Sunday, August 22, 2010

My Log 215: A wonderful documentary tells the story of what is Inside the Earth: and, of course, comes to a depressing conclusion

Forty years ago, when television was still developing, idealists like me used to believe that it should be --- and could be --- used as an instrument of education. In fact, in the first research I carried out for the National Film Board in 1971, I identified a number of social documentaries that needed to be made, and suggested CBC evenings should be devoted to a different one every night for a week, with discussion of the issues by informed panels of citizens to follow.

This was so little considered as a possibility that the committee judging the suggestions did not even consider it, but merely decided which of the proposed documentaries was worth considering as a film. Of course, my suggestion was old-fashioned Adult Education stuff, the sort of thing that CBC radio used to do in the 1950s. And, let’s face it, it was a hopelessly na├»ve suggestion, which was not followed by the CBC for a good 30 years, and then only once.

After being handed over almost holus-bolus to the horrors of commercial television, the educational possibilities of this medium have at last begun to show signs of life, as anyone can appreciate who peruses the list of documentaries available on the Top Documentary Channel.

Today I can report on one of these, called Inside Planet Earth, a really superb documentary, made in 2009 for the Discovery channel. Unlike the programme on the Trip through the Universe that I reported on in Log 209 on August 8, which was produced in a confusing, incoherent way, this programme ran neatly through from beginning to end, and contained such information as would be likely to blow the mind of almost anyone with the slightest interest in the life around us, and beneath us.

I should say, right off the top, that this strikes me as a much more important subject, more relevant to our life on Earth, than the somewhat fanciful proposals for space exploration that seem to dominate the subject of space research. After all, we are living right on top of what is inside the Earth, and since it is known to be a boiling cauldron of liquefied rock and gases, that is constantly penetrating the surface, it certainly behooves us to know as much as we can find out about it.

First, some basic facts: the Earth’s crust, which protects us from the overheated terrors of the interior, is about 30 miles deep. Humans have not been able to penetrate it more than to about eight miles, because as miners, researchers and others penetrate deeper, they find themselves in temperatures up to 130 degrees that a human cannot stand for more than about half an hour at a time. For example, the gold mines at Witwatersrand in South Africa are 2.5 miles below the surface, take two hours to reach, and are at 130 degrees Fahrenheit.

What is amazing is that down there, where chemical interactions have created gold, living organisms have been found, colonies of bacteria that exist in what is described as “an amazing diversity” 10 kilometres below the surface of the Earth.

This discovery has given rise to a theory that our solutions as to the origins of life on Earth may be incorrect: it is conceivable that when the immense pressures generated under the surface bring molten rock, known as lava, to the surface, they might have brought up some of these organisms to become the first forms of life on the planet. This theory is supported by some red rocks in Western Australia that are believed to have been created by a single-celled organism at a time that has been dated as 3.5 billion years ago. The theory is that the bacteria found their way to the surface, and using photo-synthesis, one of the by-products of which is oxygen, the essential ingredient of life, they created iron ore deposits which contain 20 times more oxygen than is in the Earth’s atmosphere.

Anyway, it has apparently been posited that 40 kilometres down, the crust gives way to the so-called mantle of the Earth, comprised of 2,000 miles of solid rock, in which nothing can grow, but which comprises the stuff that is sent up, under pressure, in the form of lava, or molten rock. At 4,000 miles deep, in the very centre, the heat is believed to be greater than on the sun’s surface.

The clashes of the continental plates, which was discovered in the 1960s as the earth’s crust continually moves, are believed to have taken down into the centre with them, probably more water than exists on the surface of Earth, perhaps as much as ten times more.

The documentary says that the key ingredient in maintaining the order of the universe is gravity, which, so far as the Earth is concerned, emanates from the centre of the Earth, and is generated by the ever-shifting, ever-changing activity that boils on there unceasingly.

This creates the Earth’s magnetic field, which sailors and others have recognized for centuries. But this magnetic field has more recently come to be recognized as the central protector of the Earth from the solar radiation that the sun is always bombarding our solar system with. Scientists knowledgeable in this field say that other planets, like Mars, have had water on their surfaces, but their core has cooled (because the planet is so much smaller than Earth), and the planet has therefore generated no magnetic field, and has become vulnerable to solar radiation that has killed off all life. The auroras, though much admired by people, are in fact caused by flashes of radiation that penetrate our magnetic field from time to time. The conclusion is that life is possible only under protection of the magnetic field. That it is slowly weakening as the central core cools is established as a fact: one area of the Earth’s surface, in the Atlantic off Brazil, already has no magnetic field and is known as the South Atlantic anomaly. In that area certain things do not work (the Hubble telescope, for example, has to shut off certain functions when in that area).

Changes in the magnetic field have led in the past to so-called reversals (the north and south poles are interchanged, for example). The last reversal, which disorients animals and birds, and creates havoc in the systems that keep life working, occurred 700,000 years ago, and there are signs, apparently, that the next reversal may be no more than 1,500 years away, with changes in the magnetic field occurring at a rate of some 6 per cent per century.

In other words, looking far into the future, the fate of the Earth is doomed; what is here will inevitably come to a meaningless end.

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