Theoretical origin of life; new earliest? (Introduction)

by David Turell , Thursday, April 14, 2022, 19:33 (736 days ago) @ David Turell

Current thought based on latest discoveries:

https://www.sciencealert.com/complex-life-may-have-started-on-earth-much-earlier-than-w...

All life on Earth likely emerged from one spark in Earth's early history. Some time later, it diversified, branching off into lineages that helped it survive.

Exactly when these moments occurred has been a point of contention in the scientific community, but new research suggests both steps may have taken place earlier than we previously thought.

The study, led by University College London researchers builds on evidence of diverse microbial life inside a fist-sized piece of rock from Quebec in Canada, dated to around 3.75 billion to 4.28 billion years.

In 2017, the researchers who discovered it speculated that structures in the rock – tiny filaments, knobs, and tubes – had been left by ancient bacteria.

But not everyone was convinced that these structures – which would push the date for the first signs of life on Earth back by at least 300 million years – were biological in origin.

However, after further extensive analysis of the rock, the team discovered an even larger and more complex structure than those which were previously identified. Within the rock was a stem-like structure with parallel branches on one side that are nearly a centimeter long, as well as hundreds of distorted spheres, or ellipsoids, alongside the tubes and filaments.

"This means life could have begun as little as 300 million years after Earth formed. In geological terms, this is quick – about one spin of the Sun around the galaxy," says lead author of the study, geochemist Dominic Papineau from UCL.

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According to the paper, some of the smaller structures could have conceivably been the product of abiotic reactions, however, the newly identified 'tree-like' stem is most likely biological in origin, as no structure like it, created through chemical reactions alone, has been found before.

In addition to the structures, researchers identified mineralized chemicals in the rock that could have been byproducts of different types of metabolic processes.

The chemicals are consistent with energy-extraction processes in the bacteria that would have involved iron and sulfur; depending on the interpretation of chemical signatures, there could even be hints of a version of photosynthesis.

This finding points to the possibility that the early Earth – only 300 million years after its formation – was inhabited by an array of microbial life.

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Prior to this discovery, the earliest fossil evidence of life was found in Western Australia, which dates back 3.46 billion years. However, similar contention exists around whether these fossils were biological in origin.

Comment: same old problem, identifying organic molecules that could have come only from life. The structure found is intriguing, but a 'look alike' is not proof. If it is life, happening so early after Earth formed in an horrendous hot situation, only God's actions could have done it.