Microfossils May Be Evidence Life Began 'Very Quickly' After Earth Formed (theguardian.com) 57
Scientists believe they have found evidence of microbes that were thriving near hydrothermal vents on Earth's surface just 300m years after the planet formed -- the strongest evidence yet that life began far earlier than is widely assumed. From a report: If confirmed, it would suggest the conditions necessary for the emergence of life are relatively basic. "If life is relatively quick to emerge, given the right conditions, this increases the chance that life exists on other planets," said Dominic Papineau, of University College London, who led the research. Five years ago, Papineau and colleagues announced they had found microfossils in iron-rich sedimentary rocks from the Nuvvuagittuq supracrustal belt in Quebec, Canada. The team suggested that these tiny filaments, knobs and tubes of an iron oxide called haematite could have been made by bacteria living around hydrothermal vents that used iron-based chemical reactions to obtain their energy.
Scientific dating of the rocks has suggested they are at least 3.75bn years old, and possibly as old as 4.28bn years, the age of the volcanic rocks they are embedded in. Before this, the oldest reported microfossils dated to 3.46bn and 3.7bn years ago, potentially making the Canadian specimens the oldest direct evidence of life on Earth. Now, further analysis of the rock has revealed a much larger and more complex structure -- a stem with parallel branches on one side that is nearly a centimetre long -- as well as hundreds of distorted spheres, or ellipsoids, alongside the tubes and filaments.
Scientific dating of the rocks has suggested they are at least 3.75bn years old, and possibly as old as 4.28bn years, the age of the volcanic rocks they are embedded in. Before this, the oldest reported microfossils dated to 3.46bn and 3.7bn years ago, potentially making the Canadian specimens the oldest direct evidence of life on Earth. Now, further analysis of the rock has revealed a much larger and more complex structure -- a stem with parallel branches on one side that is nearly a centimetre long -- as well as hundreds of distorted spheres, or ellipsoids, alongside the tubes and filaments.
Or.... (Score:1)
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Re:Or.... (Score:4, Insightful)
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Think about how much matter in involved in a supernova, and the stochastic process it was put through. Why should we think its just every iteration of the simpler molecules being produced, when that stochastic process applied to that much stuff surely reached significantly into the possible arrangements of quite complex things.
Re:Or.... (Score:4, Interesting)
Except that's far less plausible than it having evolved here.
You're not going to get any complex chemicals forming in a supernova - the temperatures are far too high to allow stable chemical bonds to form. Complex organic molecules on the order of amino acids do seem to be pretty common, but those almost certainly formed long after the star exploded, in the clouds of cooling gas left behind.
But getting from single molecules to early life is another huge leap - and the near-total vacuum of space just doesn't offer any sort of environmental organization to allow those molecules to group up and stumble into any sort of self-replicating form. A star has a density comparable to water, and within seconds of exploding the density of the ejected material will be millions of times lower and falling rapidly - meaning that despite the incredible mass of material, the average time between any of those molecules actually interacting is rapidly going to be vastly lower than it is in a single small pond of water. And the conventional wisdom is now that even a pond of organics-rich water (aka primordial soup) probably doesn't offer enough structure for protolife to form, instead it likely formed at semi-2D interface between rock and water - with the combination of ordered rock and chaotic water motion providing the structure and motive force necessary for the more complex mechanical interactions of trans-biological chemistry to get established. (aka the primordial pizza)
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the panspermia hypothesis doesn't actually answer any questions, it just pushes the question of "how did life start" off from the Earth to somewhere else.
Well, it's not just a case of turtles all the way down though. If life came from somewhere else the question of abiogenesis changes from "How could life appear in the environment of primordial Earth as we understand it, in the time frame of the existence of the planet", to "how could life appear if you have an almost infinite variety of conditions and a time frame of the lifetime of the Universe". That opens a lot of avenues of research that would be pointless if we postulated Earth life appeared on Earth.
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There are two problems with the panspermia hypothesis:
1. There is no evidence that it happened.
2. It doesn't solve any mystery. Abiogenesis doesn't appear to be difficult. Simulations of early earth show that precursors of life are generated easily.
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Only if you assume the premise that life started.
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Not really. Or at least it depends on what you mean by panspermia. (Though as others have pointed out, it doesn't actually address the question of the origin of life)
Basically, panspermia within a solar system is generally considered to be semi-plausible theory unsupported by evidence - though something like finding DNA-based life elsewhere in the solar system could change that. Impacts were likely exchanging large clumps of planetary material between planets for billions of years, and a particularly ha
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If you want to talk about the much more tractable problem of achieving movement of life forms between pl
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Okay, so you got me curious enough to do a little digging into the history of the word - sounds like it originated with a Greek philosopher ~2500 years ago, roughly the same time of the first documented proposal that the stars were other suns, so it was almost certainly referring to life spreading between planets in our own system, as those are the only ones we knew to exist.
It sounds like the idea started taking on more scientific rigor around 1834, a few years before the first measurement of the distance
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That's a mantra, almost an item of faith. It's not an observation.
