This month’s open thread.
46 James C said, ” Advanced civilizations could send machines.”
As we have already done in a rudimentary way.
” In about 40,000 years, Voyager 1 will drift within 1.6 light years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis. In some 296,000 years, Voyager 2 will pass 4.3 light years (25 trillion miles) from Sirius, the brightest star in the sky .”
re Titus @34,
Yes those organisms are incredibly complex. Some slime molds have genomes that are 10-100 times larger than our own genomes. The simplest of single celled archaea like the oxygen-producing halobacteria that likely produced the great surge of oxygen that resulted in a snowball earth more than 2 billion years ago, were already capable of photosynthesis. They had a genome, ribosomes, membranes and complex membrane proteins that converted solar photon energy to pump protons, and other complex membrane protons that utilized the proton gradient to produce ATP; i.e. stuffed full of the sort of biomolecular machines we find in extant organisms.
I totally agree with you that it is the production of this extraordinary complexity in the most simple of organisms that is the mystery. In contrast to that the evolution of complex multicellular organisms is more straightforward. One can’t look at slime moulds and consider that stuff would be easy to produce!
On the other hand 2 or 3 billion years preceded the time for which the earliest evidence for life on Earth exists, and we may as well take the point of view that that period of time is sufficient for complexity to evolve since it clearly did! But we really don’t have a clue how we got from chemicals, water, heat and solar energy to self-sustaining life. All abiogenesis ideas are simply hypotheses, even if there’s no point in considering the origin of life on Earth outside of an abiogenesis framework. But the evidence for abiogenesis in any specific form is very weak – “just-so” stories really so far.
Does life exist elsewhere in the Universe? We don’t know, but it’s certainly unscientific to state that it doesn’t on the basis that we don’t have direct evidence for this. After all we’ve only been in a position to address this question for around half a century. If I were to bet I’d say it’s very likely intelligent life does exist elsewhere simply because the Universe is so vast and because there is good evidence for some potential “Earth-ish like” planets even within the tiny bit of the Universe we’ve been able to survey….
(P.S. last para isn’t addressed specifically to you!)
Regarding confirmation of life elsewhere in the Universe. Given the rapid advancements being made in actually finding and observing planets around other stars in our own galaxy, with the analysis of the atmosphere’s of those extra-solar planets getting more and more precise and sophisticated, it seems likely that this area of research will produce the first evidence of life (and possibly even intelligent life, elsewhere in the universe. The other potential candidates for the discovery of extraterrestrial life would be the moons of Jupiter and Saturn, where rather unique combinations of factors (including the all important presence of water) could produce the factors necessary for life. Finally of course, there remains the possibility that current or past evidence for life on Mars may yet be found given the increasing evidence that water was once far more abundant on the surface.
All three of these exciting areas create an increasing likelihood that sooner, rather than later, some form of extraterrestrial life will be found. Of course, intelligent ET life would be the most profound discovery in human history, though the popularization and acceptance of this topic makes the impact of it lessen somewhat with each passing year. (i.e your grandmother would be more shocked than your children by such a discovery).
Dave, glad you found my post on SSW’s a “hoot”. As a stated non-professional in the field, my goal was to elicit reaction and conversation on the topic of SSW’s, and certainly it being a “hoot” is as good a reaction as any. My connection of SSW’s to the topography of the Tibetan and Himalayan region might seem too simple to some, yet, topographically forced planetary waves are integral to the differences we see between the southern and northern hemispheres. True, the connection specifically between the Taklamakin desert and upwardly directed Rossby waves was a rather simplistic stretch on my part, I have no doubt the the topographic uniqueness of the general region of that desert in association with the rapid rise to Tibetan plateau is one of the topographic factors that plays into the generation of planetary waves from this region. My simplistic “knee bone connected to the thigh bone” approach, was a perfect departure for me to further my understanding of planetary waves, Brewer-Dobson circulation, and their relationship to both the unique topology of the NH versus the SH, and related impacts on the severity of NH SSW’s versus SH.
Okay, let me word the question differently…. If we make it to 450ppm of CO2 or 500ppm or any other number greater than where we are now, will global average temperature follow CO2 levels exactly and start to rise MORE quickly than they are today? For example: If we’re at 450ppm by 2040 how soon would the temperature reflect that level? Would it take several more decades for the temperature to catch up or will temperature and CO2 levels stay pretty much together?
