Sunday, September 9, 2012

Change Is the Only Constant

Alan Lightman is a novelist, essayist, and physicist, with a PhD in theoretical physics from Harvard University. He writes:
Oblivious to our human yearnings for permanence, the universe is relentlessly wearing down, falling apart, driving itself toward a condition of maximum disorder.
I don’t know why we long so for permanence, why the fleeting nature of things so disturbs. With futility, we cling to the old wallet long after it has fallen apart. We visit and revisit the old neighborhood where we grew up, searching for the remembered grove of trees and the little fence. We clutch our old photographs. In our churches and synagogues and mosques, we pray to the everlasting and eternal. Yet, in every nook and cranny, nature screams at the top of her lungs that nothing lasts, that it is all passing away. All that we see around us, including our own bodies, is shifting and evaporating and one day will be gone. Where are the one billion people who lived and breathed in the year 1800, only two short centuries ago?
Over its 4.5-billion-year history, our own planet has gone through continuous upheavals and change. The primitive earth had no oxygen in its atmosphere. Huge landmasses splintered and glided about on deep tectonic plates. Then plants and photosynthesis leaked oxygen into the atmosphere. At certain periods, the changing gases in the air caused the planet to cool; ice covered the earth; entire oceans may have frozen. Today, the earth continues to change. Something like 10 billion tons of carbon are cycled through plants and the atmosphere every few years—first absorbed by plants from the air in the form of carbon dioxide, then converted into sugars by photosynthesis, then released again into soil or air when the plant dies or is eaten. Wait around 100 million years or so, and carbon atoms are recycled through rocks, soil, and oceans, as well as plants.

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