More than twenty five years ago, when reading The Urantia Book account of the early geological history of our planet, I noticed some statements about the growth of the planet and its moon, and also ocean formation, that struck me as being rather odd. However this material was followed by the book's account of continental breakup and the subsequent continental drift. I found this exciting--and that caused me to overlook the "odd" material until quite recently.

The book's account of continental drift was exceedingly prophetic if made in 1934 or even up to the time of first publication in 1955. I had once done a three semester undergraduate course in geology and distinctly remembered how the lecturer had quickly dismissed the continental drift theory of Alfred Wegener with the brief comment that there were no known physical forces that could possibly account for the splitting apart of whole continents.

A quick check on the history of the continental drift theory revealed the enormous opposition it received from leading geologists in the USA and Britain, among them Rollin Chamberlin and Sir Harold Geoffreys.

This opposition remained until around 1960 when geophysical surveys of the mid-ocean Atlantic ridge revealed that, as the Earth's mantle  melted, the molten rock was forced upwards thus causing the sea floor spreading that could account for continental drift.

Further clinching the prophetic nature of the Urantia Book account, later geophysical work revealed that the initial breakup of a supercontinent, as proposed by Wegener,  actually occurred much earlier than the 200 to 250 million years he allowed. Gradually this date was pushed back to about 500 to 600 million years to finally coincide with the Urantia Book's 750 million years BCE.

My memory of the book's "odd" account for the early formation of our planet-moon system was stimulated by a recent TV documentary on the Apollo missions to the moon starting back in the 1970's, and the contemporaneous Russian missions that also contributed a tremendous amount of valuable new scientific knowledge.

Particularly the Americans, but also the Russians, had done remarkable things that now allow us to get a much better picture of how our Earth-Moon system developed and grew. Much of this was brought about because of the extensive sampling of geological materials from many sites on both sides of the Moon, including the highest mountains, the larva plains known as mares, and many of the impact craters formed by meteors.

It was also fortunate that much of the analytical work did not take place prior to the new and quite remarkable techniques and new technology (including zircons and ion probes) for  dating of rock samples becoming well understood.

Very briefly stated, results, such as their identical ratio of oxygen isotopes (which is different from meteoric material), showed that although the basic materials from which the Earth and its satellite Moon developed are entirely similar, nevertheless there are important differences that must be explained.

Three of these differences are the complete lack of water associated with minerals and rocks from the Moon, the iron content at 30% for the Earth and 2% for the Moon, and the average density at 5.5 g/cc for the Earth and 3.3 for the Moon--the latter being about the same as the density of the Earth's crust. Heavily crystalline Moon rock samples that are more than 4 billion years of age also showed this material was once molten.

Radiometric dating showed that Moon samples from the mountain regions go back beyond four billion years from the present while the basaltic rocks from the mares formed between 3.9 and 3.1 billion years ago.

Prior to the data from these Moon missions becoming available there were three main theories for formation of our Earth-Moon system--co-accretion, fission, and capture.

• The co-accretion hypothesis suggests that the moon and the Earth were formed together from a primordial cloud of gas and dust.

• In the fission scenario, a fluid proto-Earth spun so rapidly that it ejected a mass of material that became the Moon.

• The capture hypothesis has it that the Moon formed elsewhere to be later captured in the strong gravitational field of the Earth.

Co-accretion is the means by which The Urantia Book says our Earth-Moon system formed together. There are problems. The hypothesis cannot account for the observed angular momentum of the system, nor the absence of bound water in Moon rocks, the depletion of iron, the density differences, nor the radiometric data.

The fission scenario has been extensively modeled but no one has been able to produce a computer model that will fit the known data.

The capture model has the same problem. Even with a supercomputer to direct it, the operation of capturing a satellite moon, and retaining it, requires quite extraordinary precision.

In 1981, W.K. Hartman came up with what was at first considered an outlandish proposal. He had a body of about Mars size collide with the Earth in a glancing blow. The dust cloud that  developed was mainly from the crustal material of the Earth, and, from that, the Moon was formed by accretion.

The heat generated by the impact drove off all the water from what was to form Moon rocks. The impact occurred after iron and other heavy elements had gravitated towards the center of the early molten Earth, thus accounting for the moon's iron deficiency. The model explains  the density match between the Moon and the Earth's crust, the Moon's volcanic activity that gave the lava flows, and it readily accounts for the very large amount of radiometric data collected.

