology for human culture, especially under the influence of philosophical doctrines (other than Existentialism) that will tend to encourage any future constructive dialogue between science and the humanities. In the remaining part of this chapter we shall attempt to review briefly what science has achieved in our understanding of the destinies of firstly the universe (Sec. 2). We discuss the destiny life in Sec. 3. In Sec. 4 we review approaches for getting further insights into our destinies by means of oriented efforts in space exploration. (We take into account life-detecting experiments.) Finally, in Sec. 5 we comment on the dialogue at the frontier between astrobiology and the humanities.

2. What is the likely destiny of the universe?

In Sec. 1 we have argued that the universe is comprehensible and that it is not necessary to espouse the view of pointlessness in the emergence of life. The next stage is to consider what physicists have done to formulate the problem of the evolution and destiny of the universe. The Big Bang model tells us that as time t increases, the universe cools down to a certain temperature, which at present is close to 3 0K, the so called 'cosmic microwave radiation', CMB. (It has a typical wavelength of about 2 mm, due to the enormous red shift suffered since the moment it was last scattered during the first moments of cosmic expansion.) The CMB may be considered to be a cooled remnant from the hot early phases of the universe. The CMB is assumed to have an 'isotropic' distribution, namely its temperature is assumed not to vary appreciably, independent of the direction in which we are observing the celestial sphere. The isotropy is a consequence, firstly of the uniformity of cosmic expansion; secondly, it is a consequence also of its homogeneity when its age was 300,000 years, and its temperature was some 3,000 K. On the other hand, in 1992 more precise measurements of the T = 3o K radiation began to be made by means of the satellite called the Cosmic Background Explorer (COBE). When the accuracy of the isotropy was tested with more refined measurements, it was found that there was some degree of anisotropy after all - the temperature did vary according to the direction of observation (one part in 100,000). This fact is interpreted as evidence of variations in the primordial plasma, a first step in the evolution of galaxies. The Microwave Anisotropy Probe (MAP) - an initiative of the National Aeronautics and Space Administration (NASA) - extends the precise observations of the CMB to the entire sky. The European Space Agency (ESA) will extend this work subsequently by means of the Planck spacecraft, whose launching is planned for the year 2007.
During the very earliest times of the Big Bang (10-43 second - 10-35 second), the lowest-energy state corresponded in microscopic physics (quantum mechanics) to a phenomenon called a "false vacuum." This quantum state is characterized by a combination of mass density and negative pressure that results gravitationally in a large repulsive force. In Einstein's theory of General Relativity this repulsive force is called a 'cosmological constant'. The false vacuum may be thought of as producing a corresponding repulsive force that gave rise to the scale factor R of the universe to grow (or 'to inflate') extremely fast. (Mathematically we may say that the expansion was 'exponentially fast'.) This means that R may have doubled its size roughly once every 10-43 or 10-35 second. After several doublings, the temperature, which started out at over one thousand degrees K, would have dropped to values near the absolute zero. At these low temperatures the true vacuum state may have lower energy than the false vacuum state. This phenomenon has an analogy with solid ice, which has lower energy than liquid water. Such 'super-cooling' of the universe may, therefore, have induced a rapid phase transition from the false vacuum state to the true vacuum state. The transition would have released energy (analogous to the "latent heat" released by water when it freezes). This, in turn, reheats the universe to high temperatures. In such a high temperature the particles and antiparticles of the Big Bang cosmology would have emerged. There is some evidence for an accelerating expansion of the universe, a phenomenon, that still has to be understood (Riess, A. et al, 1998). We have to learn whether the constant that on purely on theoretical grounds Einstein introduced into his equations of gravitation (the 'cosmological constant'), may represent some form of gravitational repulsion (Krauss, 1998; Ostriker and Steinhardt, 2001).
