On Life and its Origins
Reflection on how life came to be on Earth. Published February 2017 in Bilkent News.
The human mind viewed at a distance is a thing achingly beautiful; the body, however humble, has adapted appreciably along with it to harsh Planet Earth. Almost nine million other species share our planet with us, each a unique product of evolution – perhaps not all as intricate as we are, but every one as remarkable, purely because it is alive. This concept of aliveness is wild and ill-defined, a primeval call into the slick unknown; things are born and then they die, and the life in between remains a mystery. It has taken humanity a number of turbulent years to even contemplate its own conception in relation to the Earth and to evolution; there remain many questions without even a semblance of an answer, questions that derive from a fundamental curiosity that involves not only humans, but rather all life in the universe: How long have we been here? asked rosily to the darkness, Are there others like us out there? What is this thing called life – how are any of us alive?
The history of life on Earth begins in unicellular form in the muddy backwaters of our young planet at half a billion years of age. For this, scientists have hard evidence dating back 3.7 billion years, microbial and ancient, but there is still no similar proof as to the origin of life. It remains a mystery that we’ve addressed time and again in many ways, through science and religion, both of which have served their purpose to some degree; the latter deals with assurance, with faith and generalization, while the former deconstructs, predicts and observes – still, it remains a difficult matter to observe the first stirrings of life. But science theorizes, and some of the theories are utterly fascinating; they put forth tremulous answers to tremendous questions, which are discussed and revised until they grow into truth.Among these more tentative answers lies the phenomenon of abiogenesis. Experiments have demonstrated that most amino acids, which are the fundamental constituents of proteins, can be put together from inorganic substances under conditions very much like those of the early planet Earth. It follows that an external catalyst like lightning or radiation could have triggered a similar reaction, leading to the conception of life. But such a thing needn’t have happened on Earth: the substances required for life could have been formed elsewhere in the cosmos and then deposited on our young planet, and there actually have been discoveries of complex organic molecules both within and beyond the solar system. Neither theory violates the other, but we are not yet sure of the truth of either. There are of course more theories related to this remote genesis, some of which fascinate me and some of which I don’t yet quite understand; the origins of life are disputed and deeply complicated, but its history here on Earth is almost tangible. In addition to the microbes found to be just under four billion years old, there have been discoveries of biotic life dating just over the same threshold; there is now enough fossil evidence to trace simple organisms back 4.1 billion years, in the form of trace strains found in ancient rocks. If this date turns out to be accurate, it would mean that life took only 440 million years to appear on our planet; “if life arose relatively quickly on the Earth,” says one scientist with regard to this primal fossil, “then it could be common in the universe.” The distribution of life throughout the cosmos is its own problem to be dealt with, in a setting better suited to deep consideration. This modest piece has only peripherally touched on a very small number of things related to a very large subject, and has put forth no conclusions of its own. This I can only excuse by saying that I am very new to the matter and know quite little, and the limited length of my article prevents me from rambling about everything that fascinates me, of which there is an inordinate amount. There is so much to be seen, so much to be known, and only a bare promise that this can all be done through science. Yet science is meticulous and relentless, and dares to address that which reveals our smallness against the remaining unknown; the origin of life is such a topic, difficult to take apart and harder to reconstruct, but awfully pertinent to us and our existence, to the Earth as a whole, to the rest of the shimmering universe. So we wait in hopeful shadow, scrabbling at the darkness with our conjectures and experiments and observational madnesses, and try to puzzle through the solid question of aliveness; science cradles the whole world in its steady palms and posits the construction of life in the fertile confines of the Earth, its construction at a solemn distance and its terrible violence – science takes a good look at all the implications of the problem of life and says, “Perhaps this is unsolvable – perhaps I will never truly get to the bottom of it. Perhaps it will take me a very long time, and in the end it won’t ever have been relevant – but damn if I won’t try. Goddamn if I won’t try.”