I’m just trying to get some sort of idea as to how accurately temperature follows CO2 levels and how much inertia is involved between the two. Looking at past data it’s hard to get a real sense of how these things work since we’re upping CO2 levels so quickly. Thanks.
Barry Brooks and I and others had a long discussion on Fermi Paradox, which started with possibility that climatechange coudl be a reason. See this comment on relationship to fossil fuels or several later ones on civilization classes and energy requirements. To see communication from another civilization, it has to be relatively close, contemporaneous and willing to spend energy over a long time either narrowcasting at nearby stars in hopes someone will answer, or try to broadcast, thus having to deal with the inverse square law.
New Horizons gets 38Kbits/second from near Jupiter, 1Kbits from near Pluto. (But it has a delightful choice of microprocessors, rad-hard MIPS R3000s. :-))
They get 38Kb/s near Jupiter, will get 1kb near Pluto, which is currently not far from Neptune’s orbit. That’s about 30AU, compared to Jupiter’s 5AU, i.e., 6X further, so 6^2 = 36, about right.
Proxima Centauri is roughly 9,000X further, which means about 80M X more power needed if one were broadcasting. Of course, a planet has a lot more power, and antennas can be much bigger. Our galaxy is ~100,000 light-years.
Inverse-square laws are tough.
A reminder — internal combustion engines (and other high-temperature fossil fuel combustion using atmospheric air) are hot enough to burn nitrogen, producing nitrogen oxides (NOx) as well as carbon dioxide.
It’s a problem: http://onlinelibrary.wiley.com/doi/10.1002/grl.50234/abstract
World’s changing glaciers http://galaxymachine.de/2013/05/05/worlds-changing-glaciers/
On the other hand 2 or 3 billion years preceded the time for which the earliest evidence for life on Earth exists
That is not true, sorry, at least for Earth. Look it up. I apologize if this is a duplicate correction as I am not following this thread very closely.
Ray, a von Neumman Probe?
For that matter, I would venture to say our civilization will figure out a solution to your galactic cosmic rays problem within a hundred years.
Hmm, with http://www.nas.nasa.gov/SC11/demos/demo17.html suggesting that 5.4% of stars might a planet in the habitable zone, you are certainly opening up the possibility for a lot of life in the galaxy. Simon, which no. on the Drake equation do you think is most limiting? Ie do you think the probability of a suitable planets is very low; or that probability that life would form on them is very low.
re @59 whoops, yes, you’re right Thomas, I didn’t state that so well! I was referring to the long period before the evidence for photosynthetic O2 producing bacteria.
There is some evidence for life traces in 3.4-3.8 billion year old rocks, though the complexity of these putative organisms isn’t known. The fact is that the photosynthesising O2-producing organisms whose complexity we know something about had over 2 billion years to evolve, and even the microrganisms of unknown provenance at 3.4-3.8 BY had nearly 1 billion years to evolve. They presumably had similar molecular machinery (DNA/RNA/ribosomes/membranes/proteins) as better characterized archaea (‘though perhaps not!).
The fact is that even the apparently mundane species (slime moulds/simple bacteria) are incredibly complex, structurally and mechanistically, and we have little idea of how this complexity arose from the chemicals, water, heat and sunlight on the early earth.
Regarding OT extraterrestrial speculations: why not focus all of this creative energy on keeping Earth habitable? It’s the only planet that’s going to be relevant to your or your immediate descendents’ survival. There’s no shortage of actual problems and time is short.
and we have little idea of how this complexity arose from the chemicals, water, heat and sunlight on the early earth.
That also is simply not true. When you are digging a hole, quit digging and at least try to educate yourself on some of the fundamentals. Follow the energy. A lot of this is self assembling, built into the chemistry and physics. Nucleosynthesis built our atoms up from strong and weak forces, We inherited some electromagnetic complexity of the electronic shells from that process. Before that, the laws of physics themselves evolved from some Planck scale processes that we have yet to decipher. Life is clearly inevitable in the environment rich in hierarchical complexity we inhabit.
Japan is doing their first “production” attempt to mine methane hydrates. Estimate 10 years for the relative cost to come down to make it feasible/profitable on scale.
