Be very careful when looking at probabilities applied to evolution. First of all, a selection pressure of 1% can reach events that improbable (by pure random chance) in less than 10,000 generations. Secondly, the odds of a specific form of life don't matter; what matters is the odds of any form of life. If you look at just about any solution of, say, weather, the odds of exactly that solution occurring are ridiculously low; however, the odds of there being weather is esssentially 1, and the odds of certain types of weather (rain, whatever) is often quite high.
biosphere
- Thread starter Pwyll
- Start date
There is absolutely no evidence whatsoever for any kind of intervention. A scientist does not assume that just because something unlikely happened, there must be someone 'divine intervention' that caused it to happen.[/qb]</font>[/QUOTE]I did not say assume. I said consider. "we are here, therefore everything must have happened naturally" is simply not valid. in light of the odds, can you consider it?
M
Malenfant
Guest
No, I can't. If we are here, it means that whatever processes were required to happen that result in our presence must have occurred.
While that much is known, the reason why they occurred cannot be discerned. A scientist (like myself) would therefore assume - based on everything we know about how the universe works - that the probabilities simply came together, or something with a physical explanation. Someone who does not think scientifically would more likely assume that such 'natural processes' could not have happened without intervention. Again, just because something is unlikely, doesn't mean it can't happen.
Frankly, I think the view that everything is so complex that someone must have designed it that way rather belittles our universe. If one considers that everything in our universe came together naturally over billions of years without such intervention, I think it makes it a much more fascinating and beautiful place.
eiladayn pondered:
"Not quite, but close. You need a carbon filled ocean to create the amino acids, but then to create the polymer strand of the nucleotide, you need dehydration. Then you need the ocean to provide the medium for the solution to allow the replication without enzymes.....Ocean, no ocean, ocean, no ocean....hmmmm."
Sir,
Ever hear of tides? If so, imagine what they may have been like when Luna was much closer to Earth...
Plus, the carbon filled ocean creating amino acids, the dehydration for the polymer strand, and the solution requirement for enzyme replication is simply science's current best guess. It is not the answer and science doesn't claim it to be.
Unlike faith, science freely admits that it just doesn't know. However, science looks very much forward to the wonderous journey towards that knowledge.
Our sample regarding the possibility of life is far too small and our understanding of life's origins is far too murky. It is much better to simply say; "We don't know... yet!"
Sincerely,
Larsen
"Not quite, but close. You need a carbon filled ocean to create the amino acids, but then to create the polymer strand of the nucleotide, you need dehydration. Then you need the ocean to provide the medium for the solution to allow the replication without enzymes.....Ocean, no ocean, ocean, no ocean....hmmmm."
Sir,
Ever hear of tides? If so, imagine what they may have been like when Luna was much closer to Earth...
Plus, the carbon filled ocean creating amino acids, the dehydration for the polymer strand, and the solution requirement for enzyme replication is simply science's current best guess. It is not the answer and science doesn't claim it to be.
Unlike faith, science freely admits that it just doesn't know. However, science looks very much forward to the wonderous journey towards that knowledge.
Our sample regarding the possibility of life is far too small and our understanding of life's origins is far too murky. It is much better to simply say; "We don't know... yet!"
Sincerely,
Larsen
I'm not proposing a "special creation" guys, I'm saying that the odds are so long that we may very well be alone. I said early on that I don't discuss theologies, and I won't, won't even say what my personal beliefs are. I'm saying the odds are we are alone, or at least very isolated from any other life that may exist in the universe. I'm not alone in this view among scientific minds, Enrico Fermi, for one, when he was asked if he thought there were others out there said, "Where are they?", in other words if there are others why haven't we heard from them?
By the way tides don't account for the dehydration needed Mr. Whipsnade, could be clay holding the proper carbon molecules on the bottom of a shallow sea, though (Bernal thought so).
All I'm offering is an alternate view to the one Carl Sagan was such a proponent of, Mr. Sagan thought our galaxy held as many as 10,000 star-spanning civilizations in the 60's ("Cosmos"), didn't pan out though, we should've heard from them by now. Again, unless we're very isolated.
Pappy
By the way tides don't account for the dehydration needed Mr. Whipsnade, could be clay holding the proper carbon molecules on the bottom of a shallow sea, though (Bernal thought so).
All I'm offering is an alternate view to the one Carl Sagan was such a proponent of, Mr. Sagan thought our galaxy held as many as 10,000 star-spanning civilizations in the 60's ("Cosmos"), didn't pan out though, we should've heard from them by now. Again, unless we're very isolated.
