Thursday, June 08, 2006

Big bang in Antarctica - killer crater found under ice #3

Big bang in Antarctica - killer crater found under ice, EurekAlert!, 1-Jun-2006, Pam Frost Gorder, Ohio State University ... [Continued from part #2

Graphic: "Gravity fluctuations beneath East Antarctica measured by GRACE satellite," SPACE.com

Which gets me, eventually to the connection between this claimed giant meteor impact ~250 mya that it is claimed eventually helped cause Australian to split off from Antarctica ~150 million years later ~100 mya!

Australian planetary scientist, Professor Emeritus Stuart Ross Taylor (who I had quoted from in this previous post), has some other great quotes in his book, "Destiny or Chance: Our Solar System and its Place in the Cosmos" (1998) about how rare Earth is, and therefore "the odds of finding 'little green men' elsewhere in the universe decline to zero." But as a (presumed from the tone of the book) atheist/agnostic, he comforts himself that "even on this well-endowed planet, there was nothing preordained about the emergence of Homo sapiens on the plains of Africa," and "even when everything else in the environment was perfect, blind chance still ruled the development of intelligent life":

"However, despite this great flowering of life, intelligence seems to have developed only among the vertebrates, and there, rarely. Among the 24 orders of mammals, high intelligence seems to have arisen in only one, in primates. Why is this so? Clearly high intelligence has little evolutionary advantage, for it has appeared once in tens of billion attempts. As Ernst Mayr ... the biologist, has pointed out, [Mayr, E.W., "Does It Pay To Acquire High Intelligence?," Perspectives in Biology and Medicine, Vol. 37; No. 3, 1994, pp.150-154] even the development of high intelligence may not lead to the ability to communicate with distant planets. Only one of the 20 or so civilisations that have arisen on Earth in the past 5000 years has developed the technology to communicate with other possible life forms elsewhere. But even on this well-endowed planet, there was nothing preordained about the emergence of Homo sapiens on the plains of Africa. Three separate continents were available on the Earth on which the later stages of the evolution of land animals could evolve. [Pollard, W.G., "The prevalence of Earthlike planets," American Scientist , Vol. 67, November-December, 1979, pp.653-659, p.654] All these vast areas shared the benign conditions on this planet that make it such a comfortable environment for life. When life first invaded the land in the late Silurian and Devonian Periods about 400 million years ago, the scattered continents were slowly uniting into a single land mass, which we call Pangaea. During the next few hundred million years, as plants and animals evolved and the dinosaurs became dominant, this great mass began to split up. A large southern continent, called Gondwana (after an historic region of central India), sailed away. This in turn slowly fragmented into familiar pieces that now appear on our maps of the world. Australia, Antarctica and South America, carrying their cargo of animals and plants, broke away leaving Africa in isolation. Australia separated from the frozen southern continent and departed northward. Africa and India also travelled north at a rate of a few centimetres a year, finally ramming into Europe and Asia and creating from this titanic collision the mighty mountain chains of the Alps and Himalayas. So were formed the three continental masses on which the later evolution of land animals proceeded independently. Australia, isolated from the rest of the world, produced the weird marsupial animals that puzzled early explorers. In South America, the land animals and their fossil ancestors intrigued Charles Darwin by their differences from his familiar European species, but the South American monkeys, primates like us, never left the trees. Africa, in addition to the splendid array of lions, antelopes, zebras, giraffes and the rest that we all admire, managed to produce another unique species, Homo sapiens. On the other continents no species remotely resembling us arose. The sobering conclusion is that even when everything else in the environment was perfect, blind chance still ruled the development of intelligent life. When the remote possibilities of developing a habitable planet are added to the chances of developing both high intelligence and a technically advanced civilisation, the odds of finding 'little green men' elsewhere in the universe decline to zero." (Taylor, S.R., "Destiny or Chance: Our Solar System and its Place in the Cosmos," [1998], Cambridge University Press: Cambridge UK, 2000, reprint, pp.191-192)

Taylor (evidently not realising the contradiction), had earlier cited Laplace's famous reply to Napoleon who asked where God fitted into Laplace's mathematical model of the origin of the Solar System, that he had "no need for that hypothesis":

