Perilous Planet Earth Trevor Palmer Text of a Talk Presented to the Society for Interdisciplinary Studies, Redhill, Surrey, 24 September 2004 Historical Perspective Throughout the first half of the twentieth century, the gradualistic paradigm, championed in the previous century by Charles Lyell and Charles Darwin, had seemed beyond challenge. As envisaged by Darwin, biological evolution proceeded in a slow and stately fashion, through the mechanism of natural selection. As he himself put it, ‘It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each being in relation to its organic and inorganic conditions of life. We see nothing of these slow changes in progress, until the hand of time has marked the long lapses of ages…’. In Darwin’s view, ‘The extinction of species and of whole groups of species, which has played so conspicuous a part in the history of the organic world, almost inevitably follows on the principle of natural selection; for old forms will be supplanted by new and improved forms’. In contrast to this notion of extinction through competition, as new, improved species gradually developed, nineteenth century catastrophists such as Adam Sedgwick, William Buckland and William Whewell, saw the extinction of species as evidence of episodic global convulsions. Their proposed mechanism, based on the ideas of the French geologist, Léonce Élie de Beaumont, was that the gradual cooling of the Earth from an incandescent beginning gave rise to a periodic wrinkling of the crust, producing new mountain ranges and causing volcanic activity, tidal waves and the extinction of species. However, as evidence accumulated during the late nineteenth century, it became clear that there had been no world-wide episodes of mountain-building, and no general link between mountain-building and the extinctions of species. Thus, the cooling Earth model for global catastrophes was ruled out, and no plausible alternative could be found. Hence, evolutionary gradualism dominated, in supreme fashion, for over half a century. Similarly, for events in historical times, it was widely believed that the rise and fall of civilisations depended solely on human activity and never on large-scale environmental crises. In the middle of the twentieth century, Immanuel Velikovsky challenged this prevailing gradualistic paradigm, his first book, Worlds in Collision, appearing in 1950. Taking at face value the stories of celestial battles in ancient myths from around the world, Velikovsky suggested that, on several occasions in historical times, other planets of the Solar System had wandered into the vicinity of the Earth, giving rise to global catastrophes. In particular, Venus, then possessing a comet-like tail, had made a close passage around 1450 BC, causing great problems for humankind, including the plagues of Egypt mentioned in Exodus (which allowed him to date the event, on the basis of Jewish tradition). In attempting to reconcile Egyptian accounts with those of the Old Testament, Velikovsky concluded that the ‘Venus event’ had occurred in the period leading up to the conquest of Egypt by the Hyksos, conventionally dated at around 1650 BC. Hence, since this date differed by two centuries from the one he accepted for the Exodus event, Velikovsky deduced that the conventional chronology must be incorrect, and he proposed a revised one. Velikovsky was not the first to challenge the gradualistic paradigm in the twentieth century, but previous attempts had made little impact. In contrast, the powerful new synthesis proposed by Velikovsky, linking together mythology, astronomy, ancient history and chronology, caught the imagination of many. Nevertheless, it was highly controversial, and dismissed out of hand by most orthodox academics, who deemed it unworthy of serious consideration. As a consequence, the Society of Interdisciplinary Studies (SIS) was formed in 1974, to provide a forum for the open-minded discussion of Velikovsky’s ideas, together with other aspects of catastrophism and chronology. Catastrophism today Thirty years on, Velikovsky’s theories remain as controversial as ever. Leaving aside awkward questions such as how a planet could possess a comet-like tail, a particular problem is how a wandering Venus could have moved into its present orbit, which is almost circular. Although, as pointed out by Laurence Dixon in 2002, a solution is possible which is consistent with the principles of conservation of energy and angular momentum, this would require the Earth to have had its first contact with Venus in a position almost halfway to the Sun from where it is now. That would have put it well beyond the ‘habitable zone’, where water can exist in liquid form at the surface of a planet. Regardless of that, the proposed timescale presents another major difficulty. Even Velikovskian sympathisers such as Wal Thornhill have acknowledged that, if Venus had passed close to Earth in 1450 BC, Newtonian mechanics would require its present orbit to be far more elliptical than is the case. Eric Crew,