Only a small fraction of the matter in the universe is in the form of the familiar chemical elements found in the Periodic Table. It is assumed that a large proportion of cosmic matter consists of 'dark matter', whose composition consists of particles that play a role in the sub-nuclear interactions. The term 'dark matter' is not a misnomer, for the sub-nuclear particles that contribute to it, do not interact with light. However, a remarkable aspect of cosmic matter is emerging: the sum total of the standard chemical elements and the dark matter make up a small fraction of the matter content of the universe. The remaining fraction of cosmic matter has been referred to as 'dark energy' with the remarkable property that its gravity is repulsive, rather than attractive. The repulsive gravity may dominate the overall evolution of the universe. This could lead to ever increasing rates of expansion. If this scenario corresponds to the future of the universe, then there may be some surprises regarding the eventual destiny of life in the universe. Some relevant experimental insights have been forthcoming. Indeed, a high-flying balloon that flew over Antarctica has given experimental support to the cosmological view of the expanding universe. It has demonstrated that the universe is "flat". In other words, the usual rules of geometry are observed. A beam of light is not bent by gravity as it propagates. The path followed is a straight line, not a curve. But since Einstein's Theory of General Relativity was proposed, the possible paths followed by beams of light over cosmological distances require verification. Another result of the above study is the prediction that the universe will continue its steady expansion, which started at the Big Bang.
The new information provided by this experiment is presented as a map of the CMB. Small temperature variations in the CMB would allow a test of different models of the expanding universe. The map represents an image of the early Universe when it was about 300,000 years old. The current estimate of the age of the universe is over 12 thousand million years old (12 Gyr). The light that has been detected has traveled across the entire universe The project to map the CMB was called Boomerang (Balloon Observations of Millimetric Extragalactic Radiation and Geophysics). The Boomerang results support a flat universe. A perfectly flat universe will keep on expanding forever, because there is not enough matter to trigger a Big Crunch. Boomerang backs the inflation theory of the universe suggesting that the whole of the cosmos expanded from the Big Bang, with the scale factor expanding exponentially fast during the first instances of the cosmic expansion. A space mission whose objective was to overcome such difficulties is the Wilkinson Microwave Anisotropy Probe (WMAP). With this probe it was possible to obtain very accurately a map of any inhomogeneous aspects of the CMB. The confrontation of these measurements with theoretical models has confirmed the emergence of fluctuations in the very early universe. WMAP has demonstrated that the present structure of the cosmos consists of about 4 percent ordinary atoms, 23 percent matter of 'dark matter' that does not interact with radiation, and the remaining fraction (over 70 per cent) consists of a mysterious 'dark energy' having negative pressure. Last, but not least, it has given us 14 billion years as an upper bound for the age of the universe. To sum up, these results suggest that the universe is flat. We are entitled to entertain the profound hypothesis that life may have emerged within an eternal abode.

3. What is the likely destiny of life?

Having reviewed our present understanding of the eventual destiny of the cosmos, our next objective, as stated in the title chosen for this chapter, is to discuss the destiny of the phenomenon of the living process that has emerged in the universe. The origin of life is not fully understood. However, the general outline of the question of the chemical evolution of the precursors of the biomolecules has greatly advanced. Significant progress was due to John Oro, to whom this chapter has been dedicated, and to his colleagues in the field of chemical evolution: Ivanovich Oparin and Stanley Miller, before him and to his contemporaries Cyril Ponnamperuma and Sidney Fox, as well as many other organic chemists. They have traced out the likely pathways that nature may have followed during the molecular evolution that preceded the Darwinian evolution of the living cell. The seminal work of Charles Darwin in the 19th century established the basis for the second stage in the discussion of astrobiology.
Darwinian evolution is much better understood than the question of the emergence of life. In earlier works several authors have argued that evolution on Earth has taught us that evolutionary convergence is an important feature of the Earth biota. Hence, if Darwinian evolution were assumed to be a universal process (as, for instance, advocated by Dawkins, 1983), we would expect that whenever life emerges elsewhere in the universe, life would be bound largely by the same general properties that we have found on Earth. Under this assumption (the universality of biology), we can anticipate new insights in the distribution of life in the universe.
