Sunday, August 23, 2009

Charles Seife, Decoding The Universe (2006)

This book is subtitled How the New Science of Information Is Explaining Everything in the Cosmos, from Our Brains to Black Holes. The "new science" is over sixty years old by one measure --- 1948 was the year that Claude Shannon of Bell Labs, whom Charles Seife labels the "hero of information theory," recognized "that information could be measured and quantified and that it was intimately linked to thermodynamics." But in 1948, Shannon did not set out to explain black holes or how the mind processes information; he was trying to determine how much information could be carried across a telephone line or any other communication channel for that matter. Born from this inquiry was a recognition that information could be reduced to a yes or no, true or false, on or off outcome, and the smallest piece of information consisted of a binary digit (e.g., true or false) that those familiar with computer code recognize as 0, 1. The compressed nomenclature for a binary digit is a "bit."

Most communication is information rich, meaning that multiple pieces of information are represented by a stream or string of bits --- 01000111001. A 70,000 word book containing 350,000 letters, writes Seife, with each letter encoded in five bits, contains about 1.75 million bits of information, which represents less than 0.25% of the capacity of a compact disk --- the amount of space on a CD for about 10 seconds of a recorded song, which contains vastly more information than the written word.

Seife covers much of the same ground as Seth Lloyd's Programming the Universe, (see August 17, 2009 post). Where Lloyd is one of the actors in this "new science," Seife is one of those fine science writers for the general public who can turn scientific investigation into a great story. In Decoding the Universe, Lloyd arrives on the scene only at the very end of Seife's story --- the part where information theory does begin to explain black holes and the future of the cosmos. Sharing Lloyd's description of the universe as a massive information processor, Seife explains that while the universe may be infinite, information processing cannot go on forever --- and at some point information processing will stop and the gezillions of bits of information that life has stored and preserved will be dissipated (not destroyed) so it is useless and life in the visible universe (not just human life) will become extinct. Civilization is doomed (a long time from now); the laws of information have sealed our fate.

The storyline here is the renewal of quantum mechanics --- dressed for success as quantum information. Physicists have been pondering how to reconcile or unify --- mathematically and theoretically --- the very large and the very small. Quantum mechanics explains atomic behavior well in the realm of the very small; it does not explain gravity well in the realm of the very large, the domain of the theory of relativity. Some physicists have explored string theory for a solution to the problem of unifying the very small and the very large --- a quantum theory of gravity. But the mathematics underlying string theory have not yet led to a quantum theory of gravity and the theory has yet to be validated by experiment. Information theory and thermodynamics, which may explain the behavior of gravity and information in black hole, offers a promising alternative direction toward a quantum theory of gravity.

What does any of this mean for you and I? Is there any practical significance for information theory? The answer is clearly yes, and Seife points to the advancements in communications technologies that followed Shannon's 1948 paper. The Department of Defense is closely following developments in quantum computers utilizing quantum information for cryptographic applications. What mathematicians and physicists consider beautiful mathematical models can and does form the foundations for experimental testing (where we are capable of performing a test), and ultimately those experiments can become the basis for useful information --- not merely practical applications that may benefit humans and other living beings in their every day lives, but in addressing large questions about our place in the cosmos. So do not dismiss the elegant mathematics that is only understood by a few merely because they are representational of a theory. For those larger questions like --- is the universe infinite and is the arrow of time infinite? In the long run, we are all dead.

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