Posted: Sun Mar 18, 2007 4:17 pm
In the early 1900s, two theories revolutionized the way we saw our universe: quantum mechanies and general relativity. Einstein’s theories of special and general relativity describe gravity in an entirely new way; according to Einstein the planets are like marbles on a sheet of plastic. These marbles cause the plastic to warp under the weight of the marble, and subsequently the planets follow the deeper indentations in their orbits. However, relativity remained a classical theory. This means that it does not include Heisenberg’s uncertainty principle.
Quantum mechanics, on the other hand, is based on that principle. It deals with the physics of the very small, and states that there is only a probability that a particle will be at a specific point and have a specific velocity. We can find that probability, but not either its exact position or velocity. The uncertainty principle states that the more precision known about the position of a particle, the less is known about its velocity, and vice versa.
The “Theory of Everything” is currently the holy grail of the physics world. It is essentially one theory that unifies Einstein’s general theory of relativity with quantum mechanics. According to Stephen W. Hawking, this “Theory of Everything” should, in part “incorporate Feynmen’s proposal to formulate quantum theory in terms of a sum over histories. In this approach, a particle going from A to B does not have just a single history as it would in a classical theory. Instead, it is supposed to follow every possible path in space-time. With each of these histories, there are associated a couple of numbers, one representing the size of a wave and the other representing its position in the cycle—its phase” (Hawking 94).
However, there are many obstacles which must be overcome before this unified theory can be found. The main issue lies in combining quantum effects with gravity as it is defined by the general theory of relativity into what is commonly refered to as “quantum gravity.” This evaded even Albert Einstein, who spent the last years of his life trying to do just that, but at the time not enough was known about the structure of the atom. Now, on the other hand, many believe the time is ripe for the discovery of such a theory,.
Currently, there are many physicists working towards finding this “Theory of Everything,” including Stephen W. Hawking, Edward Witten, and many others. The most researched theory at the present time is superstring theory, also called M-Theory. This is a variant of the string theory that was developed by Edward Witten, and was published in the mid 1990s..
During the early years of String theory, many differing theories abounded. All of them predict extra dimensions, however, each model predicted a differing number of these extra dimensions. This was one of the major problems plaguing string theory, until it was solved in the 1990’s by Edward Witten. Witten determined that all forms of string theory are actually the same, and all those extra dimensions boil down to just 11, as demonstrated in his M-theory. He claimed that the different forms of string theory were like multiple reflections of a single theory in a mirror. The creation of M-Theory was a major advancement towards finding the ever-sought after holy grail of physics, but it is not the end of the search.
There are many in the physics world, however, who believe that strings are not the answer. String theory fails to provide any predictions that can be tested, and this leads many to call it more a philosophy than a scientific theory. Whether string theory is the “Theory of Everything” has yet to be seen, but many leading scientists, including Stephen W. Hawking predict that a Grand Unified Theory (or GUT) of physics should be discovered within the next century.
While the “Theory of Everything” still eludes even the greatest physicists of our time, there remains hope. Great advances are being made in labs around the world; the light at the end of the tunnel is glowing as bright as ever.
