Search

This is an article that analyses string theory in relation to the universe. According to string theory, the laws of physics that we see operating in the world depend on how extra dimensions of space are curled up into a tiny bundle. The Kaluza-Klein idea has been resurrected and extended as a feature of string theory, a promising framework for the unification of quantum mechanics, general relativity and particle physics. The key question is, What determines this geometry? Because there is more than one parameter, we should actually think of this vacuum energy curve as one slice through a complex, multidimensional mountain range, which Leonard Susskind of Stanford University has described as the landscape of string theory see middle illustration on page 85. With the advent of quantum field theory, empty space-the vacuum--became a busy place, full of virtual particles and fields popping in and out of existence, and each particle and field carries some positive or negative energy. INSETS: Strings and Tubes;The Hidden Space;Topography of Energy;Bubbles of Reality

This is an article about an article that Albert Einstein wrote for "Scientific American" in 1950 outlining his unified theory of physics. In a 1950 Scientific American article, Einstein outlined his unified theory of physics. Ideas poured forth from figures such as Hermann Weyl, Arthur Stanley Eddington and Theodor Kaluza. That said, the article rewards multiple readings, especially if one thinks of it as a discussion not of science but of the philosophy of science. In the case of special relativity, you can replace every instance of x, y, z and t--the coordinates that specify the position and time--with a certain mathematical function of x, y, z and t. Only a certain function will do. Quantum mechanics without gravitation explains electromagnetism, the nuclear forces and the structure of matter with exquisite precision.

This is an article on the research of the relativity theories created by Albert Einstein. Everyone wants to get a piece of Einstein. Like cannibals seeking the strength and life spirit of their victims, these misguided amateurs seem to think that by outdoing or disproving Einstein they will acquire all his prestige and acclaim. The analysis he discusses is based on a general "Standard Model Extension" in which all plausible relativity-violating terms are added to the equations of particle physics. This all-encompassing model covers every possible deviation that could trickle down to everyday physics from the high-energy pinnacle of the as yet undiscovered ultimate unified theory. Some of these models predict that extremely high frequency light should travel faster than lower-frequency light. In March of this year a team of astronomers led by Patrick Petitjean of the Institute of Astrophysics of Paris and the Observatory of Paris and Raghunathan Srianand of the Inter-University Center for Astronomy and Astrophysics in Pune, India, reported using the traditional methods pushed to the limit.

Reports on a scientific dispute over the existence of a fifth fundamental force. How this was discovered by theorists; Possibility of discrepancies in their data; Proposed explanations for these variances; Details of experiments to determine the scientific validity for this fifth force; Impact of this finding.