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The hypothesis has the time of collision at more than 4 billion years ago with the subsequent accretion being relatively rapid. At the time of collision, the Earth was already close to full size.

The Urantia Book informs us that 2.5 billion years ago the Earth was 1/10th its present mass, and, up to 2 billion years ago, the Earth and Moon were much the same size, the Earth then being 1/5th its present size. The Earth then grew rapidly due to it capturing large space bodies.

The book says that 1.5 billion years ago, the Moon was at about its present size and the Earth was 2/3 rd the final size it attained about 1 billion years ago. These data are plotted in Figure 1 below. The decrease in the mass of the Moon is because it is given as being 1/5th the Earth's final size 2 billion years ago, and attaining its present size by -1.5 billion years. Currently the mass of the Moon is about 1/80th that of the Earth. In the second section of Fig. 1, we assume the size comparison was meant to be in terms of radius rather than the mass as this removes the anomaly of the moon's collapse.

The Urantia Book tells us that 1.5 billion years ago the Earth was a fiery furnace, then for thousands of years was enveloped in a cloud of steam such that the sun never shone on its surface.

By 1 billion years ago an ocean and a land continent appeared but the atmosphere was virtually devoid of oxygen until later generated by the sea weeds and other forms of vegetable life. Reconciling this whole scenario with the available data would, I think, be quite impossible.

For example, the book's version has the mass of the moon doubling between 2.5 and 2.0 billion years ago. The Apollo missions found that those vastly extensive mares (seas) we can see from Earth are composed of the basalt from lava flows that date back  3.1 to 3.9 billion years. According to the book's version, they should be buried under hundreds of miles of accreted materials.

On Earth, modern geology has shown the existence of stromatolites on at least three  continents. These quite unique structures of limestone are known to be formed by blue green algae, and date back as far as 3.5 billion years ago. This surely is strong evidence for the existence of oceans at those times. These organisms are photosynthetic, the by-product of their chemistry being oxygen.

Initially this oxygen would have been mopped up by the excess iron dissolved in sea water and then precipitated as the ferric form of iron. The deposits from this process are found at places such as Isua in Greenland, and date back to 3.8 billion years ago. Sulfides also acted as oxygen acceptors, being deposited as 3.5 billion year old sulfate deposits (barite/gypsum) at places like Pilbarra in Western Australia. This deposition of oxidized minerals would have continued until about 1.7 billion years ago when the sea water was clear of the excess.

The 3.5 and 3.8 billion year old deposits in Australia and Greenland outcrop at the surface. By The Urantia Book's account, they would be covered to a depth of more than 1000 miles by materials accreting in the last 1.5 billion years.

Thus, prior to the start of continental drift and the initial formation of the more advanced life forms, there are considerable divergences between modern scientific discoveries and this section of the Earth and the Earth-Moon story as related in The Urantia Book. It is in the book's section on continental drift that follows this section where its story becomes so remarkably prophetic.

The reason for such divergences is consistent with statements in the book that proscribe the impartation of unearned knowledge, but allow the provision of key information. (1109) Almost nothing factual was known about the evolution of the Earth-Moon system until recently, and close to nothing was known about the early history of the Earth and its oceans. Note that continental drift had been proposed and, though rejected by most scientists, was in print.

It appears that the revelators were required to provide a framework of knowledge about Paradise, the Central Universe, the heavenly hierarchy, the universes, our own solar system, and the development of  intelligent life and human society on our own planet, all so that we could better understand our place in the overall scheme of things. (1260) But they were not allowed to tell us what we did not know pre-1934.

Working under this restriction placed the revelators in an extraordinarily difficult position. They could not complete their task satisfactorily--except they used "fill" material that would serve the purpose, even though not correct. We now know that they obtained this "fill" from the speculations of contemporary scientists--among them Moulton, Jeans, Chamberlin and Geoffreys.

A comparison of what they gave us with that  from modern science tells us that, despite the inconsistencies, the value of their account as a "universe frame" (1260) for understanding our universe careers remains quite undiminished.

But it does add a new dimension. It will prevent any realistic, long term use of the revelation as a fundamentalist icon of infallibility. And it may yet prove to be the catalyst that unlocks the fossilization process in so many moribund minds among the Urantia movement's bureaucracy.

Ken Glasziou, Australia.