RE: FACT CANNON #5: The Origin of Life on Earth – Panspermia and Cosmic Ancestry
While interesting, some of their statements are no longer true. Enzymes seem to be fairly likely from an evolutionary sense, even Nucleic acids fold into catalytic shapes.
I also disagree with statements like "life started instantaneously after the earth became suitable" thats misleading, of course it did. The components could have been combining for millions of years correctly but with no success prior to environmental suitability to support life.
Evidence point number two is contradicted by mechanism point seven. If the mechanism involved a way to spread the new biological material off of earth then that same mechanism explains biological material in the stratosphere. It also indicates that bacterial presence there is consistent with no panspermia.
As scientists we all know of this theory, it hasn't been buried or lost, it's just not as likely as other explanations. However we really don't know yet one way or the other.
Good post.
Thanks for the comment, really good to know someone’s read the post!
In this post I’m really just trying to relay H&W’s arguments from the 1981 book, so it’s unsurprising if some of it is out of date. In fact since writing this article I’ve done a lot of independent research (on the net, but trying very hard to wade through all the crap!), and I’m also about half way through Wickramasinghe’s ‘The Search For Our Cosmic Ancestry’. There is now a great deal more evidence supporting the cometary panspermia theory, even if some of the material presented in this post may be out of date. The hypothesis itself has also evolved a little in light of new evidence as would be expected of any theory of it’s age.
I’ll try to address your points though:
Personally I’m in no position to argue one way or another the likelihood of the spontaneous (though evolutionary) generation of enzymes, although I’ve seen no evidence on the net (that I’ve understood!) that suggests that this is now thought to be more likely. I’d appreciate any relatively straightforward sources you could recommend to help my understanding here!
‘Life started instantaneously after the Earth became suitable’. You may be disagreeing with my phrasing rather than the book's explanation here. I think Hoyle’s fundamental point was that if abiogenesis is such a difficult and unlikely event, why would it have happened ‘as soon as’ a suitable environment existed? (And if this is the case wouldn’t it happen all over the universe anyway? This one is my point, not Hoyle’s).
Evidence point no 2 contradicted by mechanism point 7. Yes I can see that - although again, I suspect that this is more a fault on the part of my attempted explanation rather than the theory itself. CW does address this point in his latest book very thoroughly, but yes, I concede your point as I’ve written it. Although other types of evidence can be highly suggestive, the clincher for panspermia is always going to be the confirmed discovery of biological or genetic material either in a meteorite or on an extraterrestrial body (or perhaps something more perplexing to do with the nature of the genetic code itself… but that’s for another post).
I’d challenge your point on it being less likely than other explanations though. Which explanations? I assume you’re referring to terrestrial abiogenesis? If so I think we could be in a position to have unequivocally proved panspermia one way or another within the next 30 years or so, but I don’t think we can say the same for terrestrial abiogenesis (unless things have moved radically from my understanding?). My feeling though is that study of panspermia does not seem to attract the funding or attention that it should - it is certainly no longer a fringe topic.
Given your scientific background I’d strongly suggest a read of ‘The Search For Our Cosmic Ancestry’, as said earlier there’s been a huge amount of new evidence since 1981 which is set out in the book, and I think it will address some of your concerns better than I have here.
Once again, really do appreciate your response - haven’t posted for a while and I did wonder whether anyone was still reading or whether my main audience is Bots these days!
So I will respond to some of this:
A while back some experiments were done showing that precursor biomolecules were able to be spontaneously generated from an environment similar to one found in the early earth. So there is some president that spontaneous generation of the early building blocks of life are possible. These molecules do seem to want to spontaneously assemble. However the conditions in the early earth were not conducive to the formation of the more complex molecules (IE long RNA chains... etc.) but that doesn't mean that these sorts of molecules weren't self assembling and falling apart over and over again until one day when the environment became more suitable for their stability. At this point these sort of moleucles would have seemed to appear almost overnight, all at once. Conditions occurred that provided stability to processes that were already occurring but not able to fully form to complete and stable states. This plausibly justifies why life quickly happened as soon as a suitable environment existed.
I don't think that confirms much of anything. It seems to be fairly obvious that the molecules responsible for life here on earth are energetically favorable to form. It wouldn't surprise me if these sorts of molecules were able to form in other places in space as well. I am not saying I don't think panspermia happened, I am just saying I don't know that the observation you are looking for would conclusively prove it.
I wrote a short post about the "RNA World Hypothesis." About how life could have evolved out of early simple organisms that were actually just catalytic RNA molecules. This is another fun theory about how life may have begun, and their is some precident that an RNA world may not be entirely a throwaway concept (I mean consider that the complex responsible for protein synthesis, the Ribosome, is largely a catalytic RNA complex, with a bunch of structural proteins).
At the end of the day it is going to be interesting to see as more evidence comes in regarding the early stages of life on Earth. Perhaps we really were seeded by advanced alien life, or perhaps we were seeded by random chance, or perhaps life on earth is the first life in the universe, or perhaps there is life all over the place and it is independently existing due to the properties of the elements that result in the biomolecules that create life. I do not know the answer to any of this, however it is fun to think about.
Thanks for the response. I’ve read your article on RNA World - well written and very helpful, cheers!
From your response it seems to me that you favour the view that self starting evolution is a natural process, and therefore almost inevitable across the universe? I’m not sure of the actual probability of that vs panspermia distribution, but I wouldn’t necessarily argue with it. What I personally find extremely difficult to believe is that abiogenesis could have occurred solely on Earth. That takes a leap of faith almost as great as belief in a religious creation myth. So I think we are both coming from the angle that life is very very likely to be a widespread phenomenon across the universe? That for me is the exciting prospect behind this.
Of course, both RNA World and panspermia could be accurate, there is nothing mutually exclusive between the two, panspermia would just give the other process an early boost, and then contribute to a universal gene pool to accelerate things even further.
As you say, there are a range of possible explanations - and I’m also very much looking forward to see how evidence unfolds. I’m hopeful we’ll see at least a provisional answer within our life times.
We're I to subscribe to a theory I would subscribe to one where the building blocks for life were self assembling yes. I would also suspect that to happen everywhere the necessary elements were present, and by that logic would include large amounts of the known universe. But that is more of a belief then based in actual scientific reality. :)
This has been a nice conversation, thanks for taking the time to chat and share your views!