Changes

General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory predicts,<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> a phenomenon known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref>

General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory predicts,<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> a phenomenon known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref>

== Ostensible Paradoxes ==

== Variability of the Speed of Light ==

The Theory of Relativity implies that physical constants like the speed of light have remained constant.  But at least one study suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref>

The Theory of Relativity implies that physical constants like the speed of light are constant regardless of the inertial frame of the observer.  However, the speed of light is dependent on the medium through which it travels.  This is due to the fact that when photons are transmitted through transparent materials such as glass or air, the photon incident to the surface is absorbed by the material, and another photon of the same energy is emitted.  There have also been studies which suggest that the speed of light in vacuum has itself decayed over time.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref>

"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ...  Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist.  'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref>

"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ...  Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist.  'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref>

"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ...    Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref>

"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ...    Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref>

==Pending research==

==Pending research==