A Von Neumann probe does not address the fundamental problem–it takes thousands of years to get anywhere one might find life. Out of what will the probe build its successors when it is in interstellar space–the majority of its trip? And I would love to see how you achieve any sort of reliability on a mission lasting thousands of years.
Methinks you are engaging in the time-honored tradition of waving away problems you don’t understand.
Re. Chris @ 52&62.
Thanks for providing a concise and informative description of a ‘simple’ organism. It’s even more complex than I thought!!
In my career I worked with many scientist R&D folks mainly in product development. It’s refreshing to read you describing the process of cell development as a ‘mystery’ (as to me it clearly is). I knew in their hearts they would have liked to have said that about much of their research but needed to show confidence for the continuation of their work. I understand that some things just have to be taken as a given to move to the next level. IMHO it’s the remembering that we based our science on the acceptance of a ‘mystery’ that will humble us to admit that we just have knowneldge built from our concepts rather than actual understanding. My apology, I appear to have dropped into lecture mode on my hobbyhorse. Time to call a halt…….
Brighter Clouds, Cooler Climate? Organic Vapors Affect Clouds, Leading to Previously Unidentified Climate Cooling
Today is absolutely cloudless here. (This is rare.) Nevertheless I can certainly see the aerosols imported from East Asia.
John Mashey, thanks for the link to the great SETI thread. For my money it’s “carbocide”, although I think focusing on the enormous excursion in the global carbon budget is only part of it. Similar disturbances in the other biogeochemical cycles (sulfur, nitrogen, phosphorus), on the scale of hundreds of megatons per year, are occurring simultaneously. There is no comparable event in Earth’s history; the End Permian extinction is the closest, but it’s still vastly less significant than what humans have done. It’s hard to imagine how anything survives this kind of crisis. It took some millions of years for biodiversity to recover from the Permian-Triassic mass extinction; certainly it will take Earth millions of years to recover from the human efflorescence. It may be that the surest sign of extinct intelligence on other worlds will be wrecked, poisoned, low-complexity biospheres.
Slime molds are not bacteria. They eat them.
The earliest pretty good traces of life on earth go back about 3.5 billion years. These “traces” are stromatolites. Little sedimentary rock remains from 3.5 – 4 billion years ago and most of that is too highly modified to have much trace of life. We are lucky to have some sturdy stromatolites from very long ago along with a few contemporary ones for comparison. They indicate photosynthesis, probable multi-species ecology, and niche construction.
IOW not the first life, which is thought to probably have been chemautotrophs (eat chemicals, not light) and likely to have started in an environment like a deep sea seep or vent, rich in chemical energy. We do not know how life started. Following up on last week’s discussion this paper may be interesting:
Evolution before genes
by Vera Vasas Chrisantha Fernando, Mauro Santos, Stuart Kauffman and Eörs Szathmáry
Reviewers: This article was reviewed by William Martin and Eugene Koonin.
Once life got started though it could not help evolving.
Space is big. There may easily be several advanced civilizations within our galaxy yet not within detection range. Over all galaxies in the observable universe their may be a trillion.
Re #60, James Cross “For that matter, I would venture to say our civilization will figure out a solution to your galactic cosmic rays problem within a hundred years.”
Maybe we manage to put some microbes into space before our civilization fails and goes down in global chaos. The last remains of our existence, “cyanobacteria”?
The biological aspects of directed panspermia may be improved by genetic engineering to produce hardy polyextremophile microorganisms and multicellular organisms, suitable to diverse planetary environments. Hardy polyextremophile anaerobic multicellular eukaryots with high radiation resistance, that can form a self-sustaining ecosystem with cyanobacteria, would combine ideally the features needed for survival and higher evolution. For advanced missions, solar sails can use beam-powered propulsion accelerated by Earth-based lasers or ion thrusters propulsion to achieve speeds up to 0.01 c (3 x 106 m/s), or by ion drives. Robots may provide in-course navigation, may control the reviving of the frozen microbes periodically during transit to repair radiation damage, and may also choose suitable targets. These propulsion methods and robotics are under development. Safeguards are needed against robot takeover, to assure that control remain in human control with a vested interest to continue our organic gene/protein life-form.
