Gravitational waves, or ripples in spacetime, are unthinkable if the speed of light is not "always the same, independently of who measures it":

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime."
http://community.bowdoin.edu/news/20...rs-of-gravity/

Is the speed of light "always the same, independently of who measures it"? Of course not - even Einstein knew that this is nonsense:

John Stachel: "But this seems to be nonsense. How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem over a lengthy period of time, to the point of despair." http://www.aip.org/history/exhibits/...relativity.htm

In the quotation below, the statement "four pulses are received in the time it takes the source to emit three pulses" means that the speed of light is VARIABLE - the speed of the pulses relative to the receiver (observer) is greater than their speed relative to the source, in violation of Einstein's relativity:

http://www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "The frequency of a wave-like signal - such as sound or light - depends on the movement of the sender and of the receiver. This is known as the Doppler effect. [...] Here is an animation of the receiver moving towards the source:

Stationary receiver: http://www.einstein-online.info/imag...ler_static.gif

Moving receiver: http://www.einstein-online.info/imag...ector_blue.gif

By observing the two indicator lights, you can see for yourself that, once more, there is a blue-shift - the pulse frequency measured at the receiver is somewhat higher than the frequency with which the pulses are sent out. This time, the distances between subsequent pulses are not affected, but still there is a frequency shift: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." [END OF QUOTATION]

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