January 27, 2008

Planets as Super-Organisms

Der Speigel has a fascinating piece about the theories of a Japanese scientist explaining the cycle of continental plates which provides a model of the earth's shifting plates that answers some long unsettled questions of how plate tectonics actually work.

Today, every child learns in school that the continents are enormous plates that drift on the Earth's red-hot mantle like icebergs on the ocean. Yet this hypothesis still lacks a logical and convincing foundation. Nobody has been able to explain the actual mechanics behind the motor that drives the drifting and breaking-up of the continental plates.

The inner reaches of the Earth remain shrouded in mystery. Even the surface of Mars has been explored more extensively. Because deep drilling comes to a halt after a maximum of 12 kilometers, the remaining 6,300 kilometers to the center of the Earth remain inaccessible. Researchers find themselves playing the role of armchair travelers who recount a journey from New York to Patagonia, but actually only know the way to New Jersey.

Nonetheless, Maruyama is convinced that he understands what happens deep below our feet: "The continental drift that we observe on the surface of the Earth has its counterpart in the Earth's mantle," explains the professor, his arms gesticulating like two rotors that paint a picture of the demise of a continent.

"Old, cold plates are pushed down into the Earth's mantle on the continental edges," he explains. "At this point they collect large amounts of iron. You can imagine it as something similar to water condensation." Weighted down by the iron, the plates sink farther and farther into the hot, molten rock until they reach the inner sanctum of the Earth's mantle. There, at a depth of 2,900 kilometers, they finally halt their decent and settle into "plate graveyards." This is presumably the outer edge of the earth's heavy core, where the temperature is 4,000 degrees Celsius (7,200 degrees Fahrenheit).

Brimming with enthusiasm, Maruyama continues: "But the capsized continents don't simply rest in their plate graveyards forever." Rather, they are about to experience a sudden resurrection. Heat and pressure in the depths trigger chemical processes, causing the plates to deposit their load of heavy elements. Once liberated of this burden, they become lighter than their surroundings, causing them to rise like corks in water. The result: Above the old plate graves, on the floor of the Earth's molten mantle, a mushroom-shaped upwelling of abnormally hot magma called a mantle plume makes its way toward the surface.

Eventually, the rising flow of molten rock reaches the crystallized crust and cuts through it like a welding torch. Volcanoes form, such as those on the Big Island of Hawaii. Maruyama says the red hot lava that erupts on the volcanic island comes directly from an old plate cemetery 2,900 kilometers below the surface, where the remains of an ancient continent that broke up some 750 million years ago simmer to the surface. His theory postulates the amazing comeback story of this ancient rock from the deep.

According to Maruyama, the key ingredient for the chemistry of the Earth's interior is the same one that determines the weather on the surface: water. The sunken ocean plates have old seawater locked in their mineral structure -- only a few parts per thousand, but enough to drastically change the characteristics of the rock.

...As he connects the dots from astronomy to life sciences, the outlines emerge of an all-encompassing image of entire planets, which now appear as living super-organisms.

He believes that expanding the study of life sciences to the core of our world and the depths of outer space will help us find distant relatives of our own Earth -- planets that could also sustain life.

Providing a model and structure to the observed behavior of the continental plates makes them appear to be much more like the other major earth systems and leads to the understanding of the earth as a huge super-organism. This ties the physcial forms of the earth to the living organism that James Lovelock envisioned when he described the network of life on this earth in the Gaea hypothesis.

The germ of Lovelock's theory comes from observations made of outer space photographs of the planet, in which the earth's mantle of atmosphere—drawn about her like a cloak—suggested to him a protective modification of the environment (such as a snail might find in its shell).

"If all the life organisms on earth are subtly interrelated," he reasoned, "is it not possible that it is, in fact, one organism ... one Life? And is it not possible that Life has in large measure shaped the environment of the earth to Its requirements, rather than being primarily a product of environmental circumstance?"

Life on earth, Lovelock feels, clearly exhibits the characteristic of being a single organism with man in the midst. And man, because of his nature, should be capable of functioning something like a central nervous system to the whole, thereby enhancing its development. Man, however, has failed in this responsibility and, instead, proceeds willy-nilly to alter the environment without regard for the greater organism he centers. He alters the environment on impulse ... an impulse which disregards the Life of the Whole.

The earth as a living being - our continents, the climate and the web of life that makes our home. We humans fool ourselves to believe that we are the end all and be all of this fascinating world in which we live.

via Mark Thoma

Posted by Mary at January 27, 2008 12:02 AM | Science | Technorati links |

"The earth as a living being - our continents, the climate and the web of life that makes our home. We humans fool ourselves to believe that we are the end all and be all of this fascinating world in which we live."

For a time line which suggests the fallacy of "man as the center of everything", see: A timeline

Posted by: Smashed at January 27, 2008 04:09 PM