Microbial payloads may be also planted on hyperbolic comets bound for interstellar space. This strategy follows the mechanisms of natural panspermia by comets, as suggested by Hoyle and Wikramasinghe. The microorganisms would be frozen in the comets at interstellar temperatures of a few degrees Kelvin and protected from radiation for eons. http://en.wikipedia.org/wiki/Directed_panspermia
Captcha: nceferro culture
Re Chris @52&62 in addition to my post @67
After reading your post on the building blocs of microbes I remembered a post I read a little while ago on microbes cleaning up the spilled oil in the Gulf. Found it here: http://news.discovery.com/earth/oil-microbes-bacteria-plume.htm
Well, I then got to thinking that hydrocarbon chemicals have been found in abundance in our own solar system on Titan. From your understanding would it be an option for these microbes to form in this type of environment? They seem more simple and less demanding than slime.
I read some web sites that talk about this possibility (eg. http://news.discovery.com/earth/oil-microbes-bacteria-plume.htm ). Asking if you had a view?
To summarize all my various posts over there:
Fermi Paradox just wasn’t evidence regarding the prevalence of carbocide in the galaxy, one way or another.
The science and the arguments on Earth are easily strong enough not without invoking speculation when we simply have no data and physics implies we can’t get it.
The energy requirements are simply too high for civilizations at our level to see each other, especially if expecting to intercept radio or TV. I recall reading sci-fi stories where aliens light-years away have been trying to learn about us from old TV comedies. I don’t think so, see SETI FAQ, which works the numbers.
“Even a 3000 meter diameter radio telescope could not detect the “I Love Lucy” TV show (re-runs) at a distance of 0.01 Light-Years!” One needs narrowband:
“It appears from the table that effective amateur SETI explorations can be conducted out beyond approximately 30 light years provided the processing bandwidth is near the minimum (approximately 0.1 Hz), the system temperature is minimal (20 to 50 Degrees Kelvin), and the EIRP the source (transmitter) is greater than approximately 25 terawatts.” Of course, 25TW is somewhat more than current total power used by humans.
Planets like our get hit by asteroids now and then, and if a big-enough one comes, the then-extent
civilization better have enough space capability to detect and deflect it. I.e., this is what I called “7d” in one of the later posts. The time until the next one is totally unpredictable, but the likelihood of another hit sometime is high. Of course, if the conjoined climate+energy problem doesn’t get solved over the next century or two, I’d guess it is very unlikely to be able to maintain a 7d civilization.
But, I guess the real meta-point is that one has to look at the numbers.
This one has me a little puzzled. I agree for economic growth, but I think it is nonsense for climate science. Any comments?:
“D. Ryan BrumbergNew York, NY
Theories that can be easily tested should have a high degree of consensus among researchers. Those involving chaotic and less testable questions – climate change or economic growth, physiology or financial markets – ought to have a greater level of scientific disagreement. Yet this is hardly the case for climate science. I’ve just published a paper, The Paradox of Consensus, which illustrates that the greater the level of consensus for certain classes of hypotheses (those that are difficult to test) the less truth we should assign to them. This implies there is far less truth to claims of carbon dioxide caused warming that mainstream scientists suggest.”
“Germany sets weekend record for solar power.” Just in case anyone doesn’t know what’s going on with electricity production in Germany, this article puts no gloss–and no schtick–on solar or on anything else:
This, in spite of the darkest winter there in 43 years.
“Less than an average of 100 hours of sunshine have been recorded December through February… The winter average is an already measly 160 hours of sun.”
The U.S. has a far greater solar resource than Germany does, but it is largely being wasted. The sun doesn’t always shine–but almost, where the resource is really good. Then again: the nuke doesn’t always work; and it has massive costs when it fails–compared to more flexible solutions.
Electricity rates where I am have been raised to cover the costs of a continuing unplanned nuclear plant outage.
Meanwhile the sun shines just fine where the resource is best.
Financing renewables, and building them out as needed, provides flexibility and the opportunity to incorporate tech improvements as time goes on.
@64 really Thomas? I’m surprised you haven’t got your Nobel yet!
In fact, “A lot of this is self assembling, built into the chemistry and physics” is no explanation.
