Aeschylus Posted October 10, 2004 Posted October 10, 2004 Yes it can be shown that say for examaple a planet orbiting a star it is the instaneous psotion of the star that is important to how a star will affect that planet grvaitionally, BUT this not what we talk about when we talk about 'the speed of gravity'. Light is an electromagnetic wave and it is produced by a 'changing' electrogmanetic field. Electromagnetism and gravity are simalir in sevral ways (the most obvious being the inverse square law), in general relativty 'changing' gravitatioanl fields produce gravitational waves which is analgous to light, it is the speed of these wave sthat we call the speed of gravity; stars generally do not produce gravtitional waves (they do not occur in spherically symmetric spacetime). The fact that it is the instaneous postion of a body thta is important in your example is not important as this does not necessarily imply instaneous transfer of information as it is grvaitybwaves thta represent the transfer of information in gravitational fields (or to look at it another way the gravtional field itself is not 'changing').
philbo1965uk Posted October 10, 2004 Posted October 10, 2004 My post you refer to has been pulled.I cannot find the thread.I tried to elaborate and when it seems i made factual points the admin pulled the topic.You see because the other uses in this forum cannot now view my post it must have made arguments that were correct and admin couldnt stomach that the other physics academics would see they were talking the shite not me.....as for the above you mention gravity waves,what gravity waves are you referring to,nobody has proved their existance,or that their waves???.You cannot offer your above explanation of my post,your denying the facts i put forward.I do not wish to argue with you only debate,But if you want to hide from the fact the instantanious position of a body is important.If gravity waves do exist they must be continuous therefore my arguement must mean gravity is faster
Sayonara Posted October 10, 2004 Posted October 10, 2004 No, the posts were removed - as you well know - because they were petty bickering that did not in any way answer the question.
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