"The orbits of the planets, although elliptical as every schoolchild now is told, are in fact nearly circular. This regular arrangement led Laplace to the concept that the system had arisen far in the past from a primitive rotating cloud, the `solar nebula'. This idea has survived. This was in contrast to the ideas of Newton, who had believed that the Solar System had been created in its present form only a few thousand years earlier. Laplace however was an inhabitant of the Age of Enlightenment. Born into what we would now call a middle-class farming family, he had survived the French Revolution and was a distinguished member of the French scientific establishment at the beginning of the nineteenth century. He was able to show that the apparent variations in the orbits of the planets were self-correcting and so God was not needed to adjust the system. Laplace gave a copy of his famous book to Napoleon, to whom he had taught mathematics when the Emperor had been an artillery cadet. Bonaparte, seeing no mention of God, presumably the designer of the system, asked Laplace about this omission. Laplace, having solved the problem that had bothered Newton, made his famous reply that he had `no need for that hypothesis' [Brush, S.G., "A History of Modern Planetary Physics," Vol 1. Cambridge University Press, 1996, p.20] A watershed had been crossed. Now the solar system could be considered as having arisen by the operation of natural processes from a primitive beginning, rather than being created perfect in the instant. This marks the beginning of modern attempts to understand how the Sun and the planets came into being." (Taylor, 1998, p.15)

But as Taylor had written in the article I had cited in that previous post, Laplace was wrong as "attempts to find some general formulae for recreating the detail of the Solar System are likely to be on the wrong track" since "Local accidents have predominated over general theories":

"These new discoveries reinforce the message from our own system. Nothing resembling our Solar System has been discovered. The conditions that existed to make our set of planets are not easily reproduced elsewhere. Indeed, no two planets in the Solar System are alike. Likewise, the 80-odd moons are also odd characters that defy efforts to put them into pigeonholes. So it should have come as no surprise that when nature tried elsewhere to build planets the end result was different. We are left with the conclusion that attempts to find some general formulae for recreating the detail of the Solar System are likely to be on the wrong track. Local accidents have predominated over general theories, just as some overlooked detail of the landscape may ruin the course of a battle that was planned according to the best principles of military strategy." (Taylor, S.R., "The Solar System: An Environment For Life?," in Walter, M., ed., et al., "To Mars and Beyond: Search for the Origins of Life," Art Exhibitions Australia: Sydney & National Museum of Australia: Canberra, Australia, 2001, p.67)

Earlier in the same article he noted that "Many unique and unrepeatable events occurred as the planets were put together. So the formation of planets like the Earth is not an inevitable result that could be repeated like a gigantic computer program":

"HOW ARE PLANETS MADE? The most popular current theory is that planets are built up `brick by brick' from smaller bodies called planetesimals. This is usually referred to as the planetesimal hypothesis. There is a lot of evidence for the former existence of planetesimals during the formation of the Solar System. For example, the large tilts of many planets (the Earth's is 23.5 degrees) have been caused by collision with very large bodies well over 1000 kilometres in diameter. The rapid 24-hour spin of the Earth is probably due to a giant impact that probably formed the Moon as a by-product. Venus, in contrast, has almost zero tilt and is rotating very slowly backwards, taking 243 Earth days for one rotation. Perhaps Venus never experienced a giant impact. The large icy giant, Uranus, 14 times more massive than the Earth, is lying on its side. A body the size of the Earth would be needed to tip Uranus over, while collisions with a body between three and 10 Earth masses would be needed to produce the 27-degree tilt of Saturn. All the planets spin. All the planets spin at different rates. These observations all point to the growth of planets in our system from a series of large bodies rather than from dust or small - less than 10 kilometre diameter - bodies. The ultimate significance is that many chance collisions occur randomly while planets are growing. Many unique and unrepeatable events occurred as the planets were put together. So the formation of planets like the Earth is not an inevitable result that could be repeated like a gigantic computer program, but partly depends on random events during the early history of the nebula. Venus, Earth and Mars (we have no data for Mercury at present) all appear to have lost volatile elements such as lead, sodium, potassium as well as water. This appears to be typical of the entire inner Solar System. The most plausible model is that early violent solar activity swept away not only the gaseous elements, but also ices and volatile elements that had not condensed." (Taylor, 2001, p.59. Emphasis original)

This is a good (or bad!) example of atheist/agnostics' `heads-atheism-wins-and-tails-God-loses' thinking. If the Solar System arose as the result of simple natural laws, then science has "no need for that [God] hypothesis." But if the Solar System arose as the result not of simple natural laws, but by a series of unique events, then again, science has "no need for that [God] hypothesis"!

[Concluded in part #4]

Stephen E. Jones, BSc (Biol).
`Evolution Quotes Book'

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