Gap between life and non-life (split from What if god...)

[Khanzhoren]

I understand your explanations very well and they are not really new things for me. But let's say typically, has anyone ever given a realistic quantitative estimate of the duration of the chemical process that could correspond to abiogenesis?

Edited Monday at 02:12 PM by Khanzhoren

[studiot]

Just now, Khanzhoren said:

I understand your explanations very well and they are not really new things for me. But let's say typically, has anyone ever given a realistic quantitative estimate of the duration of the chemical process that could correspond to abiogenesis?

Do you really think this is a sensible question ?

We do not have a recipe book for life of any description.

So let us say I show you a large opaque black bottle and say this black bottle has grains of sand in it. How many grains doe it contain ? You may not examine the bottle or know how big the sand grains are.

That is a far far easier task.

[swansont]

3 hours ago, Khanzhoren said:

What I simply wanted to say is that, if I'm not mistaken, there hasn't been any direct evidence or direct observation of the process of abiogenesis, so it remains theoretical

The direct evidence is that life exists, and previously it didn’t.

Direct observation is a canard trotted out by people who aren’t familiar with science. Tip: don’t ever study modern physics if you expect this. You will be very disappointed.

[TheVat]

There are also hypothesized abiogenesis accelerator environments, such as around seabed hydrothermal vents, which are areas conducive to chemosynthesis, possibly the first kind of metabolism on Earth.  

[Khanzhoren]

2 hours ago, studiot said:

Do you really think this is a sensible question ?

We do not have a recipe book for life of any description.

So let us say I show you a large opaque black bottle and say this black bottle has grains of sand in it. How many grains doe it contain ? You may not examine the bottle or know how big the sand grains are.

That is a far far easier task.

As a reminder, I asked this question because another person previously mentioned a long duration to conclude that direct observation (possibly in laboratory) would probably not be possible due to this . Then you spoke about duration in relation to chemical kinetics when i asked why He/she said that.

1 hour ago, swansont said:

Direct observation is a canard trotted out by people who aren’t familiar with science. Tip: don’t ever study modern physics if you expect this. You will be very disappointed.

May be you don't understand what I mean by direct observation Or perhaps I expressed myself poorly. Anyway I mean by it " an experimental observation of the transition of a non-living system to a living system in a laboratory or something like that ". Otherwise, as far as I know, modern physics also has an experimental aspect of this kind.

Edited Monday at 04:47 PM by Khanzhoren

[studiot]

Just now, Khanzhoren said:

I understand your explanations very well and they are not really new things for me.

I understand from this claim that you did not actually understand my explanation at all or you would not have said

Just now, Khanzhoren said:

(possibly in laboratory)

Because in a laboratory you would have control over the concentrations.

What I also meant was we do not know what concentrations to control. That follows directly from my description of chemical kinetics.

[Khanzhoren]

It seems to me that there are some misunderstandings in our discussion. So, I will simply rephrase my question differently : Do you think it would be possible to observe the abiogenesis process in a laboratory and within a reasonable timeframe?

[iNow]

5 hours ago, Khanzhoren said:

This statement is unrelated to the hypothesis of the existence or non-existence of a god

Are you unaware of how comparisons work?

[Khanzhoren]

What do you mean? Anyway, perhaps there are misunderstandings, or perhaps I didn't express myself clearly, but to be clear: my previous statement concerns solely, at its level, the problem of the experimental observation of the abiogenesis process.

[exchemist]

10 minutes ago, Khanzhoren said:

What do you mean? Anyway, perhaps there are misunderstandings, or perhaps I didn't express myself clearly, but to be clear: my previous statement concerns solely, at its level, the problem of the experimental observation of the abiogenesis process.

But how is this any different from us not being to observe directly geological processes, say, or the formation of stars? 
 

There are many aspects of science that depend on inference of a process from observations, without being able to observe the process directly. Do you think the origin of life is unique in this respect, for some reason? If so, what?

Edited Monday at 05:21 PM by exchemist

[Khanzhoren]

32 minutes ago, exchemist said:

But how is this any different from us not being to observe directly geological processes, say, or the formation of stars? 

There are many aspects of science that depend on inference of a process from observations, without being able to observe the process directly. Do you think the origin of life is unique in this respect, for some reason? If so, what?