DNA doesn’t self assemble. It requires the action of specific enzymes on nucleotide triphosphates which themselves have to be produced by the action of other enzymes. Proteins don’t self-assemble. The constituents must first be linked onto extremely complex transfer RNA molecules with high fidelity, and then brought to a ribosome with numerous specific sites for regulated assembly, with peptide bonds formed by the action of specifc enzymes and so on and on …
We’re pretty sure this extraordinary level of complexity encoded in genomes was present in the earliest “simple” organisms for which we have evidence (certainly those O2-producing photosynthetic bacteria of 2-odd billion years ago, and likely the trace evidence for bacteria in sediments dated to 3-odd billion years ago).
We really don’t understand how this level of complexity arose out of early chemicals on Earth. If you really do know the answer that’s incredible! I suspect however that the first billion years of evolution on Earth is a closed book that we can only hypothesize about. Of course, it’s possible that in time we might be able to reproduce some meaningful elements of this in the lab and then we’ll be able to say that this or that were possible steps towards the generation of biochemical complexity…
The San Onofre nuclear plant had a new, supposedly improved steam generator installed about two years ago. It was improved a little too much, resulting in a small, within permissible limits, leakage of steam that had been in the core into the system, also sealed, in which water is boiled and condensed in a Rankine cycle. This is being seized upon as an excuse to shut down the plant forever. You can vote in a not-very-significant poll here.
Here’s a mental snack to chew on:
We are the result of a virtually infinite number of 3D nanoprinters driven by photons and ratchets instead of typewriters and monkeys.
Now we take it to the next level – the anthropocene will be the shortest epoch ever, as we can direct our own evolution, and if we survive that as a viable species, and manage to retain volatile information and skills, then the next epoch will come soon – the cybercene, or cybocene.
If an organism can metabolise pure energy in a 100% closed loop system, instead of deriving energy from converting high energy food to lower energy waste and then having to convert that waste back into food again, then that organism would not be constrained to having to live on a planet – it could survive billions of years in the centre of an asteroid for example feeding off nuclear decay.
Nature did what it could here with what there was here, tracing a precarious path through the varying circumstances and environments there were, until now.
Now we could do better – and that’s rather disquieting!
If only there was a way to save and load consciousness.
I want to know what will happen over the next few million years…
An advanced civilization sends out two probes to two nearest star systems. When each probe arrives, it builds two more probes to the nearest star systems. When they arrive, etc. etc. The galaxy is 90,000 light years across. If the probes can go even a a small fraction of light speed, in a couple hundred million years, they are all over the galaxy.
The replicated probes are built from materials at the destination, not during the flight.
You seem to have startlingly little imagination about the capabilities of civilizations more advanced than ourselves.
There are only a few good arguments for why they are not here. Life or at least intelligent life is rare. Few intelligent creatures are interested in exploring the universe and we are an exception. Life is only recently becoming intelligent in the galaxy. “Life finds a way.”
Ask yourself this (and disregard the temptation to bring a deity into it): How much was the existence of intelligent life “coded” in as an inevitability into the very first nanoseconds of this particular universe’s existence? Indeed, the hundreds of billions of galaxies, as these little islands where gravity forces the nuclear fires of fusion to ignite, become inevitable seedbeds for life.
You ought to look at my own post and the links on the theory about timeline for origin of life. The argument is that life originated about 9.5 billion years ago and it took about 5 billion years to get the level of the complexity of the most primitive organisms on Earth. Hence, life didn’t arise on Earth.
Just to get the timeline right:
Earth 4.5 billions years ago
First life 3.5 billion years ago – your namesake prokaryotes
The problem is that prokaryotes are already fairly sophisticated and a billion years, when you factor in the cooling time, isn’t a lot of time to self-assemble one of them. So the problem of how this occurred isn’t trivial or can’t be dismissed with the statement it is built into chemistry and physics as some have implied on this thread.
From there it takes about 3 billion years to evolve bilateria. The first one most likely a worm.
really Thomas? I’m surprised you haven’t got your Nobel yet!
I’m not surprised that you haven’t even bothered to do even a superficial amount of research on subjects that you so easily hand wave away. Your lack of knowledge of rudimentary chemical and biochemical evolution is obvious.
There are a large variety of energy and biochemical pathways that can lead to self assembling macromolecules. Take your pick. Nature has already chosen.
