Slashdot Mirror
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?
80 percent of all studies are wrong...
We all know that the Flying Spaghetti Monster created life, you fools!
Sure, this is an interesting paper with important ramifications - but I don't see how it has any bearing on the theory of panspermia.
Surely it only takes one tiny droplet of life-carrying comet water to make it into earth's early oceans without being boiled into sterility. If conditions were right, that initial small pocket of bacteria or virii could multiply to cover the planet in a matter of years.
You can't tell me that over millions of years and millions of impacts, not one would come down at a sufficiently low speed or favorable grazing angle to gently melt comet ice into an existing ocean.
Given what we've observed of Mars meteorites ending up on Earth, it's perfectly possible for life from one part of the universe to spread from planet to planet - and even solar system to solar system.
If you buy into the idea that there was life elsewhere in the universe long before life has been found to have existed on Earth - then panspermia is very possible.
My problem with that theory is that it doesn't answer any questions about how life formed in the first place. There still has to be an origin world - and explaining how life appeared there is just as hard as explaining how it might have formed here in the absence of panspermia.
www.sjbaker.org
> 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
So panspermia allows for a scientific explanation of life's formation
that is perhaps more plausible than formation on early Earth.
Scientific? Sounds to me like you have a untestable theory for the origins of life. You can test components of the theory, but ultimately you always be able to say... well sure it came from somewhere else, but it's been millions/billions of years and all of the concrete evidence has been washed away.
Well, the panspermia theory is a bit like intelligent design - it is not one theory, but several theories, however, the panspermia theories have a chance to be proven true, while the ID theories tend to be proven wrong.
Examples:
- the cosmos helped life come into existance by simple organic molecules that were
- formed in space
- ejected from a planet
- life spread through our solar system, that is:
- from mars
- the asteroid belt was formely a planet hosting life which
- DNA/RNA came from space
- bacteria survived a journey through the cosmos
The study reported by slashdot makes some of these theories unlikely, but not all of them.
I'm still trying to figure out what people mean by 'social skills' here.
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.
Notice he has two parts in the statement. IF we detect life elsewhere, we can make comparisons. Life elsewhere, in itself, wouldn't be the proof, it's just a necessary condition to make observations. Many other theories on the origin and nature of early life could be strengthened or invalidated if we found it elsewhere and had more than a single sample to study. This is not unique to the theory of panspermia, although of course the outcome validating the theory would be that both samples available to us would in fact show enough similarities to indicate a common origin.
Comment removed based on user account deletion
I didn't say that we necessarily need panspermia to explain the origins of life, or that the theory is testable.
If we find a perfectly good explanation for the origins of life on Earth - then that is still not proof that life actually did start here.
That means that Panspermia is unfalsifyable - which is a bad thing for a scientific theory. All you can do is to presume that it's false until someone proves otherwise.
But the previous post questioned why Panspermia could possibly be of any help in explaining the origin problem. I merely pointed out the theoretical possibility that Panspermia might some day be an important explanation of how this happened.
If you somehow managed to utterly PROVE that life could not possibly have originated on early Earth, science would be in deep trouble without something like the Panspermia theory which allows one to hypothesise other sets of conditions and longer timescales.
Suppose we found evidence that life could not have formed without some particular chemical compound that cannot ever have existed at earthly temperatures and pressures? Then you'd be forced to admit that life started elsewhere. In a sense, you could prove panspermia by showing that life could not have come from early earth. Given that there is demonstrably life here now, you'd have proven that it had to have come from elsewhere.
A true test of Panspermia would require us to find another planet - perhaps one very similar to Earth and to demonstrate that life here and life there shared striking similarities that could not have arisen by chance. For example, if both life forms had similar long stretches of 'junk' DNA. You'd be unable to show that the 'life originated on earth' theory was true anymore because by symmetry, it might have arisen on planet-X and travelled here instead of the other way around.
So Panspermia might be proved, conclusively. If we found evidence of life on (say) Mars and could demonstrate that this life bore striking resemblances to Earthly life. You'd then be forced to admit that the overwhelmingly most likely explanation was that life could travel from one planet to another. You'd still be left with the question of whether it originated on Earth, on Mars or in some yet other place...but the idea that life could be formed in one place and travel to another would be demonstrably true.
www.sjbaker.org
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.
