Alien life may not be carbon-based, new study suggests

[Admin]

Self-sustaining chemical reactions that could support biology radically different from life as we know it might exist on many different planets, a new study finds.

Alien life may not be carbon-based, new study suggests : Read more

 

[rod]

"In the new study, researchers searched for autocatalysis beyond organic compounds. They reasoned that autocatalysis could help drive abiogenesis — the origin of life from lifelessness."

I read the paper, Ref - Assessment of Stoichiometric Autocatalysis across Element Groups, https://pubs.acs.org/doi/10.1021/jacs.3c07041, 18-Sep-2023. “Abstract Autocatalysis has been proposed to play critical roles during abiogenesis. These proposals are at odds with a limited number of known examples of abiotic (and, in particular, inorganic) autocatalytic systems that might reasonably function in a prebiotic environment..."

My note (from the paper), “Using this strategy, we surveyed the literature published in the past two centuries for reactions that can be organized into CompACs that consume some chemical species as food to synthesize more autocatalysts.”

I recommend reading Charles Darwin letters on the warm little pond from 1871 and 1882. Charles Darwin in 1882 acknowledged there was no worthwhile evidence that life emerges from non-living matter, let alone spread around in the galaxy or among exoplanets. For all the efforts in science to demonstrate abiogenesis for the origin of life on Earth, no worthwhile evidence confirms this today or demonstrates a law of nature that describes abiogenesis, something Charles Darwin hoped would be established in science in his 1882 letter. We have Newton’s laws of motion, but no law of abiogenesis seen in nature and quantified as an example. The paper states about DNA (only 1 reference): “In contrast to autocatalytic cycles observed in biochemistry that may involve dozens of reaction steps and/or biomacromolecules (e.g., the Calvin cycle and DNA replication), CompACs are much simpler since they usually consist of only two or three reactions. Such simplicity could be important for a primitive, life-like autocatalytic system to emerge and persist. An autocatalytic cycle with fewer reaction steps tends to have a higher “carrying capacity”, (13) and it is arguably easier to find naturally occurring or laboratory-generated conditions that allow every reaction in a smaller autocatalytic cycle to occur.” My note, how this demonstrates non-living matter evolved into a single cell with DNA and grew and evolved into the tree of life we see on Earth today and in the fossil record, is a mystery to me.

 

[rod]

Space.com also published reports on JWST seeing carbon on Europa and waiting to see Bennu asteroid sample with carbon, that could evolve into life on Europa and Earth. Now we have this article on abiogenesis where non-carbon-based life may arise somewhere else in the galaxy using a different paradigm. I agree with Charles Darwin in his 1882 letter. There is yet to be shown to the public, the worthwhile evidence that demonstrates life in any form (carbon based or other), evolved naturally from non-living matter. Since Charles Darwin 1871 letter where he documented the warm little pond, we are still waiting here, just like Charles Darwin was still waiting to show abiogenesis in 1882.

How much asteroid material is NASA's OSIRIS-REx probe delivering to Earth this weekend?

NASA's OSIRIS-REx mission is delivering a precious haul of asteroid dirt and gravel to Earth this weekend. How much of this space-rock stuff will there be? How much asteroid material is NASA's OSIRIS-REx probe delivering to Earth this weekend? : Read more

forums.space.com

 

[COLGeek]

While I haven't read the paper yet, I would offer a comment regarding the "little pond". In the cosmic span of time, from Darwin's observations to today, is not even the time of a "blink of the eye". Expecting life to form in the pond seems rather unrealistic given what we understand regarding the age of our planet and the universe.

Regarding non-carbon life, aside from our "personal" experience, I am not surprised by the notion that life could be "something-based", other than carbon. The vastness of the universe and all contained within it are not something we remotely understand.

 

[rod]

COLGeek expresses thinking I find common on the origin of life here or anywhere else in the Universe. The problem is how Charles Darwin approached this issue. He looked to see evidence for abiogenesis that confirmed his letters and acknowledged in 1882, there still was none. We can talk about the size of the solar system here or the vastness of the universe, does not show abiogenesis took place at all, not even one time let alone multiple times, over, and over again.

