Theoretical origin of life: cosmic dust delivered proteins (Introduction)

by David Turell , Saturday, March 02, 2024, 15:53 (56 days ago) @ David Turell

To a prebiotic Earth:

https://www.nature.com/articles/s41550-024-02212-z

"Abstract
Earth’s surface is deficient in available forms of many elements considered limiting for prebiotic chemistry. In contrast, many extraterrestrial rocky objects are rich in these same elements. Limiting prebiotic ingredients may, therefore, have been delivered by exogenous material; however, the mechanisms by which exogeneous material may be reliably and non-destructively supplied to a planetary surface remains unclear. Today, the flux of extraterrestrial matter to Earth is dominated by fine-grained cosmic dust. Although this material is rarely discussed in a prebiotic context due to its delivery over a large surface area, concentrated cosmic dust deposits are known to form on Earth today due to the action of sedimentary processes. Here we combine empirical constraints on dust sedimentation with dynamical simulations of dust formation and planetary accretion to show that localized sedimentary deposits of cosmic dust could have accumulated in arid environments on early Earth, in particular glacial settings that today produce cryoconite sediments. Our results challenge the widely held assumption that cosmic dust is incapable of fertilizing prebiotic chemistry. Cosmic dust deposits may have plausibly formed on early Earth and acted to fertilize prebiotic chemistry."

Another view: https://www.universetoday.com/165875/cosmic-dust-could-have-helped-get-life-going-on-ea...

"Life on our planet appeared early in Earth’s history. Surprisingly early, since in its early youth our planet didn’t have much of the chemical ingredients necessary for life to evolve. Since prebiotic chemicals such as sugars and amino acids are known to appear in asteroids and comets, one idea is that Earth was seeded with the building blocks of life by early cometary and asteroid impacts. While this likely played a role, a new study shows that cosmic dust also seeded young Earth, and it may have made all the difference.

"Although we’ve long known that cosmic dust accumulated on early Earth, it’s not been seen as a major source for early life because of how it accumulates. With comet and asteroid impacts, a great deal of prebiotic material is present at the site of the impact. Dust, on the other hand, is scattered across Earth’s surface rather than accumulating locally. However, the authors of this new work noted that cosmic dust can accumulate and be concentrated in sedimentary deposits, and wanted to see how that might play a role in the early appearance of terrestrial life.

"Using estimates of the rate of cosmic dust accumulation in the early period of Earth and computer simulations of how that dust could accumulate in sediment layers over time, the team looked at how concentrated deposits might form. One of the things they noticed was that while cometary impacts could create a local spike in prebiotic material, the amount deposited by cosmic dust was much higher. They also found that the melting and freezing of glacial areas could significantly increase the concentration of chemicals from the dust. For example, for early sub-glacial lakes, the concentration of prebiotic chemistry from dust would have been much higher than that found at impact sites. This means that cosmic dust could have played a much larger role in the appearance of life than impacts.

"There is still much we have to learn about early life on Earth and how life can form from prebiotic chemistry, but it is clear that life on Earth is only possible because of extraterrestrial chemistry. From dust came the building blocks of life, and so we and every living thing on Earth can trace its lineage back to the early chemistry of dust in the solar system."

Comment: it's the same old story, just mix up some proteins and life will magically appear. Now, certainly proteins had to get here for life to happen, but that happening is just a whole 'nother story requiring something supernatural. Just recognize the pile of reqired contingencies.