It is clear that some large scale phenomena like geological processes and formation of stars  cannot be reproduced in a relatively limited space  and time and they are still occuring so there are some other ways to observe/study them more or less directly. Regarding the origin of life, it is unique in the sense that it is a key step in evolution around which there are still many important unresolved questions. I naturally wonder about a possible reproducibility in the laboratory or not; I think it's an obvious question to ask.   

Edited Monday at 05:53 PM by Khanzhoren

[exchemist]

12 minutes ago, Khanzhoren said:

It is clear that some large scale phenomena like geological processes and formation of stars  cannot by reproduced in a relatively limited space  and time and they are still occuring so there are some other ways to observe/study them more or less directly. Regarding the origin of life, it is unique in the sense that it is a key step in evolution around which there are still many important unresolved questions. For my part, I naturally wonder about a possible reproducibility in the laboratory or not; I think it's an obvious question to ask.   

Hmm, but all you are saying is that we don’t as yet have a model for the process. That’s what makes it an object of study, of course. 

Wondering about reproducibility in the lab is the sort of thing only someone with little understanding of the science would do. As a “question to ask”, it is very naïve - or disingenuous, but in your case I’ll assume naïvety, pro tem. The biochemistry of a living organism is very complex indeed. There is no reason to expect that assembly of all the components required, in a functional form, could  be accomplished in a lab on a human timescale. Other contributors to the thread have already made this point.

[CharonY]

26 minutes ago, Khanzhoren said:

It is clear that some large scale phenomena like geological processes and formation of stars  cannot be reproduced in a relatively limited space  and time and they are still occuring so there are some other ways to observe/study them more or less directly. Regarding the origin of life, it is unique in the sense that it is a key step in evolution around which there are still many important unresolved questions. I naturally wonder about a possible reproducibility in the laboratory or not; I think it's an obvious question to ask.   

It is not a key step in evolution as such, as it predates evolution as we understand a fair bit (there is the concept of molecular vs organismal evolution, but they refer to different aspects.

Also, time is not the real issue. The critical biochemical processes do not happen on geologial time scales. Rather, the issue is pinpoint the exact boundary conditions that have co-occured to make the formation of the first biomolecules possible. One fairly simple one is the question if abiogenesis actually happened on Earth. The findings of certain organic molecules on asteroids could indicate that completely different conditions than those on Earth might have given rise to them. On the other hand, it is possible that those are not related to life on Earth or that they had to come in via asteroids or other mechanisms and meet other conditions that were present on Earth.

[iNow]

It also requires us to clearly define what constitutes life and what are the boundaries of those metrics between "is life" and "is not life."

So, we could do all kinds of things in a lab only to have our fair contributor here move the goal posts and say, "yeah but THAT's not life."

[studiot]

Just now, Khanzhoren said:

perhaps I didn't express myself clearly

You were very clear, but just plain wrong.

 

Just now, Khanzhoren said:

It is clear that some large scale phenomena like geological processes and formation of stars  cannot be reproduced in a relatively limited space  and time

It is very far from clear to me.

You are just not understanding what you are being told, perhaps that is why you have not responded to my previous post.

 

Let us take a much simpler example of chemical kinetics that we can calculate.

The chemical reaction between two of the commonest molecules in the universe.

Consider a cluster of hydrogen gas.

We can calculate the minimum size required for this to ignite as a fusion reaction, forming a star, or the for the time we would have to wait to expect such an ignition to happen.

But we do not have the necessary information to do this the the many times more complicated series of reaction that are necessary for life to occur.

[swansont]

22 hours ago, Khanzhoren said:

May be you don't understand what I mean by direct observation Or perhaps I expressed myself poorly. Anyway I mean by it " an experimental observation of the transition of a non-living system to a living system in a laboratory or something like that ". Otherwise, as far as I know, modern physics also has an experimental aspect of this kind.

Meaning you want to see it in real-time, which is also an unreasonable request. There  are areas of science that have elements which rely on historical observation (e.g. astronomy, geology) rather than experiments in a lab. We know* abiogenesis happened. We know* the solar system formed, and each of the planets.

*have evidence, combined with the best science we can apply

21 hours ago, Khanzhoren said:

It is clear that some large scale phenomena like geological processes and formation of stars  cannot be reproduced in a relatively limited space  and time and they are still occuring so there are some other ways to observe/study them more or less directly. Regarding the origin of life, it is unique in the sense that it is a key step in evolution around which there are still many important unresolved questions. I naturally wonder about a possible reproducibility in the laboratory or not; I think it's an obvious question to ask.   