The lipid bilayer membranes themselves are more or less self assembling.
re @72 Titus
Yes it’s possible and I’m more than happy with that hypothesis. However those particular oil-eating bacteria also have very high biochemical complexity! They have a full set of standard biochemical machinery required for life: genomes, ribosomes, a large number of enzymes, extremely complex membrane associated electron transfer chains for “capturing” the “energy” contained in the electron rich hydrocarbons in manageable bits. Those particular bacteria require oxygen (as terminal electron acceptors to power the oxidative catabolism that taps the energy contained in the hydrocarbons), just like we do. Seems like they’re a great boon for helping to clean up oil spills!
There are several theories/hypotheses for the environments in which life may have started. The early organisms on Earth didn’t consume oxygen since there wasn’t much around, and more likely used sulphur, or maybe CO2, as the electron acceptor in electron transport chains or were methanogens that lived on CO2 and hydrogen. There are living examples of all of these types of organisms today. They all have complex biochemical machinery. It’s quite likely that the earliest organisms used simpler inorganic molecules as primary electron donors (e.g. carbon monoxide or hydrogen, ammonia, sulphide) rather than hydrocarbons which themselves require quite a bit of energy to “synthesise”.
So yes maybe those particularly environments (deep sea vents; warm mud pools) were optimal environments for the origin of life on earth and quite possibly other planets in the Universe. But we really don’t have much of a clue how the complex biochemical machinery in these organisms that we see in their modern counterparts came to be. I think it’s worth being quite clear about that since it’s always a good idea to be clear about the nature of the problem when considering a line of scientific enquiry (like abiogenesis!).
Maybe my “lack of imagination” stems from the fact that my day job is building satellites. Technology is not magic. It has limitations, and some of them are inherent. As a colleague says, “Failure is not an option. It’s a standard feature.” Let’s look at the facts. It took Voyager >40 years to leave the Solar System. New Horizons was optimized to make a very fast trip to Pluto–10 years. It will take it at least 20 years to leave the Solar System. On its way out of the solar system it won’t pass closer than a few 10s of thousands of miles to any object other than its target–that doesn’t give it much material to construct progeny even in the Solar System. Once outside the solar system, we’re talking at least hundreds of years in transit to the nearest stellar system…which has no planets. During that time, it will be exposed to a continual flux of HZE radiation that will degrade its materials and electronics. It will have to survive carrying its own very limited energy, which will be largely depleted by the time it reaches its destination. It will have no way of replenishing its energy. If it had photovoltaics to use stellar light, they would be degraded to the point of uselessness by radiation when it reached any star.
Here’s a hint–assuming technology will come up with a miraculous solution isn’t a viable design strategy.
Ed @ 74
Not finding the source. Seems to be making some denialist assumptions about how climate science works.
Anyhoo,you might enjoy this:
Environmental Ignorance Is Bliss
@8 James Cross,
Of course you may very well be right James. However it’s not a very satisfactory argument to my mind, since it simply shoves the problem to some other time and place. Who’s to say that the complexity of the simplest self-replicating organism (say some sort of archaea or bacterium) couldn’t have evolved on Earth in 500 or 800 million years?! We simply don’t know – one of the very many imponderables about the origins of life!
Incidentally, although we’re pretty clear about the complexity of the O2-producing photosynthetic cyano-type bacteria living 2-2.5 billion years ago (they likely had a compleement of photosynthetic “machinery” of the sort we would recognise today), we really don’t know the nature of those organisms whose traces are dated to around 3.5 billion years ago. They might have been rather simpler. After all some extant microrganisms can generate a proton gradient directly from sunlight and use this to power ATP synthesis in the absence of an electron transport chain. So we know that there were very likely much simpler organisms than bacteria back then just by analogy with extant microorganisms. It may well be the case that these could evolve in 1 billion years or less – but we don’t know!
Re #81, James Cross
Yes, i think that during impact events – an environment forms which is favorable to produce the desired outcome, when the right recipe (such as the right temperature/habitability and simplest forms of life are present).
The Sharov and Gordon paper is [edit -moderator]. Their definition of “complexity” is arbitrary. See this:
@82 Thomas, you’re absolutely right that membrane can self-assemble. Of course membrane forming lipids that we find in all organisms are complex molecules with energy requirement in their biosynthesis. Very simple amphiphiles (e.g. soapy/detergent like molecules) can self associate but these generally don’t form membranes – they form micelles or monolayers. But since one of the seemingly essential factors of living organisms is that they compartmentalize themselves from the environment with which they interact it seems a reasonable hypothesis that the early formation of some kind of membrane was important for evolution of life. Couldn’t agree more.