Pappy
M
Malenfant
Guest
An obvious way to dehydrate and rehydrate something would be on a beach, between high and low tides. At high tide, molecules are washed further inland than the low tide can reach, so they dehydrate. Then the high tide comes back and rehydrates them.
OK.
What I'm really trying to point out is that there might not be ANY other life out there. It's beginning to look like it might be much rarer than Carl Sagan and his adherents thought in the 60's and 70's. I'm afraid now I have to agree with Fermi, where are they?
I REALLY would give all I own to ride in a starship. I grew up listening to Sagan and company telling me we were on our way. I read H. Beam Piper, Robert Heinlein, Isaac Asmimov and E.E. "Doc" Smith, aliens aabounding, and I'm old enough that the ONLY way I'll ever ride in a starship is if aliens bring me one, but I'm afraid its gonna happen, gosh darn it!
Sagan and his cronies promised me aliens, where are they?......OR am I just a whiney old man?
Pappy
What I'm really trying to point out is that there might not be ANY other life out there. It's beginning to look like it might be much rarer than Carl Sagan and his adherents thought in the 60's and 70's. I'm afraid now I have to agree with Fermi, where are they?
I REALLY would give all I own to ride in a starship. I grew up listening to Sagan and company telling me we were on our way. I read H. Beam Piper, Robert Heinlein, Isaac Asmimov and E.E. "Doc" Smith, aliens aabounding, and I'm old enough that the ONLY way I'll ever ride in a starship is if aliens bring me one, but I'm afraid its gonna happen, gosh darn it!
Sagan and his cronies promised me aliens, where are they?......OR am I just a whiney old man?
Pappy
No, I can't. If we are here, it means that whatever processes were required to happen that result in our presence must have occurred.[/qb]</font>[/QUOTE]so the starting point, the unchallenged dogma, is "no god". then the facts are considered, then the evidence is examined, then the possibilities are evaluated. no wonder there is no evidence of any god - it is defined away.
one wonders how far this goes. someone writes elsewhere in this thread that a scientist is willing to say he doesn't know. this characterization does not seem to be entirely accurate.
number of planets we have significantly explored: 1
number of planets we know to harbor life: 1
that suggests to me that 1 is exactly the odds
[/QB]</font>[/QUOTE]you're not following the thread accurately, but your point is worth addressing.if a priori assumptions are discarded, since the original life formation event did happen, and since the odds of it happening naturally (for the purposes of this discussion) are 1 / 1.7x10^361, then the odds that it happened unnaturally are 1 - ( 1 / 1.7x10^361 ).
The "600 pairs dna chain" argument is way off in left field. Why? DNA isn't life. DNA is the molecular punch-card deck for a complex set of molecular machines that DECODE DNA sequences to make proteins. Amino acids cannot simply attach themselves to a string of DNA to form proteins.
There are coded loops (more of a cross shape actually) that attach to various amino acids and they in turn bind to molecular assemblers (ribosomes) reading the three-base encoded sequences in a chain of RNA which was assembled off of a temporarily unzipped piece of DNA.
There are other molecular assemblies that facilitate the copying, the unzipping and all the other stuff involved. DNA is a long ways down the line from whatever life began as.
Arguing that 600 base pairs of DNA need to self-assemble for life to begin is like arguing that mainframes only happen after punch-cards come into being and sort themselves into a program. By the time you're looking at DNA (and that's another assumption -- surely there are other ways to pass on genetic information) you're looking at a whole complex molecular system.
Look at Just Enough Molecular Biology for Computer Scientists if you need a refresher on the way it all works on Earth. Even in our own cells, cellular DNA/RNA and mitochondral DNA/RNA use different 3-unit codes to assemble proteins. To imagine that life elsewhere uses precisely the same system and the same coding seems ludicrous.
"Life, Origin of", an article in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight discusses some of the possibilities, including proto-cell membranes, self-assembling RNA and ribosomes that have been evolved in vitro in various experiments.
The worst problem with the "600 pairs" approach is that we really do not know haw life evolved in the beginning -- which makes any such statistical wand waving as divorced from reality as the computations of the 19th century scientist who "proved" that anyone travelling faster than 30 MPH would suffocate. Tell that to anyone who rides a motorcycle.
Experiments have demonstrated again and again that generating the basic compounds and structures of life is astonishingly easy in any number of primitive environments. What the next steps are between that and life we don't know, but I'm of the opinion that it's a LOT more common than the pessimistic statiticians imply.
There are coded loops (more of a cross shape actually) that attach to various amino acids and they in turn bind to molecular assemblers (ribosomes) reading the three-base encoded sequences in a chain of RNA which was assembled off of a temporarily unzipped piece of DNA.