So the fact that we can observe various processes that are elements of geology or star formation, that’s fine, but observing biological elements is not? (see e.g. the Urey-Miller experiment, which formed amino acids from simpler compounds)

 

22 hours ago, Khanzhoren said:

As a reminder, I asked this question because another person previously mentioned a long duration to conclude that direct observation (possibly in laboratory) would probably not be possible due to this . Then you spoke about duration in relation to chemical kinetics when i asked why He/she said that.

If a critical reaction has a low probability, you might need time to compensate for having a limited population of reactants.

(p-p fusion in the sun, as an analogy, takes on average about a billion years. But that’s overcome by having many orders of magnitude more than Avogadros number of protons.)

Since we only know that it happened but not the specific pathway, we don’t know what that potential bottleneck might be 

[Ken Fabian]

12 hours ago, Khanzhoren said:

I understand your explanations very well and they are not really new things for me. But let's say typically, has anyone ever given a realistic quantitative estimate of the duration of the chemical process that could correspond to abiogenesis?

Not quite that, but I did try to get some perspective on how many opportunities there might be for chance chemistry (within a mixture of lifeless "organic" chemicals that includes many essential biochemical components, pre-made) to come up with life.

1.3 billion cubic kilometres of liquid water (on Earth ie one planet)
= 1,300,000,000,000,000,000,000,000 ml
About 1,000,000 bacteria per ml live in sea water, so if the chemical precursors for those are present in primordial sea water we get enough to make...
= 1,300,000,000,000,000,000,000,000,000,000 bacteria's worth.
Give it 500 million years of chemical reactions that happen at much faster than 1 per second per ml rates
I'll be very conservative and say only 1 reaction per second... (actually thousands to millions?)
= 15,750,000,000,000,000 seconds x 1,300,000,000,000,000,000,000,000,000,000 bacteria's worth
= 20,475,000,000,000,000,000,000,000,000,000,000,000,000,000,000 opportunities for random chemistry + selection make the appropriate complex chemistry for earliest ‘simple’ life.

Now this isn't intended to be definitive by any means - add a few zeros for faster than 1 reaction per ml per second or subtract a few zeros for not everywhere having the conditions if that makes you happier.

It doesn't require randomly making a bacteria, which is a highly evolved life-form, just much simpler precursors. It is just an attempt to see how "very unlikely" fits with extremely large numbers of opportunities for "unlikely" to happen. 

To me 20,475,000,000,000,000,000,000,000,000,000,000,000,000,000,000 opportunities looks so likely as to be effectively inevitable.

Edited Tuesday at 02:47 AM by Ken Fabian

[studiot]

5 hours ago, Ken Fabian said:

Now this isn't intended to be definitive by any means - add a few zeros for faster than 1 reaction per ml per second or subtract a few zeros for not everywhere having the conditions if that makes you happier.

Ken you also need to consider temperature.

At the temp of space (say 3^o) or at the more comfortable temperature of an Earthlike planet (say 300^o) or at the temperature of a hydrothermal vent (400^o to 450^o).

The Arrhenius equation is very relevant here.

[dimreepr]

4 minutes ago, studiot said:

Ken you also need to consider temperature.

At the temp of space (say 3^o) or at the more comfortable temperature of an Earthlike planet (say 300^o) or at the temperature of a hydrothermal vent (400^o to 450^o).

The Arrhenius equation is very relevant here.

Why, what temperature prevents?

[swansont]

1 hour ago, dimreepr said:

Why, what temperature prevents?

It’s a matter of rate, not prevention. k = Ae^(-Ea/RT)

Low temperatures inhibit overcoming the activation energy

Also if the molecule tended to dissociate owing to a high temperature, it wouldn’t be around very long.

[Ken Fabian]

 @studiot Just my crude attempt to give "unlikely" some perspective. Planets are very large. Hundreds of millions of years are a very long time. Chemical compounds are very small and there are vast quantities of them.

In practice I fully expect there were large volumes with not much (but not zero) relevant chemistry is happening, literally cold - and yet those still got lightning (that Miller-Urey tries to simulate). Those "coldspots" could be important, as well as "hotspots" as places where more complex or vigorous chemical reactions occur - I seem to recall something about abiogenesis and water turning to ice and in the process concentrating the chemicals that were within it; being subjected to freezing/melting might conceivably play a part.