Perhaps the leading approaches for searching for life elsewhere in the cosmos are the exploration of the Solar System and the search for intelligent signals through windows of the electromagnetic spectrum. The latter is known as the search for extraterrestrial intelligence (SETI). Since the pioneering days of the 1960s, bioastronomers have followed the lead of Frank Drake by probing various windows of the electromagnetic spectrum for evidence of narrow-frequencies signals (Drake and Sobel, 1992; Ekers et al, 2002). Such output presumably would be characteristic of other civilizations, instead of being the product of natural phenomena, such as supernova explosions or regular emissions from pulsars. The search for other intelligent civilizations in the SETI project might have some implications in the philosophy of religion.
Our religious traditions go back to Jewish theology. There is a sole omnipotent God who created heaven and earth, and subsequently life on earth. This view of our origins has traditionally been referred to as a 'first' Genesis. But revelation through the scriptures never raises explicitly the possibility of the plurality of inhabited worlds. In 1584 Giordano Bruno made a speculative, but significant reference to the possibility of ubiquitous life in the universe (Bruno, 2000). In the late 16th century Bruno's statement led to a bitter and tragic controversy in the frontier between science and religion. However, due to the present progress both in science and religion, we are now aware that there is no evident incompatibility between religious traditions and the possibility that we may not be alone in the universe. What is exciting about the emergence of the new science of astrobiology is that we can explore in strictly scientific terms the possibility of whether the evolution of intelligent behavior is inevitable in an evolving cosmos, as already assumed implicitly by the above-mentioned SETI project.

4. To understand further the destiny of life we should search for a Second Genesis

In the previous two sections we have looked firstly at the possible destiny of the universe. Secondly, we considered the living process that has emerged through chemical and biological evolution on Earth, and possibly elsewhere. The next step in our discussion is dictated by the fact that the theory of Darwinian evolution is not a predictive theory. In order to get further insights as to what can be the eventual destiny of life in the universe that might not be evident from our current knowledge of biology, we should search for alternative manifestations of the living process. This may occur either in planets, or satellites in our own solar system, or even in other solar systems. Intelligent signals from other civilizations are in principle detectable. The fact remains though that our lives are short we would like to have further insights into our destiny.
After almost half a century of searching for intelligent life in the universe - with extraordinary technological progress in the detection equipment used in the SETI project - sadly, no intelligent signals have so far been identified. But technology not only has progressed in recent years in the field of bioastronomy, it has also progressed especially in the exploration of the Solar System with missions planned by the main space agencies, so as to be in principle capable of detecting microscopic life.
The search for extraterrestrial life has been attempted for the first time on the surface of planet Mars. A quarter of a century ago the Viking missions were in a position to detect life, although their results were not convincing to most scientists. The search continues today with Mars being the present target of several space missions. Yet, given the harsh conditions for the survival of extremophilic microorganisms on the Red Planet, the best digging equipment with present technology is still unable to probe as far as the more likely sites, deep underground, where we expect abundant liquid water to be present. Assuming that Darwinian evolution is a universal process (Dawkins, 1983), we, and others, have argued in previous papers in favor of the inevitability of the origin and evolution of life, including intelligence. We have also argued and that the role of contingency has to be seen in the restricted context of parallelism and evolutionary convergence (Akindahunsi and Chela-Flores, 2004; Conway Morris, 2003).
Convergence, however, is not restricted to biology, but it has some relevance in other realms of science. The sharp distinction between chance (contingency) and necessity (natural selection as the main driving force in evolution) is relevant for astrobiology. Independent of historical contingency, natural selection is powerful enough for organisms living in similar environments to be shaped to similar ends. For this reason, it is important to document the phenomenon of evolutionary convergence at all levels, in the ascent from stardust to brain evolution. In particular, documenting evolutionary convergence at the molecular level is the first step in this direction. Our examples militate in favor of assuming that, to a certain extent and in certain conditions, natural selection may be stronger than chance (Conway-Morris, 1998).
We, together with others (Pace, 2001), discuss the consequences of the hypothesis of the possible universality of biochemistry, one of the sciences supporting chemical evolution. Evolutionary convergence can be viewed as a 're-run of the tape of evolution', with end results that are broadly predictable; hence, if life arises again elsewhere in the cosmos, we would expect some degree of convergence with terrestrial life.