The point is that all of the properties of molecules that you refer to (e.g. a degree of self-organization resulting from the hydrophobic effect, hydrogen bonds, electrostatic interactions and so on) simply describe the fundamental properties that nature has at hand. It’s not an explanation for how life came to be. After all mixing together amino acids in solution doesn’t generate proteins; nor does mixing together nucleotide phosphates generate RNA. These things don’t self-assemble! Perhaps some degree of association can be achieved by interactions on clays or mica in a dehydrated state; maybe transient chemical reactions that can link amino acids together result in insoluble di-amino acids that precipitate from solution and so protected from hydrolysis to the thermodynamically-favourable monomers. There are lots of guesses and hypotheses relating to some of the problematic factors considered important for abiogenesis. Of course once you’ve built these very complex molecules (poly nucleotide phosphates or poly amino acids) they will tend to adopt conformations defined by those molecular forces.
Anyway, I would say that it is you that is hand-waving in your suggestion that we know how life began and biochemical and biomolecular complexity arose on an early earth! I don’t think we do, ‘though I’m very happy for you to inform us.
If you actually read my post linked above, you will see I make much the same points as you do. Nevertheless, I think the study I link to and post about makes some very provocative arguments.
Get ready for most fossil fuels.
Japan is doing their first production-level test of their methane hydrates mining system. Economic feasibility is estimated to be a decade out.
James Cross mentions the Sharov and Gordon claim that life originated 9.7 billion years ago. Be cautious with this; these kinds of extrapolations annoy evolutionary biologists, e.g., PZ Myers (Graaarh, physicists BIOLOGISTS).
I have skepticism about the theory too.
From my own reply on my post:
“To me a bigger issue is how do evolutionary forces come into play before we have the viable organisms. Best estimates are that the simplest organisms would need at least several hundred genes. So evolution would need to be working on combinations of nucleotides and proteins that might not have been totally viable organisms for billions of years to arrive at the complexity of what we see today as the most primitive organisms. It is hard to imagine how that could happen in nature since it would seem that would require some very unique, protected, and stable environment for that entire time.
On the other hand explaining how several hundred genes could assemble themselves might be even more difficult.”
O.K. yes I’ve just had a look at your blog post and the paper you refer to. It’s a silly paper isn’t it? You can see some howlers with a quick perusal. For example:
i) During evolution organisms (including very simple ones) have evolved “proof-reading” and DNA repair mechanisms. These will almost certainly have been relatively late players in the genotypic and phenotypic armoury. It seems quite reasonable to me that the early evolutionary process (e.g within the first 0.5 – 1 billion years) would have been accompanied by a very large degree of mutations, gene duplication and other processes that power genetic diversity with less developed proofreading and repair mechanisms. So a steep part of the early genome complexity curve seems entirely reasonable to me. There is zero basis for a linear extrapolation to zero. That’s almost as silly as extrapolating 3 oC climate sensitivity back to zero [CO2] to predict the temperature of a CO2-free earth.
2. The authors use extant organisms to assess genomic complexity. However we don’t know what the genome complexity of “prokaryotes” was 3.5 BYA, even if we can assess the prokaryotic genome complexity of contemporary species. One might expect it was considerably lower 3.5 BYA. Since the slope of the authors curve is heavily dependent on the “Prokaryote” point we could quite easily get a “Time of Origin” of say, 7 BYA, simply by adjusting the log10 genome size down from 5 point something to log10 4 point something.
Maybe life did arrive from earth from elsewhere – I wouldn’t say that Sharov and Gordon provide any evidence one way or another…
I like your blog post. On one of your points I would say that there is quite a bit of evidence for loss of genomic complexity in some bacterial species in the natural world. The sort of study that I believe Craig Venter is doing, i.e. deleting bacterial genes to establish what is the smallest genomic complement compatible with a functional bacterium, addresses that point very nicely…
THe origin of life is very difficult to formulate but I would suggest that it is supramolecular and hence arose at the mesoscopic level which is apparently diffuclt to visualise and only recently has it come under the scrunity of earnest scientific study. Don know if th origin of life is to be found here but self organising principles apply at this level and far from equilibrium thermodynaics can supply the mix an energy for complex chemicals to form and evolve.
insights to come and there is a scientist who has done a lot of work in this field and his video is somewhat intruiging
DNA doesn’t self assemble
The point is chris, is that you are making incredibly stupid and naive statements on a science forum where people can see easily see through the nonsense you are presenting. The fact that DNA exists in this universe is demonstration enough that it can self assemble, even invoking panspermia, short of invoking divine intervention, which I suspect you are proposing.