And yet, when fighting alternative models like "Intelligent Design", everyone pretends scientific findings were cast in stone.
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
"If it is just us, it seems like and awful waste of space" - Carl Sagan 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 ans
Say there was an ocean on earth, and something big slammed into it, vaporizing all the water. Wouldn't that water just eventually precipitate back down?
I mean, vaporizing something like a person would pretty much destroy them, but it doesn't do much to eliminate individual atoms, it just moves them around. So the ocean itself might be turned into water vapor, but then where does that all go?
I'm sure a big enough impact could blow matter up into space, where it'll float away never to bother the busy earth again, but I would think that most matter gets propelled outwards from an impact, not up. So wouldn't a meteor hitting an ocean just spread the water around?
One time I threw a brick at a duck.
Regardless of what you think of the grandparent's stance on creation (and the complete absurdity of it that you imply), his point about scientists saying "we know" instead of "we currently believe" is still valid.
You only responded to one part of his statement, but I'm more curious as to what others think of the other half. Personally I agree with that point.
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
Many of the plaintiffs in lawsuits against idiotic creationist "equal time" laws have been religious figures. Do not make the assumption that all religious people buy into the creationist agenda.
Logic, m'boy, logic. If you're gonna spout off psuedo-science like the pros, you gotta get a hold of some logic.
why would man and animals need eyes if they couldn't see before, sight is a very high-level ability, a creature without sight doesn't realise he needs it? What does "realise he needs it" have to do with anything? Evolution is not intentional, evolution is not a "force". Nothing decides to evolve. A species ability to visually perceive offers many advantages, depending on the environment. Mate recognition, prey recognition, predator awareness, etc.
Also in 'natural selection' humans would have been eaten by everything without sight no matter how developed the brain was.
Which humans? Modern humans? There's no sense behind those ears, boy! Modern humans can create weapons and modify their environment to prevent being "eaten by everything". If you're talking pre-historic humans, I'd be willing to bet that a fair number of them were eaten.
Still, the ability to form even primitive weapons is an amazing advantage. Plus, do you really think people were always as they are today (physically, senses, etc)?
If we came from the ocean then why can't we breath underwater and if we are the most 'evolved' of creatures then why are the birds flying around the earth like it's going out of fashion? We're wingless, can't go underwater without breathing equipment, the ascent of man? Yeah right.
Who judges humanity as the "most evolved?" You? Last I checked, no mammals have gills, and the set of species that is truly amphibious is rather limited and primitve.
How do you propose a warm blooded animal should go about absorbing the incredible amount of oxygen necessary to maintain a fast metabolism with something like gills? What does Genesis 1:1 have to say about that?
I'm sure if these 'scientists' really thought about it, evolution is absured, mutation is more accurate, but I wasn't a piece of garbage from 10000 billion years ago. I mean even micro-biology points to an intended design. How come nobody talks about entropy no more? Oh if we we're the offspring of monkeys then why arn't monkeys turning into humans?
Ahh, here we see the real truth. It's personal, isn't it? You just couldn't possibly have been from genetic lineage decended from something more primitive, could you? News flash buddy: Just because you want something to be a certain way, doesn't make it so.
Your "intended design" is completely and totally without evidence in reality. The so-called "evidence" is nothing more than fanciful thought expirements based on theology rather than logic. Put it this way: any "designer" with the ability to exactingly design all the myriad forms of life is equally capable of "designing" a process by which life can adapt, change and mutate to best suit its environment over time. I suspect that a being with that much power is perfectly capable of making you an "offspring of monkeys", whether you like it or not.
(pssst.. nobody's forgotten about entropy, it's just that we're all sick of listening to very confused creationists try to bend the second law of thermodynamics to fit their will)
"Interesting, because this directly contradicts the Nova mini-series Origins that just finished running on PBS. Science never stops moving."
Those inclined to believe the Bible and feel skeptical when science apparently contradicts it, should take comfort in the fact that science's story has changed over the century whereas (relatively) the Bible's has not.
