Artículos con la etiqueta ‘Velocidad de la Luz’

How to Build a Time Cloak with Mirrors

Por • 17 ago, 2013 • Category: Ciencia y tecnología

Miguel Lerma at Northwestern University in Evanston, Illinois, goes even further. Lerma has worked out how to build time cloaks that can operate for arbitrarily long periods of time using little more than a few cleverly placed mirrors. The new approach creates temporal holes that are equal to the time it takes the light to travel the extra distance. So by making this distance arbitrarily long, by bouncing the light back and forth off the Moon or for example, it ought to be possible to make holes in time of almost any length. That’s an impressively simple trick but it is not the first time that physicists have shown that invisibility cloaks are actually much easier to make than had been thought. A couple of months ago, physicists unveiled an invisibility cloak that used mirrors rather than metamaterials to hide objects of almost any size.



The quantum vacuum as the origin of the speed of light

Por • 3 mar, 2013 • Category: Crítica

We show that the vacuum permeability and permittivity may originate from the magnetization and the polarization of continuously appearing and disappearing fermion pairs. We then show that if we simply model the propagation of the photon in vacuum as a series of transient captures within these ephemeral pairs, we can derive a finite photon velocity. Requiring that this velocity is equal to the speed of light constrains our model of vacuum. Within this approach, the propagation of a photon is a statistical process at scales much larger than the Planck scale. Therefore we expect its time of flight to fluctuate. We propose an experimental test of this prediction.



From aether theory to Special Relativity

Por • 3 mar, 2013 • Category: Leyes

This way of thinking the spacetime emanates from our daily experience and lies at the heart of Newton’s Classical Mechanics. Nevertheless, in 1905 Einstein defied Galileo addition of velocities by postulating that light travels at the same speed c in any inertial frame. In doing so, Einstein extended the principle of relativity to the electromagnetic phenomena described by Maxwell’s laws. In Einstein’s Special Relativity the ether does not exist and the absolute motion is devoid of meaning. The invariance of the speed of light forced the replacement of Galileo transformations with Lorentz transformations. Thus, relativistic length contractions and time dilations entered our understanding of the spacetime. Newtonian mechanics had to be reformulated, which led to the discovery of the mass-energy equivalence.



Extending Einstein’s theory beyond light speed

Por • 14 oct, 2012 • Category: Educacion

Einstein’s theory holds that nothing could move faster than the speed of light, but Professor Jim Hill and Dr Barry Cox in the University’s School of Mathematical Sciences have developed new formulas that allow for travel beyond this limit. “Our approach is a natural and logical extension of the Einstein Theory of Special Relativity, and produces anticipated formulae without the need for imaginary numbers or complicated physics.”