دانلود کتاب Gravity's Arc: The Story of Gravity from Aristotle to Einstein and Beyond

The amazing history of our understanding of gravity, which still remains quite incomplete, cannot help but make one recognize the total absurdity of the flawed mathematical models claiming to understand all-but-unknowable relationships between various complex physical aspects of our planet and, at the same time, predict global temperatures decades away when we have not mastered local temperatures a week away.

The notion of gravity as a force is fairly new--it dates back only to Isaac Newton in the seventeenth century. Before that, Aristotle's view held sway for 2,000 years. Aristotle saw gravity as a property of matter. Newton considered it a somewhat mysterious force.

Under Albert Einstein's theory of general relativity, gravity is neither of these things. Instead, it sees gravity as a manifestation of curvature in the geometry of space-time. As John Wheeler put it, "Matter tells space how to curve. Space tells matter how to move."

Given the radically evolving understanding of something as basic as gravity, surely it is unscientific in the extreme for believers in a manmade global warming crisis to claim their particular theory is beyond debate.


Irreconcilable Theories

In many ways, general relativity turns our everyday notion of gravity on its head.

Throw a ball straight up in the air and, in Newton's eyes, a graph of its height versus time shows the ball traveling in a parabola. Einstein's new vision of gravity, which superseded that of Newton, posited that a massive body--in this case the Earth--curves the coordinate system itself. So instead of following a curved path in a flat (Cartesian) coordinate system, the ball actually follows a minimum-distance path, or geodesic, in a curved coordinate system, returning to the thrower's hand at a later time because the geodesic leads it there.

Einstein's 1905 special theory of relativity implicitly included gravity waves. Despite incredible efforts to measure these waves, they have eluded scientists.


Additional Theory Needed

Scientists no longer seriously doubt such waves exist, since Joseph Taylor and his graduate student Russell Hulse first discovered a pair of rotating binary stars and recorded their energy emissions for the next 20 years, showing variations attributable only to waves of gravity. In 1993 they received the Nobel Prize in physics for their work.

But a big problem still exists, because as we get closer to a complete picture of the theory of relativity in the universe, we have gotten no closer to fitting into it the quantum theories of how subatomic particles operate in that same universe. It isn't that they predict different results; instead, they are like different pieces of equipment that cannot be connected.

We lack a mathematical interface to solve the problem, and have not a clue how to build one. Hence the search goes on for the holy grail of physics, an all-embracing theory.


Lessons of Complexity

While scientists studying gravity recognize the current limitations of their knowledge, global warming activists are much less humble. Somehow, pseudo-scientists think they can link together myriad uncertainties in the Earth's climate system and make assertive predictions that cannot be scientifically supported within even a single order of magnitude.

The difficulty of really understanding gravity, which the reader may once have thought to be a relatively simple concept, will bring home the grotesque foolishness of the climate change predictions being bandied about in our daily life in recent years.


Princeton Connections

Of significant interest near the end of the book is a story of two young radio astronomers at the University of Massachusetts, both now at Princeton, who received the Nobel Prize in 1993 for their 1974 contribution to our still-limited understanding of gravity. These men are now part of an esteemed university department that holds three faculty members on record as expressing their disbelief in the snowballing hype regarding the theory that humans are causing a global warming crisis.

I admit to a strong bias for this book, as it is heavy with references to Einstein, a man with whom I had a literal nodding acquaintance at Princeton, as well as worshipful praise of Princeton's recently deceased emeritus professor of physics John Wheeler, who taught my freshman physics class.


Humbling Experience

This book will offer you a partial understanding of black holes, dark matter, and dark energy, which today fill the minds of theoretical physicists enamored with the ways of our universe and our solar system within it.

Gravity's Arc is a book only for those with true intellectual curiosity coupled with a complete lack of intellectual ego, as it will cow the most astute of its readers. Great minds operate well above most of us mere mortals.

But that is why I recommend it to those who are interested in science and have no fear of a wounded ego.

To my mind, approaching the myth of a human-induced global warming crisis indirectly, by learning the complexity of what you may once have thought to be a simple matter, will give you the depth of perspective to do battle with untrained people who cannot grasp the complexity of a problem they see in only the most shallow and incomplete manner.


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Jay Lehr, Ph.D. ([...]) is science director of The Heartland Institute.