Sunday, September 28, 2008

The Science of Day After Tomorrow

Kuldip Dhiman

Physics of the Impossible
by Michio Kaku.
Allen Lane, Penguin Books. Pages 330. £8.

COULD we one day develop weapons that could shatter an entire planet to smithereens? Could we make people and objects invisible? Could we design machines that would generate their own energy? Is it possible to launch spaceships that travel faster than light?

In Physics of the Impossible, Michio Kaku takes us on a singular scientific journey to find answers to such questions. The main purpose of this exploration, however, is to make science popular. Teaching science is not easy, especially theoretical physics, but the author makes an interesting juxtaposition of science fiction on one hand and hard science on the other to lure the reader into the fascinating world of force fields, gravity, matter, antimatter, subatomic particles, black holes, wormholes, parallel universes, anti-universes.

Michio Kaku, who holds the Henry Semat Chair in Theoretical Physics at the City University of New York, cites examples from popular science fiction novels and films to make his exposition lively and interesting. He confesses that it was science fiction that inspired him to become a scientist.

Good science fiction writers these days have a competent knowledge of science and natural laws, although they sometimes stretch their imagination to suit their plot. Of course writers like Arthur C. Clarke have shown that scientists could learn a thing or two from fiction.

The writer tells us that some of inventions and gadgets mentioned in sci-fi literature are theoretically possible, while others are not, at least not with the science we know. However, to say something is not possible at all is not very prudent. For instance, the great physicist Lord Kelvin declared in 1899 that radio had no future, heavier-than-air machines would never be possible, and X-rays would prove to be a hoax. All these have actually happened. What was impossible yesterday is commonplace today.

Most of us fantasise about becoming invisible, reading the future, travelling to other galaxies, and going back in time. Examining these fantasies thoroughly, Kaku divides them into three categories: Class I impossibilities are those that are impossible today but as they do not violate the known laws of physics, they might be possible one day. Teleportation, antimatter, psychokinesis, and invisibility come under this category. Time machines, hyperspace travel, travel through wormholes are Class II impossibilities. They will take thousands of years to develop. And Class III impossibilities violate the known laws of physics, so as far as we are concerned they are really impossible. But if they ever materialised, they would change the world beyond our imagination.

At a deeper level, this book is an excellent introduction to the development of scientific theories and concepts. History of science shows that some ideas are born through sheer genius, and there are those that are products of happy accidents. And some ideas begin with a particular individual, but they are eventually developed by a string of others over centuries. There are also cases of near misses. For example, James Clerk Maxwell, who developed the classical electromagnetic theory among other things, might well have come up with the idea of relativity over a hundred years before Albert Einstein. But oddly enough, Maxwell did not realise that his equations allowed for distortions of space-time.

We now move on to the latest in the world of science. Frenzied research in the last two centuries has upturned our conventional scientific wisdom. The Newtonian theory, for instance, does not allow teleportation as objects do not move until a force is applied upon them, and they do not suddenly disappear and appear elsewhere. But this happens all the time in the quantum domain. We might ask if one could use the laws of the quantum theory to create a machine that could teleport people? Surprisingly, the answer is a qualified 'yes', says the author.

The book then focuses on something that has kept theoreticians busy for the past hundred years. In the beginning of the 20th century, Einstein gave us theory of special relativity, and Max Planck advanced his quantum theory. The former theory gives an excellent account of the macroscopic world, and the latter of the microscopic world of atomic particles. The problem is that these theories are incompatible with each other. Since one of the fundamental principles of science is to have one theory to explain all phenomena, physicists have been trying to unify these two theories without much success.

A heightened enthusiasm is seen among physicists with the formulation of the string theory. It just might successfully unify the quantum theory with gravity, but there are five ways in which this could be done. In 1994, Edward Witten of Princeton's Institute for Advanced Study and Paul Townsend of Cambridge University speculated that all five string theories were in fact the same theory, but only if we add an 11th dimension. From the vantage point of the 11th dimension, all five different theories collapse into one. And the bewildered scientists are back to square one.

Making science as interesting as fiction, Michio Kaku's fascinating book is sure to inspire many youngsters to take up science, just as he was in his childhood by reading science fiction.

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