|Theory of the Universe Confirmed|
have used a supercomputer to shed new light on one of the most
important theories of physics, the Standard Model, which encapsulates
understanding of all the material that makes up the universe. This
30-year-old theory explains all the known elementary particles and
three of the four forces acting upon them - however, it excludes the
force of gravity, which is its shortcoming.
Physicists have been trying to find the missing pieces in the jigsaw that would extend the Standard Model into a complete theory of all the forces of nature. However, the landmark findings by researchers at the Universities of Edinburgh and Southampton, and their partners in Japan and the US, confirm the Standard Model to even greater precision than before, deepening the puzzle.
The project's enormously complex calculations relate to the behaviour of tiny particles found in the nuclei of atoms, known as quarks. In order to carry out these calculations, the researchers first designed and built a supercomputer that was among the fastest in the world, capable of tens of trillions of calculations per second. The computations themselves have taken a further three years to complete.
Their result shows that the Standard Model's claim to be the best theory invented holds firm. It raises the stakes for the riddle to be solved by experiments at the Large Hadron Collider at CERN, which will switch on later this year. Physicists' efforts to confront Standard Model predictions using the most powerful computers available with the most precise experiments offer no clues about what to expect.
Professor Richard Kenway of the University of Edinburgh's School of Physics said:
Although the Standard Model has been a fantastic success, there were one or two dark corners where experimental tests had been inconclusive, because vital calculations were not accurate enough. We shone a light on one of these, but to our enormous frustration, nothing was lurking there.
Professor Chris Sachrajda of the University of Southampton's School of Physics and Astronomy said:
Modern supercomputers and improved theoretical techniques are allowing us to explore the limits of the Standard Model to an unprecedented precision. The next stage will be to combine such computations with new experimental results expected from the Large Hadron Collider to unravel the next level of fundamental physics.
The research, published in Physical Review Letters, was supported by the Science and Technology Facilities Council.
Source: The University of Edinburgh
Symmetry and the Beautiful Universe
To every differentiable symmetry generated by local actions, there corresponds a conserved current.
Nobel laureate Leon M. Lederman and physicist Christopher T. Hill explain how modern physics is shaped by the theorem of German mathematician Emmy Noether (1882-1935) -- stating a deep correspondence between conservation laws and symmetry principles. Symmetry, they point out, is the basic underlying principle that defines the laws of nature and controls the universe. It has become one of the most reliable lodestars for scientists working on the fundamental laws governing the universe.
"Physicists in earlier times viewed the physical world as composed of 'gears and pulley,.'" the authors point out. "They tended to view symmetry as more of a sideshow, a toy, arising in an occassional situation involving a symmetrical configuration that could help simplify a specific physics problem but that played no profound role in the deeper dynamic fabric of the physical world.
"It was Albert Einstein who brought in a new kind of thinking with his development of the theory of special relativity. Einstein's perspective was modern: he sought a kind of underlying naturalness to extract the true laws of physics and discovered far deeper principles of symmetry than had been seen before. Noether's theorem was born out of this new perspective.
"The idea of underlying symmetries and Noether's theorem have led ultimately to the discovery of the unifying principle governing all the known forces in nature."
The authors endeavor to explain the elegant concept of symmetry and its profound ramifications to understanding life on Earth and the nature of the universe at large. They address topics like time, energy, spacetime, inertia, parity, quantum mechanics, and even time reversal. The following equation derived from the principle of symmetry, for instance, states that time can run forward and time can run in reverse:
This book is more topical than mathematical, however, and readers with a basic understanding of math and physics should be able to comprehend the profund importance of symmetry.
"The scientific history of the universe has been divined from countless experiments, observations, and measurements, using telescopes and microscopes (particle accelerators), ultimately synthesized into mathematics," the authors point out.
"Our intent is to show that this photograph of knowledge -- here sharp and well focused, there still fuzzy, and way over there still shrouded in total mystery -- is nonetheless governed by a universal and steadfast set of laws of physics. These laws are not yet completely understood, but they endure, govern, and control the awesome history of the universe itself."
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