This is does not mean that religion ought to ignore and deprecate science. Things like that Galileo business provide powerful insights into how to interpret scripture. If the Bible says "sunrise" it should be interpreted phenomenologically. That is as an observation of brute phenomena and one should not take that as an explanation of the mechanism that gave rise to the phenomena. (Incidentally, the weatherman is not a flat-earther because he tells us sunrise/sunset times.)
With this phenomenological principle in mind, someone who believes in the Bible will be able to interpret its statements about God according to that same phenomenological principle. Troubling verses about God "doing evil" are thus explained. To wit, God establishes things like gravity and hydrodynamics that move in predictable patterns. When those patterns conspire to crush us, via tsunami or hurricane, we perceive evil fom God's hand.
But the character behind these phenomena is more reflective of the scientific principles of natural law.
I suppose I should ask for an offering at this point. Instead, I'll ask that we all work a little harder at our science so we can better predict natural forces and prepare for them.
That's just because such "theories" either ignore any inconvenient facts, or revise the "theory of Creation" so that it is impossible to disprove (and then pretend that's what the "theory" said all along). Eventually, they can say (like you did) that their theory has been stable longer than the physically-testable theories, and is therefore somehow "better".
You obviously haven't read much about the Church of the FSM. Part of their Articles of Faith is that the FSM continually adjusts reality so that you can neither prove nor disprove its existence - much like the fanatics who insist that the Bible is the literal truth say that their "ever-truthful" God created the world thousands of years ago, complete with all the physical evidence that makes us think it is billions of years old.
This theory also directly contradicts another theory I saw this month in Sky and Telescope, which referred to this article. This one is for the formation of the outer gaseous planets and the kuiper belt. The basis of the theory is that the orbits of all the gas giants should have been closer to the sun, as they would have required a much denser gas-and-dust cloud than would have existed as far out as they are now. As well, the kuiper belt would have formed closer to the sun.
Due to gravitational interactions between the gas planets and the kuiper belt objects, Jupiter's orbit shrinks and Saturn, Uranus and Neptune expand, with the latter two actually changing place and moving into much more elliptical orbits before settling down into their current orbits. These larger orbits put both planets squarely into the primordial kuiper belt and, well, cause the Late Heavy Bombardment.
"No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
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.
The best place to form and spread from may not necessarily be the best place to grow up. Maybe life on Earth originated in Jupiter's atmosphere or moons, for example, and then spread to Earth. Earth may be a better place to grow more diverse and complicated. It is sort of a "comparative advantage" of life economics.
Table-ized A.I.
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.
Do you believe God made the Universe, Heaven, Earth, and everything in it?
I do.
Science is the word we use to describe our research trying to find God through evidence of his Creation.
You think Man authored the Laws of Physics which scientists hold so dear? Think again. No man set Avagadro's constant, or any of the other parameters of our observable universe.
If God did create us, did he intend us to try to find Him, or mull around like a bunch of obedient ignorant sheep doing the bidding of those who take it in their mind to control us?
Think of what each faction is trying to do. Scientists are trying to understand God's creation and what our place in it is supposed to be. Damn near every religion I have even run across is full of control and obedience to men, often without ANY concrete evidence of truth, just hearsay.
Now, in the BIBLE you referred to, even there, if you take the BIBLE to be literally the Word of God, it is full of warnings of the false prophet.
Personally, I feel a lot closer to my Creator knowing I can see and verify His work, knowing full good and well I am seeing work of intelligent design. I do not feel comfortable at all dealing with people who sell me a relationship with my Creator like they would sell me a speculative stock investment, based on hearsay and faith that its a sound investment.
Maybe I am a bit jaded by now, but it seems all I have seen religions do is fight. I get the idea all this fighting pleases God about as much as I appreciate my cats fighting. Believe me, I derive no pleasure at all in seeing my cats all scratched up, ears mangled, and bloody.
Am I supposed to believe there is a God up there somewhere who tells various factions all over the Earth to gather in his name and smite the other ones?
Or does simple knowledge of human behavioural psychologies and obedience structures indicate the Gods of Religion are just some entity created by men so they could use it to control other men?
If God created me with sufficient intelligence to seek Him, why is he gonna hold it against me for doing exactly that?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]