As i read these different reports from space.com on abiogenesis, I compare to Charles Darwin letters of 1871 and 1882 for a look back in science on the topic of the origin of life. https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-7471.xml, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-13711.xml

Charles Darwin hoped that someday evidence would be shown for life evolving from non-living matter but in his time, none was known that was *worth anything* and the *law of continuity* would provide this, also a general law of nature for abiogenesis. None of this in science is proven at present. There is no general law of abiogenesis seen operating in nature. So, here is a summary of four points in these letters that I learned. 1. A warm little pond is postulated for the origin of life on Earth but Charles Darwin thought if abiogenesis operating in a warm little pond in his time, perhaps such life evolving from non-living matter would be quickly destroyed by existing life and eaten. 2. No good evidence for abiogenesis taking place in Charles Darwin time seen in nature. 3. The law of continuity is needed for abiogenesis to work apparently, and 4. Someday a general law of nature developed to describe and show abiogenesis like other laws of nature, for example the laws of motion or law of gravity. Apparently all four I list here are missing in science today, even with natural law operating in nature in a uniform manner, i.e., *law of continuity*.

There should be established via the scientific method, a general law of nature demonstrating how abiogenesis converts non-carbon-based elements into a different form of life, like silicon based, same applies to converting carbon in an asteroid to life on Earth with DNA. Charles Darwin hoped for this in 1882, still some are hoping here but not defining like Newton's laws of motion or gravity. Because of this situation, I consider such reports promoting a belief system seeking to be viewed as a real science paradigm, IMO.

 

[Helio]

The idea of silicon-based life is not new. Star Trek, in the 60’s, had at least one episode involving this. [I think they were rock-like beings.]

Si seems to be a distant second in its ability to form both with other elements and itself. This greatly limits its chances to form necessary complex molecules, such as proteins.

But, studying other forms only improves our understanding of complex forms, just like studying other planetary atmospheres will improve our knowledge of ours.

Darwin never presented an abiogenesis theory. He did present a great theory that showed how an existing species, which often generate new varieties with reproduction, could, after many millions of years, evolve into new species. His Origins book was not on life’s origins (abiogenesis) but of one species originating from another species.

He didn’t do much speculating on what bio process produced these changes to varieties in his original publication since Mendel’s work was unknown to him. He was not accepted into mainstream science due largely to this issue, though the more popular theories also suffered from this problem.

In subsequent publications, he offered one suggestion that might explain trait consistency, but it came across as ad hoc, because it was. Thus, it’s his first book that has the highest regard.

Abiogenesis , especially in his day, was known to be even more suppositional, and in no way was detrimental to his evolutionary model.

Einstein’s SR (Special Relativity) theory never required the incorporation of gravity. GR gave us the bigger picture with gravity, just as genetics advanced Darwin‘s work. Just as Einstein was mostly unknown until after he was able to demonstrate GR, Darwin was not mainstream until genetics became understood.

 

[rod]

Helio, interesting post#6. I went back and checked Origin of Species to see what Charles Darwin said about the origin of life in the work vs. his letters of 1871 and 1882. There clearly was a big change that took place.

“…Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”

Ref - https://archive.org/detail s/originofspecies00darwuoft/page/n539/mode/2up

IMO, these views expressed about the origin of life in his work did not invoke abiogenesis and nature creating life all its own by natural processes. His 1871 and 1882 letters changed the paradigm, astrobiology and biology today went with that model change to explain the origin of life, whether carbon based, or silicon based.

A better URL for Origin of Species, https://archive.org/details/originofspecies00darwuoft/mode/2up

See pages 528-529.

 

[Atlan0001]

I don't know if anyone else here has ever read E. E. "Doc" Smith Sci-Fi. His 'Lensmen' series has fascinated me ever since I first read it as a teenager ages ago. It still does fascinate me many decades later, especially his concept that life has body physicality but is not any particular body physicality based. That life is complex beyond body composition. Which is to say that life itself on its many levels of [mass-energy] is multi-dimensionally 'complex' or 'complexity' based life structure . . . no more, no less.

