Rainbow meteorite discovered in Costa Rica may hold building blocks of life

Jul 27, 2020
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Quoting from the article:

"The Japanese Hayabusa2 probe, launched in 2014 with the goal of sampling the asteroid Ryugu, is already on its way back with Ryugu dust onboard, a sample that may contain carbonaceous chondrite, Sokol noted.

These asteroid scraps will be truly pristine, having never touched the atmosphere or sat atop rainforest soil," Sokol wrote."

end quote.

Apparently Sokol (referring to the sample as "pristine") has not heard of solar and cosmic radiation. Since their sample was taken from the surface of the asteroid instead of a deep core sample, it is difficult to understand how it can be "truly pristine". One imagines that billions of years of intense radiation might have a significant impact on the chemical composition of organic compounds.

Actually it is not only Sokol who refers to such samples as "pristine". There seems to be a consensus among these scientists that their studies are attempting perfection from "pristine" samples, which is over-sold based on what has been analyzed so far. Any attempts at sampling pristine material would require substantial bore samples, and even then you would need data from several depths to confirm the findings. The composition of surface material would likely be vastly dissimilar to deep core samples, and nearly impossible to "deconvolute" to obtain its original chemistry.

In any event, this radiation might result in both assembly and degradation of compounds, depending on exposure levels and organic content. Inorganic content could also play a role in both mechanisms, with some possibly catalytic as well as stereo-selective. All of life on earth uses a number of stereo-isomers, particularly polymers.

Still, it remains very interesting that these objects are the source of a wide variety of abiotic organic chemicals that seeded the earth for abiogenesis to begin some 4 bya.
 
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"One imagines that billions of years of intense radiation might have a significant impact on the chemical composition of organic compounds."

Indeed. And intense solar UV radiation is the problem for life to evolve on the early Earth as well as life on Mars, in the past or even now.
 
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Apparently Sokol (referring to the sample as "pristine") has not heard of solar and cosmic radiation. Since their sample was taken from the surface of the asteroid instead of a deep core sample, it is difficult to understand how it can be "truly pristine".

Sokol is referring to the sample not being contaminated with Earth material and especially organics or prokaryote processes, which would confuse whether or not the material is produced biotically (most likely) or abiotically.

It is a good point that radiation skews mineral and molecule compositions, but they can account for some or all of that bias. (Say, by having samples from differing depth, which they took IIRC by sampling the initial surface and after an impactor had gouged it.)

Yes, the demonstration of organics all over the universe - from the atmosphere of carbon stars and out - is interesting for astrobiology, I think that is the main finding in these cases.
 
And intense solar UV radiation is the problem for life to evolve on the early Earth as well as life on Mars, in the past or even now.

Your usual response to anything in astrobiology, whether irrelevant or not. (Not, in this case.) Also a claim dearly in need of reference.

Meanwhile, as far as we can probe biology, the universal ancestor lineage evolved in the deep ocean far from any UV production of compounds [ https://www.nature.com/articles/nmicrobiol2016116 ].
 
Certainly lends credence to [superstitious myth text reference without any credence and - specifically here - no support from the observations].

Biblical passages (Christian or otherwise) are all well and good

On the contrary I think, it is generally considered rude to post erroneous superstition on a science site. C..f how people do not intrude on these sects' magic rituals to proclaim on known facts that reject the empirical basis for such ritual, that would be bad manners as well as disruptive.. While rude manners is understandable as all the argument they have, it is still not excusable.

Especially rude is the idea of large scale magic agency now, it is certainly not the case that there is an "absence of science". (Remember that agnosticism too is belief "in the absence of science".) We now know that space is flat, so the universe is a zero energy system, and its expansion is adiabatic, so it is a zero work system - it is on large scales entirely spontaneous process and spontaneous beginnings (if any - inflation before the hot big bang is naturally eternal). No magic agency 'created' the universe or acted within it, we can easily observe that now with the latest generation of cosmological surveys.
 
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It doesn't matter Mr. Larsson, if its a usual response or not. What matters is if it is the truth or not. No reference is needed for the effect of intense UV radiation on DNA. UV lamps are routinely used. What does matter is that the last common ancestor at the base of the tree of life is a microbial hyperthermophile that is also an microAEROphile. Aquifex species are aerobic hyperthermophiles that use elemental sulfur, hydrogen, and trace amounts of OXYGEN in ecosystems near hot hydrothermal vents (Stetter, 1991). Not likely on an early Earth supposedly anoxic for a billion years.
 
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It doesn't matter Mr. Larsson, if its a usual response or not. What matters is if it is the truth or not. No reference is needed for the effect of intense UV radiation on DNA. UV lamps are routinely used.

"What matters is if it is the truth or not." Indeed, there is nothing more important than the truth!

No doubt about the irradiation effects of UV on DNA, Very nasty to be sure. Tears it apart.

In any event, the fossil evidence indicates that life "surfaces" from the depths very early, probably a little under 4 bya. If there was significant UV radiation, it would have perished, unless its protein content was 50% DNA repair mechanisms, a highly unlikely scenario.
 
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" If there was significant UV radiation, it would have perished.." Exactly. That's precisely why the standard view of the anoxic atmosphere / ocean origin of life and history of early life is not correct. And the reason why there was never any life on Mars. Without an ozone screen there could be no life. No oligonucleotides or polypeptides (leading to nucleic acids and proteins) that require the input of energy and the loss of water.
 
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One of the most likely events leading to a "rapid" oxygenated atmosphere is for the evolution of the photosynthetic reaction center (PRC) relatively early in some surface life form(s), which arose following their formation in the ocean's depths. The PRC is a remarkably complex mechanism that extracts energy from the sun and converts it into sugar. One of its primary bi-products is, of course, oxygen.

Much of the evolution of this mechanism would likely have occurred in relatively shallow water, where UV could not penetrate very deeply at any rate, but the light that powers the PRC is in the visible range, which will do no damage to DNA. So one can see how the oxygenation can occur with the most primitive photosynthetic algae, prior to their organization into stromatolites. Some of these mats have been dated to ca. 3.7 bya. If this is correct, the original algae would likely have arose a few hundred million years before this, since evolution was not exactly galloping along almost 4 bya!
 
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Not only do Aquas Zarcas and Murchison contain the building blocks of life, they probably came from a minor Solar system body on which life originated before migrating to Earth. Two less modified carbonaceous chondrites, Allende and Acfer-086, probably contain the first protein Hemolithin, presumably from the same body. Unlike the Earth, a minor solar system body can easily have deep freezing/thawing cycles and a closed hydrological system with desalination by freezing. These can concentrate chemicals necessary for life enough to favor the formation of early biomolecules, e.g., Hemolithin.