There are other molecular assemblies that facilitate the copying, the unzipping and all the other stuff involved. DNA is a long ways down the line from whatever life began as.
Arguing that 600 base pairs of DNA need to self-assemble for life to begin is like arguing that mainframes only happen after punch-cards come into being and sort themselves into a program. By the time you're looking at DNA (and that's another assumption -- surely there are other ways to pass on genetic information) you're looking at a whole complex molecular system.
Look at Just Enough Molecular Biology for Computer Scientists if you need a refresher on the way it all works on Earth. Even in our own cells, cellular DNA/RNA and mitochondral DNA/RNA use different 3-unit codes to assemble proteins. To imagine that life elsewhere uses precisely the same system and the same coding seems ludicrous.
"Life, Origin of", an article in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight discusses some of the possibilities, including proto-cell membranes, self-assembling RNA and ribosomes that have been evolved in vitro in various experiments.
The worst problem with the "600 pairs" approach is that we really do not know haw life evolved in the beginning -- which makes any such statistical wand waving as divorced from reality as the computations of the 19th century scientist who "proved" that anyone travelling faster than 30 MPH would suffocate. Tell that to anyone who rides a motorcycle.
Experiments have demonstrated again and again that generating the basic compounds and structures of life is astonishingly easy in any number of primitive environments. What the next steps are between that and life we don't know, but I'm of the opinion that it's a LOT more common than the pessimistic statiticians imply.
The "600 pairs dna chain" argument is way off in left field. Why? DNA isn't life. DNA is the molecular punch-card deck for a complex set of molecular machines that DECODE DNA sequences to make proteins. Amino acids cannot simply attach themselves to a string of DNA to form proteins.
There are coded loops (more of a cross shape actually) that attach to various amino acids and they in turn bind to molecular assemblers (ribosomes) reading the three-base encoded sequences in a chain of RNA which was assembled off of a temporarily unzipped piece of DNA. There are other molecular assemblies that facilitate the copying, the unzipping and all the other stuff involved. DNA is a long ways down the line from whatever life began as.
Arguing that 600 base pairs of DNA need to self-assemble for life to begin is like arguing that mainframes only happen after punch-cards come into being and sort themselves into a program. By the time you're looking at DNA (and that's another assumption -- surely there are other ways to pass on genetic information) you're looking at a whole complex molecular system.
Look at Just Enough Molecular Biology for Computer Scientists if you need a refresher on the way it all works on Earth. Even in our own cells, cellular DNA/RNA and mitochondral DNA/RNA use different 3-unit codes to assemble proteins. To imagine that life elsewhere uses precisely the same system and the same coding seems ludicrous.
"Life, Origin of", an article in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight discusses some of the possibilities, including proto-cell membranes, self-assembling RNA and ribosomes that have been evolved in-vitro in various experiments.
The worst problem with the "600 pairs" approach is that we really do not know how life evolved in the beginning -- which makes any such statistical wand waving as divorced from reality as the computations of the 19th century scientist who "proved" that anyone travelling faster than 30 MPH would suffocate. Tell that to anyone who rides a motorcycle.
Experiments have demonstrated again and again that generating the basic compounds and structures of life is astonishingly easy in any number of primitive environments. What the next steps are between that and life we don't know, but I'm of the opinion that it's a LOT more common than the pessimistic statiticians imply.
There are coded loops (more of a cross shape actually) that attach to various amino acids and they in turn bind to molecular assemblers (ribosomes) reading the three-base encoded sequences in a chain of RNA which was assembled off of a temporarily unzipped piece of DNA. There are other molecular assemblies that facilitate the copying, the unzipping and all the other stuff involved. DNA is a long ways down the line from whatever life began as.
Arguing that 600 base pairs of DNA need to self-assemble for life to begin is like arguing that mainframes only happen after punch-cards come into being and sort themselves into a program. By the time you're looking at DNA (and that's another assumption -- surely there are other ways to pass on genetic information) you're looking at a whole complex molecular system.
Look at Just Enough Molecular Biology for Computer Scientists if you need a refresher on the way it all works on Earth. Even in our own cells, cellular DNA/RNA and mitochondral DNA/RNA use different 3-unit codes to assemble proteins. To imagine that life elsewhere uses precisely the same system and the same coding seems ludicrous.
"Life, Origin of", an article in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight discusses some of the possibilities, including proto-cell membranes, self-assembling RNA and ribosomes that have been evolved in-vitro in various experiments.
The worst problem with the "600 pairs" approach is that we really do not know how life evolved in the beginning -- which makes any such statistical wand waving as divorced from reality as the computations of the 19th century scientist who "proved" that anyone travelling faster than 30 MPH would suffocate. Tell that to anyone who rides a motorcycle.