The universality of biochemistry suggests that in solar system missions, biomarkers should be selected from standard biochemistry. Given the importance of deciding whether the evolution of intelligent behavior has followed a convergent evolutionary pathway, and given the intrinsic difficulty of testing these ideas directly (by means of the SETI project), we can alternatively begin testing the lowest stages of the evolutionary pathway within the Solar System. Indeed, within a few years we will be in a position to search directly for evolutionary biomarkers on Europa, the Jovian satellite. We have considered that if extant microorganisms were to be encountered, a possible set of evolutionary biomarkers may be considered (Chela-Flores, 2003).
Testing evolutionary biomarkers clearly lies in the distant future. The next mission has been called "The Jupiter Icy Moons Orbiter" (JIMO). Sadly, it will not be in a position to use the submersible (a 'hydrobot') that we visualized in the late 1990s (Horwath et al, 1997). However, it will be in a position to undertake a variety of experiments in situ. Given the length of time before we can test reliable biomarkers directly, a full discussion at the present time of the feasibility of carrying out a proper test is timely. In this sense the discussion of biomarkers is reasonable at the present stage, since the Galileo mission has already provided us with a wealth of information about the chemical non-water-ice elements on the icy surface (McCord et al, 1998; Carlson et al, 1999). The careful interpretation of such information might conceivably lead us to reliable bioindicators without actually penetrating Europa's icy surface. JIMO is expected to determine specific locations where the icy surface is thin enough for an eventual penetration of a submersible. Besides, testing directly the Europan icy surface with a lander is a possibility that is being taken seriously.
The discovery of other solar systems suggests that their formation seem to be analogous to ours. This is compatible with extensive knowledge of interstellar matter (Ehrenfreund and Charnley, 2000). From the assumed universality of biology it seems inevitable that intelligent behavior will emerge in the cosmos, provided certain conditions favorable to the presence of continuous life on a given planet (or satellite) are maintained. One of these conditions is that early stages in the formation of a solar system are characterized by a heavy bombardment period. This period would end after a few hundred million years. Consequently, planetary conditions over geologic time are likely to allow the continuous presence of life, as it has already occurred on our own planet, once the heavy bombardment ceased.
Observational techniques continually improve (the Terrestrial Planet Finder and ESO's large telescopes are now under construction). These new instruments will allow to estimate the duration of the initial heavy bombardment in other solar systems, as well as the subsequent life-favorable quiescent period. These future observations should give us a more precise idea of the temporal constraints that allow the continuous presence of life on a given planet. In our own solar system the most attractive site for the search for life has already been explored. The Galileo mission to Jupiter and its satellites completed an eight-year period of continuous exploration in the year 2003. This mission focused our attention on Europa, the second Galilean satellite with respect to its distance from Jupiter. In the 17th century Galileo discovered Europa together with three other satellites Io, Ganymede and Callisto. However, Europa remains the leading contender for being the host of an independent evolutionary line. A second evolutionary line could, in principle, be brought to our attention in the foreseeable future. JIMO is an ambitious project intending to orbit three of the planet-sized moons of Jupiter (one of them, Ganymede, is the largest satellite in the Solar System, bigger than the planets Mercury and Pluto). In fact, the Galileo Mission already has given us data to suggest that Ganymede, Callisto and Europa may harbor large oceans underneath their icy surfaces. Not only is there strong evidence for the internal oceans in the Jovian system, but also Jupiter's large icy moons appear to have three ingredients essential for the origin and sustained evolution of life, namely, water, energy and the necessary chemical molecules.
