tgkprog 2008-02-19 12:13:28 | from http://www.orkut.com/CommMsgs.aspx?cmm=28433022&tid=2583773577075764617 (needs google login) Unfortunately, laws of physics and special relativity has a limit speed of 'C' which is assigned with the nature for the maximum speed achievable for any particle. That's relatively old Physics. The statement "speed of light is a constant(C)" is a tautology given that standard units of distance and time are related by the speed of light. Every observable object is given to be moving slower than light because it remains within the future/forward light cone propagating from its position at any instant. Take a thought experiment instead. Stand up in a clear space and spin round. It is not too difficult to turn at one revolution each two seconds. Now, suppose the moon is on the horizon. How fast is it spinning round your head? It is about 385,000 km away so the answer is 1.21 million km/s, which is more than four times the speed of light! It sounds ridiculous to say that the moon is going round your head when really it is you who is turning, but according to the General theory of relativity, all coordinate systems are equally valid including revolving ones. So isn't the moon going faster than the speed of light? BTW, tachyons ( particles that travel faster than light ) haven't been experimentally validated, but they turn up quite often in modern physics of spontaneously broken symmetry of scalar fields, and in some versions of string theory, and the likes. The key, though, is that you have to rise above the concept of local causality, which requires a paradigm shift in human thinking. |

Stephen Brooks 2008-02-19 20:40:26 | --[but according to the General theory of relativity, all coordinate systems are equally valid including revolving ones.]-- Yes, but the equations of general relativity include the metric tensor g _{μν} that defines distance in that coordinate system. The laws of physics in an arbitrary coordinate system also include the metric tensor in such a way that it cancels the effects from accelerating or rotating reference frames.In reference frames moving at a constant velocity, the laws of physics require no corrections. But in an accelerating system (rotating or accelerating) you get correction terms appearing as things like centrifugal force or being pushed to the back of the car as it accelerates. |

tgkprog 2008-04-04 00:15:36 | thanks |