Excerpts from a news item with my comments bolded and in square brackets.
Ancient Aust deposits show early Earth crust, ABC, November 18, 2005 ... Tiny zircon crystals dug up from ancient Australian deposits appear to have been formed right after the birth of the planet - a finding that suggests that early on the Earth had a cool crust much like today's that could have harboured life, scientists say. [Also at Livescience & ABC] Most remnants of the very early crust, formed more than 4 billion years ago, are gone - recycled as part of the steady ongoing process known as plate tectonics. But the little zircon crystals survived, Professor Stephen Mojzsis of the University of Colorado says. He and his colleagues say the key was a rare metal element known as hafnium. It is found with the zircons. "This is one of the few Earth materials that we know of that is capable of surviving recycling of the crust," he said. ... Dr Mojzsis and his colleagues found their clues in sedimentary rocks from the Jack Hills in Western Australia, which date to almost 4.4 billion years ago. [I lived at Newman in the Pilbara region in the early 1980s but despite the timeless landscape and spectacular geology, I did not then realize that the underlying Pilbara craton was one of the oldest parts of the Earth's crust.] "First we determined how old these little grains were," Dr Mojzsis said. Their composition suggested they were formed at the right temperatures for making crust and in the presence of water, the researchers report in the journal Science "It was thought that the (early) world looked more like a lunar blasted landscape than a water-filled world with a continental landscape," Dr Mojzsis said. But he said the finding now showed that within a few hundred million years of its creation, the planet had the three necessary elements for life - water, energy and organic compounds. "Now we see that was probably true back to 4.5 billion years ago," Dr Mojzsis said. "This helps us explain how the Earth became the habitable world it is." [If this holds up, then the Earth would be more specially fine-tuned for life than previously thought, and panspermia theories would be unnecessary.] It also might mean that life can occur easily - if the conditions can be right so soon after a planet forms, he said. "We don't know how life got started. But if it happens so quickly, that might mean it's common - that it's easy," he said. "[That is fallacious: that life originated on Earth as soon as it could, does not mean that it is "easy", and therefore "common". The conditions on Earth may have been unique in the entire Universe and the origin of life may not have been fully naturalistic (since naturalism is false). If Mojzsis et al. think that the origin of life from non-living chemicals is "easy", then why has not life (or anything even remotely like it) yet appeared in any chemical evolution experiments when the conditions of the early Earth are reproduced, i.e. why has "the scientific annexe dedicated to the problem of the origin of life ... not been marked by a series of sweeping and spectacular advances - the norm for science - but has lurched indecisively across a landscape dotted with stumbling blocks and crevasses" (see below)?] And that looks well for finding habitable planets outside Earth." ... [Conway Morris has a different view, "Distant solar systems are now being discovered at a remarkable rate ... but ... the results so far are distinctly discouraging: worlds without number, but strange, hostile, and most probably uninhabitable":
"In the absence of direct evidence for extraterrestrial life, the question of the ubiquity of life in the cosmos really hinges on discovering how easy it might be to synthesize life and on reassuring ourselves that there are mansions a-plenty to allow a near-infinitude of evolutionary experiments. Yet, as I shall try to demonstrate ... the scientific annexe dedicated to the problem of the origin of life has not been marked by a series of sweeping and spectacular advances - the norm for science - but has lurched indecisively across a landscape dotted with stumbling blocks and crevasses. Nor does the discovery that the processes of organic chemistry permeate the galaxy offer any more than a crumb of hope. ... And is there really a plurality of worlds, a trillion planets endowed with an unimaginable range of biological diversity, while on a favoured handful ... millions of alien `children' wait for the 'bedtime' story ... ? Distant solar systems are now being discovered at a remarkable rate ..., but, as we shall see, the results so far are distinctly discouraging: worlds without number, but strange, hostile, and most probably uninhabitable." (Conway Morris S., "Life's Solution: Inevitable Humans in a Lonely Universe," Cambridge University Press: New York NY, 2003, pp.22-23).]The earliest signs of life on Earth are 3.5 billion-year-old filaments and tubes in lava deposits in South Africa that appear to have been left by bacteria. In 2001, Dr Mojzsis and colleagues published a study showing evidence of water on Earth's surface 4.3 billion years ago. "The view we are taking now is that Earth's crust, oceans and atmosphere were in place very early on, and that a habitable planet was established rapidly," he said. "The evidence indicates that there was substantial continental crust on Earth within its first 100 million years of existence."It looks like the Earth started off with a bang."... [Mojzsis does realize that "[life on] the Earth started off with a bang" is yet another problem for evolution, because "in its original context there was a very strong underlying assumption that such a process of spontaneous generation could be possible only if there were enough aeons of time" (my emphasis):
"There seems to be a feeling that there is some general and quite simple principle that keeps on being overlooked. ... In this context, it is surely interesting that Francis Crick can write 'An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle, so many are the conditions which would have had to have been satisfied to get it going. ' [Crick F., "Life Itself," 1981, p.88] Crick is careful to continue by pointing out that the time available ..., the diversity of habitats, and combinatorial possibilities of chemistry do not exclude life originating 'by a perfectly reasonable sequence of fairly ordinary chemical reactions'. [Ibid] More than two decades on from Crick's ruminations, however, it still remains the case that the notion of an infinitesimally unlikely series of chemical reactions - that from our perspective can be described only as a 'near miracle' ... remains the unbidden and silent observer at much of the discussion of how life originated. Yet, as Iris Fry ... reminds us, such terminology is effectively that of creationism. Put this way, nearly everyone will ask that the now unwelcome guest should vanish through the adjacent wall, and agree that for all their differences (soup, clay, clouds ...) they share the common hypothesis that the steps from inert to vital must be those of an unbroken continuity. It would be an uncomfortable corollary if the series of meetings, interactions, and reactions of those few chemicals that led to the origin of life were little more than a series of fortuitous and happy flukes. If so, a scientific campaign for understanding the origin of life is not, to put it mildly, going to be straightforward. It is hardly surprising that George Wald wrote, 'One has only to contemplate the magnitude of this task [of making life] to concede that the spontaneous generation of a living organism is impossible. Yet here we are as a result, I believe, of spontaneous generation.' [Wald G., "The origin of life," Scientific American, Vol. 191, August 1954, pp.45-53] This quotation has become justifiably famous, but it is sometimes forgotten that in its original context there was a very strong underlying assumption that such a process of spontaneous generation could be possible only if there were enough aeons of time. As we shall now see, there probably were not, and to make matters worse what obviously did happen in our Solar System may itself be either a very rare occurrence, or, dangerous thought, possibly unique." (Conway Morris S., "Life's Solution: Inevitable Humans in a Lonely Universe," Cambridge University Press: New York NY, 2003, pp.67-68).]
PS: See tagline quote for another installment of Paley's design argument.
Stephen E. Jones, BSc (Biol).
"Problems of Evolution"
"Neither, secondly, would it invalidate out conclusion, that the watch sometimes went wrong, or that it seldom went exactly right. The purpose of the machinery, the design, and the designer, might be evident, and in the case supposed would be evident, in whatever way we accounted for the irregularity of the movement, or whether we could account for it or not. It is not necessary that a machine be perfect, in order to shew with what design it was made: still less necessary, where the only question is, whether it were made with any design at all." (Paley W., "Natural Theology: or, Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature," [1802], St. Thomas Press: Houston, TX, 1972, reprint, pp.3-4)
Posts
No comments:
Post a Comment