I know some here have heard the saying, "The thing (of whatever physicality) develops a life of its own!" Nothing could be truer . . . from a one celled creature -- and quantum physically lower -- up through a body of countless cells, up and down through whole universes having lives of their own (to include the living structures and infrastructures of dynamic frontier and static utopian civilizations (that I discussed -- to his delight -- for three hours with the Curator of the Korean Museum during a tour of Seoul, Korea. At the request of the Curator, the tour bus left me behind and came back by to pick me up later)).

 

[Helio]

Thanks Rod, that's a great quote that I vaguely recall from reading most of his book.

There is no small background story that could be imagined for his statement, especially given the emergence of scientific interests that may have started around 1800. Rev. William Paley's, Natural Theology, was one of Darwin's favorite books, as well as, a great call for everyone to go out and enjoy discovering stuff. For young Darwin, he excelled in his remarkable beetle collections. [I was more of a Beach Boy fan, myself. ]

Paley applied scientific observations to religious views, arguing that if you stumbled upon a watch lying on the road, you would know it was made by intelligent beings. Likewise, the more complex eye has to have been made by someone even more intelligent (ie God). This is an example of why Darwin took many years to present enough in the way of arguments to present an alternative, at least one where the intelligence was more in the laws themselves that would allow even greater diversity of creation. The large book, Origins of the Species, was actually his small book. Once he got a letter from Wallace stating the same tenets he held (e.g. natural passive selection) he was highly depressed, but Wallace convinced him to publish, so we got his abbreviated book. [Wallace saw how the more disease-resistant would help advance a variety over another, which would, or could, lead to a new species.] IIRC, they were together in a premiere presentation.

Also, recall that Darwin's plan was to become a parson, and likely would have become one had he not been invited to be company for the captain of the Beagle. His years of travel on that ship gave him focus on how varieties could progress to become new species. That was the heart of his extensive work, and not about even more challenging questions, which he at times addressed secondhandedly, like abiogenesis.

 

[Unclear Engineer]

I think that there is likely to be a probabilistic element to how auto autocatalysis of various chemicals could lead to complex life forms. If carbon has a higher probability of autocatalyzing materials than silicon does, then carbon life forms would emerge instead of silicon life forms.

But, the probability of that may depend highly on the parameters of the local environment. Higher temperatures and/or pressures might result in different chemistries having higher probabilities of succeeding in producing self-sustaining "life" forms.

Because all chemistry seems to happen faster at higher temperatures and higher pressures, I would not be surprised if some sort of life form based on an element that is not carbon could evolve in a dry environment that is extremely hot by our Earthly standards.

Such a high temperature life form visiting Earth would be somewhat like us Earthlings visiting our South Pole. Such extraterrestrials would probably need temperatures that would be lethal to us Earthlings. We would not be able to "shake their hands in welcome" without injuries to all involved.

 

[billslugg]

Carbon has a big advantage in any race to form life at STP. When oxidized, carbon turns into CO and CO2, which are both gases, thus are ubiquitous in the environment.

When silicon oxidizes it forms beach sand, extremely stable and unlikely to participate in further reactions. Yeah, I know, "sand gets everywhere" but that is not what I'm talking about.

Perhaps silicon might work well in some high temperature, high pressure regime somewhere.

 

[billslugg]

Such a high temperature life form visiting Earth would be somewhat like us Earthlings visiting our South Pole. Such extraterrestrials would probably need temperatures that would be lethal to us Earthlings. We would not be able to "shake their hands in welcome" without injuries to all involved.

And what would happen if they were made of antimatter? We could lose half of Secaucus!!

 

[Unclear Engineer]

And what would happen if they were made of antimatter? We could lose half of Secaucus!!

Yes, but think how happy that would make our BBT believers - they could finally prove that there really was a lot of antimatter made somewhere by their "bang"! And, maybe those anti-guys would know those monopoles!