Experiments have demonstrated again and again that generating the basic compounds and structures of life is astonishingly easy in any number of primitive environments. What the next steps are between that and life we don't know, but I'm of the opinion that it's a LOT more common than the pessimistic statiticians imply.
M
Malenfant
Guest
No. The starting point is "what do we see, and what do we know that can explain it?". Then if we don't know of something that can explain it, we extrapolate from what we do know until we find something that does. And if we can't extrapolate to something that does explain it, THEN we say "we don't know and need more data". But usually, we find some explanation that agrees with the data.
But at no point to we shrug our shoulders and say 'oh well, it must be divine intervention'. In a sense, 'god' is written out of it, yes - because in pretty much every case there is a rational explanation and one doesn't need to resort to faith.
See above. It's accurate. It's just that scientists generally don't like giving up when there's an scientific explanation out there.
Commander Drax
SOC-12
We can discuss the numbers and the probabilities forever but one thing that I do know, is the scientific principle of 'Mediocrity', in other words the life here on earth is nothing special and neither is the solar system which supports it, there are countless sun like mid sequence stars out there all of which are stable enough to support a life bearing planet, and we also know from recent observations that other solar systems have been proven to have planets (although so far we've only detected the very large gas giants type planets, there is no reason to doubt that the smaller rocky body, inner system type planets like the earth do exist. After all it happened here why couldnt it happen anywhere else.) As for life, does it have to be carbon based!, does it have to have DNA or RNA, surely these things are only relevent to the life that developed here on this planet. We also rather smugly assume that any intelligences out there would be rational and have patterns of thought or motivations similar to our own, again there is no basis to belive this. Sorry for getting wacky now but I personally belive that our solar system has been interdicted by Intelligent extra terrestrial life as after all we are a developing species and currently too dangerous to let loose on an interstellar level (like an IISS red zone!), and that perhaps our solar system has been deliberately shielded from any radion noise generated by this civilisation. Recently we've lost contact with the Voyager probe so perhaps it passed through the shield! Yes I agree I do sound nuts right now, but this belief is no less valid than all of the other trains of thought and rationals described so far in this forum, in that it cannot be proved. (And before you reply I am aware that the official sources said that the nuclear powerplant on Voyager simply ran down.)
Sorry, at no time did I say DNA was life, what I said was in order to have life as we know it you need a strand of DNA 600 pairs long and that gave3 rise to my statistical quote of odds. The proto cell membranes mentioned by Tanuki, were NOT cell membranes, but reminiscient of same.
As for the experiments resulting in amino acids, I did address that above. Amino acids are a long way from what is required for replicating life.
All that is neither here nor there, my main point is we have absolutely NO evidence of any life any where outside our own biosphere and how can any scientist then assume that there are others, without a shred of evidence?
As for divine intervention, look at my posts, I have not mentioned any divine intervention, only that there is NO evidence of life anywhere else.
Hope I'm wrong, but we don't want to bank on it.
No life doesn't HAVE to be carbon-based, but that is most likely, carbon is the most plentiful element fo use for biological compounds.
Commander Drax, I hope you're right, maybe when we grow out of our childhood, the aliens will let us into the club.
Pappy
As for the experiments resulting in amino acids, I did address that above. Amino acids are a long way from what is required for replicating life.
All that is neither here nor there, my main point is we have absolutely NO evidence of any life any where outside our own biosphere and how can any scientist then assume that there are others, without a shred of evidence?
As for divine intervention, look at my posts, I have not mentioned any divine intervention, only that there is NO evidence of life anywhere else.
Hope I'm wrong, but we don't want to bank on it.
No life doesn't HAVE to be carbon-based, but that is most likely, carbon is the most plentiful element fo use for biological compounds.
Commander Drax, I hope you're right, maybe when we grow out of our childhood, the aliens will let us into the club.
Pappy
M
Malenfant
Guest
Well, yes, you are being silly. This is a textbook example of Occam's razor - you interpret the fact that we haven't seen any evidence for alien life as being because we're in some big 'Red Travel Zone', or behind some big shield. I on the other hand assume that either it's out there and we haven't found any yet (either because it's too far away or we don't have the right technology to detect it), or it's not out there at all. While neither option can be proved as yet, my more rational assumptions are much less ridiculous and crazy-sounding than yoursOriginally posted by Commander Drax:
Sorry for getting wacky now but I personally belive that our solar system has been interdicted by Intelligent extra terrestrial life as after all we are a developing species and currently too dangerous to let loose on an interstellar level (like an IISS red zone!), and that perhaps our solar system has been deliberately shielded from any radion noise generated by this civilisation. Recently we've lost contact with the Voyager probe so perhaps it passed through the shield! Yes I agree I do sound nuts right now, but this belief is no less valid than all of the other trains of thought and rationals described so far in this forum, in that it cannot be proved. (And before you reply I am aware that the official sources said that the nuclear powerplant on Voyager simply ran down.)
