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Because naturally-occurring amino acids are nothing new. You can make them yourself by sticking some chemicals together and applying energy to the mixture [0].

Because naturally-occurring amino acids are nothing new. You can make them yourself by sticking some chemicals together and applying energy to the mixture [0]. "Building blocks of life" is a phrase with no strong definition. Science journalists like to apply it to anything from water to DNA chains, though those are very different molecules in terms of complexity. 0: https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment

pfdietz 4y ago
Especially when the life-relevant amino acids are mixed with all sorts of irrelevant amino acids, with the concentration of any particular species of molecule declining exponentially with the number of atoms it contains. This is supposed to be exciting?
- MattPalmer1086 4y ago
  It is uncertain where the amino acids on earth came from. A leading theory is that asteroids and comets seeded the early earth with a good mix of them. So it is a data point supporting the idea that they could have been a source of these molecules. You may or may not find that exciting.
  - pfdietz 4y ago
    I just find it an indication that formation of amino acids is not that important as a bottleneck for the origin of life. It's also not that surprising, as you'd expect life to use monomers that are fairly stable (and therefore could be formed by random processes, because of that stability.)
jerf 4y ago
It's important to understand what amino acids are, if you want to know why this is more "interesting, but only somewhat so, science" than "groundbreaking news that changes our view of life in the universe": https://en.wikipedia.org/wiki/Amino_acid#General_structure https://en.wikipedia.org/wiki/Amino_acid#General_structure Those may seem complicated, but you have to also remember an "amino acid" is the entire family, and carbon tends towards "a bit complicated" naturally because it has so many bonds it needs to fill in. Fill an environment with carbon and the right other elements and it isn't "surprising" that amino acids form, it's inevitable. Like, literally unavoidable, you couldn't stop it if you tried. "The right environment for amino acids" would also be full of many other larger structures. It's a thing carbon does no matter where it is, not an exception. They would just be, if you'll pardon the convenient anthropomorphization, pointlessly larger structures, not doing anything in particular or having any particularly interesting properties beyond size. You get similarly large carbon structures in the soot of a fire, for instance. Compare with hemoglobin, just to pick a popular protein of moderate size: https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme This is a specific combination of 574 amino acids, in the correct chirality. Some deviations are possible that will retain functionality, it isn't that exact 574 amino acids, but there's limited variation possible. "Things useful for life" are much more than just bare amino acids. This isn't something that should be downplayed; it is legitimately interesting, but at the same time, it doesn't materially move our probabilities on any particular theory of life because it was always predictable that amino acids would exist elsewhere in the universe. At a bare minimum for excitement would be demonstrating some sort of significant chirality preference. That would turn some heads.

pfdietz 4y ago

Especially when the life-relevant amino acids are mixed with all sorts of irrelevant amino acids, with the concentration of any particular species of molecule declining exponentially with the number of atoms it contains. This is supposed to be exciting?

MattPalmer1086 4y ago
It is uncertain where the amino acids on earth came from. A leading theory is that asteroids and comets seeded the early earth with a good mix of them. So it is a data point supporting the idea that they could have been a source of these molecules. You may or may not find that exciting.
- pfdietz 4y ago
  I just find it an indication that formation of amino acids is not that important as a bottleneck for the origin of life. It's also not that surprising, as you'd expect life to use monomers that are fairly stable (and therefore could be formed by random processes, because of that stability.)

jerf 4y ago

It's important to understand what amino acids are, if you want to know why this is more "interesting, but only somewhat so, science" than "groundbreaking news that changes our view of life in the universe": https://en.wikipedia.org/wiki/Amino_acid#General_structure https://en.wikipedia.org/wiki/Amino_acid#General_structure Those may seem complicated, but you have to also remember an "amino acid" is the entire family, and carbon tends towards "a bit complicated" naturally because it has so many bonds it needs to fill in. Fill an environment with carbon and the right other elements and it isn't "surprising" that amino acids form, it's inevitable. Like, literally unavoidable, you couldn't stop it if you tried. "The right environment for amino acids" would also be full of many other larger structures. It's a thing carbon does no matter where it is, not an exception. They would just be, if you'll pardon the convenient anthropomorphization, pointlessly larger structures, not doing anything in particular or having any particularly interesting properties beyond size. You get similarly large carbon structures in the soot of a fire, for instance. Compare with hemoglobin, just to pick a popular protein of moderate size: https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme This is a specific combination of 574 amino acids, in the correct chirality. Some deviations are possible that will retain functionality, it isn't that exact 574 amino acids, but there's limited variation possible. "Things useful for life" are much more than just bare amino acids. This isn't something that should be downplayed; it is legitimately interesting, but at the same time, it doesn't materially move our probabilities on any particular theory of life because it was always predictable that amino acids would exist elsewhere in the universe. At a bare minimum for excitement would be demonstrating some sort of significant chirality preference. That would turn some heads.