I am starting this thread as a follow-on from the latter discussion stages of the
‘Not sure what I saw’ thread.
One of the factors influencing the ‘chances of exo-life in the universe discussion', which is of primary importance, is how life can start from pre-biotic chemicals. There is no firm answer to this, (& there probably never will be unless of course, neutrinos actually do violate causality and we can go back in time to find out ..
), but theory might give us a glimpse into it all.
So here goes … what is 'Abiogenesis' ? ...
Wiki defines Abiogenesis as ...
Quote:
In natural science, abiogenesis or biopoesis is the study of how biological life arises from inorganic matter through natural processes, and the method by which life on Earth arose.
Most amino acids, often called "the building blocks of life", can form via natural chemical reactions unrelated to life, as demonstrated in the Miller–Urey experiment and similar experiments that involved simulating some of the hypothetical conditions of the early Earth in a laboratory.
In all living things, these amino acids are organized into proteins, and the construction of these proteins is mediated by nucleic acids, that are themselves synthesized through biochemical pathways catalysed by proteins. Which of these organic molecules first arose and how they formed the first life is the focus of abiogenesis.
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So, since the Miller-Urey experiment, Wiki lists about 10 'models', (or tentative statements/hypotheses), all having varying degrees of evidence or scientific rationale behind them.
Given that:
- these 'models' are science's best attempts at describing how it all started;
- the basic environments described by these 'models' ultimately give rise to our present definitions of past and present 'Habitable Zones' and;
- the most likely process leading to life follows the sequence: bio-monomers, bio-polymers then finally molecules to cells;
- life metabolises, regulates its internal environment, grows, responds to stimuli, contains information, replicates and evolves;
1) What does the reader think might be the closest model so far developed for abiogenesis and how simple does this mean 'exo-life' might be, (ie: as far as for the purposes of searching for it) ?
2) How close have we come to making an exo-life discovery, so far ?
3) How much significance does the presence of these 'models' add to the confirmation of discovered exo-life, should such a discovery occur ... and why? (Eg: can a discovery ever be claimed without them ?)
Cheers