Sunday, 11 March 2018

From the origin of conscious life to us and beyond


Lent 2018: Day 26

Once, not so very long ago, the vast majority of people, asked where life came from, would have stated categorically that it was the result of divine intervention...


And then, in 1952, Stanley Miller at the University of Chicago, did an experiment in which he flashed sparks of electricity through water, ammonia, methane and hydrogen. He wanted to replicate the atmosphere of Earth in its earliest days, through which lightning would zig-zag. The result - after five days, a brown sludge formed; amino acids, organic molecules. Primordial soup. The publication of Miller's work caused a major stir around the world - life had been created in a test tube! Now there was no need for God - this (coupled with evolution) is how we came about!

But hang on a minute - there's still a mighty long way from simple amino acids to complex proteins, to the double-helix structure of DNA, to self-replicating bacteria. In the decades that followed, many more experiments into prebiotic chemistry were carried out, synthesising ever-more complex molecules. But to date, science has yet to create living, procreating beings in a test tube. Which is not to say that many scientists today still believe that divine intervention was necessary to create life on Earth.

The notion of panspermia, of life propagating itself across galaxies, is one of the theories (along with deep-sea vents) as how those amino acids eventually turned into living beings. Studies of meteorites that fell to Earth (such as the Murchison meteorite which fell on Australia in 1969), suggest that DNA and RNA components, the building blocks for life, may have formed extra-terrestrially in outer space and been brought to earth, seeding a fertile biosphere that had all the right conditions in which they could thrive and replicate.

This is all clearly important, but at some stage, that life would have become conscious. Now, given that in Humanity in a Creative Universe, Stuart A. Kauffman says that Mind is a part of the universe and did not originate with life, he is open to the notion that "even simple life has rudimentary consciousness and free will." One way or another, consciousness "must have evolved enormously to yield the human mind, cognitive, emotional, intuitive, sensate.." And here Kauffman confesses to being in a quandary; either consciousness resides in the atom, in which case it appeared in the universe very shortly after Big Bang, or at the time the first compound organic molecules became self-replicating life forms.

All this in the 4.1 billion years since the first cells are believed to be formed (Earth is 4.5 billion years old). Around 3.5 billion years ago lived the most recent population of organisms from which all organisms now living on Earth have a common descent (the Last Universal Common Ancestor, LUCA), a single-celled organism with a ring of DNA floating freely within it. In the intervening years between the last LUCA dying and the first Homo Sapiens being born, an amazing parade of life forms has come and gone; 99% of all the species that ever lived on Earth are now extinct.

Now just imagine the massive leap from single-celled organisms to us. That took around 3.5 billion years. Not imagine a leap of that same magnitude that can be attained over the next 3.5 billion years. What angelic beings could exist then? How great their consciousness? [The Sun is expected to remain stable for the next 5 billion years, but the Solar System should not be a constraint for our descendants. Never mind the technology - just consider that consciousness...

This time last year:
Changing Jeziorki, late winter

This time four years ago:
A night of musical enchantment

This time five years ago:
A selfless faith

This time six years ago:
Ul. Profesorska after the remont

This time seven years ago:
Lent kicks off again, for the 20th year in a row for me

This time eight years ago:
Half way through Lent

This time ten years ago:
Spring much closer 

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