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I think life (event from chemistry to biochemistry) is rare because we can think of each planet as a specific combination of chemistry composition. All these co

I think life (event from chemistry to biochemistry) is rare because we can think of each planet as a specific combination of chemistry composition. All these combinations, even if they exist in the order of billions, is still a limited amount of possible combinations of chemical properties. In a lab we can reproduce these combinations in ideally a much greater number. So my insight is that we can create chemical processes in a lab at a much higher rate and with much more interesting combinations that nature can. And still life hasn't arose in the lab. This seems to me like a sensible experiment that can somewhat prove that if we can't do it in the lab, where we're free to combine whatever we want, then why should it be "easy" for nature with its limited amount of combinations.

vikramkr 7y ago
Because nature has way more time and space than we do. And life hasn't arisen in the lab (on earth by humans at least) yet, but it's certainly arisen in nature at least once, so those factors seem to clearly outweigh our ability to experiment
- agumonkey 7y ago
  But Nature doesn't optimize for life. It had billions of years and insane amount of space to do whatever. We ~may be able to focus search on life sustaining chemical combinations ?
  - vikramkr 7y ago
    Nature does optimize for life because by definition the result of any optimization is life. Natural selection is a powerful force. And with time, nature optimizes for chemical reactions that self replicate without the biases and weaknesses of human science. We aren't patient enough to wait as long as nature is willing to and we are biased because we keep trying to replicate life like ours. Nature also had panspermia and other techniques to spread life around once it gets going, it only needs to figure it out like once per galaxy under some sets of assumptions
    - agumonkey 7y ago
      Yeah but optimization is not linear, earth gave way to a path to lifeforms, other places not so much, they end up lifeless local maxima. Saying space and time can't be a simple factor to dismiss local human research.
gus_massa 7y ago
> each planet as a specific combination of chemistry composition But with any combination you try in the laboratory you get a very similar brown goo with a similar chemical composition. There are few atoms that are common and like to stick together to form molecules, so you get mostly some molecules with C, O, N, S, P, and H. Carbon atoms are happy to form long molecules. If you add a lot of Nitrogen atoms in a molecule, it is usually a good explosive and will react spontaneously (at low concentrations it only self destruct, it is difficult to get high concentrations and get an explosion). If you add a lot of Oxygen atoms two of them may decide to pick a Carbon atom and go away, something like molecule --> CO2 + smaller molecule So after a while you get brown goo a mix of molecules with more Carbons and a few of the other atoms. If you start with different mixes and different energy sources, you get a similar composition. There is some mix of molecules that are the result of random chemistry. In this mix you get the building blocks of a lot of important current biological molecules, IIRC you get all the building blocks of RNA. RNA is a weird kind of molecule because they can induce reactions in other molecules and they can sorta self replicate like DNA. So one of the hypothesis is that the first life like thing has/was a bunch of RNA. Life on Earth needed like 1 billon year to appear https://en.wikipedia.org/wiki/Life#Origin https://en.wikipedia.org/wiki/Life#Origin . So for an undirected a experiment you need 1E9 years x 5E14 m^2, instead of a graduate student that has only 4 years x 1m^2 x 1m if s/he is running the experiment in a giant reactor instead of a beaker. That is a difference of more than 23 magnitudes orders. For a directed experiment, nobody really knows. Perhaps the firs step is to get a lucky RNA of length 20 and you must try the 4^20 combinations until you get a crappy first version of a self reproductive RNA, that is not very good and only can make a good copy per year. Can you call it alive? Is this really the first step? Perhaps its length is 40, that needs exponential more combinations. The initial RNA had probably more than 4 bases, so the search space is even bigger and more difficult to estimate. Perhaps the first step is to create small soap-like balls and put them near something like a thermal vent that release H2? Perhaps the first "life" form use some sulfur compound to get energy? Nobody is sure.

vikramkr 7y ago

Because nature has way more time and space than we do. And life hasn't arisen in the lab (on earth by humans at least) yet, but it's certainly arisen in nature at least once, so those factors seem to clearly outweigh our ability to experiment

agumonkey 7y ago
But Nature doesn't optimize for life. It had billions of years and insane amount of space to do whatever. We ~may be able to focus search on life sustaining chemical combinations ?
- vikramkr 7y ago
  Nature does optimize for life because by definition the result of any optimization is life. Natural selection is a powerful force. And with time, nature optimizes for chemical reactions that self replicate without the biases and weaknesses of human science. We aren't patient enough to wait as long as nature is willing to and we are biased because we keep trying to replicate life like ours. Nature also had panspermia and other techniques to spread life around once it gets going, it only needs to figure it out like once per galaxy under some sets of assumptions
  - agumonkey 7y ago
    Yeah but optimization is not linear, earth gave way to a path to lifeforms, other places not so much, they end up lifeless local maxima. Saying space and time can't be a simple factor to dismiss local human research.

gus_massa 7y ago

> each planet as a specific combination of chemistry composition But with any combination you try in the laboratory you get a very similar brown goo with a similar chemical composition. There are few atoms that are common and like to stick together to form molecules, so you get mostly some molecules with C, O, N, S, P, and H. Carbon atoms are happy to form long molecules. If you add a lot of Nitrogen atoms in a molecule, it is usually a good explosive and will react spontaneously (at low concentrations it only self destruct, it is difficult to get high concentrations and get an explosion). If you add a lot of Oxygen atoms two of them may decide to pick a Carbon atom and go away, something like molecule --> CO2 + smaller molecule So after a while you get brown goo a mix of molecules with more Carbons and a few of the other atoms. If you start with different mixes and different energy sources, you get a similar composition. There is some mix of molecules that are the result of random chemistry. In this mix you get the building blocks of a lot of important current biological molecules, IIRC you get all the building blocks of RNA. RNA is a weird kind of molecule because they can induce reactions in other molecules and they can sorta self replicate like DNA. So one of the hypothesis is that the first life like thing has/was a bunch of RNA. Life on Earth needed like 1 billon year to appear https://en.wikipedia.org/wiki/Life#Origin https://en.wikipedia.org/wiki/Life#Origin . So for an undirected a experiment you need 1E9 years x 5E14 m^2, instead of a graduate student that has only 4 years x 1m^2 x 1m if s/he is running the experiment in a giant reactor instead of a beaker. That is a difference of more than 23 magnitudes orders. For a directed experiment, nobody really knows. Perhaps the firs step is to get a lucky RNA of length 20 and you must try the 4^20 combinations until you get a crappy first version of a self reproductive RNA, that is not very good and only can make a good copy per year. Can you call it alive? Is this really the first step? Perhaps its length is 40, that needs exponential more combinations. The initial RNA had probably more than 4 bases, so the search space is even bigger and more difficult to estimate. Perhaps the first step is to create small soap-like balls and put them near something like a thermal vent that release H2? Perhaps the first "life" form use some sulfur compound to get energy? Nobody is sure.