5 ms·

I'm not sure this addresses the right problem. You could mix every amino acid, every nucleoside, all known sugars, a bunch of phosphate and any metal salts you

by aazaa 6y ago

I'm not sure this addresses the right problem. You could mix every amino acid, every nucleoside, all known sugars, a bunch of phosphate and any metal salts you'd like in a giant flask, stir for a long time and end up with nothing even close to a self-replicating system at the end of it all. An origin of life requires an organizational leap that's quite nebulous at this point. Somewhere between building blocks and membranes is the place to be looking for chemical systems that start to show signs of self-propagation.

sgillen 6y ago
Not convinced there is one “right place to look” at this point. There is still so much we don’t know, one experiment won’t answer these questions. Also it seems some of the reactions created in this study do “self replicate” in some sense. In the sense that some of the chemical reaction cycles they found self reinforce and create more of the original molecule.
- mensetmanusman 6y ago
  Yes, the interesting thing is that as humans we know: 1) There are things too complex to understand without brute computation 2) Complexity is unbounded 3) Our current method of calculation would require all the energy in the known universe to even calculate a human being’s wave function...
tachyonbeam 6y ago
It's important to remember that our planet had ocean-sized flasks and hundreds of millions of years to evolve life. The organizational leaps required could involve extremely low-probability events that are nearly impossible to replicate in a lab. However, these events only needed to happen once.
- pfdietz 6y ago
  However, the complexity gap is exponential in the size of the molecules. Viewed in that light, the difference between an ocean and an eyedropper is inconsequential.
- jdashg 6y ago
  Don't forget: It's size of oceans times age of life times the untold number of worlds where life's had a chance to form but just didn't get lucky! It's a galactic survivorship bias where only the luckiest of planets evolve to ask "why us?"
  - tachyonbeam 6y ago
    With the caveat that variance is infinite when N=1, life seems to have come about fairly early after our planet became survivable. That suggests that if the right conditions are present, life might not be so unlikely.
adrian_b 6y ago
Of course, by mixing any substances you will never obtain anything, because eventually the system will reach some equilibrium state. What is needed is a continuous flux of energy and precursor substances, like a source of volcanic gases, or, more likely, an alkaline hydrothermal vent. Only under the action of such a continuous flux, complex systems may emerge. The simplest example is the appearance of oscillations when you attach a source of energy to various simple arrangement of devices. For the appearance of life, besides the continuous flux of energy and simple molecules, catalysts were required, which must have been metallic sulfides, mainly of Fe, Co and Ni. If we would reproduce such a setup now, a large variety of organic compounds would be synthesized. A similar process can be used to obtain synthetic gasoline. Nevertheless, for the unlikely event of creating a self-replicating system, a very long time will be needed and also the chance of the right combination of metallic sulfide catalysts being located in close proximity and the chance of favorable proportions of the precursors in the flux of gases. For now, we do not know enough to be able to estimate how likely or unlikely was the appearance of life, but we know that it was possible (I mean we know that this is possible from chemistry, independently of the fact that we know that we exist). Such an estimation would become possible only after someone will succeed to design a self-replicating system similar with the first life forms. The first life forms probably not only did not have nucleic acids but also did not use yet phosphate in any way and they were not cellular but they were attached on the surface of minerals. At some point, but probably later than achieving replication, they might have had the form of membranes closing pores of minerals in hydrothermal vents, before the membranes became able to close, forming cells with an interior separated from the exterior. Closed cells could appear only after having a more complex metabolism and various kinds of ionic pumps, while the earlier membranes closing mineral pores could passively exploit the ionic fluxes of the hydrothermal vents.

by aazaa 6y ago

sgillen 6y ago

Not convinced there is one “right place to look” at this point. There is still so much we don’t know, one experiment won’t answer these questions. Also it seems some of the reactions created in this study do “self replicate” in some sense. In the sense that some of the chemical reaction cycles they found self reinforce and create more of the original molecule.

mensetmanusman 6y ago
Yes, the interesting thing is that as humans we know: 1) There are things too complex to understand without brute computation 2) Complexity is unbounded 3) Our current method of calculation would require all the energy in the known universe to even calculate a human being’s wave function...

tachyonbeam 6y ago

It's important to remember that our planet had ocean-sized flasks and hundreds of millions of years to evolve life. The organizational leaps required could involve extremely low-probability events that are nearly impossible to replicate in a lab. However, these events only needed to happen once.

pfdietz 6y ago
However, the complexity gap is exponential in the size of the molecules. Viewed in that light, the difference between an ocean and an eyedropper is inconsequential.
jdashg 6y ago
Don't forget: It's size of oceans times age of life times the untold number of worlds where life's had a chance to form but just didn't get lucky! It's a galactic survivorship bias where only the luckiest of planets evolve to ask "why us?"
- tachyonbeam 6y ago
  With the caveat that variance is infinite when N=1, life seems to have come about fairly early after our planet became survivable. That suggests that if the right conditions are present, life might not be so unlikely.

adrian_b 6y ago

Of course, by mixing any substances you will never obtain anything, because eventually the system will reach some equilibrium state. What is needed is a continuous flux of energy and precursor substances, like a source of volcanic gases, or, more likely, an alkaline hydrothermal vent. Only under the action of such a continuous flux, complex systems may emerge. The simplest example is the appearance of oscillations when you attach a source of energy to various simple arrangement of devices. For the appearance of life, besides the continuous flux of energy and simple molecules, catalysts were required, which must have been metallic sulfides, mainly of Fe, Co and Ni. If we would reproduce such a setup now, a large variety of organic compounds would be synthesized. A similar process can be used to obtain synthetic gasoline. Nevertheless, for the unlikely event of creating a self-replicating system, a very long time will be needed and also the chance of the right combination of metallic sulfide catalysts being located in close proximity and the chance of favorable proportions of the precursors in the flux of gases. For now, we do not know enough to be able to estimate how likely or unlikely was the appearance of life, but we know that it was possible (I mean we know that this is possible from chemistry, independently of the fact that we know that we exist). Such an estimation would become possible only after someone will succeed to design a self-replicating system similar with the first life forms. The first life forms probably not only did not have nucleic acids but also did not use yet phosphate in any way and they were not cellular but they were attached on the surface of minerals. At some point, but probably later than achieving replication, they might have had the form of membranes closing pores of minerals in hydrothermal vents, before the membranes became able to close, forming cells with an interior separated from the exterior. Closed cells could appear only after having a more complex metabolism and various kinds of ionic pumps, while the earlier membranes closing mineral pores could passively exploit the ionic fluxes of the hydrothermal vents.