We hear nowadays from news channels that once in a century flood has come or once in a century something else has come. Humans are increased exponential. The population was 3 billion 20-30 years back now it is more than 6 billion. And it is estimated that it can reach 8 billion another decade. Humans are inhabiting more and more dangerous places prone to floods unaware of future catastrophes. We cannot see things half a century from now. We erect cities ignorant of planetary science. We believe we have become prosperous and build great cities to one day be erased to dust in a couple of days in a great flood.
The recent flood in Pakistan is proof that water can wash great cities. We need to take this planetary science seriously. We are too concentrated on politics and business as usual. Great suffering will be due to humanity if we continue to neglect the science already available. We are building our own grave.
Climate change and grave warnings from top scientists, we are neglecting them for business as usual. We need to reduce fossil fuel and carbon emissions and also non carbon emissions that increase global warming.
We need to stop hurting our planet. More on it soon.
Showing posts with label geology. Show all posts
Showing posts with label geology. Show all posts
Monday, October 4, 2010
Wednesday, October 21, 2009
Plate tectonics
It is interesting to know why mountains form and the cause of volcano and plate tectonics.
The Cascade range extends from western Canada to California-nevada ranges.
Subduction discovered
A profound consequence of seafloor spreading is that new crust was, and is now, being continually created along the oceanic ridges. This idea found great favor with some scientists, most notably S. Warren Carey, who claimed that the shifting of the continents can be simply explained by a large increase in size of the Earth since its formation. However, this so-called "Expanding Earth theory" hypothesis was unsatisfactory because its supporters could offer no convincing mechanism to produce a significant expansion of the Earth. Certainly there is no evidence that the moon has expanded in the past 3 billion years. Still, the question remained: how can new crust be continuously added along the oceanic ridges without increasing the size of the Earth?
This question particularly intrigued Harry Hess, a Princeton University geologist and a Naval Reserve Rear Admiral, and Robert S. Dietz, a scientist with the U.S. Coast and Geodetic Survey who first coined the term seafloor spreading. Dietz and Hess were among the small handful who really understood the broad implications of sea floor spreading. If the Earth's crust was expanding along the oceanic ridges, Hess reasoned, it must be shrinking elsewhere. He suggested that new oceanic crust continuously spreads away from the ridges in a conveyor belt-like motion. Many millions of years later, the oceanic crust eventually descends into the oceanic trenches — very deep, narrow canyons along the rim of the Pacific Ocean basin. According to Hess, the Atlantic Ocean was expanding while the Pacific Ocean was shrinking. As old oceanic crust is consumed in the trenches, new magma rises and erupts along the spreading ridges to form new crust. In effect, the ocean basins are perpetually being "recycled," with the creation of new crust and the destruction of old oceanic lithosphere occurring simultaneously. Thus, Hess' ideas neatly explained why the Earth does not get bigger with sea floor spreading, why there is so little sediment accumulation on the ocean floor, and why oceanic rocks are much younger than continental rocks.
The Cascade range extends from western Canada to California-nevada ranges.
Subduction discovered
A profound consequence of seafloor spreading is that new crust was, and is now, being continually created along the oceanic ridges. This idea found great favor with some scientists, most notably S. Warren Carey, who claimed that the shifting of the continents can be simply explained by a large increase in size of the Earth since its formation. However, this so-called "Expanding Earth theory" hypothesis was unsatisfactory because its supporters could offer no convincing mechanism to produce a significant expansion of the Earth. Certainly there is no evidence that the moon has expanded in the past 3 billion years. Still, the question remained: how can new crust be continuously added along the oceanic ridges without increasing the size of the Earth?
This question particularly intrigued Harry Hess, a Princeton University geologist and a Naval Reserve Rear Admiral, and Robert S. Dietz, a scientist with the U.S. Coast and Geodetic Survey who first coined the term seafloor spreading. Dietz and Hess were among the small handful who really understood the broad implications of sea floor spreading. If the Earth's crust was expanding along the oceanic ridges, Hess reasoned, it must be shrinking elsewhere. He suggested that new oceanic crust continuously spreads away from the ridges in a conveyor belt-like motion. Many millions of years later, the oceanic crust eventually descends into the oceanic trenches — very deep, narrow canyons along the rim of the Pacific Ocean basin. According to Hess, the Atlantic Ocean was expanding while the Pacific Ocean was shrinking. As old oceanic crust is consumed in the trenches, new magma rises and erupts along the spreading ridges to form new crust. In effect, the ocean basins are perpetually being "recycled," with the creation of new crust and the destruction of old oceanic lithosphere occurring simultaneously. Thus, Hess' ideas neatly explained why the Earth does not get bigger with sea floor spreading, why there is so little sediment accumulation on the ocean floor, and why oceanic rocks are much younger than continental rocks.
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