100 yr anniversary of General Relativity

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http://www.sciencemag.org/site/special/generalrelativity/

 

100 years ago Einstein developed his theory of general relativity. According to general relativity, gravity is due to the local warping of spacetime due to the presence of mass-energy. It is general and not special relativity because it is, well, more general. It rests on the principle of equivalence where acceleration is equivalent to the local presence of gravity. Special relativity results from considering reference frames that are at constant velocity, and leads to length contraction and time dilation-- empirically confirmed time and time again and widely used in science and technology (nuclear weapons are a spectacular if deadly confirmation of the reality of special relativity. A consequence of general relativity in particular is  for instance, the sun warps the very fabric of spacetime, somewhat analogously to how the presence of a bowling ball warps a large rubber sheet it rests on.

 

Where spacetime is more strongly bent, there are measurable consequences. For instance, the earliest confirmation of general relativity was the prediction of the anomalous precession of Mercury's orbit because Mercury is farther down in the gravitational well of the sun and time goes more slowly there than it does for other planets as a consequence. General relativity explains a number of other effects also, including gravitational lensing ( http://en.wikipedia.org/wiki/Gravitational_lens) as well as the orbital change of binary neutron stars and is used in our technology. Your GPS would not work without special AND general relativistic corrections. Another prediction general relativity makes is the existence of gravitational waves. Experimental confirmation of these is already established through astronomical observations of the orbits of certain objects but is more directly sought through enormous interferometers (see: http://en.wikipedia.org/wiki/LIGO) seeking to measure gravitational waves-- these are the waving of the fabric of spacetime itself due to certain massive objects interacting.

 

Though these ideas may seem esoteric and counter intuitive, and they are that, they make powerful and precise predictions. This is also widely considered a very beautiful and elegant theory, and perhaps can be seen as a tribute to God's handiwork as Creator.