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Study Puts Hole In Comet Theory Of Life's Origin
Astervitude writes "A new study by US and Japanese scientists has put a serious dent into one version of the popular panspermia theory that credits comets for bringing the seeds of life to Earth. Surveys conducted by the University of Arizona, the National Astronomical Observatory of Japan and others now show that objects from the main asteroid belt between Jupiter and Mars were largely responsible for the period of Late Heavy Bombardment that ended 3.9 billion years ago. UA Professor Emeritus Robert Strom believes that no more than 10 percent of the Earth's water comes from comets and any oceans then extant would have been 'vaporized by the asteroid impacts during the cataclysm.'" Interesting, because this directly contradicts the Nova mini-series Origins that just finished running on PBS. Science never stops moving.
New study by scientists disagrees with programme made by television professionals to give the illusion of education to the masses?
;)
Shocking!
I don't read your sig, why do you read mine?
> Why would it be easier to believe that life began elsewhere
> than to assume that life started here on Earth?
Two reasons:
1) We have some idea of the early conditions on Earth - but maybe
we have a hard time believing that those were conducive to
forming life from scratch. If life started elsewhere then there
is almost no limit to the range of concievable temperatures, pressures,
gravity, radiation and chemical environments in which it might
ultimately have formed.
2) Time: Is the Earth old enough for that very early phase of going
from completely non-biological materials to DNA, cell walls, etc?
If not - then panspermia explains that by saying that life was
around in some other place LONG before the Earth was formed.
So panspermia allows for a scientific explanation of life's formation
that is perhaps more plausible than formation on early Earth.
www.sjbaker.org
> 80 percent of all studies are wrong...
Which means that there is only a 20% chance that the study that shows that "80% of studies are wrong" is right.
Which means that we have no idea what the probability of error is without doing a lot more studies on the subject.
My head hurts.
www.sjbaker.org
Yes, but, as you point out, the Problem with the Idea of Panspermia is that it does not explain how life arose -- it just shifts the blame for it (as it were) elsewhere.
Edward@Tomato - /home/Edward/ man woman
man: no entry for woman in the manual.
"Qua!?"
Increasingly complex molecules competed for energy and material to form larger and more sustainable molecules. The molecules that arranged themselves by chance to absorb the most energy and strongest structure surivied the longest, and this process continued until basic structures combined in a symbiotic relationship that would help sustain the period of those structures existance. This process continues until basic cell structures formed, and again combined by chance to form larger structures. Eventually the strongest and most energy effecient structure was developed by chance through the process of natural selection until we had basic repoductive structures. Mutations which led to longer life and thus more chance of reproduction continued until movement and adaption were constituents, from there entire structures began to work together to from basic cells, which over time developed processes for reproduction and survival through chance combination and mutation. Cells began to grow in complexity in a bid for survival, by chance some began working together to form multicellular groups, which became organisms with adaption relative to the abilities of each cell, then came encoded cellular variation to ensure multicellular groups continued to form by precedence. Over much time increased numbers of simple structures combined to form larger and more complex structures witht he ability for their own kenetic movement beyond growth, because of the natural selection of moveable multicellular organisms made them more adaptable then others and thus more likely to reproduce. Eventually all sorts of mutation and chance combination occured which would lead to ever more complex structures with better adaptability till the first regonizable biological systems formed. From there we have basic sea life and countless steps later down the evolution chain, human beings.
Of course, it might be out of order, and one would have to know that the time this would take would be immense.
For those who make the chance argument, stateing that such complex structures canot possibly arise by chance i say:
Look at the size of the universe, there must be at least 125 billion galaxies, each with roughly 100 billion stars, each with the possibility of terrestrial planetoids, each with a massive surface area with plenty or energy and materials for the possibility of forming the molecular strutuces by chance that are a prelude to life. Then take that number, and times it by the age of most galaxies.....All of a sudden the chance doesnt seem so small.
As for complexities, whos to say life is complex, its equally possible that life is mearly countless basic systems working symbiotically for the goal of survival and reproduction. I give the cargo cult as ana example: In World War 2 several tribes worshiped American cargo planes because the ability and complexities of human flight were so vast to them that the cargo planes could only be explained as items of a supernatural nature. It never appeared to them that these planes were not godly and no complex beyond their understanding, such is a cargo plane simply a number of systems discovered by humans by chance working in parrallel.
As for thurther complexity: If life is so complex that the possibility of chance is so small, then how does one explain oru manipulation of life, for example insulin producing bacteria, or the mapping of the genome. How does one explain the evolution and appearance of new viruses and bacterial strains by chance.
Life is beautiful, it is wonderous and magestic, but it is not beyond our understanding. It arose by chance, it's growth is determined by evolution and it is not complex. It just appears that way to some.