And what flows from the hotspots into the large oceans may be subjected to different conditions that are themselves critical. The big oceans may be crucial simply for carrying and dispersing partway precursors from tropics to icy polar regions and past other hotspots.

We know that some asteroids are rich in many of biochemistry's building blocks (Bennu samples have a lot). In shallow water a meteor impact zone would be especially rich in them. Such meteors can have and almost certainly will have impacted around hydrothermal vent systems - making an even hotter hotspot. Not everywhere is the same - geological processes concentrate as well as erodes and dissipates minerals.

My point is that with such a large and chemically varied planet the odds of conditions within so much water turning out to be just right are not small, even if the places critical chemistry occurs may be - will be - smaller than the whole.

 

Edited Tuesday at 09:38 PM by Ken Fabian

[studiot]

Just now, Ken Fabian said:

My point is that with such a large and chemically varied planet the odds of conditions within so much water turning out to be just right are not small, even if the places critical chemistry occurs may be - will be - smaller than the whole.

Ken I am not getting at you, indeed some of my comments were directed at this statement from CharonY

23 hours ago, CharonY said:

On the other hand, it is possible that those are not related to life on Earth or that they had to come in via asteroids or other mechanisms and meet other conditions that were present on Earth.

 

I call your and everyone elses' attention to the following paper, desccribed by Prof Benton as

"One of the msot daring papers ever published .... yet one of the msot influential papers of the 20th century"

Extra Terrestrial Cause for the Cretaceous - Tertiary Extinction.

Nature  6th June 1980

Alvarez , Alvarez, Asaro and Michel.

It introduced the famous iridium spike and a formula for the geological effects of meteorite impact.

 

My point is that we just do not have enough information to calculate probabilities so readily.

Which is why I offered something we can calculate and swansont kindly amplified.

 

As regards meteor impact there exist very serious barriers to the idea that these relatively delicate 'precursors' arrived by meteorite.

Do you have a recipe book by the way ?

Meteorites are known to have enough energy to melt and even boil rocks, by the impact,  so what would impact do to precursors ?

 

[CharonY]

This is not my field, but there are a various studies looking at OC at extremes and how they might (or might not) contribute to creating potential precursor. A study discussing specifically at heating (as in atmospheric entry) is found below. The relevant part is that organic matter is not lost entirely (as in fully combusted) but sees some re-ordering of the organic components.

https://doi.org/10.1016/j.epsl.2020.116266

 

 

[studiot]

One point I keep making that only swansont seems to appreciate concerns 'precursors'.

Most replies seem to assume there is only one 'precursor', which is of course, impossible for building more complex molecules.

But not only do we need at least two precursors and reactions,  all the evidence suggests that we need a whole chain of them.

The important point is that we do not know the length or composition of that chain.

These fact pose immense difficulties in estimating overall probabilities and Ken's efforts are far too simplistic.

For instance the reaction that produces precursor A may occur in one galaxy and the reaction that produces precursor B may occur in another or at a time beyond the lifetime of the A molecule. And the new AB molecule must have a lifetime long enough to participate in the next reaction for the next stage.

The treatment of the volume over which the concentration is calculated is important.

So selecting nice concentrations and reactions rates is unviable.

 

If I were asked to suggest a calculation scheme I would suggest assigning partial probabilities to each stage of a probability tree and considering the consequences of 1, 2, 3, 4 ....n  stages.

This approach is taken in engineering Limit State Analysis and Design and that is complicated enough; the reaction pathway to life almost certainly has many more stages.

 

[TheVat]

There's some pretty interesting theorizing out there, on how early anaerobic metabolism could get started.  Iron-sulfur world is one example.  (this is another one depending on hydrothermal vents, of which I'm a fan)  Looks at how complexity can become self-accelerating, which could be a key development.

https://en.wikipedia.org/wiki/Iron–sulfur_world_hypothesis

 

The carbon fixation metabolism became autocatalytic by forming a metabolic cycle in the form of a primitive sulfur-dependent version of the reductive citric acid cycle. Accelerated catalysts expanded the metabolism and new metabolic products further accelerated the catalysts. The idea is that once such a primitive autocatalytic metabolism was established, its intrinsically synthetic chemistry began to produce ever more complex organic compounds, ever more complex pathways and ever more complex catalytic centers....