There has recently been some speculation that life started on Mars, and then got blasted to earth by an asteroid or something. Molybdenum is very important to life (eukaryote evolution was delayed by 2 billion years because it was unavailable), and the origin of life is easier to explain if Molybdenum is available. The problem is that Molybdenum wasn’t available in the right time frame on Earth, but it was on Mars.
Anyway, assuming this speculation is true, Mars had the best conditions for starting life, but Earth had the best conditions for life existing, and it is unlikely conscious life would have evolved without either of these planets being the way they are. Thus, this could be another part of the Great Filter.
Side note: I find it amusing that Molybdenum is very important in the origin/evolution of life, and is also element 42.
As someone pointed out to me when mentioning this to them, to be a candidate for Great Filter there would need to be something intrinsic about how planets are formed that cause these two types of environments to be mutually exclusive, else it seems like there isn’t sufficient reduction in probability of their availability. Is this actually the case? Perhaps user:CellBioGuy can elucidate.
Well it took a while for that summoning to actually take effect.
The point I was making that that is not necessarily a strong contender (as in many orders of magnitude) because of two things. One, all stars slowly increase in brightness as they age after settling down into their main sequence phase and their habitable zones thus sweep through the inner system over time (though this effect is much stronger for larger stars because they age and change faster). Secondly, its probable that most young smaller planets tend to have much more in the way of atmospheres than later in their lives just due to the fact that they are more geologically active then and haven’t had time for the light molecules to be blasted away. And if terrestrial planets follow any sort of a power rule in their distribution of masses, there should be multiple Mars-size planets for every Earth sized planet.
At this point I would say that any speculation on the exact place and time of the origin of life is premature, that there’s nothing to suggest that it didn’t happen on Earth, but that there is little to suggest that it couldn’t have happened elsewhere within our own solar system either even if we have little reason to think it had to (besides adding the necessity that it later moved to the very clement surface of the Earth, the only place in the solar system that can support a big high-bimoass biosphere like ours).
I honestly don’t know much about the proposed molybdenum connection. Some cursory looking about the internet suggests that molybdenum is necessary for efficient fixation of nitrogen from the air into organic molecules by nitrogenase, the enzyme that does most of that biological activity on Earth. I would be surprised though if that were the only way it could go, rather than just the way it went here...
EDIT: upon further looking around, I am worried that the proposed molybdenum connection could be correlation rather than causation. Most sources claiming that the presence of lots of soluble molybdenum is a prerequesite for a big complicated biosphere seem to be looking for a reason for this to be the case and not talking much about the simpler possibility that that is simply correlated with the time at which the deeper water not immediately touching the atmosphere moved from a reducing environment to an oxidizing environment in which the soluble forms are more stable...
EDIT 2: By the way, seriously, do not listen to the stuff in the ‘journal’ of cosmology that Robin Hanson periodically uncritically posts about panspermia between star systems and early-universe biogenesis and diatoms in meteors. It’s complete bullshit.
There has recently been some speculation that life started on Mars, and then got blasted to earth by an asteroid or something. Molybdenum is very important to life (eukaryote evolution was delayed by 2 billion years because it was unavailable), and the origin of life is easier to explain if Molybdenum is available. The problem is that Molybdenum wasn’t available in the right time frame on Earth, but it was on Mars.
Anyway, assuming this speculation is true, Mars had the best conditions for starting life, but Earth had the best conditions for life existing, and it is unlikely conscious life would have evolved without either of these planets being the way they are. Thus, this could be another part of the Great Filter.
Side note: I find it amusing that Molybdenum is very important in the origin/evolution of life, and is also element 42.
As someone pointed out to me when mentioning this to them, to be a candidate for Great Filter there would need to be something intrinsic about how planets are formed that cause these two types of environments to be mutually exclusive, else it seems like there isn’t sufficient reduction in probability of their availability. Is this actually the case? Perhaps user:CellBioGuy can elucidate.
Well it took a while for that summoning to actually take effect.
The point I was making that that is not necessarily a strong contender (as in many orders of magnitude) because of two things. One, all stars slowly increase in brightness as they age after settling down into their main sequence phase and their habitable zones thus sweep through the inner system over time (though this effect is much stronger for larger stars because they age and change faster). Secondly, its probable that most young smaller planets tend to have much more in the way of atmospheres than later in their lives just due to the fact that they are more geologically active then and haven’t had time for the light molecules to be blasted away. And if terrestrial planets follow any sort of a power rule in their distribution of masses, there should be multiple Mars-size planets for every Earth sized planet.
At this point I would say that any speculation on the exact place and time of the origin of life is premature, that there’s nothing to suggest that it didn’t happen on Earth, but that there is little to suggest that it couldn’t have happened elsewhere within our own solar system either even if we have little reason to think it had to (besides adding the necessity that it later moved to the very clement surface of the Earth, the only place in the solar system that can support a big high-bimoass biosphere like ours).
I honestly don’t know much about the proposed molybdenum connection. Some cursory looking about the internet suggests that molybdenum is necessary for efficient fixation of nitrogen from the air into organic molecules by nitrogenase, the enzyme that does most of that biological activity on Earth. I would be surprised though if that were the only way it could go, rather than just the way it went here...
EDIT: upon further looking around, I am worried that the proposed molybdenum connection could be correlation rather than causation. Most sources claiming that the presence of lots of soluble molybdenum is a prerequesite for a big complicated biosphere seem to be looking for a reason for this to be the case and not talking much about the simpler possibility that that is simply correlated with the time at which the deeper water not immediately touching the atmosphere moved from a reducing environment to an oxidizing environment in which the soluble forms are more stable...
EDIT 2: By the way, seriously, do not listen to the stuff in the ‘journal’ of cosmology that Robin Hanson periodically uncritically posts about panspermia between star systems and early-universe biogenesis and diatoms in meteors. It’s complete bullshit.
(Are you Adele Lack Cotard?)
Like in Synecdoche, New York? No… it is an abbreviation of my real name.