I always think, that maybe the reason ID and creationalists fight progress and science is they think that discovery is taking the magic and beauty away from life. But instead, what they dont realise, is that all it is doing it discovering more beautiful and wonderous details. We are not finding answers, only more questions. We are giving power to ourselves and whatever purpose we serve. There is no need to be afraid, no need to be ignorant, only a need to be open to the wonders that surround us and fuel the need for discovery that comes with conscienceness.
If conditions were right, that initial small pocket of bacteria or virii could multiply to cover the planet in a matter of years.
I do not disagree completely, but one word is definitely wrong in this sentence. Virii.
A virus is a parasitic lifeform, that "lives" only inside of a living cell. No cell - no life, no multiplication, no evolution and no spreadnig. Outside of a living cell a virus is an inactive lump of protein and nucleic acid.
Other tahn that, a virus is a potent driver of evolution by mixing up its host genome, possibly creating new genetic structures.
Ni.
Personally I always hate panspermia. It seemed to fail Occams Razor pretty soundly. Yes, life on this planet came from an asteroid or comet from another planet. Well, if life can exist there to bring it here why can't it just develop here. Seemed like a big waste of time to me. I see no reason we cannot have a homegrown abiogensis on good old Earth. It's not like we hit some major hitch and need an alternate explanation that explains nothing.
It is no longer uncommon to be uncommon.
Comment removed based on user account deletion
Although the panspermia theory is intriguing, it does NOT answer the question of the origin of life -- was it from another planet that was inoculated by an even earlier comet..... It's like the theory that the Earth rides on the back of a giant turtle/ But what does that turtle ride on? Or is it turtles all the way down.
If we are to assess the probability that life is exogenous or endogenous to Earth, we must ask about the relative probability of: a) life forming on a planetary body versus b) life forming on a planetary body which then survives being blasted into space, travelling interstellar distances, happening to collide with another forming planet of just the right composition (without ever venturing too close to some hot star), and surviving that collision.
Even if the probability of life arising on a planet very very low, the relative probability of endogenous versus exogenous origin is very skewed toward endogenous origin. Because exogenous origin requires both endogenous origin (somewhere else) and then a low probability trip between planets, exogenous origin would seem to be very unlikely unless there are large numbers of planets with endogenous life that spew lots of interstellar-traversing chunks. But if there are large numbers of planets with with their own endogenous life, then the probability of life forming on Earth endogenously must also be high and trump the low likelihood of life just happening to make it from somewhere else.
Two wrongs don't make a right, but three lefts do.
That's an interesting comment that glosses over many of the statements of science that are commonly excepted so much as "fact" that anyone that points out inconsistancies in them is labeled as anti-science or ignorant. Of course we are always learning more and yesterday's accepted theories have to adapt to new knowledge, but the virulence some people have for defending pet theories borders on intolerance. /. you get modded into oblivion. Please note I didn't relate it to Creationism or Intelligent Design, it's just that the theory of evolution itself has about as many holes as IE. Sure, right now it's the best idea going, but that doesn't mean it's the end of the conversation. Yet questioning it all usually does end the conversation.
A good case in point is evolution, where if you don't mention it in a glowing light on
If thou see a fair woman pay court to her, for thus thou wilt obtain love
People have to understand what "we know" means. Adults have to take everything we hear with some number of grains of salt. Scientific statements of "we know" are more reliable than metaphysical statements of "we know", and adults should understand that for ourselves.
Which is why it's important for people to learn about science before tehy accept its knowledge. Just like it's important for us to learn about religion. Not just to learn the science, like reading it in _Discover_ magazine, or to learn the religion, like reading it in a bible. But we need to learn how the "knowledge system" works: its history, its failures, its successes, its alternatives and their histories. Just like we don't need to learn enough science to be scientists in order to appreciate science (and our world that it explains), we don't need to become experts in the discipline, to become scientists or clerics. We need to understand what the strengths and limitations are, and what it means when a scientist or a cleric says "we know", "I believe" or "this is". Otherwise, we're just faking it, and we will make all kind of mistakes, without ways to recover. And that's very dangerous, considering how powerful are these ways of knowing, whether they're right or (especially when) they're wrong.
--
make install -not war
Well, I will point out that the various theories of Creation in the last few hundred years has been far more stable than any scientific theory put forward.
That is because ignorance is stable.
Perhaps it would be better if science types started using rhetoric like "We Think" or "We Believe" instead of "We now know..."
We 'science types' usually do. The problem is that if we start saying 'we believe' too much in public, our ideas get attacked as 'just another form of religion'.
I mean, the version of Darwinism that was taught in my school has pretty much been shot to heck, but my Biology teacher sure enough said, "This is how it happened."
That is because the science taught at school has to be simplified hugely. The version of almost any scientific idea taught at school is largely wrong. The idea is to open minds to the principles of science.