But anyway - for starters, both of the Voyagers' RTG power supplies are still up and running and they're still broadcasting. In fact, last month the data received from them indicated that they were getting to the edge of the Sun's magnetic field
(see http://voyager.jpl.nasa.gov/ for details).
Second, there's no 'principle of mediocrity' in science. The fact that we're on an ordinary (if not slighly large) terrestrial planet around an ordinary G-type star in a reasonably ordinary (if not somewhat large) spiral/barred spiral galaxy was not assumed beforehand - it's just what we've discovered through rational observation.
The problem all stems from religious dogma of our place in the universe - it's not that science has a 'principle of mediocrity', it's that religion has a 'principle of specialness' that states that everything was made solely for us and we're the most important beings in the universe. Mankind really has to get over its ridiculous ego - there is no reason whatsoever to assume that we are special in any way, yet we still have a tendency to believe the 'comforting lies' that some religions (Christianity especially) tell us about how important we are. The reality, as best as we can tell, is that we are utterly insignificant in time and space, and if we die out, if any observers exist outside our planet then they won't even notice our passing (in fact, in all likelihood they haven't even noticed we're here, since we've not noticed them either). While this undoubtedly scares some people, it's something we're probably going to have to get used to/come to terms with.
M
Malenfant
Guest
Because we have no evidence to assume that it CAN'T be there either. We can theorise about situations where life as we know it can exist, be it in the oceans of Europa or on ancient Mars. But there's no theory that can specifically preclude the existence of life elsewhere, therefore it's a valid avenue of research. But just because we theorise about it, doesn't mean it does actually exist. A lot of things are possible in theory, but just aren't found naturally for a variety of reasons.
There isn't, true. But that lack of evidence for something doesn't mean that something doesn't exist. It could equally mean that we haven't found it yet. Don't forget, we're still pretty new at searching for life and other worlds around other stars. Give it another 10 or 20 years and we'll probably be seeing terrestrial planets around other stars and doing spectroscopic scans of their atmospheres, which should give us strong clues about whether there is life on their surfaces.
Carbon is the most likely basis for life because it most readily forms complex molecules. While Silicon has similar general properties (ie it's got a valency of 4), it isn't anywhere near as reactive and so much less likely to be the basis of life. Everything else simply can't make the complex molecules.
Exactly, Malenfant (cool name, by the way). We are just beginning to realize how right Sagan and followers were about planetary systems and their frequency, apparently he was very nearly right on about the number of stars with planets out there.
And I'm not assuming there is no life out there, I'm saying there is no evidence at all, but most people seem to assume there IS life outside our biosphere. Essentially, I want everyone to realize what leap of faith THAT is.
As to carbon based life, I wasn't clear, I meant that carbon was most likely because there is just more carbon than say silicon, based on our own environment, that may be really, really wrong elsewhere.
I think a Traveller campaign without aliens might be very interesting, or a campaign based on a situation like that found in "Mote in God's Eye", where a very advanced human empire meets a new and as yet, unknown alien race.
But if we ARE special we better get ourselves off this planet, before some cosmic accident wrecks all the life there is, huh?
Pappy
And I'm not assuming there is no life out there, I'm saying there is no evidence at all, but most people seem to assume there IS life outside our biosphere. Essentially, I want everyone to realize what leap of faith THAT is.
As to carbon based life, I wasn't clear, I meant that carbon was most likely because there is just more carbon than say silicon, based on our own environment, that may be really, really wrong elsewhere.
I think a Traveller campaign without aliens might be very interesting, or a campaign based on a situation like that found in "Mote in God's Eye", where a very advanced human empire meets a new and as yet, unknown alien race.
But if we ARE special we better get ourselves off this planet, before some cosmic accident wrecks all the life there is, huh?
Pappy
M
Malenfant
Guest
You may not realise this, but our environment is mostly silicon! It's a primary rock-forming element - just about every rock-forming mineral contains it (which is why rocks are usually referred to as silicates). Quartz is silicon dioxide, Feldspar, Mica, and Olivine are complex silicate minerals...
There's much more silicon on Earth than carbon
There's a japanese hard-sf comic called '2001 Nights' that's well worth picking up, about Man exploring and looking for intelligent life in the universe, but finding none. But he does find some evidence for it in the past, and lots of animal/plant life.
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