When Did Proto-Life Emerge in the Universe?

6a00d8341bf7f753ef0133edb95240970b-320wi Three of Europe's cosmologists believe that the key to understanding the origin of life lies in identifying the time onset and the conditions which prevailed in our universe when life was first fashioned. Based on recent cosmological measurements complex life appeared on Earth 9.6 Gyrs (9.6 billion years) after the Big Bang.

However, these life forms may have been derived from earlier life forms, perhaps proto-life which emerged within a few billions years after the Big Bang according to research by Nicola Poccia, Alessandro Ricci, Antonio Bianconi all physicists with Sapienza University of Rome. The team theorizes that life could have emerged in different regions in the cosmos in the time range between 1.5- 9.6 Gyrs, the time range that marked the onset of dark energy domination in the universe, coupled with rapid star formation and supernovas.

These events raise the possibility that the increase of dark energy, coupled with the stellar synthesis of the elements necessary for life, could be related to the emergence of life in the universe.

In these last years a large amount of experimental information on the nature and physiology of living cells has become available.There is now an abundance of data which indicates that the emergence of the living phase of the matter in the cell is related to the onset of a particular phase of condensed matter. Integral to life, of course, is energy. It is energy which gives matter the dynamic qualities we associate with life.

Exactly what, however, were those conditions which gave rise to life?

First and firemost,  energy is required for the cell to function, to repair itself, to replicate, and to pass on information. Dark energy could be of relevance in an unknown way for the emergence of life in our universe. In fact some of the recent estimates for the emergence of life in the universe is correlated with the onset of the dominance of dark energy

The team plotted the hypothetical emergence of life in the actual time scale of the Universe, with temperature versus time, elapsing after the Big Bang. The quantitative measure of the time elapsed from Big Bang to today has been an object of scientific debate for years. There is now a growing scientific consensus that the age of the Universe is around 13.69 ± 0.13 Gyr (from 13.82 to 13.56 billion years ago), and this is based on Cepheids as the fundamental principal of extragalactic distances, and with distance believed to be directly related to time.

In the standard Big Bang model of our Universe, following the creation, the Universe underwent an accelerated stage of expansion: the inflationary era in a short stage (10-34 sec). Two successive stages of deccelerated expansion followed inflation: the radiation dominated, followed by the matter dominated eras. The consensus of opinion is that 74% of the universe consists of dark energy, 22% dark matter, and 0.005% radiation.

The onset of the dominance dark energy began around 4-5 Gyr after the creation of the Universe. Possibly, the measured cosmic acceleration could arise from the repulsive gravity of dark energy related with the quantum energy of the vacuum.

The cosmic microwave background radiation provides a further indication about the temperature of the Universe as it is today versus what it must have been following the Big Bang. Therefore it is possible to make scientific estimates as to the evolution of the temperature of the Universe.

It is thought that as matter cooled, it underwent phase transitions, which triggered or allowed the condensed matter in the Universe to undergo and form multiple complex phases. The non-living to living matter transition is related to these transitions that occur in a temperature range from a maximum of about 390 K, and a minimum temperature of about 240 K.

It is recognized that not all extraterrestrial life in the universe may be like the life of Earth. It may have different genetic codes, no genes at all, or be comprised of silicon, ammonia, or sulfuric acid for example. However, we know for a fact that living matter on Earth depends upon and requires the synthesis of 23 different elements; and most of these elements are produced during stellar nucleosynthesis or may be produced and then dispersed at the end of the life time of a star, in a supernova explosion. Thus, all the stuff of life is found in stars.

It is unknown when the first stars were formed in the Big Bang model. Based on computer simulations, the first protostars may have been created between 200 million to 400 million years after the Big Bang. These are believed to have undergone supernova after a few million years.

According to various computer models, these first stars were the seeds for later stars such that by 10 to 12 billion years ago, the universe was bright with stars many of which also underwent supernova, spreading the seeds not just for additional stars, but for life.

In fact, there is now a growing body of evidence suggesting that the first proto-genes and the first forms of proto-life may have been fashioned around 10 billion years ago, or within a few billion years thereafter. Many scientists also believed that these first proto-life forms or actual living cells were spread from star system to star system and from planet to planet via mechanisms of panspermia. It has been proposed life on Earth may have been encased in meteors, asteroids, and broken planets ejected from a "parent" solar system during the red giant phase of the central star's death, which was then followed by supernova. Some of this life containing debris fell to Earth and became part of this planet.

In fact, Earth has 92 stable elements which were a product of a supernova explosion that was trapped by the sun about 9 Gyrs after the Big Bang. However, this finding does not support what has been described as "hard panspermia", that is, the transfer of fully formed life to this planet, but the possibility that life on Earth originated on Earth; perhaps following the delivery of proto-cellular material (via "soft panspermia") which led to an RNA world and then complex DNA-based cellular life.

Which begs the question: what unique conditions on Earth would have triggered the formation of fully formed life?

The emergence of complex cellular life in the Earth could have been produced early in the history of this planet when the water temperature on Earth was around 320 K and the Universe age was 9.8 ± 0.43 Gyrs.It is now well established that a variety of complex single celled microbes, including archae and thermophile bacteria, can thrive and reproduce at extremely high temperatures, dying (or forming spores) only as temperatures approach 394 K. "Does this mean that hyperthermophiles were created during these high temperatures?" asks the researchers. "Not necessarily. However, what it tells us is that similar forms of life could have also been fashioned, perhaps from proto-cells during the early phases of this universe, such as during phase transitions involving rapid temperature changes. Thus it is possible that life has had several genesis events."

In addition to stars, another source of energy which permeates the universe is "dark energy." Dark energy is a hypothetical form of energy which is believed to permeate the entire universe and to contribute to its expansion and to the dynamic nature of this universe, preventing matter from clumping together, and filling all of empty space. The existence of a dark and unclustered energy component responsible for more than 70 % of the overall density of our universe is supported by the latest cosmological data.

The consensus of opinion is that the onset of the dark energy phase took place around 4.4 ± 0.2 Gyrs and this has been accompanied by an epoch of universe acceleration starting at 6.9 ± 0.2 Gyrs after the Big Bang. This is well within the range of time that many are now estimating that life or proto-life may have first began to form in this universe, i.e. around 10 billion years ago.

These events raise the question of whether an increase of dark energy in the universe at that time could have an influence on the emergence of life. Dark energy is related to the whole universe and can affect multiscale phenomena ranging from microscale to nanoscale, so why not life the team asks?

Correlations or associations, however, are not causation. Nevertheless, there is a growing consensus that life did not begin on Earth, that life may be widespread throughout the cosmos, and that life, or at least proto-life, may have had its onset billions of years before the formation of this planet and possibly 4 billion or more years after the Big Bang. Therefore, it is imperative, the physicists add, that we ask what unique conditions may have prevailed during th
is time and how might these conditions have contributed to the origin or multiple origins of life?

They conclude that, first, the proximity between the time onset of the emergence of life and the time onset of the dominance of dark energy in our Universe and the rapid phase of star formation and supernova, and second, the similar interaction energy scale supports the hypothesis that dark energy, coupled with the nuclear synthesis of all the necessary elements for life, may have played an unknown but significant role in the origin and stability of living biological systems and may have contributed to the origins of life.

Casey Kazan via the Journal of Cosmology

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