Your posts are essentially content free. The origin of life is something that you can easily research to get your self up to speed on the state of thinking in this domain. What you are suggesting is that we are ignorant about how this phenomenon (life) might arise in the universe as we currently understand it, which is complete nonsense. Get a grip.
There is a wiki page on this subject, with references. Please pursue them.
Ray’s comments illustrate fact that those who actually work on advanced technology tend not to believe in magic.
As one tiny hint, the satellite I mentioned use MIPS R3000s (I’m one of the original designers) in a rad-hard version, running at all of 12Mhz, not GHz.
It’s nice to talk of vonNeuman probes, but the things we do to shrink transistors and make chips run faster do not necessarily play well in space.
Maybe Ray will favor us with a few words on component lifetimes and radiation in space.
Why aren’t the amazing space probes here? 0) their extreme impracticallity. 1) if you brush 0 aside, they probably passed through here a billion years ago. 2) [correlated with 0] probe makers are rare. 3) advanced life forms are rare 4) the probes are not here because you made them up.
Self assembly of life? Some of us have some knowledge of what forms and what does not in the time frame of our experiments (usually just a few days). Life does not, not even close.
Billions of years/trillions of monkeys? Where is the evidence that such is called for? It’s hard to have a feel for just long a million years really is but it is very long for chemistry. I ask the billion or even hundred million year faction this. How long would the right environment (whatever it is) remain stable on young earth?
I’m not sure what you are thinking but you seem to be thinking. Forget slime molds. They’re protists and way out of anybody’s league around here. (Some, not Eli to be sure, might say “So are bacteria” but never mind). You are on the right track in thinking of an easy source of chemical energy. However, today’s environment is full of raw oxygen, which is just too reactive. Indeed, for life’s beginning a reducing environment is better.
You might like to learn of Miller’s last experiment. After the original Miller-Urey experiment, research indicated that the early atmosphere was probably close to redox-neutral rather than reducing. Miller-Urey type experiments with various neutral atmospheres yielded much amino acid quantity and variety. In what must have been a face-palm moment, it was noticed that the spark discharge experiment was producing nitrites and nitrates, which would oxidize amino acids. So: correct for this and …
“A Reassessment of Prebiotic Organic Synthesis in Neutral Planetary Atmospheres”
“We also found that the addition of oxidation inhibitors prior to hydrolysis resulted in the recovery of several hundred times more amino acids than reported previously, suggesting that primitive ocean chemistry may also have been an extremely significant aspect of endogenous organic synthesis.”
The researchers found that the most ancient aerobic process was the production of pyridoxal, or the active form of vitamin B6, they report today in Structure. This reaction appeared about 2.9 billion years ago, along with an oxygen-producing enzyme called manganese catalase. This enzyme detoxifies hydrogen peroxide by breaking it down into water and oxygen. Caetano-Anollés hypothesizes that early organisms got the oxygen they needed to produce vitamin B6 from this breakup of hydrogen peroxide. The authors argue that these ancient organisms would have encountered massive amounts of hydrogen peroxide in their environment due to the bombardment of glacial ice by ultraviolet radiation, which can generate the compound.
“It’s a great paper in terms of the evolution of protein [domains],” says Paul Falkowski, an evolutionary biogeochemist at Rutgers University in New Brunswick, New Jersey, who wasn’t involved in the study. But Timothy Lyons, a biogeochemist at the University of California, Riverside, is skeptical that high levels of hydrogen peroxide were produced by glaciers. “There is little direct evidence for a hydrogen peroxide spike at this time,” he says. Still, he says the study is a compelling effort at pinpointing the evolutionary origin of aerobic metabolism. http://news.sciencemag.org/sciencenow/2012/01/the-first-oxygen-users.html
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