We live on a planet where, for about 4 billion years, life has existed and has never been extinguished and then re-started within that time period. But similarly (neglecting panspermia in all it's various Imperial New Clothes), at the time that life originated on Earth the conditions were such that life could originate with an immensely high probability - say a 0.0001% probability of it ari
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>if life ever existed on Mars it probably still does,
I suppose to a certain degree it is a matter of faith - but it assumes little more than that life on Mars became at least a fraction as hardy and versatile as it did here.
Every available habitat on Earth is packed with life - including a vast number of slow-living chemovore microbes in the rocks deep underground, possibly all the way through the crust and down into the mantle. Those wouldn't care if the atmosphere went away - they couldn't compete on
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On the subject of articles of faith, there's another one. I don't think I've ever made that unsupported assertion, even in jest. Maybe it's an artefact of having had to do a lot of crystal symmetry operations in my head while working out the petrology of rocks at the microscope - call it a few thousand hours work spread over 4 years - but I know that I can't support a claim like that from the evidence I've seen.
People
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> can't support a claim like that from the evidence I've seen.
What evidence have you seen of, e.g. a protein made with right-handed amino acids being built with a few amino acids replaced by left-handed versions, and still performing the same function? I can't think of any reason to even begin to believe it's possible.
Minerals are different - their raw materials come in a 50-50 mix of chiralities (unlike anything made by life), and more importantly they have no functional requirements. A mineral is *in
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Oh, you're thinking about substituting L- for D- in an existing system? I'm not interested in that - I'm thinking about origin of life, not hacking a pre-existing system. Totally different question. Do people think that "substituting in an existing system" is an important question?
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>Oh, you're thinking about substituting L- for D- in an existing system? I'm not interested in that - I'm thinking about origin of life, not hacking a pre-existing system.
Ah, so we've been talking past each other. Yes - I mentioned a chirality swap *specifically* in the context of right-handed life not being able to evolve into a left-handed mirror of itself. E.g. if we found life on Mars that was chemically identical to Earth life, excepted left-handed, we could be all but certain that the two somehow
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Ummm, I think the UCGA bases in RNA are chiral - but I'd have to check. Hmmmm ...
Which rather implies that the bases themselves are not chiral. (I saw a mention that the purine group in RNA and DNA bases is made by metabolism of gl
Re: Or.... (Score:2)
Regardless if panspermia is how life started on this planet, I think it is the proper policy toward all other planets.
Want to see some aliens? Just bombard Mars with every microbe, lichen, fungus, and whatever else might take hold.
Repeat the process for every other planet and moon in the solar system, and eventually beyond it.
Then sit back and wait a few million years. Iâ(TM)m sure something cool will happen.
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This would not produce aliens. It would produce terrestrial lifeforms which have spent their life cycles off Earth. Every astro-, cosmo-, taiko- naut produces around a kilogram a day of such life forms, and they are considered so important that they are thrown over the side to burn up in the atmosphere.
Wait a few million years, and you'd evolve lifeforms whose biochemistry and genetics would poi
Re: Or.... (Score:2)
So if life started somewhere else in the universe and we got here through panspermia does that make us alien or terrestrial by your standards?
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I suppose I'd better point out that
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Pretty much. As we still have not figured out how to create life artificially, this may be a lot more complex than some people think or even impossible with what we currently can do or know. I used to think, Evolution, fine, that will do it. But Evolution is really just a refinement and differentiating process, i.e. an optimization process. It usually is not able to create things but starts from an already relative initial state. Hence these days I think this may go either way, panspermia or creation from n
Increased Chances (Score:1)
So the "increase in chance" of life existing elsewhere has increased from "almost absolutely certain" to what?
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Sven and Ole have a story about that: https://www.jokesblogger.com/2... [jokesblogger.com]
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I really do not know from where you take that. The "anthropological principle" still very much applies. We just do not know at all how likely not having life on earth would have been as we have no basis for an estimate. As we still have no clue what life actually is, we cannot go that way either for an estimate. It is, for example, quite possible that some statistically exceptionally unlikely thing happened on earth and that we are the only instance of life in this universe.
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Discussing absolute probabilities in the face of the (potentially) infinite is nonsensical. Instead you need to discuss the *normalized* probability - i.e. what are the odds of life arising per trillion stars?
Normalized probability lets you discuss far more interesting things, like the average distance between life-bearing planets.
Old news (Score:2)
It all happened in the first six days.
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Well, that would at least explain why everything is so messed up: Hasty, shoddy work by an incompetent...
It will keep getting older (Score:2)
Because it's so much cooler and you can write papers on it even if the evidence is kind of fuzzy.
well we already know that (Score:1)
like on the 5th or 6th day? /s
And It May Not Be. (Score:2)
Stop putting could or might or maybe in headlines. I want facts not some persons whimsical fantasy about what they don't know.
I MAY be an alien from another world and then again I MAY not be. See how retarded it sounds?
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If you're looking for absolute truth you'll want to find a church, temple, mosque, or maybe a book of fairy tales.
