Asteroid Impacts and Life on Earth

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Discussion Overview

The discussion centers on the role of asteroid impacts in delivering water and organic materials to Earth, which some participants suggest may have contributed to the origins of life. The conversation explores theories of abiogenesis, the formation of organic molecules, and the conditions necessary for life to emerge, including the significance of water and other organic compounds.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that while asteroids are believed to have brought significant amounts of water to Earth, the question remains how such molecules could initiate life.
  • One participant mentions abiogenesis as a key concept, highlighting the transition from inorganic materials to organic molecules, but acknowledges that the exact mechanisms remain unknown.
  • Another participant emphasizes the importance of water's properties in facilitating chemical reactions necessary for life, arguing that it is not just a few molecules but rather vast quantities that are crucial.
  • Speculations are offered regarding the nature of early cells, suggesting they may have lacked lipid membranes and instead had proteinaceous walls, which could allow for a simpler origin of life involving RNA and proteins.
  • One participant points out that meteorites also deliver organic compounds, including amino acids, to Earth, which could play a role in the origins of life.
  • References to specific meteorites, such as the Murchison meteorite, are made to support claims about the delivery of organics to Earth.
  • Deep-sea hydrothermal vents are suggested as a potential environment for the emergence of early proto cells.

Areas of Agreement / Disagreement

Participants express a range of views regarding the mechanisms of life's origins, with no consensus reached on the specifics of how water and organic materials contributed to the emergence of life. Multiple competing hypotheses are presented, indicating ongoing debate and exploration of the topic.

Contextual Notes

Some claims rely on assumptions about the conditions of early Earth and the nature of prebiotic chemistry, which remain unresolved. The discussion includes references to specific scientific concepts and theories that may not be universally accepted.

Anonymous 69
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Scientists say when asteroids showered on Earth they were the ones who brought water to Earth which started life. But how did few molecules of water started life on earth?
 
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Nobody knows.
It's called abiogenesis.
Here is a link to the wiki page: https://en.wikipedia.org/wiki/Abiogenesis

One presumed step in the process is the creation of organic molecules from inorganic materials: rocks, water, and gases.

Perhaps the real trick is to go from there to an organic molecule (or system) that can self-replicate and mutate in any natural prebiotic environment. I don't believe anyone has discovered that trick.
 
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Anonymous 69 said:
Scientists say when asteroids showered on Earth they were the ones who brought water to Earth which started life. But how did few molecules of water started life on earth?

They didn't bring a "few" molecules, they brought more than 1018 metric tons. The reason this is important to life is because water forms a medium in which an enormous range of chemicals can mix together, which in turn allows thousands of different chemical reactions to occur. In addition, water's polar properties (meaning one side of it is charged negative and the other side is positive) cause the folding of certain molecules we call proteins and provides a mechanism for the construction of cell membranes. All of these things are requirements for all known life.
 
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I wish to offer speculations that

1) the first cells had no lipid membranes, but only proteinaceous walls vaguely like the outer layers of prokaryotes and viruses... This hypothesis affords you the option of getting started with only RNA and protein.

2) TRNA. Binds amino acids. On to the rybose opposite the nucleobase [2a]. This suggests that an early RNA strand could have used ribose as the translator intermediate with all of the nucleobases on one side of the backbone, templating for all of the amino acids on the other. Indeed [2b], only the pyrimidines U,C have known prebiotic precursors. So possibly the first RNA strands were purely Pyramidine based. And so had no self binding. Or double Helix forming structural. Capabilities. A pure pyrimidine RNA strand would remain single stranded And linear, an ideal template for amino acid. Linkage.

[2a] https://www.atdbio.com/img/articles/protein-synthesis-tRNA-large.png
[2b] http://astrobiology.com/2018/12/life-has-a-new-ingredient.html
 
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Anonymous 69 said:
Scientists say when asteroids showered on Earth they were the ones who brought water to Earth which started life. But how did few molecules of water started life on earth?

As well as water 1000s of organics in the form of meteorites fall to Earth every year, some of these organics contain amino acids alcohols and bases already formed

This one fell 1969 and has been studied intensively since, the fragments when collect weighed over 100kg

https://en.wikipedia.org/wiki/Murchison_meteorite

I would google deep sea vents as a starting point for first proto cells

https://www.livescience.com/26173-hydrothermal-vent-life-origins.html
 
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