The evidence from Galileo suggests that melted water on Europa has been in contact with the surface in geologically recent times and may still lie relatively close to it. Observations of Callisto and Ganymede would provide additional comparisons that would contribute towards our understanding the three moons. The JIMO mission would support one of astrobiology's main objectives: to explore the Solar System in a well-focused effort to obtain insights into how life is distributed in the universe. Consequently, this would help us take the first steps in our understanding of the destiny of life in the universe. We have mentioned above that it is still premature to explore the extraterrestrial oceans of the Jovian system by means of submersibles. But for learning whether a Second Genesis has occurred, probably a lander may be sufficient. We should recall some aspects of the icy Europan surface: it is possible that matter from the interior of the satellite may be raised to the surface itself. The Galileo mission has led to the discovery of a phenomenon called 'lenticulae' that are interpreted as surface areas on Europa, whose origin is matter from its deep interior. A JIMO lander, without penetrating the icy shell, may be sufficient to retrieve information that might shed some light on its subsurface ocean that may be pregnant with life.

5. Insights into our destinies from astrobiology, philosophy and theology

We have considered throughout this chapter a common frontier of astrobiology, philosophy, as well as other branches of the humanities. We have attempted to show that an interdisciplinary exchange across the border is not only possible, but also it may be profitable for the whole of human culture. Indeed, science is not contradicted by the main monotheistic religions of the world. A conflict is not expected to arise with the potential discovery of a Second Genesis. Instead, a dialogue could emerge with a discussion of the evolution of all the attributes of man, including those that are of prime importance for theology, namely the spirit of man that may distinguish humans from the ancestors of the Homo line. However, if we remain within the constraints that the science of biology has imposed onto itself - namely that the life sciences are based on observation (for instance, the evidence supporting natural selection), or on experiment (for example, in biochemistry), the question of man's spirit and soul should not enter into biology, but a dialogue across the frontier should always be encouraged.

6. References

Akindahunsi, A. A. and Chela-Flores, J. (2004). On the question of convergent evolution in biochemistry, In: J. Seckbach, J. Chela-Flores, T. Owen, T. and F. Raulin (eds.) Life in the universe: from the Miller experiment to the search for life on other worlds. Springer, Dordrecht, The Netherlands. (In press.)
Bruno, G. (2000). De l'infinito, universo e mondi, Venice, 1584. [English translation: On the infinite universe
and innumerable worlds, Cambridge, 1650]. For a more precise bibliographic reference: Giordano Bruno 1548-1600, Biblioteca di Bibliografia Italiana Vol. 164, Roma, Leo S. Olschki Editore, pp. 105-106.
Camus, A. (1991). The Myth of Sisyphus And Other Essays, New York, Vintage International.
Carlson, R. W., Johnson, R. E. and Anderson, M. S. (1999). Sulphuric acid on Europa and the radiolytic sulphur cycle, Science, Vol. 286: 97-99.
Chela-Flores, J. (2001). The New Science of Astrobiology From Genesis of the Living Cell to Evolution of Intelligent Behavior in the Universe, Kluwer Academic Publishers, Dordrecht, The Netherlands.
Chela-Flores, J. (2003). Testing Evolutionary Convergence on Europa. International Journal of Astrobiology 2: 307-312. http://www.ictp.trieste.it/~chelaf/ss13.html.
Chela-Flores, J. (2004). Astrobiology's Last Frontiers Distribution and destiny of Life in the Universe, In: J. Seckbach (ed.) Origins: Genesis, Evolution and the Biodiversity of Life. Springer, Dordrecht, The Netherlands, pp. 667-679.
Conway Morris, S. (1998). The Crucible of Creation. The Burgess Shale and the Rise of Animals. London, Oxford University Press, p. 202.
Conway Morris, S. (2003). Life's Solution: Inevitable Humans in a Lonely Universe. Cambridge, Cambridge
University Press.
Coyne S. J., G. (1996). Cosmology: The Universe in Evolution, In: J. Chela-Flores and F. Raulin (eds.) Chemical Evolution: Physics of the Origin and Evolution of Life, Dordrecht, Kluwer, pp. 35-49.
Davies, P. (2003). Universal truths, The Guardian, January 23, 2003.
(cf., http://www.guardian.co.uk/online/science/story/0,12450,879894,00.htm).