 

[rod]

Some interesting discussion on this space.com article. I note from the report, "However, scientists have long wondered if alien life might evolve based on significantly different chemistry. For example, researchers have long speculated that silicon might also serve as a backbone for biology."

Helio mentioned about Star Trek and this was the Horta creature

https://en.wikipedia.org/wiki/The_Devil_in_the_Dark, "Kirk and his security team search for the creature. Spock, suspecting it may be a silicon based lifeform, modifies their phasers to be more effective against silicon. They encounter the creature—which has the appearance of molten rock—and fire upon it, breaking a piece of it off."

Okay, I recently watched this episode (again), very entertaining. Now we have reports of ultra short period and ultra dense exoplanets too.

Scientists believe exoplanet Gliese 367 b is probably a solid ball of metal,

Scientists believe exoplanet Gliese 367 b is probably a solid ball of metal

We can't understand nature without understanding its range. That's apparent in exoplanet science and in our theories of planetary formation. Nature's outliers and oddballs put pressure on our models and motivate scientists to dig deeper.

phys.org

ref - Company for the Ultra-high Density, Ultra-short Period Sub-Earth GJ 367 b: Discovery of Two Additional Low-mass Planets at 11.5 and 34 Days*, https://iopscience.iop.org/article/10.3847/2041-8213/ace0c7, 14-Sep-2023. “Abstract GJ 367 is a bright (V ≈ 10.2) M1 V star that has been recently found to host a transiting ultra-short period sub-Earth on a 7.7 hr orbit. With the aim of improving the planetary mass and radius and unveiling the inner architecture of the system, we performed an intensive radial velocity follow-up campaign with the HARPS spectrograph—collecting 371 high-precision measurements over a baseline of nearly 3 yr—and combined our Doppler measurements with new TESS observations from sectors 35 and 36..."


Maybe the Horta lives there

 

[Unclear Engineer]

On a more serious note: Silicon when oxidized does make for some hard materials. I am wondering what the autocatalysis reactions that they discovered really create, and with what elements to produce what molecules. We do manage to make things like silicones here on Earth. see https://en.wikipedia.org/wiki/Silicone . Those involve oxygen. I wonder what would happen with sulfur in place of oxygen in silicon chain molecules at high pressures and temperatures.

It would have been nice if the article had told us directly about any of the autocatalysis products that looked like they might be the basis for non-carbon based life.

 

[Pogo]

While there may be many families of reactions that could allow forms of life, maybe some at what we think of as extreme environments, and some may even produce a loose definition of life, I think that would be very primitive, I doubt there would be anything very complex.
I agree with Bill, a being exhaling sand would not do nearly as well as one exhaling CO2.
I can’t imagine thorium beings with an element that disappears, albeit slowly. We irradiate ourselves enough with C14 and K40, without zapping ourselves with all of our main ingredient.

 

[Unclear Engineer]

Silicon beings would not necessarily be exhaling sand (silicon oxide), they might be exhaling sulfur dioxide, or even hydrogen sulfide. see https://en.wikipedia.org/wiki/Silicon_disulfide

Thinking broadly, why couldn't a life form be based on reduction instead of oxidation chemistry for its energy source? Remember to consider the environment might be a high pressure, high temperature hydrogen rich atmosphere with a "sea" of stuff very unlike water.

I am not saying that there is such a molecular path to alternative life forms, I am just saying we need to stop restricting our thinking to being inside the terrestrial box if we want to explore the concept.

 

[Helio]

Yep, there's a big difference between CO2 (gas, unless frozen) and SiO2 (crystal; silica sand).

It is incredibly important that molecules be able to mix, which is why a liquid environment is so important.

Of course it's much worse for life when a planet like GJ 367 b orbits in a perpetual heat blast zone so that only its core remains. Equilibrium temp. there is about 1815 F.