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Indeed. In addition, the physicalist faith also serves nicely these days for those that want their religion to be a bit less obvious.
I know that many/most people have trouble dealing with uncertainty. I do really not understand why that is though and why many people embrace fantasies as truth just to escape the horror of not knowing. Uncertainty in many things large and small is just a fact of existence and denying it makes everything worse in the long run.
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Very fucking funny.
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So.. no science headlines then?
All of life is full of uncertainty. Anyone claiming to know the truth is lying to you, and quite possibly themselves.
One of the cornerstones of science is recognizing that fact, which means that any scientific assertion should *always* express uncertainty. And since the people writing (and reading) the headlines generally don't have the first clue as to how to meaningfully discuss shades of uncertainty, nebulous terms like "may" must take their place.
The paper in Science (Score:3)
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That paper is "Metabolically diverse primordial microbial communities in Earthâ(TM)s oldest seafloor-hydrothermal jasper" - which I'll have a read of in the next cup of coffee.
An earlier paper on the same deposits. [nature.com]
An earlier paper [lyellcollection.org] where the team demonstrate that geochemical biosignatures can be preserved through metamorphism. (This may be paywalled - I can d/l the paper for you if necessary.)
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No comments, no moderation points ; lots of comments, lots of moderator points. (I am a moderate user, and I get
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Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Anyone skeptical of the bird/dinosaur parity, needs to look at a duckling in first molt as it stands up, extends its wings, and looks like some sort of post-atomic disaster movie pterodactyl-creature with a cuter face.
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Oh man! (Score:1)
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If your planet evolves life just reboot it a few times, that will usually clear it up.
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You mean you though we were doomed? Still a very real possibility...
The odds against Panspermia are astronomical (Score:1)
Question: (Score:1)
Is new life still being formed all the time near these vents? Or are the conditions not right for that now. Why it does being early meaning more chances of life, if the window for it to happen is still the same size?
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*mean
Re: new life being formed (Score:1)
https://www.sciencedaily.com/r... [sciencedaily.com]
More than a mile beneath the ocean's surface, as dark clouds of mineral-rich water billow from seafloor hot springs called hydrothermal vents, unseen armies of viruses and bacteria wage war.
Like pirates boarding a treasure-laden ship, the viruses infect bacterial cells to get the loo
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Probably not.
Avoiding "robotvoice"'s [slashdot.org] rabbit hole into the world of viruses (which most biologists think are higher life forms which have ditched a lot of their genetics and almost all of their biochemistry), the greater relevance of this question to Origin(s) Of Life (OOL) is that in the OOL scenario, the fluids can have relatively high concentrations of small organic molecules for feeding an incipient metabolism. But modern waters have been filt
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The first to the table eats the materials that any second (third, fourth ...) potential origin of life in that environment would have used to continue to evolve to being replicating and metabolising. The second prize winner gets eaten.
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Is new life still being formed all the time near these vents? Or are the conditions not right for that now. Why it does being early meaning more chances of life, if the window for it to happen is still the same size?
In a nutshell, what caused life to evolve was (in part) the long time to for simple organic compounds to react to form more complicated ones, etc. This complex mixture of interacting materials was essentially for early evolution.
Now, if there is any kind of this buildup, something living comes along and eats it.
So, no. Life is not newly evolving - the micro environments around the vents are similar, but the macro environments are WAY different these days.
RTFP - not certain if they're fossils or not (Score:3)
There is also considerable uncertainty about the dating of these rocks. Most people have focussed on the old end of the range "possibly as old as 4280 Ma" but you also need to bear in mind the young end of the range "at least 3750 million years (Ma)" ; now these are both pretty old rocks, but that 500 Ma uncertainty in age is longer the than the gap between the construction of the Solar system and the older end of the date range.
Some years ago there was a rather controversial claim (Mojzsis, S. J. et al. Evidence for life on Earth before 3,800 million years ago. Nature 384, 55â"59 (1996)) of evidence of a biosphere back into this time interval. In some respects, that's a no-brainer - if you accept the biogenicity of the 3500 Ma microfossils reported from Australia, then you're also accepting a significant history of life well before then. So that claim (and this one) isn't exactly paradigm breaking, or even coffee-spraying. But going further back into time, you're also getting further away from the conditions in which we know life flourishes (today's conditions) into more speculative ones. We're still significantly unsure about the conditions on the Hadean Earth - in terms of atmosphere composition (including oxygen fugacity), surface temperatures (yes, liquid water was present in at least some places, but how many?), the degree of asteroid (or comet, as if that made a difference) bombardment ...
To me, the most interesting point in the analysis is that they also report sulphur isotope enrichments which (TTBOMK) is a new field for the isotope geochemistry of OOL. They don't have many directly relevant references in this area, but I think this paper is going to be cited a lot. Sulphur isotopes certainly fractionate in present day life, and it is generally considered an essential element for life, so one would expect isotopic differentiation there. Whether this is biotic differentiation, or abiotic differentiation ... time will tell.