Dawkins, R. (1983). Universal Darwinism, In: D. S. Bendall, (ed.), Evolution from molecules to men. London, Cambridge University Press, pp. 403-425.
de Duve, C. (1995). Vital Dust Life as a Cosmic Imperative. New York, HarperCollins, pp. 296-297.
de Duve, C. (2002). Life Evolving Molecules Mind and Meaning. New York, Oxford University Press.
Drake, F. and Sobel, D. (1992). Is there anyone out there? The scientific search for Extraterrestrial Intelligence. Delacorte Press: New York.
Ehrenfreund, P and Charnley, S. B. (2000). Organic molecules in the interstellar medium, comets and
meteorites: A voyage from dark clouds to the Early Earth, Ann. Rev. Astron. Astrophys. 38: 427-483.
Ekers, R. D., Kent Cullers, D., Billingham, J. and Scheffer, L. K. (eds.) (2002). SETI 2020. SETI Press, Mountain View CA.
Hegel, G. W F. (1967). Philosophy of Right, London, Oxford University Press.
Heidegger, M. (1996). Being and Time, A Translation of Sein und Zeit, 1927 (SUNY series in Contemporary
Continental Philosophy), New York, State University of New York Press.
Horvath, J., Carsey, F., Cutts, J. Jones, J. Johnson, E., Landry, B., Lane, L., Lynch, G., Chela-Flores, J., Jeng, T-W. and Bradley, A. (1997). Searching for ice and ocean biogenic activity on Europa and Earth, In: R. B. Hoover (ed.) Instruments, Methods and Missions for Investigation of Extraterrestrial Microorganisms, The International Society for Optical Engineering, Bellingham, Washington USA. Proc. SPIE, 3111: 490-500. http://www.ictp.trieste.it/~chelaf/searching_for_ice.html.
Husserl, E. (1999). The Idea of Phenomenology, Dordrecht, Kluwer Academic Publishers.
Kierkegaard, S. (1981). The Concept of Anxiety, Kierkegaard's Writings, Vol 8, Princeton, Princeton
University Press.
Kierkegaard, S. (1986). Fear and Trembling, London, Penguin Books.
Krauss, L. M. (1998). The end of the age problem and the case for a cosmological constant revisited. Astrophysical Journal 501: 461-466.
McCord, T. B., Hansen, G. B., Clark, R. N., Martin, P. D., Hibbitts, C. A., Fanale, F. P., Granahan, J. C., Segura, N. M., Matson, D. L., Johnson, T. V., Carlson, R. W., Smythe, W. D., Danielson, G. E., and the NIMS Team (1998). Non-water-ice constituents in the surface material of the icy Galilean satellites from the Galileo near-infrared mapping spectrometer investigation, Jour. Geophys. Res. Vol. 103: No. E4, 8603-8626.
McKay, C. P. (2001). The search for a Second Genesis in our Solar System, In: Chela-Flores, J., Owen, T. and
Raulin, F. (eds), The First Steps of Life in the Universe, Dordrecht, Kluwer Academic Publishers,
pp. 269-277.
Ostriker, J. and Steinhardt, P. (2001). The Quintessential Universe. Scientific American, January, pp. 37-43.
Pace, N. R. (2001). The universal nature of chemistry, Proc. Natl. Acad. Sci. 98: 805-808.
Riess, A. G., Filippenko, A. V., Challis, P. (1998). Observational evidence from supernovae for an accelerating universe and a cosmological constant. Astronomical Journal 116: 1009-1038.
Russell, R. (2001). 'Life in the Universe: Philosophical and Theological Issues', CTNS Bulletin The Center for
Theology and the Natural Sciences 21: 3-9 (Spring 2001). [This paper was presented at the Sixth Conference
on Chemical Evolution and first appeared in Chela-Flores, J., Owen, T. and Raulin, F. (eds)
The First Steps of Life in the Universe, Dordrecht: Kluwer Academic Publishers, pp. 365-374.
Sartre, J. P. (1947). Situations, I, Paris, Gallimard.
Spinoza, B. (2002). Ethics, London, Everyman.
Weinberg, S. (1977). The first three minutes. London, Fontana/Collins.
Weinberg, S. (1993). Dreams of a final theory. London, Vintage International.