 

[rod]

FYI, we have very dense exoplanets now like GJ 367 b and others close in to their parent stars that are super-puffs, very low densities. New low-density exoplanet discovered with TESS, https://phys.org/news/2023-09-low-density-exoplanet-tess.html, “Using NASA's Transiting Exoplanet Survey Satellite (TESS), an international team of astronomers has detected a new exoplanet orbiting a distant star. The newfound alien world, designated TOI-1420 b, has an exceptionally low density."

Now another new report using JWST indicates that TRAPPIST-1 b may not have an atmosphere.

James Webb Space Telescope's first spectrum of a TRAPPIST-1 planet, https://phys.org/news/2023-09-james-webb-space-telescope-spectrum.html

Ref - Atmospheric Reconnaissance of TRAPPIST-1 b with JWST/NIRISS: Evidence for Strong Stellar Contamination in the Transmission Spectra, https://iopscience.iop.org/article/10.3847/2041-8213/acf7c4, 22-Sep-2023. “Abstract TRAPPIST-1 is a nearby system of seven Earth-sized, temperate, rocky exoplanets transiting a Jupiter-sized M8.5V star, ideally suited for in-depth atmospheric studies. Each TRAPPIST-1 planet has been observed in transmission both from space and from the ground, confidently rejecting cloud-free, hydrogen-rich atmospheres..."

Using abiogenesis on exoplanets as the foundation of astrobiology, seems to have many challenges emerging now in exoplanet studies, much more than the 1871 letter of Charles Darwin with his warm little pond scenario. His 1882 letter looked for a general law of nature to be established in science describing how non-living matter can evolve naturally, into a simple form of life. So far, still missing in science.

 

[sciencecompliance]

There should be established via the scientific method, a general law of nature demonstrating how abiogenesis converts non-carbon-based elements into a different form of life, like silicon based, same applies to converting carbon in an asteroid to life on Earth with DNA. Charles Darwin hoped for this in 1882, still some are hoping here but not defining like Newton's laws of motion or gravity. Because of this situation, I consider such reports promoting a belief system seeking to be viewed as a real science paradigm, IMO.

This doesn't really seem like fundamental law of nature material to be honest, but rather an emergent property of certain chemical environments. As a side note, regardless of what Darwin said, unless you invoke supernatural forces, if you believe that the universe started without life present (as science would suggest), then clearly abiogenesis would have to have happened in one form or another at some point since we can clearly observe life today. Regardless of how life on Earth formed, at some point in the history of the universe, life had to evolve from simpler chemical reactions.

 

[rod]

This doesn't really seem like fundamental law of nature material to be honest, but rather an emergent property of certain chemical environments. As a side note, regardless of what Darwin said, unless you invoke supernatural forces, if you believe that the universe started without life present (as science would suggest), then clearly abiogenesis would have to have happened in one form or another at some point since we can clearly observe life today. Regardless of how life on Earth formed, at some point in the history of the universe, life had to evolve from simpler chemical reactions.

Very interesting here sciencecompliance. I note what Charles Darwin said in his 1882 letter.

To Daniel Mackintosh 28 February 1882, "...With respect to the main purport of your note I hardly know what to say.— Though no evidence worth anything has as yet in my opinion been advanced in favour of a living being, being developed from inorganic matter, yet I cannot avoid believing the possibility of this will be proved some day in accordance with the law of continuity3 I remember the time above 50 years ago when it was said that no substance found in a living plant or animal could be produced without the aid of vital forces!4 As far as external form is concerned Eozoon shows how difficult it is to distinguish between organised & unorganised bodies—5 If it is ever found that life can originate on this world, the vital phenomena will come under some general law of nature— Whether the existence of a conscious God can be proved from the existence of the so-called laws of nature (i.e. fixed sequence of events) is a perplexing subject, on which I have often thought, but cannot see my way clearly— If you have not read W. Graham’s “Creed of Science” it would I think interest you, & he supports the view which you are inclined to uphold.—6", ref - https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-13711.xml

You stated "but rather an emergent property of certain chemical environments." IMO, this sounds very similar to what Charles Darwin looked for in is 28-Feb-1882 letter, "the vital phenomena will come under some general law of nature"